Standard Procedures for Underwater Engineering Operations

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STANDARD PROCEDURES FOR UNDERWATER ENGINEERING OPERATIONS

Shell Exploration & Production

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STANDARD PROCEDURES FOR UNDERWATER ENGINEERING OPERATIONS CONTENTS AUTHORITY FOR ISSUE AUTHORITY FOR AMENDMENT AMENDMENT RECORD LIST OF ABBREVIATIONS PREFACE AMENDMENT HISTORY

SECTION 1

STANDARD OPERATING PARAMETERS Chapter 1 Operational Workscopes Chapter 2 Location/Positioning Chapter 3 Equipment Chapter 4 Inspection Operations Chapter 5 Information Control Centre

SECTION 2

GUIDE TO THE STANDARD PROCEDURES FOR UNDERWATER ENGINEERING OPERATIONS Chapter 1 Introduction Chapter 2 Standard Procedures Chapter 3 Method of Use Chapter 4 Task Coding System and Component Task Sheets Chapter 5 Procedure & Component Numbering System Chapter 6 Anomaly Reporting and Criteria Chapter 7 Reporting

SECTION 3

INSPECTION PROCEDURES (Excluding Pipelines and Risers) I 01 003 Debris Survey and Recovery I 01 007 General Video Survey I 06 001 Seabed Profile and Scour Survey I 06 003 Linear Profile Scour Survey I 10 001 Dimensional Damage Survey to Steel Structures I 15 001 Weld Inspection I 15 002 Wall Thickness & Ultrasonic Inspection - General I 15 003 Flooded Member Detection I 20 001 Concrete Surface and Damage Inspection I 20 002 General Concrete Surface Inspection - Subsea and Topside I 30 001 Seawater Inlet Inspection I 32 001 Boat Landing and Barge Bumper Survey

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I 43 001 I 49 057 I 60 004 I 97 001 I 97 002 SECTION 4

Caisson Inspection Talon Joint Inspection Cathodic Protection Monitoring Inspection of Abandoned / Suspended Wellhead Inspection of Subsea Tree (Production and Water Injection)

CONSTRUCTION PROCEDURES R 01 011 Dredging R 26 001 Installation and Removal of Clamped Blanking Flange R 48 001 Installation and Removal of Blind Flange R 48 002 Installation and Removal of Inlet Blanking Plug (ROV

SECTION 5

PIPELINE AND RISER PROCEDURES I 41 001 Riser and J-Tube Inspection I 90 001 Valve Assembly Spool Piece (VASP) Inspection I 90 002 Pipeline Damage Inspection I 91 001 Igloo Inspection - Fulmar Tee Skid I 91 002 Subsea Intervention Valve (SSIV) Inspection - Northern Business Units I 91 003 Igloo Inspection - WELGAS Number 1 and 2 I 91 004 Igloo Inspection - 20 Inch Fulmar 'A' to St Fergus Gas Pipeline I 91 005 Igloo Inspection - Subsea Umbilical Splitter Box Brent Alpha Under Review I 91 006 Subsea Intervention Valve (SSIV) Inspection - ONEgas Business Unit I 91 007 Igloo / Manifold Inspection – General I 91 008 Igloo Inspection - Brent Spar Manifold - ROV I 91 009 Igloo Inspection – Osprey to Dunlin A Flowline Bundle Carrier Pipe I 93 001 Pipeline Protection Cover Inspection I 98 001 Concrete Protection Covers and PBSJ Inspection NON-STANDARD TASKS Under Review R 90 003 Under Review R 90 053 APPENDIX 1

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Pipeline Span Stabilisation Installation of Protection Mattresses

REFERENCES

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AMENDMENT RECORD The signature for each amendment indicates that the amendment was correctly incorporated in accordance with the Amendment Instruction Sheet. AMENDMENT NUMBER

PERSON INCORPORATING AMENDMENT INTO MANUAL NAME

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SIGNATURE

DATE AMENDED

DESIGNATION

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LIST OF ABBREVIATIONS ACFM

Alternating Current Field Measurement

ACPD

Alternating Current Potential Drop

AS

Arc Strike

BA

Breathing Apparatus

BCS

Burmah Castrol Strip

BDC

Bottom Dead Centre

BFU

Brent Field Unit

BS

British Standards

CGF

Conductor Guide Frame

CNS

Central North Sea

COABIS

Component Oriented Anomaly Based Inspection System

CP

Cathodic Protection

CTS

Component Task Sheet

CVI

Close Visual Inspection

DMC

Data Management Controller

DOWS

Draft Operational Work Scope

DPR

Daily Progress Report

DSV

DSV/MSV operating on behalf of UEIP

DV

Digital Video

DVD

Digital Video Disk

DVI

Detailed Visual Inspection

ECI

Eddy Current Inspection

EMA

Electro Magnetic Array

FMD

Flooded Member Detection

FOWS

Final Operational Work Scope

GBS

Gravity Based Structure

GRP

Glass Reinforced Plastic

GVI

General Visual Inspection

H2S

Hydrogen Sulphide

HAT

Highest Astronomical Tide

HAZ

Heat Affected Zone

HAZID

Hazard Identification

HDM

Horizontal Diagonal Member

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HIRA

Hazard Identification & Risk Assessment

HM

Horizontal Member

HMI

Head Mining Installation (OIM Dutch Sector)

IBIS

Inspection Based Information System (Pipelines Database)

IEC

International Electrotechnical Commission

IMCA

International Marine Contractors Association

IMR

Inspection, Maintenance and Repair

ISO

International Organization for Standardization

JPG (JPEG)

Joint Photographic Experts Group (Digital Image Format)

JRA

Job Risk Assessment

LAM

Linear Angular Measurement gauge

LAT

Lowest Astronomical Tide

LSA

Low Scale Activity

m

Metres

mm

Millimetres

mV

Milli Volts

MGR

Marine Growth Removal

MGS

Marine Growth Survey

MPG (MPEG)

Moving Picture Experts Group (Digital Video Format)

MPI

Magnetic Particle Inspection

NFU

Northern Field Unit

NDT

Non Destructive Testing

NNS

Northern North Sea

NUI

Normally Unattended Installation

OCM

Offshore Construction Manager (Contractor)

OIM

Offshore Installation Manager

OM

Offshore Manager (Contractor)

OOE

Offshore Operations Engineer (Shell Representative)

OWS

Operational Work Scope

P&ID

Piping & Instrumentation Diagram

PBSJ

Pressure Balanced Safety Joints

PEC

Pulsed Eddy Current (Wall Thickness Reading System)

PLBM

Production Linear Block Manifold

PLEM

Pipeline End Manifold

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PM

Parent Metal

PON

Petroleum Offshore Notification

PSS

Platform Services Supervisor

PVC

Polyvinyl Chloride

RPS

Radiation Protection Supervisor

RC

Reinforcement Cap

ROV

Remotely Operated Vehicle

ROVSV

ROV Support Vessel

SOD

Subsea Operations Department

SOE

Subsea Operations Engineer

SOW

Scope of Work

SROU

Surface Read Out Unit

SSIV

Sub Sea Intervention Valve

STLB

Submerged Turret Loading Buoy

S-VHS

Super VHS

SWL

Safety Working Load

TA

Technical Authority

TDC

Top Dead Centre

TRA

Task Risk Assessment

UC

Undercut

UMC

Underwater Manifold Centre

UMDB

Underwater Maintenance Data Bank

UT

Ultrasonic Thickness (Test)

VASP

Valve Assembly Spool Piece

VDM

Vertical Diagonal Member

VM

Vertical Member

WILBM

Water Injection Linear Block Manifold

WRF

Work Request Form

WT

Wall Thickness

WROV

Workclass ROV

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PREFACE This manual defines the personnel, equipment specifications, procedures, guidance on the detailed planning and execution of procedures involved in the underwater inspection, maintenance and repair of offshore structures, risers, pipelines and igloos within Shell Exploration & Production Europe (EPE). The manual is intended to provide information to project, structural and pipeline engineers, and will also be used to instruct contractors of the requirements for underwater engineering operations. It can be used with or without the Shell adopted computer-based data management systems, COABIS (Component Oriented Anomaly Based Inspection System) and IBIS (Inspection Based Information System), however the numbering and task coding systems to be used are those based on the COABIS system. Equipment and techniques for underwater inspection work are continually being developed or changed and therefore, from time to time, Sections of the manual may be found to be no longer appropriate or in need of amendment or addition. Where this occurs, comments are to be forwarded to the Custodian. The manual is divided into five sections providing information on the following; Section 1

Standard Operating Parameters This section states the methods to be adopted with respect to:

Section 2

Chapter 1.

The production and use of Operational Workscopes

Chapter 2.

Location, Datum and Positioning methods to adopt

Chapter 3.

General Construction and Inspection equipment specification, legislation and methods of use

Chapter 4.

Types of inspection carried out, and specifies the distinctions between General, Detailed and Close visual inspections (GVI, DVI & CVI)

Chapter 5.

Contractor obligations with respect to providing suitable facilities and involvement offshore, with respect to data gathering offshore

Guide to the Standard Procedures for Underwater Engineering Operations This section states: Chapter 1.

The reasons why Standard Procedures are adopted by Shell EPE

Chapter 2.

Information on - Standard Procedures; production of new Standard Procedures; production of Non-Standard Procedures and Standard Procedures in COABIS

Chapter 3.

The method of use of Standard Procedures, and the requirements for production of a Non-Standard Procedure

Chapter 4.

The full list of Shell EPE Tasks codes based on the COABIS task coding system

Chapter 5.

How Standard Procedure numbers are obtained, and the full list of Shell underwater component type code numbering

Chapter 6.

The method of reporting anomalies, and gives the full list of Shell EPE anomaly criteria

Chapter 7.

For all Shell EPE offshore operations conducted - how reports and data gathered are to be submitted; the format of the Job Completion Report to be submitted; the method of numbering, labelling and format of all types of data gathered; and the format of Job Closeout Notes

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Section 3

Inspection Procedures (excluding Pipelines and Risers) This section contains Standard Procedures specific to the inspection of offshore structures both steel and concrete, and their appurtenances, excluding Risers, J-Tubes, Pipelines and most Subsea Facilities.

Section 4

Construction Procedures This section contains Standard Procedures specific to construction tasks, which are not subject to changes due to local variations.

Section 5

Pipeline and Riser Procedures This section contains Standard Procedures specific to the inspection of offshore Risers, J-Tubes, Pipelines and most Subsea Facilities

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AMENDMENT HISTORY Amendment No/ Date.

Subject

DS Job No

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General Review.

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Amended Prelims; Section 2, Contents and Chapter 6; Section 3, Procedure I-43-001; Section 5 Procedures I-90-001, I-91-007 and added Procedure I-91-002.

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Am 02 08/05

Amend Prelims and add Procedure I-97-001 to Section 3.

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Am 03 04/06

Amend Prelims and Procedures I 43 001, I 90 001 and I 41 001. Add Procedures I 90 002, I 91 001, I 91 003, I 91 004 to Section 5.

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Procedures I 93 001, I 91 005, I 91 008, I 91 009 and I 98 001 incorporated into Section 5.

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Am 05 03/12

Major changes throughout all of Section 2, Chapter 6 Anomaly Reporting and Criteria.

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SECTION 1 STANDARD OPERATING PARAMETERS CONTENTS

CHAPTER 1 OPERATIONAL WORKSCOPES CHAPTER 2 LOCATION / POSITIONING CHAPTER 3 EQUIPMENT CHAPTER 4 INSPECTION OPERATIONS CHAPTER 5 INFORMATION CONTROL CENTRE

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SECTION 1 CHAPTER 1 OPERATIONAL WORKSCOPES CONTENTS Para

Page

1

INTRODUCTION

3

2 2.1 2.2 2.3 2.4 2.5

GENERAL INFORMATION AND POLICIES Obligation to Read and Comply Obligation to Report Errors Management of Changes Document Control Timely Completion of Operational Workscopes

3 3 3 4 5 6

3 3.1 3.2 3.3 3.4 3.5 3.6 3.7

OPERATIONAL WORKSCOPE SEQUENCE OF PREPARATION Initiation of Work (Work Registration Form) Sponsor Scope of Work (SSOW) Outline Operational Workscope (OOWS) and Kick Off Meeting Draft Operation Workscope (DOWS) Hazard Identification & Risk Assessment (HIRA) Final Operational Workscope (FOWS) Offshore Receipt

6 6 6 7 7 8 8 8

4 4.1 4.2 4.3

FORMAT AND CONTENT OF OPERATIONAL WORKSCOPES Physical Document Format Content

8 8 9 9

5 5.1 5.2

OPERATIONAL WORKSCOPES Introduction Format for Operational Workscopes

9 9 9

6

APPROVALS

10

7 7.1 7.2

CREATION OF ‘COST CODES’ (JOB NUMBERS) Introduction Cost Code Creation

10 10 10

FIGURES No 1 2

Page COABIS Entry Form Workscope Development Flowchart

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CHAPTER 1 OPERATIONAL WORKSCOPES 1

INTRODUCTION Written instructions (termed Operational Workscopes) are required for all field operations undertaken by the Underwater Operations Department. The instructions are written, approved and distributed with a view to achieving the following aims: (1)

The Underwater Operations Work Resource and the Field Unit Facility involved always work to precise and unambiguous work instructions with all foreseeable requirements defined.

(2)

Prior to implementation written instructions are available for review by all parties concerned.

(3)

Hazards and control measures are systematically reviewed and refined to precisely target Health Safety & Environment instructions to the job.

The recognised categories of instructions and their authors are: (1)

Operational Workscopes authored within the Underwater Operations group, in Consultation with the Diving Contractor.

(2)

Operational Workscopes authored by the Diving Contractor or other Engineering Contractor in consultation with the Underwater Operations group.

(3)

Fast track Operational Workscopes authored by the Underwater Operations group and endorsed by the Diving Contractor and vice versa.

(4)

IBIS (Inspection Based Information System) Workscopes that allocate specific underwater Operations Department Standard Procedures.

(5)

Field instructions authored by the Shell Offshore Operations Engineer.

The policy specified in this Chapter covers routine and fast track Operational Workscopes. The flowchart (see Figure 2) contained at the back of this section, further emphasis the process. Field generated work procedures are employed only when absolutely necessary for protection of technical integrity or to authorise routine jobs of opportunity that are covered by Underwater Engineering Operations Standard Procedures, one example being simple cargo lifts. Procedures generated offshore require to be reviewed by the Underwater Operations Focal Point or their deputy prior to implementation. 2

GENERAL INFORMATION AND POLICIES

2.1

Obligation to Read and Comply Field personnel must familiarise themselves with the instructions and seek clarification, as necessary, prior to starting work. A TRA will always be carried out offshore prior to commencement of the work. This activity is the offshore acceptance of the operational workscope.

2.2

Obligation to Report Errors The Operational Workscope is a vehicle to allow persons within multiple organisations with varied experience, expectations, viewpoints and locations to agree on a relatively precise sequence of work instructions. A disciplined approach to work requires that agreed procedures be faithfully executed.

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On occasion new information becomes available, previously unrecognised problems arise, or common sense begs for a change or deviation of the procedure. Circumstances will often dictate carrying on with the original instructions. Nevertheless, any and all persons have an obligation to raise concerns regarding work instructions with their supervisor. 'I was just following the procedure' is an unacceptable excuse for silently proceeding with a work instruction the person on the job knows to be wrong. 2.3

Management of Changes Field deviations from the published Operational Workscope are to be documented in writing and processed in accordance with the Contractors policy. The appropriate level of supervisory agreement for the change is always to be obtained in advance. Where additional work is requested by the Shell offshore operations Engineer a formal request shall be submitted to the Contractor on the vessel (see Additional Work Request Form) and the appropriate level of local change control initiated. Four levels of change are recognised: Minor Change

Minor change in workscope. The Jobsite Task Risk Assessment (JS-TRA) is not affected by the change. Approved by the Dive Supervisor.

Local Review Change

The existing JS-TRA no longer applies. A new JS-TRA is conducted. Any new hazards arising from the change are standard hazards routinely addressed in the safety section of the workscope. The change does not require another location or facility to change their planned activities. The Contractor Operations Superintendent can approve the change for the Contractor. The Shell Offshore Operations Engineer approves the change once he is satisfied it has been handled in accordance with the Contractors procedures and good practice.

Onshore Review Change

The existing JS-TRA no longer applies. A new JS-TRA is conducted. An additional hazard arising from the change is one known to have particularly hazardous potential (e.g. oxyarc burning), or supporting actions are required from persons not onboard the vessel, or an unanticipated dive is required. The Contractor Operations Superintendent suggests a change and advises his onshore management of the proposed change. The Shell Offshore Operations Engineer is advised of the proposed change and is satisfied it has been handled in accordance with the Contractors procedures and good practice. He may need to liaise with the Field Unit Facility to support the change. He advises the Underwater Operations Department of the circumstances.

Fundamental Change

A totally different execution concept is required to accomplish the task. The worksite is found to be unsafe and it cannot be readily remedied. A new revision of the Operational Workscope is required.

It is a matter of judgement as to what category a change falls into. Examples are outlined below for guidance. Change

Appropriate Supervisory Action

Diver finds spanner size is incorrect

Minor Change. Dive Supervisor arranges to have the correct spanner deployed and notes it in the working copy of the Workscope.

A stud bolt to be removed under the workscope is found to be frozen tight. • Cut using hydraulic nut splitter

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Local review change. The Superintendent and Shell Offshore Operations Engineer are notified. A JS-TRA is conducted to assess occurrence and control of all potential hazards arising from use of the hydraulic nut splitter. The change is approved by the Superintendent and the discussion minuted.

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The Shell Offshore Operations Engineer approves that change, satisfied that the Contractors own procedures and good practice have been observed in addressing the change. The work can proceed. Dive Supervisor arranges to have the correct nut splitter deployed and notes it in the working copy of the Workscope. Change control document included in the final report. • Cut using abrasive disk

Local review change. The Superintendent and Shell Offshore Operations Engineer are notified. A JS-TRA is conducted to assess occurrence and control of all potential hazards arising from use of the cutting tool. The change is approved by the Superintendent and the discussion minuted. The Shell Offshore Operations Engineer approves that change, satisfied that the Contractors own procedures and good practice have been observed in addressing the change. The work can proceed. Dive Supervisor arranges to have the correct abrasive disk deployed and notes it in the working copy of the Workscope. Change control document included in the final report.

2.4

• Cut using Oxy-arc burning

Onshore Review Change. Oxy-arc burning is known to have significant hazardous potential.

Dive Supervisor finds work access requires 35m of diver tether.

Local Review Change. Use of an umbilical longer than 30m is mentioned in the Workscope Diving hazards list. The Superintendent and Shell Offshore Operations Engineer are notified. A JS-TRA is conducted to assess occurrence and control of all potential hazards arising from use of a longer tether. The change is approved by the Superintendent and the discussion minuted. The Shell Offshore Operations Engineer approves that change, satisfied that the Contractors own procedures and good practice have been observed in addressing the change. The work can proceed.

A ROV job cannot proceed due to debris that must be removed by divers

Local Review Change. The Superintendent and Shell Offshore Operations Engineer are notified of the problem. The situation is discussed onboard and a plan to utilise divers to remove the debris is agreed. A JS-TRA is conducted and the risks have been mitigated to ALARP. The need for this dive was not anticipated in the Workscope, not even as a contingency. The Underwater Operations Focal Point onshore is advised of the diving requirement.

A ROV job adjacent to a seawater inlet cannot be completed by the ROV. The inlet cannot be idled.

Local Review Change. The Underwater Operations Focal Point onshore is notified the work cannot be safely completed as planned. A new or revised Workscope is required.

Document Control Copies of the latest version of all Operational Workscopes or other job instructions are held in the Department job files, even if fieldwork is never undertaken. Job file copies of Draft Operational Workscopes are discarded upon completion of fieldwork. All Operational Workscope transmittals are made through the Underwater Operations Department. Whenever a Workscope document (OOWS, DOWS or FOWS) is sent to an addressee outside the underwater Operations Department, a document transmittal is prepared by the Shell onshore data base controller. Document transmittals are logged on a computerised database to allow easy review of the status of a given Operational Workscope. Preparation and loading of document transmittals is carried out by the data base controller.

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All procedures, drawings etc shall be supplied in electronic format. ‘Livelink’ shall be used as the online document database providing electronic storage and access for documents and procedures. 2.5

Timely Completion of Operational Workscopes Final Operational Workscopes are to be approved, published and ready for transmittal offshore no less than two weeks prior to job execution as scheduled in the Four-Week-Look ahead. If this deadline cannot be met utilising routine mail circulation of approval copies, consideration should be made to hand carry or to use ‘Livelink’ to electronically transmit workscopes in order to expeditiously secure the required approvals and ensure the workscope is distributed.

3

OPERATIONAL WORKSCOPE SEQUENCE OF PREPARATION

3.1

Initiation of Work (Work Registration Form) Active Operational Workscope preparation begins on a job once a Sponsor submits a Work Registration Form. The WRF must be fully completed by the job sponsor and should include all necessary budget approvals. The work registration is reviewed by the underwater Operations Focal Point, who will assign a Job Leader (i.e. one of the Underwater Operations Engineers) to the work and decide if circumstances dictate use of a Fast track Operational Workscope. Any conditions of acceptance are noted on the form and the endorsed copy is returned to the Sponsor. A COABIS ‘Cost Code’ (Job Number, See Section 7 below) is raised by the COABIS Database Controller. The Job Leader is responsible for ensuring written instructions are authored, reviewed and circulated in accordance with the department policy. Operational Workscopes are generally prepared by or under the supervision of the Job Leader.

3.2

Sponsor Scope of Work (SSOW) Once the requirement for work has been identified the Job Leader confers with the Sponsor and provides guidance to aid the Sponsor in preparing a Sponsor Scope of Work (SSOW). The scope is structured to utilise Standard Procedures or previous similar jobs insofar as possible. Detail is added until the Job Leader is satisfied that he has sufficient understanding of the sponsor's requirements to make his own Outline or Fast track Workscope. Information items that must be supplied by Sponsors are:

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(1)

The objective of the job and operational constraints, i.e. Summary of tasks, method statement etc.

(2)

Operating Facility actions for establishing a safe worksite. Typical subjects are isolations of pressurised piping, electrical equipment, hydraulically actuated equipment, seawater inlets, and any other remotely controlled facilities,

(3)

Information needed to comply with government/asset regulations - Hydrotest pressures, environment issues (i.e. PON), data sheets for chemicals supplied by the Sponsor etc.

(4)

Legible A3 size copies of relevant drawings i.e. P&IDs, system and equipment layouts and details.

(5)

Details of Sponsor supplied equipment, materials, and services.

(6)

Asset scheduling, aspirations/constraints.

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3.3

Outline Operational Workscope (OOWS) and Kick Off Meeting From the information received, if appropriate, the Job Leader will prepare an Outline Operational Workscope (OOWS), which contains sufficient information for the Draft Operational Workscope (DOWS), which may (dependant on workload) be produced by the Diving Contractor. The OOWS will include as a minimum: (1)

The SSOW (including attachments WRF etc. and any other supporting information),

(2)

Identification and discussion of diving/ROV hazards and execution constraints (per consultation with the Underwater Operations Focal Point),

(3)

If applicable the allocation of applicable Standard Procedures, or copy of a previous similar job.

(4)

Method statement of the job execution concept agreed with the sponsor.

(5)

Designs or concept sketches of any installation equipment,

(6)

List of illustrations required.

Alternatively a Kick off meeting may be held in lieu of a formal OOWS Kick off Meeting Once the WRF and all the relevant information has been gathered, the Job Leader will hold a kick off meeting with all interested parties – Sponsor, Dive contractor etc. The purpose of the meeting is to discuss all aspects of the job, clarifying the workscope, identifying constraints, interfaces, isolations, identifying all necessary information and identifying the relevant action parties. A method statement and summary of tasks will be a fundamental outcome of the Kick off meeting. A date for the issue of the DOWS shall also be agreed. This meeting shall be minuted and copies of the minutes are to be posted in live link by the job leader 3.4

Draft Operation Workscope (DOWS) The Diving Contractor prepares the DOWS (Rev. A1) in accordance with Para 4.0 of this Chapter and within the agreed time frame. The Job Leader will monitor the timely production of the DOWS and prompt the Diving Contractor as necessary to meet the required schedule. Subsequent revisions of the DOWS, will be numbered A2, A3, accordingly. The Job Leader reviews the DOWS prior to it being submitted for official distribution, it is the principal task of the Job Leader to ensure that the DOWS is mature enough to be distributed for review. Word processing assembly of the Workscope always starts using the current Workscope Template as a foundation. Once the DOWS is deemed ready for issue (see paragraph above) the Diving Contractor will endorse the DOWS cover sheet in the relevant approval box prior to submitting it for distribution and review. Consideration can be made to reviewing using ‘Livelink’, and or distributing electronically but all transmittals must be recorded in the transmittal database. Distribution is defined on the cover sheet and Shell Expro distributions are handled by the Underwater Operations Department. The commented copies are all routed to the Job Leader for collation of comments. The Job Leader is to resolve conflicting comments before returning the DOWS to the Contractor for revision. The Job Leader will determine detail/breakdown of the COABIS CTS sheets. This breakdown is to be agreed will all relevant parties, and any suggested changes discussed with the Underwater Operations Job Leader. Agreed changes will be implemented by the Job Leader.

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3.5

Hazard Identification & Risk Assessment (HIRA) A HIRA is a legal requirement. It can be performed at any point that a procedure is deemed to be in a robust state, i.e. at A2, A3 or C1 stage, where no significant changes to the workscope are anticipated. Recommendations from the HIRA may entail changes to the DOWS or FOWS. This onshore safety meeting is conducted to capture all safety aspects of the work, to evaluate risks and make recommendations on how to mitigate those risks. The results of the HIRA are to be made available for offshore reference. The HIRA is to be chaired by the Diving Contractor, with relevant parties from the Contractor, Shell and any relevant Sub-Contractors to attend. Attendees should include HSE representatives, Project Engineer, Job Leader, other technical authorities, offshore representatives, diving or ROV personnel, as required.

3.6

Final Operational Workscope (FOWS) The Dive Contractor reviews and applies the changes requested and forwards one approval copy of the FOWS to the underwater Operations Department for circulation (Rev. C1). The Department records receipt of the FOWS and sends it to the Job Leader. The Job Leader reviews and approves the FOWS and is responsible for its final approval cycle. To expedite processing the FOWS cover sheet can be signed with minor comments and typographical errors flagged. Revisions to concept are discouraged and must be rigorously justified. The FOWS cover sheet should not be signed if the reviewer believes a concept revision is required or if he judges a comment or typographical error to be other than 'minor'. Re-submittals should have later revision codes (e.g. C2) if copies other than the signature copy are in existence. The Job Leader returns the original FOWS with signed off cover sheet to the Diving Contractor for final update and publishing. Copies are distributed per an agreed distribution list: •

3.7

Currently three copies to onshore Shell Database Controller, and up to 16 copies to the DSV/ROVSV.

Offshore Receipt Offshore recipients on the DSV/ROVSV who will execute the job, review the FOWS and conduct a Task Risk Assessment (TRA). In the event an unacceptable flaw is found in the FOWS, work is not to proceed until it is revised either using a change control process, or a Fast track Operational Workscope amendment developed. In no event are offshore personnel to undertake the work, unless they are confident it is safe and reasonable to execute. Also no work is to start unless an appropriately signed version ‘C’ of the FOWS is available or a field instruction (backed up by an onsite TRA) has been carried out. The latest revision status of the FOWS is indicated on the ‘Latest Look ahead Schedule’, issued by Underwater Operations Cost/Planning Engineer.

4

FORMAT AND CONTENT OF OPERATIONAL WORKSCOPES

4.1

Physical Document The document is to be of A4 size dimensions. Drawings will typically be reduced to size A4 with, if required, some A3. These would require folded and bound into the document. No drawings larger than A3 shall be used in the workscopes. The document is to be comb bound to permit easy photocopying. The outside covers are to be durable plastic. With respect to larger workscopes, consideration should be made by the Engineer responsible for production of the FOWS, in consultation with the Job Leader and other parties, to bind drawings, appendices and any other relevant documents in a separate volume.

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4.2

Format The format is to comply with the current Word-for-Windows Workscope Template.

4.3

Content The workscope shall contain clear step-by-step instructions detailing the work to be carried out. It shall detail the objective of the work identifying the platform/asset preparation/isolation work that has to be carried out prior to and during the execution of the work. The workscope shall contain all the necessary drawings, sketches and, where appropriate, storyboards. The workscope shall highlight all safety concerns associated with the work identifying any risks have been mitigated.

5

OPERATIONAL WORKSCOPES

5.1

Introduction There are generally two types of operational workscopes, remedial/construction workscopes and Inspection workscopes. Inspection workscopes differ from remedial or construction workscopes because of their dependence upon standard inspection procedures, the use of ROV techniques and of their relationship with COABIS. To ensure consistency of inspection instructions and results, Inspection Operational Workscopes utilise COABIS CTS sheets as the foundation for the work instructions. Remedial/construction workscopes are normally based upon previous similar intervention jobs and will always be a detailed step-by-step sequence giving clear and unambiguous instructions for the execution of the work.

5.2

Format for Operational Workscopes The Operational Workscope is authored starting with the same Word-for-Windows Workscope Template as any other Workscope. (1)

Introduction

General overview of the worksite, brief summary of the objectives of the workscope, a schedule and sequence of the work and a summary of tasks. A field layout is also to be included in this section.

(2)

Safety and Environmental HSE

This section will start with a safety summary, which will briefly identify the particular hazards associated with carrying out the work. It shall identify whether an onshore HIRA has been conducted and refer to the appropriate document. The remaining section will identify each known hazard. Discuss how it arises and how it is to be controlled, with a view to the whole job.

(3)

Specific Communications

Offshore/Onshore, List of contacts

(4)

Operational Procedure

This section shall fully detail the work to be carried out. It shall be a step-by-step sequence of events detailing all activities and equipment required, complete with all safety and hold points identified. This section shall include all preparation, isolation, installation and commissioning activities. For complex jobs this section may be further subdivided into discrete sections. All sections shall have a summary at the beginning describing the objectives of each section. Where appropriate include a decision tree specifically for fault analysis and investigation.

(5)

Composite Equipment List

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Highlighting specific/specialist equipment required.

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(6)

Drawings, Sketches & Photographs

General drawings, P&IDs and photographs that apply to the job as a whole. Drawings are typically obtained from the Structure/facility UMDB, unless none exist, where suitable alternative drawings are to be employed. They should identify any safety issues, such as caisson locations and depths, chain anchor catenaries. For intervention tasks P&IDs and relevant system schematics must be included.

(7)

Attachments & Appendices

Contains Work Status Report (Listing of CTS and estimated times); as appropriate, CTS Sheets highlighting specific requirements by CTS; Appendices such as COSHH sheets; Specialist equipment manuals; Checklist matrix of required work at the location (Optional, usually used for FMD member listings).

APPROVALS The draft and final documents are circulated for comment and approval and distributed in the same manner as other Operational Workscopes (Paragraphs 3.3 to 3.5). The Fast track Operational Workscope is a work instruction and responsibility for undertaking these tasks lie with the diving contractor. Diving contractor approval must be secured.

7

CREATION OF ‘COST CODES’ (JOB NUMBERS)

7.1

Introduction Once a WRF (Work Registration Form) has been established, a ‘Cost Code’ is assigned to the work. This is generated by COABIS in numerical order. Creating a Cost Code outside of COABIS may result in duplication of assigned job numbers.

7.2

Cost Code Creation COABIS creates a Cost Code, based on the Installation; Year; Work Type; Sponsoring Unit; and Sequential number. Installations, Subsea Facilities and Pipelines shall be referenced by a Code, which for pipelines and some associated facilities cross reference to the Inspection Based Information System (IBIS) codes for pipelines. These codes are inbuilt in to the COABIS system, but where COABIS is not used the codes will be given within the relevant workscope. Examples of these codes are as follows: Structure Code

BA

- Brent Alpha`

Facility Code

EGRT

- Egret Subsea Facility

Pipeline Code

N0205

- 8 inch Gas Export Anasuria to Fulmar

The Sponsor Unit is selected from the following list, where the initial letter is incorporated in the Cost Code, prior to the final three numbers of the Cost Code. B N C E W Z P I T

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Brent (Including Risers) Northern (Including Risers) Central (Including Risers) ONEgas East ONEgas West Integrated Systems (Pipelines) Projects Subsea Insurance Third Party

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The Work Type is selected from the following list, where the number shown is incorporated in the Cost Code as the third last digit. (1)

Inspection

(2)

Construction

(3)

Repairs

(4)

Topside (Lifts, Support)

(5)

Vessel Overheads

(6)

De-Commissioning

(7)

Production Wellheads

(8)

Trials

From the above a Cost Code is generated in the form shown below:-

AA/2004/C302

Installation / Year / Sponsoring Unit - Work Type – Sequential Number Auk Alpha / 2004 / Central (C) – Repair (3) – 02 (2nd Job Planned for Auk A in 2004) In addition to the above, a description of the works, the Sponsor and an Account Number is entered into Coabis. The COABIS entry form is shown below:

Figure 1

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COABIS Entry Form

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INITIATE WRF (SPONSOR)

APPROVE WRF

ALLOCATE JOB LEADER

CREATE JOB FILE AND LIVELINK

COABIS JOB No. ACCOUNT No.

CIRCULATE WRF

JOB LEADER

SPONSOR SCOPE OF WORK

CONTRACTOR

JOB FILE

OUTLINE SCOPE OF WORK JOB LEADER KICK OFF MEETING

DEVELOP PROCEDEURE

ISSUE DRAFT OWS

CIRCULATE FOR REVIEW

SPONSOR

PEER REVIEW ENGINEER

CONTRACTOR

PEER REVIEW ENGINEER

CONTRACTOR

JOB LEADER COLLATES COMMENTS

ISSUE FOWS FOR SIGNATURE

SPONSOR

FOWS PROCEDURE SIGNED

PUBLISH

Figure 2

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Workscope Development Flowchart

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SECTION 1 CHAPTER 2 LOCATION / POSITIONING CONTENTS Para

Page

1

INTRODUCTION

3

2 2.1 2.2 2.3 2.4 2.5 2.6

PROCEDURE Datum Points Structural Numbering System Distance Measurement Structural Clock Notation System Weld Clock Notation Structural Compass Heading and Depth Notation System

3 3 3 3 3 3 4

3

SEABED SURVEY

4

FIGURES No 1 2 3 4

Page Shell EPE Offshore Coordinate Reference Systems Node Saddle Clock Notation Conductor Notation Continuous Element Notation

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CHAPTER 2 LOCATION / POSITIONING 1

INTRODUCTION A systematic approach is to be carried out to define the location of defects or anomalies. The objective of such an approach is to allow consistent relocation of these features in subsequent years.

2

PROCEDURE The definition of the location of anomalies requires the use of a number of concepts. These are Datum Points, the Structural Numbering System, Distance Measurement and Clock Notation. These concepts are outlined in Paras 2.1 to 2.6.

2.1

Datum Points The position of any item of interest must be measured from a datum point. A datum point can be any readily available, identifiable and repeatable static reference point.

2.2

Structural Numbering System Each structure has a systematic numerical identification system that allows particular points or elements of the structure to be described. This numbering system is to be used when describing the location of the datum point.

2.3

Distance Measurement The distances are to be measured in metric units and an indication of the accuracy of the measurements must be given.

2.4

Structural Clock Notation System The clock notation system is used to describe the location of a feature around a cylindrical element. For the purpose of the system, cylindrical elements are divided into four categories.

2.5

(1)

Horizontal and diagonal elements. These include horizontal, horizontal diagonal and vertical diagonal members, riser stubs and pile guide supports. See Figures 2 and 3.

(2)

Vertical elements (primary). These elements form an integral part of the installation and include legs, vertical members, conductors and guides and caissons. See Figures 2 and 3.

(3)

Vertical elements (secondary). These elements are associated with larger structural components and would, for example, be pile sleeves and grout pipes. See Figures 2 and 3.

(4)

Continuous elements. These elements go through both horizontal and vertical phases and would include risers and J tubes. See Figure 4. The convention, as it applies to each of these categories, is described as follows: (a)

Horizontal and diagonal elements. 12 o'clock is at the top of the member and the clock is viewed from the mid-point of the brace towards the node. See Figure 2.

(b)

Vertical elements (primary and secondary). 12 o'clock is taken at platform north and the clock is always viewed in plan. See Figure. 2.

Weld Clock Notation Node saddle welds are always to be viewed from the brace to the node with the imaginary clock facing the viewer.

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The 12 o'clock position is to conform to prevailing structural clock notation system. The 12 o'clock position and clock orientation shall conform to the structural clock notation system for all butt welds. See Figure 3. 2.6

Structural Compass Heading and Depth Notation System This location method should be used when a Remotely Operated Vehicle (ROV) is being used to survey a large vertical cylindrical element of a structure. Any findings should be reported against the vehicle's depth and it’s heading when viewing the anomaly straight on.

3

SEABED SURVEY The CONTRACTOR shall carry out all offshore survey and positioning WORK using the coordinate reference system and datum shift parameters from WGS84 supplied by the COMPANY, at the time of the work. For guidance see Figure 1 Shell EPE Offshore Co-ordinate Reference Systems.

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Figure 1

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Shell EPE Offshore Coordinate Reference Systems

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PLATFORM NORTH

3 12

6 9

12

3

9

6

VERTICAL DIAGONAL

3

6

12

9

12 3

HORIZONTAL DIAGONAL

9 6

HORIZONTAL

12 3

9 6 VERTICAL

12

HORIZONTAL

3

9 VERTICAL DIAGONAL

6

VERTICAL

12 3

9 6 9 12

Figure 2

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6 3

Node Saddle Clock Notation

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1

3

2

GRID NORTH

PLATFORM NORTH

4

D

N C B

A

CONDUCTOR BRACING WELD NOTATION

3 12

12

12 9

9

3

3 12

CONDUCTOR NOTATION

6 9

3

3

12

9 12

9

PLATFORM NORTH

3 12

12 9

9

3

3 12

6 9

PLAN

Figure 3

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Conductor Notation

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12

9

12

3

A

9

D Z

6

3 6 VIEW ON ARROW Z

1 16 2 14 13

12

3

9

15

3 X

4

6 SECTION A - A

12

A A 3

9

B

6

B

SUPPORT

12

3

9

6

SUPPORT

SECTION B - B

12

3

9

C C

6

12

12

3

9

9

3 6

6

VIEW ON ARROW X

VIEW ON ARROW Y SECTION C - C

Figure 4

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Continuous Element Notation

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SECTION 1 CHAPTER 3 EQUIPMENT CONTENTS Para 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.7.1 1.7.2 1.7.3 1.7.4 1.7.5 1.8 1.8.1 1.8.2 1.8.3

Page SPECIFICATIONS General Hydraulics Electrical High Pressure Water Jetting Equipment Low Pressure Dry Air Grit Entrained Cleaning Equipment Lifting Equipment Video System General Video Lighting Video Standards Onboard Video Suite Topside Video Digital Images/Stills Underwater Images Topside Images Format

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CHAPTER 3 EQUIPMENT 1

SPECIFICATIONS

1.1

General All items of equipment are to be supplied together with a complete set of operating instructions and technical literature. The equipment is to be suitably protected for the environment in which it is to be operated. The depth rating of the equipment is to be adequate to allow it to operate at all depths specified in the work scope. All external controls are to be accessible and easily manipulated by the operator and have clear identification and markings. Suitable measures are to be taken to protect and prevent the loss of equipment when at/or transferring to or from the worksite. The equipment is to be maintained and operated in accordance with the manufacturer's instructions. Where appropriate, lifting pad eyes and attachments are to be correctly tested and certified, including Non Destructive Testing (NDT) certificates for welded components. All supplied equipment is to be compliant with any conditions required by UK legislation, and where required is also to be compliant with the ‘Provisions and Use of Work Equipment Regulations 1998’ (PUWER). When working outside of the UK sector, equipment is to comply with the local government legislation. References below are only made to the relevant UK legislation.

1.2

Hydraulics All equipment for diver operation is to be fitted with 'dead man' type triggers. Triggers are to be surrounded by guards designed to prevent accidental operation. Cutting discs or brushes are to be suitably guarded.

1.3

Electrical All underwater electrical equipment is to comply with the latest revision of the International Marine Contractors Association (IMCA) Diving Division, ‘Code of Practice for the Safe Use of Electricity Underwater’.

1.4

High Pressure Water Jetting Equipment All high-pressure water jetting equipment is to comply with the latest revision of the IMCA Diving Division ‘Code of Practice for the Use of High Pressure Water Jetting Equipment by Divers’. All operators are to be instructed in the use of the equipment.

1.5

Low Pressure Dry Air Grit Entrained Cleaning Equipment Two-way communication, Topside Operator/Diving Supervisor is to be maintained during system operation. All operators are to be instructed in the use of the equipment.

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Expendable grit utilised must comply with SI 2002 No. 2677, ‘The Control Of Substances Hazardous To Health’ (COSHH). 1.6

Lifting Equipment All lifting equipment is to be compliant with ‘The Lifting Operations and Lifting Equipment Regulations 1998’ (LOLER). A LOLER Lift Plan is required to be completed for all lifting operations.

1.7

Video System

1.7.1

General All video recorders shall be of the Super-VHS format for direct recording from diver or ROV, and shall use tapes of three-hour duration. S-VHS tapes are to be used for all underwater recordings. On completion, one copy shall be made again on S-VHS. Additional copies may be requested, some of which may be required on Standard-VHS format tapes. In every case the video recording suite should be capable of recording and playing back 400 line resolutions as a minimum. VCRs are to be set up to avoid synchronisation faults such as picture hooking.

1.7.2

Video Lighting Video lighting is to conform to the following:

1.7.3

(1)

To be designed and arranged to give optimum video.

(2)

'Spot lighting' on diver helmet video e.g. SSS Mk II lights are not acceptable.

(3)

Should be diffused to give even lighting across the picture and not cause burn-out or shadowing, e.g. OE 1132 lights, or better, are acceptable.

(4)

Not to cause unacceptable colour cast.

(5)

Must give good colour rendition and separation.

Video Standards The video system will be assessed using the Shell Video Assessment Test Kit and Procedures. The following video standards are applicable for live video:

1.7.4

(1)

Diver Observation ROV camera e.g. Tiger. SIT 550 lines resolution, 9 clear steps on the grey scale Colour 500 lines resolution, and clear colour separation.

(2)

ROV general purpose/pilot camera. SIT 550 lines resolution, 9 clear steps on the grey scale. Colour 500 lines resolution, clear colour separation and good colour rendition.

(3)

ROV Inspection Camera/Diver Helmet mounted camera. SIT 550 lines resolution, 9 clear steps on the grey scale. Colour 500 lines resolution, clear colour separation.

Onboard Video Suite The onboard video suite will include but not be limited to: -

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(1)

Cameras

(2)

Video Recorders (S-VHS format)

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(3)

Video Overlay Units

(4)

COABIS Video Overlay system

(5)

Timers

(6)

Microphones

(7)

Monitors (Super - VHS Resolution)

(8)

Lighting

All units are to be compatible within the system suite to CCIR Standard (PAL Format for colour). Recorded video to be 400 lines resolution with 9 clear steps on the grey scale, clear colour separation and good colour rendition. 1.7.5

Topside Video A digital video camera may be required for topside inspections, and occasionally for video of topside construction tasks. The required specification for a topside video camera is given in the contract document.

1.8

Digital Images/Stills

1.8.1

Underwater Images Underwater Digital Images will be required in the following cases: (1)

As a matter of course, of all anomalies where such an image suitably conveys details of the anomaly.

(2)

Where specifically requested in the Workscope, Standard Procedure or by the Shell Offshore Representative.

(3)

During construction operations, where specified in the Workscope, requested by the Shell Offshore Representative, and/or to enhance the reporting of findings / operations conducted.

Where possible the image should be captured directly from the diver or ROV camera picture direct, so as not to lose picture quality. Where an item arises that was not initially captured, images can be obtained from relevant video footage, or if practicable, a return visit should be made to the item of interest whilst the vessel is still on location to obtain direct digital stills. 1.8.1.1

Image Requirements Most video inspections should be run using COABIS, with built in video overlay. For this reason, and with the additional date/time overlay required for all video inspections, most of the required information should automatically be available on the video overlay, providing sufficient details of the subject in question. The following information, as a minimum, is required on a Digital Image: (1)

Date/Time (Standard Overlay)

(2)

Component Number (Standard COABIS Overlay), or Component Description

(3)

Cost Code / CTS (Additional Input)

(4)

Brief Description (Additional Input)

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Items (3) and (4) should be on the same line, so as not to obscure the component. Where possible a scale should be employed, i.e. when taken from a divers video camera. Additional information that may be required, as dictated by the subject, would be Eastings and Northings, which again would automatically be superimposed from the ROV video overlay. 1.8.1.2

Stand Off/General View Where specified in the workscope, as a result of an anomaly, or on instructions from the Shell Offshore Representative, Stand Off/General View Digital Images will be taken. The images are to clearly show the overall worksite, if possible, from two opposing sides, i.e., nodal locations 12 and 6 o'clock or 3 and 9 o'clock. If a series of images are to be taken they are to proceed in a logically agreed continuous sequence.

1.8.1.3

Weld Node / Close Up Images Inspections may require images to be taken to highlight defects or repairs, i.e. remedial grinding. In these instances the image will be restricted to the area of interest. Full weld mosaics are not required. For such images, in addition to the above data, the following is also to be included on image:

1.8.2

(1)

The Datum Mark will be the start position - 'O' mm in all instances.

(2)

Scale at least 150mm long, with 5mm and 10mm increments clearly visible. Scale to be positioned between 25mm and 50mm from the weld / item of interest.

(3)

Distances from datum to be marked in 100mm increments, i.e. 0, 100, 200, 300, 400mm etc., covering the area of interest. The scale used (2) should suitably span these increments to give the exact position from datum. For welds this numbering is to run in a clockwise direction around the member or chord as site conditions dictate. For other items of interest the numbering is to view from left to right.

(4)

'C1' anomalies or defect grinding areas are to be highlighted using colour coded magnetic arrows, or suitably marked using image editing software.

(5)

Where mosaics are required, suitable overlap between consecutive images is required, so that the full area of interest is covered, with unambiguous results.

Topside Images A Digital Camera will be required to take topside Digital Images in the following cases: (1)

For topside inspections as requested in the Workscope, Standard Procedure and where critical anomalies exist.

(2)

During construction operations, where specified in the Workscope, requested by the Shell Offshore Representative, and/or to enhance the reporting of findings / operations conducted, i.e. images of recovered chokes.

The required specification for a topside camera is given in the contract document. 1.8.3

Format All digital still images should be supplied in .JPG format.

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The file size should be kept to the minimum, possible without affecting the quality of the image. Software may be used to reduce the file size, or convert the original image format to .JPG. Software will be required to suitably enhance the image with labels and indicators. Paint Shop Pro, or Adobe Photoshop are the preferred software to be supplied for Shell personnel use where required.

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SECTION 1 CHAPTER 4 INSPECTION OPERATIONS CONTENTS Para

Page

1

INSPECTION

3

2

SURVEILLANCE OF INSPECTION

3

3 3.1 3.2 3.3

VISUAL INSPECTION SPECIFICATIONS General Visual Inspection - GVI Detailed Visual Inspection - DVI Close Visual Inspection - CVI

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CHAPTER 4 INSPECTION OPERATIONS 1

INSPECTION Inspection shall include but not be limited to:

2

(1)

Video recording and Digital Still Images

(2)

Identification and cleaning

(3)

Scour, debris surveys and debris removal

(4)

NDT techniques, (visual, MPI, ultrasonics, ACFM, FMD, PEC, etc.)

(5)

Surveys: (a)

Marine growth

(b)

Dimensional

(c)

Corrosion

SURVEILLANCE OF INSPECTION The Contractor shall ensure the Inspection Diver's helmet is fitted with CCTV at all times during all underwater activities and inspection related works. Such CCTV coverage is to be capable of clearly showing positions of equipment as necessary, and work locations (including close-up views where anomalies may be noted). All anomalies shall be recorded by diver description. Such recording will be made direct by the diver and all diver conversation will be repeated, for clarity, by the Dive Supervisor, or Inspection Controller.

3

VISUAL INSPECTION SPECIFICATIONS

3.1

General Visual Inspection - GVI This type of inspection is generally carried out by ROV. The purpose of the inspection is to establish the overall impression of the condition of the component and its attachments without any cleaning and to detect any major departures from the original or previously known condition. Any anomalies found during this type of inspection are likely to be of fairly large scale such as dents, holes, buckling, missing members, debris, scour, mud build up, etc.

3.2

Detailed Visual Inspection - DVI This type of inspection is generally carried out by ROV or divers. The purpose of the inspection is to establish the condition of the component and its attachments and detect defects that would otherwise be obscured by marine growth. A limited amount of cleaning will be required to carry out this inspection. Soft marine growth should be removed by either water jetting, scrapers and/or wire brushes, the standard of cleaning will be sufficient to enable details of the component to be seen. It will not normally be necessary to remove hard marine growth unless it obscures detail. Care is to be taken during the cleaning to ensure any surface coatings are not damaged.

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Any anomalies found during this type of inspection are likely to be large cracks in concrete surface, gross cracks in welds, cracks in conductor guides, clamp bolts missing/loose, corrosion, etc. 3.3

Close Visual Inspection - CVI Divers generally carry out this type of inspection. However, it may be carried out by ROV. For ROV CVI the vehicle should be parked. Either zoom or manipulator mounted video camera and light package is to be used to scan the area at extreme close range (typically 20 - 100mm stand-off). Scanning speed over surface is to be 0.5 to 1 metre per minute. The purpose of the inspection is to establish a detailed inspection of areas of specific interest, typically welded joints and concrete joints. A higher standard of cleaning is required for this type of inspection, for welded joints all marine growth is to be removed and the area to be grit cleaned to SA 2.5. For concrete surfaces it will be necessary to remove all hard and soft marine growth, worm cast stains can be left in place unless they obscure detail. The standard of cleaning will be sufficient to enable details of the component to be seen. Care is to be taken during the cleaning of concrete surface/joints to ensure any bitumen/epoxy coating is not damaged. For diver inspection the area to be inspected is to be marked up in increments to enable any defects/blemishes to be accurately located, sized and plotted with reference to a known datum point. For ROV inspection, the area to be inspected is to be clearly identified using SIT and/or colour CCD, with the ROV at sufficient stand off for the area to be shown in relation to identifiable features. This precludes the requirement for the area to be marked up in increments. However, any defects noted are to be marked up using a 'Propelling Wax Crayon' at a distance of 75 to 150mm either side of the defect. A single line or 'X' is sufficient, again this should be shown in the stand off video sufficiently to identify its position with regard to a known feature. Any anomalies found during this type of inspection are likely to be weld cracks/defects, concrete cracks/blemishes. Anomalies found by ROV may result in diver intervention to accurately size the defect. Alternatively, the ROV should use a rod, marked in suitably sized increments, i.e. 10mm, held in the vehicles manipulator. Dependant on the item to be inspected, the scale should be in the form of two rods mounted at 90 degrees to each other, to give horizontal and vertical dimensions, without need to rotate the manipulator

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SECTION 1 CHAPTER 5 INFORMATION CONTROL CENTRE CONTENTS Para 1 1.1 1.1.1 1.1.2 1.1.3 1.2

Page OPERATIONAL OBLIGATIONS Facilities Information Control Centre Dive Control Data Recorders Workstation ROV Data Recorders Workstation Data Recording

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CHAPTER 5 INFORMATION CONTROL CENTRE 1

OPERATIONAL OBLIGATIONS The Contractor is responsible for providing suitable facilities for the gathering of inspection data and recording of activities conducted during maintenance and repair operations. The Contractor is responsible for various tasks during these IMR programmes; in addition to the completion of these IMR works. The QAQC Coordinator shall act as the focal point for liaison with the Diving Superintendent/ROV Party Chief for all information relating to the planning, performance, recording and reporting of the work. The following details these obligations:

1.1

Facilities The following facilities are to be provided to allow data gathering, compilation of data gathered and completion of reports:

1.1.1

Information Control Centre An office is required for the use of the Shell QAQC Coordinator, and/or the Contractors IMR Co-ordinator. The office is to be equipped with the following: •

Monitors to allow views all works carried out by either diver or ROV from any workstation. This should be linked into the video suite, listed below, to allow recording of any of these views.

•

It will have full communications to all workstations and an uninterrupted power supply regulator for working with computer systems. Communications links shall include suitable KU Band telephone external linkage for both phone and fax, and full IT linkage enabling utilisation of email and the internet, with a dedicated ‘Yac-Fax’ (or similar) account.

•

2 x COABIS computers complete with 17” flat screen monitors and DVD+RW drives. The following software is required: •

Microsoft Office 2000, or compatible.

•

Microsoft Project.

•

AutoCAD LT 97 or higher and a drawing viewer – e.g. Voloview Express.

•

Adobe Acrobat.

•

Paint Shop Pro V.8 (or Photoshop V5).

•

1 x Laser printer (networked). Minimum specification equivalent to HP LaserJet 5M, supplied with spare toner cartridges.

•

1 x A3 colour printer (networked), supplied with spare toner/ink cartridges.

•

1 x A3 colour scanner (networked).

•

An A3/A4 photocopy machine complete with reducing/enlarging multi-feed and sorting facilities for the use of the QAQC/Coordinators, supplied with spare toner cartridges and suitable paper.

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1.1.2

1.1.3

•

A video suite for reviewing/copying of tapes, comprising of two Panasonic AG7350 S-VHS tape decks (or similar) and one YC colour monitor (minimum 16 inch screen size). This suite should allow copying of video from a topside digital Camcorder, to S-VHS.

•

The office will have sufficient space to allow preparation of workscopes and fast track workscopes for issue, and for the production of multiple reports.

•

Suitable shelving, with bad weather fixings, will be required with sufficient clearance for A4 ring binder sized manuals.

•

Suitable cupboards or A4 shelving (+2m in length) to allow storage of the full compliment of COMPANY platform Underwater Maintenance Database Manuals (UMDB’s).

•

Two x 3 drawer filing cabinets.

•

1 x White board.

Dive Control Data Recorders Workstation (1)

An NDT/work control station providing working facilities for the Data Recorder, with suitable desk space to allow review of workscopes and for writing/marking up of data records. This station shall have full communications link with divers and Dive Supervisor, as well as monitors for receiving video input from divers and ROV. Facilities for recording video inputs shall be provided (Super-VHS format), complete with microphone.

(2)

The master video recorder will be equipped with a video overlay card, to allow control by the COABIS system, as well as a separate video overlay unit for manual use.

(3)

A networked COABIS installed computer dedicated for the Data Recorder’s use, will be available at the Data Recorders workstation, without recourse for them to move position whilst operating the video suite. The computer will have a video grab facility, to allow direct real time video grabs and grabs from videotape. The computer will have its own e-mail account. The computer will be loaded with the following minimum software; •


•

AutoCAD LT 97 or higher and a drawing viewer – e.g. Voloview Express.

•

Adobe Acrobat.

•


(4)

Filing cabinets, shelves, etc. to hold all work scopes and dive procedures, plus all other work related information including the UMDB Manuals supplied by Shell EPE.

(5)

A suitable area shall be available for the set up, charging and maintenance of inspection equipment, such as CP and WT meters.

(6)

Control of the subsea MPI unit should be possible from the Dive station or Data Recorders workstation.

ROV Data Recorders Workstation Facility should be available at each ROV station, to allow recording of Data. To facilitate this, the following is required as a minimum: (1)

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Suitable desk space for the Data Recorder to allow review of workscopes, and for writing/marking up of data records. This station shall have full communications link to the Dive Supervisor and Bridge.

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(2)

A monitor for reviewing the ROV video picture. Facility to record to S-VHS video, any of the ROV camera pictures, including all relevant overlay, i.e. date, time, depth and heading. Where seabed surveys are required, easting and northing overlay from a continuous feed, of the ROV’s position is to be recorded. CP overlay is also required. Facilities for recording video inputs shall be provided (Super-VHS format), complete with microphone.

(3)

The master video recorder will be equipped with a video overlay card, to allow control by the COABIS system, as well as a separate video overlay unit for manual use.

(4)

A networked COABIS installed computer dedicated for the Data Recorders use, will be available at the Data Recorders workstation, without recourse for them to move position whilst operating the video suite. The computer will have a video grab facility, to allow direct real time video grabs and grabs from videotape. The computer will have its own e-mail account. The computer will be loaded with the following minimum software; •


•

A drawing viewer – e.g. Voloview Express.

•

Adobe Acrobat.

•


Data Recording A Data Recorder will be required to be at the Dive Control and ROV workstations when inspection and construction work is ongoing, that requires the recording of operations both in the form of video and or/written accounts.

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SECTION 2 GUIDE TO THE STANDARD PROCEDURES FOR UNDERWATER ENGINEERING OPERATIONS CONTENTS

CHAPTER 1 INTRODUCTION CHAPTER 2 STANDARD PROCEDURES CHAPTER 3 METHOD OF USE CHAPTER 4 TASK CODING SYSTEM AND COMPONENT TASK SHEETS CHAPTER 5 PROCEDURE & COMPONENT NUMBERING SYSTEM CHAPTER 6 ANOMALY REPORTING & CRITERIA CHAPTER 7 REPORTING

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CHAPTER 1 INTRODUCTION 1

INTRODUCTION The main aims of producing Standard Procedures for Underwater Engineering Operations are as follows: (1)

To reduce the number of procedures that have been produced in the past on similar work.

(2)

To assist the Engineer in the preparation of the Scope of Work.

(3)

To standardise the format and collate the Standard Procedures into a single volume to facilitate easy reference.

(4)

To specify to the contractor the method and the precise standards to which the work is to be performed.

(5)

To specify personnel qualification necessary to carry out the specified works.

(6)

To carry out all works in a safe and most efficient manner.

(7)

To standardise procedures for ‘ad hoc’ jobs to maintain quality and safety.

The adoption of Standard Procedures for Underwater Engineering Operations, in combination with a procedure numbering and task coding system will significantly enhance the system for both the Engineer and Database Operator.

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SECTION 2 CHAPTER 2 STANDARD PROCEDURES CONTENTS Para

Page

1

STANDARD PROCEDURES

3

2

NEW STANDARD PROCEDURES

3

3

NON-STANDARD PROCEDURES

3

4

STANDARD PROCEDURES IN COABIS

3

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CHAPTER 2 STANDARD PROCEDURES 1

STANDARD PROCEDURES Standard Procedures are written to free the Engineer from the task of writing the requirements of the work, e.g. take colour video, carry out Magnetic Particle Inspection (MPI) examination, etc. For the Contractor the Standard Procedures will specify that he carry out the work to a prescribed standard. The procedures included within Sections 3, 4 and 5 of this manual, have set tasks to be carried out due to the repetitive nature of the procedure. Optional set tasks are also listed. The method in which to carry out both these set and optional tasks are detailed within the relevant Standard Procedure. The majority of the Standard Procedures are for inspection work, due to the repetitive nature of the inspection requirements. Due to their nature, only a few repair and construction procedures are repetitive and can be covered by a Standard Procedure included within this manual.

2

NEW STANDARD PROCEDURES Where a new standard procedure is to be developed it shall conform to the following format: (1)

Work Method. This section briefly outlines the scope of the Procedure and whether the work contained therein is to be accomplished by diver, ROV or a combination of both.

(2)

Task Options. This section provides a list of Task Options required for the particular Procedure.

(3)

Operating Procedure and Specification. This section details the method of accomplishing the work and the particular requirements that the work must be carried out to. It also gives the minimum qualifications for the personnel who are to carry out the works.

Included in this part, where applicable, are references to contractor/manufacturer procedures for operation of specialist equipment, e.g. FMD, ACFM & PEC, etc. Where indicated these procedures are to be applied to the task in hand. 3

NON-STANDARD PROCEDURES Other forms of repair and construction procedures are always ‘one off’. Their development cannot be covered within this manual, however previous workscopes created for various types of interventions are saved within Shell EPE archives both electronically and in hard copy format, in deep storage. Electronically, the most recent of these are stored within the Shell EPE Livelink database back to 1997. These can be recalled and changed appropriately.

4

STANDARD PROCEDURES IN COABIS The Standard Procedures are built into the Component Orientated Anomaly Based Inspection System (COABIS), with the associated designated set and optional tasks. For Inspection Tasks, set times are assigned to each task, which vary based on the component being operated on, and method of inspection, i.e. diver or ROV. These times are set based on historical data. This allows for a quick method of estimating the time required to inspect a particular riser, caisson, wellhead, etc. Times however can be altered as required, based on other variables, such as access restrictions. For Construction Tasks, times cannot be so easily assigned, and will require altering to suit.

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Where non-standard procedures are conducted, COABIS allows for any number of tasks from the total task listing can be allocated as appropriate. The list of the tasks and their associated COABIS task codes are given in Chapter 4.

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SECTION 2 CHAPTER 3 METHOD OF USE CONTENTS Para

Page

1

METHOD OF USE

3

2

WORK UTILISING A STANDARD PROCEDURE

3

3

NON STANDARD WORK

3

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CHAPTER 3 METHOD OF USE 1

METHOD OF USE When the requirement for work on a particular component, group of components or structures arises, the sponsoring engineer will first check through Sections 3 to 5 in order to establish if there is a suitable procedure within the current list of standards that will satisfy the requirements of the work. If a suitable procedure is located, proceed as in Para 2, or if the work is non-standard, proceed as in Para 3.

2

WORK UTILISING A STANDARD PROCEDURE When a Standard Procedure is located that satisfies all or most of the requirements of the work it will effectively reduce the contents of the Scope of Work to a listing of Job Number; Job Title; Components to be inspected; relevant Standard Procedure number; and any specific options to carry out under the Standard Procedure. If there is some additional work or some changes these will be identified in the relevant operational workscope. The preparation and distribution of an Operational Work Scope (OWS) is covered in Section 1, Chapter 1.

3

NON STANDARD WORK If there is no Standard Procedure available, the sponsoring engineer will be required to complete a much more detailed Scope of Work to enable a suitable procedure to be produced (See Section 1, Chapter 1). The sponsor's Scope of Work shall provide the following information: (1)

Detailed description of the work to be carried out.

(2)

General description of the worksite.

(3)

Review of the existing worksite and the historical context for the work.

(4)

Reasons for modifying the existing situation.

(5)

What it is that is to be installed, removed or inspected.

(6)

Details of all sponsors supplied equipment.

(7)

Any other generally informative comments.

This Scope of Work will be handed over to the Subsea Operations Job Leader, the focal point for the preparation of the OWS. The preparation and distribution of OWS is covered in Section 1, Chapter 1.

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SECTION 2 CHAPTER 4 TASK CODING SYSTEM AND COMPONENT TASK SHEETS CONTENTS Para

Page

1

INTRODUCTION

3

2

TASK CODE SYSTEM

3

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CHAPTER 4 TASK CODING SYSTEM AND COMPONENT TASK SHEETS 1

INTRODUCTION When preparing an operational workscope (see Section 1, Chapter 1) a workscope will be subdivided into one or several logical sections. These sections are called workpacks or CTS’s (Component Task Sheets). CTS’s ultimately form part of the final report (See Section 2, Chapter 7). There are no hard and fast rules regarding creation of CTS’s - they should merely be logical divisions of an operational workscope, discrete manageable sections which can be executed and reported against, and which can be assigned an estimate of duration. Each CTS consists of a number of tasks. These work tasks enable specific information such as estimated times, actual times and other unique data i.e. CP readings to be recorded against. The CTS’s and tasks assist in planning and estimating similar activities on similar jobs. The tasks form part of COABIS and the Task Code system logically groups like tasks together under set categories to facilitate quick reference. Due to a review of the Standard Procedures and tasks conducted, some Task Codes no longer utilised have been removed from paragraph 2 below. These removed tasks and their associated historical data remain within the COABIS database.

2

TASK CODE SYSTEM The Task Listing will be made up of 2-3 Alpha character code as follows: Task Code

Description

CH - Check CH-BLT

Bolt Check (Visual and by Hand)

CH-LKS

Check for Leaks

CH-VLV

Valve Position Check

CH-FXW

Check Armawrap (Flexi-Wrap)

CL - Cleaning CL-DRG

Dredge Pump

CL-GRT

LP Dry Grit Clean

CL-INS

Clean for Inspection

CL-MGR

Marine Growth Removal

CN - Construction CN-COM

Commissioning Observation

CN-DPR

Deck Preparation

CN-EQP

Deploy Equipment

CN-FLG

Align/Pull in Spools

CN-FLS

Flushing Operations

CN-FLT

Tension & Wrap Flanges

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Task Code

Description

CN – Construction (Continued) CN-FXW

Remove/Apply Flexi-Wrap

CN-GRB

Build Grout Bag Support

CN-GRD

Remedial Grinding

CN-GRT

Grouting Operation

CN-HVL

Heavy Lift

CN-IAN

Install Anode

CN-IGC

Install/Recover GRP Covers

CN-INC

Install/Recover Clamp

CN-IPC

Install Pile Cap

CN-JUM

Connect/Disconnect Jumpers

CN-LRG

Large Construction Task

CN-MAT

Lay/Recover Mattresses

CN-MUD

Mud Removal

CN-PIG

Pigging Operations

CN-PRT

Pressure Test

CN-RBP

Remove/Replace Blanking Plate

CN-RGR

Remove Grill/Replace Grill

CN-RIG

Rig/Derig Worksite

CN-RPL

Open or Close Roof Panel

CN-STD

Standard Construction Task

CN-TCH

Trenching Operation

CN-TEN

Tension Studs

CN-TOP

Topside Assistance

CN-VLC

Valve Operation

CP – Cathodic Potential Measurement CP-CON

Contact Measurements

CP-CONC

Concrete Proximity Readings

CP-GSC

G-Scan CP Survey

CP-PRX

Proximity Measurements

CP-ZON

Zonal CP Survey

CU - Close-Up Inspection (Weld)

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CU-CVI


CU-DVI


CU-MPI


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Task Code

Description

DB - Debris DB-CHK

Visual Debris Check

DB-REM

Debris Removal

DM - Dimensional Survey DM-SCR

Scour Survey

DM STD

Standard Dimensional Task

IN - Other Inspection Tasks IN-CMT

Comments and Details

IN-ECI

Eddy-Current Inspection

IN-ERS

Talon ERS Survey

IN-FMD


IN-GSC

G-Scan Direct Current Readings

IN-OTH

Other Inspection Task

IN-RAD

Radiography

IN-SSC

Swain Sea-Clip DC Measurement

IN-UT

Ultrasonic A-Scan Inspection

IN-UTA

Ultrasonic A Scan

LI - CU Linked Technique Tasks (Weld) LI-CVI


LI-DVI


LI-MPI


MG - Marine Growth MG-GEN


PH - Photography PH-DIG

Digital Image

PH-TOP

Topside Digital Still Images

PI - Pipeline PI-203

Bare Metal Incident

PI-500

Anode

PI-CP

CP on Damage

Task Code

Description

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PI – Pipeline (Continued) PI-CSE

Confirmation of Span End

PI-CSS

Confirmation of Span Start

PI-GEN

General Pipeline Task

PI-SPN

Pipeline Span Rectification

VD - Video VD-DIV

Diver Video

VD-ROV

General ROV Video

VI - Visual Inspection VI-AW

Anode Wastage Measurement

VI-AWD

Detailed Anode Check

VI-CVI


VI-DVI


VI-GVI


VI-PNT

Coating Assessment

VI-ROV

ROV Worksite Check

VI-SPZ

Splash Zone Inspection

VI-TOP

Topside Inspection

WT - Wall Thickness

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WT-DIG

Measurement U/T Thickness

WT-PEC

Pulsed Eddy Current

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SECTION 2 CHAPTER 5 PROCEDURE & COMPONENT NUMBERING SYSTEM CONTENTS Para

Page

1

INTRODUCTION

3

2 2.1 2.2 2.3

NUMBERING SYSTEM Type of Work Component Code Sequential Number of the Procedure

3 3 4 9

3

STANDARD PROCEDURES

9

4

REGISTER OF PROCEDURE NUMBERS

9

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CHAPTER 5 PROCEDURE & COMPONENT NUMBERING SYSTEM 1

INTRODUCTION The intention behind the Procedure Numbering System is threefold and is explained as follows:

2

(1)

To convey a certain amount of information relating to the nature of the work (Tasks).

(2)

To identify the type of component the work is being applied to.

(3)

To group procedures related to work on similar components together in a logical manner.

NUMBERING SYSTEM The numbering system conveys three items of information relating to the procedure.These items are categorised as follows: (1)

Type of Work

(2)

Component Code

(3)

Sequential number of the procedure within its Component Code.

A typical example of a procedure number is given below illustrating the above three items of information. TYPE OF WORK (SINGLE CHARACTER)

COMPONENT CODE (2-DIGIT)

SEQUENTIAL OF THE PROCEDURE (3-DIGIT)

I

15

057

The number of characters and digits will not exceed six in total. An explanation of each of the above three categories follows: 2.1

Type of Work There are five possible codes within this category as follows: (1)

I - Inspection This includes work not only performed by diver, but survey work carried out by ROV and topside visual inspection carried out from the diving/ROV support vessel.

(2)

C - Construction This covers all work installing equipment underwater.

(3)

R - Repair Includes change out of faulty equipment.

(4)

M - Maintenance and general underwater operations This includes routine submarine hose change-outs, opening and closing subsea valves, general underwater maintenance and operations.

(5)

X - Miscellaneous Non Specific.

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Component Code The codes within this category are primarily, with some exceptions, based upon the UMDB system where each component on a structure is given a unique number. This unique numbering system is as per the Engineering Reference Document, Tag Numbering System Code of Practice (Shell Document Number EA/116), Appendix 8, 9 and 10. The Main Structure Component Codes (General) are as follows: Non Specific Components

00 - 09

Structural Steel Jacket

10 - 19

Structural Concrete

20 - 29

Structural General

30 - 39

Pipework Systems

40 - 49

Valves

50 - 59

Cathodic Protection System

60 - 69

Anchoring System

70 - 79

Universal Joint

80 - 89

Spare

90 - 99

These main sections are further sub divided as follows: (1)

Non Specific Components (00 - 09) 00 - Work created offshore and for COABIS operators use (Defunct) 01 - General Arrangements (Non specific components) 02 - Frame / Elevation / View (External) 03 - Row / Elevation (Internal) 04 - Level / Plan (from above) 05 - Level / Plan (from below) 06 - Seabed 07 - Ancillary Systems GS’s 08 - Trials and testing of new underwater equipment and products 09 - Spare

(2)

Structural Steel Jacket (10-19) 10 - General - Scour Survey 11 - Section of Leg 12 - Horizontal Member 13 - Diagonal Member 14 - Vertical Member 15 - Node/Intersection

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16 - Skirt Pile Guide 17 - Spare 18 - Spare 19 – Spare (3)

Structural Concrete (20 - 29) 20 - General - Scour Survey 21 - Shaft 22 - Cell Domes; Caisson Roof and Star Cell (Upper) 23 - Cell/Caisson Wall and Raft 24 - Spare 25 - Construction Joint 26 - Infill, Temporary Opening and Penetration 27 - Embedments 28 - Spare 29 - Spare

(4)

Structural General (30 - 39) 30 - Structural (General) 31 - Steel Hull 32 - Boat Fender, Landing and Riser Protector 33 - Platform, Walkway and Support 34 - Ladders and Grab Rungs 35 - Conductor Guide Frame 36 - Baseframe, Mudmats/Support Structures (Secondary Steelwork) 37 - Baseframe (Seabed) 38 - Compartment/Float Tank 39 - General Attachments (Mooring Eyes, Pipeline, Anchor Lugs, Padeyes- Central Shaft).

(5)

Pipework Systems (40 - 49) 40 - General 41 - Riser 42 - J-Tube 43 - Pump Casing, Caisson Drain, Cutting Chute 44 - Hose and Flotation Collars 45 - Manifold 46 - Clamp/Guide Assemblies 47 - Coupling 48 - Flange and Site Weld 49 - Conductors and Talon Connectors.

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(6)

Valves (50 - 59) 50 - Valves 51 - Oil Valve 52 - Gas Valve 53 - Water Valve 54 - Air Valve 55 - Transducers 56 - Spare 57 - Spare 58 - Spare 59 – Spare

(7)

Cathodic Protection System (60 - 69) 60 - General 61 - Anode - Section of Leg 62 - Anode - Horizontal Member 63 - Anode - Diagonal Member 64 - Anode - Pipework System 65 - Anode - Vertical Member 66 - Anode - Skirt Pile Sleeve 67 - Anode - Steel Hull 68 - Anode - Tank, Float, Compartment 69 - Anode - Platform, Baseframe, Base (Seabed) and Conductor Guide Frame

(8)

Anchoring System (70 - 79) 70 - General (Guides and Stoppers) 71 - Anchor 72 - Anchor Block 73 - Chain Cable (with Shackle) 74 - Wire Cable 75 - Chain/Cable Anchorage 76 - Anchor Coupling 77 - Transponder 78 - Spare 79 - Spare

(9)

Universal Joint (80 - 89) 80 - Universal Joint 81 - Universal Joint Assembly 82 - Universal Joint Seatings 83 - Spare

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84 - Spare 85 - Spare 86 - Spare 87 - Spare 88 - Spare 89 - Spare The Subsea Facility Component Codes (General) are as follows: Wellheads/Trees

200 – 209

Towheads

210 – 219

Structures and Steelwork

220 – 229

Manifolds

230 – 239

Pipework

240 – 249

Valves

250 – 259

Cathodic Protection System

260 – 269

Control Systems

270 – 279

(10)

Wellheads / Trees (200 - 209) 200 - Wellheads/Trees 201 - Guidebases 202 - Guideposts 203 - spare 204 - spare 205 - spare 206 - spare 207 - spare 208 - spare 209 - spare

(11)

Towheads (210 - 219) 210 - Towheads 211 - spare 212 - spare 213 - spare 214 - spare 215 - spare 216 - spare 217 - spare 218 - spare 219 – spare

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(12)

Structures and Steelwork (220 - 229) 220 - Structure and Steelwork 221 - Access Panels 222 - Piles 223 - Secondary Steelwork 224 - Trawlboard Deflectors 225 - Cocoon Protective Structures 226 - spare 227 - spare 228 - spare 229 - spare

(13)

Manifolds (230 - 239) 230 - Manifolds 231 - Manifold - Linear Block 232 - Manifold - Recoverable Valve Module 233 - Manifold - Chemical 234 - spare 235 - spare 236 - spare 237 - spare 238 - spare 239 - spare

(14)

Pipework (240 - 249) 240 - Pipework 241 - Oil Flowline Jumper 242 - Gas Flowline Jumper 243 - Water Injection Flowline Jumper 244 - Spool Pieces 245 - Control and Umbilical Connections 246 - Clamps/Guides 247 - Flowmeter Spools 248 - Flanges 249 - spare

(15)

Valves (250 - 259) 250 - Valves 251 - Oil Valves 252 - Gas Valves 253 - Water Injection Valves 254 - Air Valves

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255 - Hydraulic Valves 256 - Methanol Valves 257 - Chemical Injection Valves 258 - Pressure Monitor Valves 259 - Test Valves (16)

Cathodic Protection System (260 - 269) 260 - Cathodic Protection System 261 - Anodes - Guidebase 262 - Anodes - Tree 263 - Anodes - Towhead 264 - Anodes - Junction Box 265 - Anodes - Manifold 266 - Anodes - Other 267 – Anodes - Pipework 268 - spare 269 – Corrosion Monitoring

(17)

Control Systems (270 - 279) 270 - Control Systems 271 - Panels 272 - Control Modules 273 - Umbilicals / Weaklinks 274 - Control System Jumpers 275 - Junction Boxes 276 - Accumulators 277 - Acoustic Module 278 - Transducers / Transponders 279 - Spare

2.3

Sequential Number of the Procedure Each procedure will be given a sequential number commencing from 001 within the aforementioned Component Code Group

3

STANDARD PROCEDURES Standard Procedures will be coded in the same manner as specified in Para 2.

4

REGISTER OF PROCEDURE NUMBERS The register of the Procedure Codes will be maintained by Shell. Therefore any new procedures that are created will be correctly categorised and given their unique number by Shell.

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SECTION 2 CHAPTER 6 ANOMALY REPORTING & CRITERIA CONTENTS Para

Page

1

REPORTING - MSV/DSV ACTIVITIES

2 2.1 2.1.1 2.1.2 2.1.3 2.1.4 2.1.5 2.1.6 2.1.7 2.1.8 2.2 2.2.1 2.2.2 2.2.3 2.2.4 2.2.5 2.2.6 2.2.7 2.2.8 2.2.9 2.2.10 2.2.11 2.2.12 2.2.13 2.2.14 2.2.15 2.2.16 2.2.17 2.2.18 2.2.19 2.2.20 2.2.21 2.3 2.3.1 2.3.2 2.3.3 2.3.4 2.3.5 2.3.6 2.3.7 2.3.8 2.3.9 2.3.10 2.3.11 2.3.12 2.3.13 2.3.14

SUBSEA INSPECTION ANOMALY REPORTING Anomaly Reporting Requirements Levels of Reporting Critical Anomaly Reporting (General) Critical Anomaly Reporting (Leaks) Steel Sub-Structures Concrete Sub-Structures (Brent Bravo, Charlie and Delta) Risers Buoyant Structures (FPSO’s) Existing Anomalies Anomaly Reporting and Limits – Steel and Concrete Structures Index of Terms Anode Wastage Burial Caissons Cathodic Protection Chain Coating Damage Concrete Condition Corrosion Debris Flooded Members Lack of Integrity Leaks Marine Growth Physical Damage Relative Movement Scour Talon Connector Variance from Specification Wall Thickness Weld Defect Anomaly Reporting and Limits – Risers, J-Tubes, Pipelines and Umbilicals Index of Terms Anode Wastage Burial Cathodic Protection Coating Damage Corrosion Debris Lack of Integrity Leaks Marine Growth Physical Damage Relative Movement Scour (Pipeline) Scour (Igloos)

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3 3 3 3 3 4 5 5 5 6 6 6 6 7 7 7 7 8 8 8 8 8 9 9 9 9 9 10 10 11 11 11 11 12 12 12 12 12 13 13 13 13 13 14 14 14 14 15

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Scour (Wellheads) Wall Thickness Critical (C1) Anomaly Process Leak Sample Notification and Delivery Ashore

15 15 16 17

FIGURES No 1 2

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Page Example Sample Analysis Request (SAR) Form Blank Sample Analysis Request (SAR) Form

17 18

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CHAPTER 6 ANOMALY REPORTING & CRITERIA 1

REPORTING - MSV/DSV ACTIVITIES Consistency, accuracy and completeness of anomaly records is extremely important, to provide sufficient information to the relevant engineers, to minimise the amount of re-inspection/ambiguities.

2

SUBSEA INSPECTION ANOMALY REPORTING

2.1

Anomaly Reporting Requirements

2.1.1

Levels of Reporting Two categories of anomaly are specified with differing reporting requirements. (1)

Category One (C1). Critical; requiring immediate reporting. Not greater than 24hrs from initial identification.

(2)

Category Two (C2). Not Critical; typically issued 14 days after completion of the work.

The anomaly reporting and limits to assign to appropriate category, are highlighted in greater detail in paragraph 2.2 (Anomaly Reporting and Limits – Steel and Concrete Structures) and paragraph 2.3 (Anomaly Reporting and Limits – Risers, J-Tubes, Pipelines and Umbilicals). The operational vessel’s offshore Daily Progress Report (DPR), is to reflect all anomalies identified during the previous 24hr period and their criticality. Where COABIS is utilised, full details of all anomalies raised are included within the DPR automatically for the previous 24hr period. For DPR clarity, due to the potentially high numbers of anomalies raised, only critical (C1) anomaly reports are to be left in the DPR, with non-critical (C2) anomalies removed and replaced by a statement on how many C2 anomalies were raised for that previous 24hr period. All anomalies are to be included in the final and interim Job Reports issued. The individual anomalies should be updated to reflect any additional information gathered, or remedial action undertaken prior to the Job Report being issued. Examples of critical immediately reportable anomalies for steel jackets, concrete and buoyant structures are listed in brief in the paragraphs ‎2.1.4, ‎2.1.5, ‎2.1.6, ‎2.1.7 and more fully in sections ‎2.2 and ‎2.3 below. 2.1.2

Critical Anomaly Reporting (General) Items falling within the critical category are of two basic types. (1)

Those representing a serious risk to integrity of the installation.

(2)

Those where immediate response will generate a significant cost effective action.

Critical anomalies will be reported via the DPR as above. In addition, or where COABIS is not utilised, the individual C1 anomalies will be sent ashore for review within 24 hours. This report is to be sent once all suitable details have been gathered. These details should include sketches, digital images, video clips (if possible place in Livelink), etc, to suitably establish the nature and extent of the anomaly. Should further investigations be carried out, the subsequent findings are to be updated into the relevant C1 anomaly and redistributed accordingly. Prior to sending of the DPR or above C1 anomaly report, the anomaly text and accompanying data are to be checked for correctness.

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0153-001

The order in which the C1 anomaly is initially reported, via either the DPR or Anomaly Report, is not fixed and will be dependent on when the anomaly is found and data gathered. For all C1 anomalies, or where immediate action or further guidance is deemed to be required, the Shell Offshore Operations Engineer (OOE), should immediately contact the relevant Shell Subsea Operations Engineer (Job Team Leader), or Duty Engineer (for the sector in which operations pertain), dependant on availability. During working hours, the Job Team Leader is to be contacted, who will inform the Shell Sponsoring Engineer, who will report to the Technical Authority, if not the same person. If the Job Team Leader is unavailable, or outside of working hours, the Duty Engineer is to be informed, who will contact the Job Team Leader; Shell Sponsoring Engineer and/or Technical Authority, dependant on availability, severity of the findings and actions required. The Duty Engineer should only give advice, based on suitable knowledge of the systems worked on, or after consultation/referral with the relevant Job Leader, Sponsoring Engineer or Technical Authority (TA) as specified in the workscope. No repair work should be undertaken without suitable instruction within this line of communication. The DPR distribution list will include the operational workscope Job Leader and Sponsor, Offshore Installation Manager (OIM), Operations Supervisor (OS) and the Subsea Maintenance & Intervention department Data Management Controller (UIE-T-PS) as a minimum for the workscopes and installations covered in the relevant 24hr period. As such notification of any C1 anomaly will be supplied to the controlling installation via the DPR for the previous 24hr period. Copies of the C1 anomaly report and any associated data are to be e-mailed directly to the Shell Subsea Maintenance & Intervention department Data Management Controller, Inspection department team, workscope Job Leader, workscope Sponsoring Engineer, relevant Installation OIM and OS. The relevant e-mail addresses are included in the workscope. All C1 anomalies are subsequently held within the COABIS database. Should a C1 anomaly be downgraded offshore (to C2) since its appearance in the DPR, then the Shell Data Management Controller must be notified of its new level of criticality. Should the criticality of a C1 anomaly be downgraded offshore after submission of a C1 report ashore, then all parties previously informed of the report must be notified of its new level of criticality. The above reporting route is documented in Section 2, Chapter 7, Figure 1 – Flow Chart for Work Execution Reporting. The specific C1 anomaly process, report distribution and follow up process is charted in section 2 ‎ .4 below. 2.1.3

Critical Anomaly Reporting (Leaks) In line with the above, the following is required specifically for leak reporting: Where a leak is found, a concerted effort is to be made to identify the exact location of the leak. Identify any associated damage, or other cause. If it is not possible to identify the location of the leak then a statement is to be made in the COABIS report, both anomaly and main, explaining the reason why identification was not possible. This is so that an assessment of the best method of any follow up actions, including inspection by diver can be made. The assumed leak type is to be stated, oil, gas, hydraulic, methanol or other. The rate of leak is to be estimated and suitably described, with sufficient anomaly video footage taken to allow onshore assessment of the rate and location. Take digital still images if appropriate. The anomaly is to state the location of the leak, rate and facility operational status. Provide a suitably annotated drawing to complement the report and any video/images taken. Description of rate is to be restricted to number of bubbles and rate (i.e. x bubbles per/sec, champagne type, constant, intermittent, etc...). No volume estimate is to be made, unless some measuring device has been used.

2-6-4

Am 05 03/12

0153-001

Any leaks identified during the inspection are to be reported to the controlling installation, once sufficient data has been gathered. For UK installations this is to enable the installation to raise a suitable PON1 notification to the appropriate government agency within 6 hours of being informed of the leak. For none UK installations this is again to allow appropriate reporting by the installation to the relevant national authority. This notification should initially be relayed verbally to the installation, with the Critical C1 anomaly report subsequently issued as per 2.1.2 above, with full and accurate details of the anomaly to avoid any miscommunication of the leak details. The Critical C1 anomaly report is to be accompanied by sketches, photos and video as e-mail restrictions allow. This leak data gathering and reporting process is charted in section ‎2.4 below. Should sampling equipment be available, unless otherwise stated in a workscope or Master Anomaly, leak samples are to be taken as follows: 

Where a new gas leak is identified.



For an existing gas leak where no sample has previously been taken.



For fluids where there is doubt as to the composition of the leak substance, i.e. hydraulic, methanol or other.

No crude oil samples are to be taken unless otherwise requested in a workscope. Method of sample delivery ashore including notification is covered under section 2 ‎ .5 below. 2.1.4

2.1.5

2.1.6

Steel Sub-Structures (1)

Missing, torn, buckled, dented, and flooded members.

(2)

Cathodic protection.

(3)

Weld defects, cracks /linear defects.

(4)

Caisson defects.

(5)

Talon Joints

(6)

Scour

Concrete Sub-Structures (Brent Bravo, Charlie and Delta) (1)

Spalling of concrete exposing internal steel reinforcement through impact or other reasons.

(2)

Crack-like opening of construction joints.

(3)

Scour.

(4)

Tubular steel conductor guide frames anomalies as Steel Sub-Structures.

Risers (1)

Significant physical damage, missing/loose clamps, relative movement and leaks.

(2)

Cathodic protection.

(3)

Corrosion.

(4)

Scour.

Am 05 03/12

2-6-5

0153-001 2.1.7

2.1.8

Buoyant Structures (FPSO’s) (1)

Buckling/distortion of steel shell components of any large diameter hulls.

(2)

Excessive wear/abrasion/mechanical damage to individual chain links to tether system and anchor piles.

(3)

Deterioration of concrete anchor blocks as indicated by cracking and spalling.

(4)

Items (1) to (5) of Paragraph 2 ‎ .1.3 and Items (1) to (3) of Para 2‎ .1.5 are also applicable.

Existing Anomalies It must be noted that at this stage in the operational life of Shell's installations, there exists a large number of previously identified, apparently serious defects, which have been evaluated and do not affect the fitness for purpose of the installation. COABIS contains details of these anomalies within a Master Anomaly database, which gives instruction on what actions to take when encountered.

2.2

Anomaly Reporting and Limits – Steel and Concrete Structures

2.2.1

Index of Terms

2-6-6

C1

Category One Reporting

C2

Category Two Reporting

AW

Anode Wastage

BU

Burial

CA

Caissons

CD

Coating Damage

CC

Concrete Condition

CW

Chain Wear

CP

Cathodic Protection

CR

Corrosion

DB

Debris

FM

Flooded Members

KS

Kenter Shackle

LI

Lack of Integrity

LK

Leak

MG

Marine Growth

PD

Physical Damage

RM

Relative Movement

SC

Scour

SD

Shell Distortion

TC

Talon Connector

VS

Variance from Specification

WD

Weld Defect

WT

Wall Thickness

Am 05 03/12

0153-001 2.2.2

2.2.3

2.2.4

Anode Wastage (1)

Components.

Sacrificial anodes.

(2)

Anomaly.

Wastage 90% (C2).

(3)

Action.

Take Proximity Reference CP’s at anode and protected steel near to anode. Assess wastage, video and digital images. Where possible provide dimensions of anode material (l x w x d).

(4)

Checks.

DB, CR, PD, other assignable causes.

Burial (1)

Component.

Tubular framing members.

(2)

Anomaly.

Any (C2).

(3)

Action.

Record % cover. Record depth at top of burial referenced to a known datum, and depth of burial if this can be calculated.

(4)

Checks.

DB, PD.

Caissons (1)

Components.

Firewater, service water, cuttings.

(2)

Anomaly.

Any visible cracks/holes (C1). In particular such areas are likely to occur at the location of the pumps. WT loss due to internal pump corrosion  50% of nominal thickness (C2). Wear due to relative movement within clamp / guide  20% (C2). Any debris blocking inlets. Marine growth cover  30% (C2).

(3)

Action.

For wear at clamp/guide - Determine range of movement relative to a fixed datum; estimate/determine WT loss; take CP’s; video and digital still images. Clean as necessary. For WT loss at pump - increase standard WT readings local to areas of loss 50%. Clean & DVI same areas (See Standard Procedure I-43-001). Record and dimension anomaly boundaries. For blockage 30% - Clear inlets (obtain permission of platform).

(4) 2.2.5

Checks.

Clamps/guides – WT, RM, LI clamps/guides and primary structure attachments. At Pump - WT, CR.

Cathodic Protection (1)

Components.

All structural members, caissons, sacrificial anodes.

(2)

Anomaly.

On steel components  -650mV (C1). Between –650mV and –800mV (C2). -1150mV (C2). On sacrificial anodes, outside of the range –900mV to –1150mV (C2).

(3)

Action.

Confirm bonding, identify anomalous reading boundaries, look for causes, video.

(4)

Checks.

CR, DB, AW, LI, other assignable causes.

Am 05 03/12

2-6-7

0153-001 2.2.6

Chain (1)

Components.

Anchor chains/Chain Stoppers.

(2)

Anomaly.

Loss of link diameter 0-20% (C2). Loss of link diameter 20%, cracking (C1). Loss of link stud, Kenter Link plug, rock/debris contacting chain (C2).

2.2.7

2.2.8

2.2.9

2.2.10

2-6-8

(3)

Action

Dimension, protect from further wear, video.

(4)

Checks.

PD, DB, CW, KS, other assignable causes.

Coating Damage (1)

Components.

All.

(2)

Anomaly.

Any significant coating damage to a component (C1/C2 as deemed necessary). Bare metal exposure with significant pitting corrosion C1.

(3)

Action.

Determine nature i.e. abrasion, coating breakdown (blistering), exposure of primer or exposure of bare metal. Where required condition of exposed bare metal i.e pitting, corrosion. Record position from selected datum; take dimensions (l x w x d); video and digital images.

(4)

Checks.

DB, CR, CP, assignable causes.

Concrete Condition (1)

Components.

All on gravity platform.

(2)

Anomaly.

Concrete spalling (C2) Concrete spalling about embedment plates (C1). Cracks 1mm (C2) >1mm (C1). Other blemishes categorised in accordance with OTH 84 206 & OTH 87 261 (C2).

(3)

Action.

Record extent of anomaly. Reference defect to known datum/attachment. Measure area and depth of loss of cover. Record orientation, length, width and depth of cracks and mark up limits for future monitoring. Video and digital images. Extend inspection outside any set area to fully define defect.

(4)

Checks.

DB, PD.

Corrosion (1)

Components.

All except sacrificial anodes and debris.

(2)

Anomaly.

Pitting 2mm deep (C2).

(3)

Action.

Dimension, note density of coverage, surface profile, pit gauge readings on pitting, WT readings covering area using a 25mm grid, minimum area to be inspected 100mm sq. Video and digital images.

(4)

Checks.

AW, DB, CP, WT.

Debris (1)

Components.

All.

(2)

Anomaly.

Hazardous to divers, in contact with risers/structure, causing damage, abrasion etc., blocking inlets, video remaining debris, (C2).

(3)

Action.

Determine type, quantity and position, check for damage and take CP’s. Remove if a diver/ROV hazard. Video on completion of removal, checking for any associated damage.

(4)

Checks.

PD, CR, CP.

Am 05 03/12

0153-001

2.2.11

2.2.12

Flooded Members (1)

Component.

Tubular members.

(2)

Anomaly.

Members not designated, as being flooded and therefore not reflecting design intent, or not having previously been identified as being flooded. (C1).

(3)

Action.

Check flooding in associated members. GVI member, with particular attention to the end welds, for any evidence of gross defect, or other possible cause. Any further inspection requirements, i.e. weld ACFM/MPI, to be requested by Sponsoring Engineer, based on C1 anomaly raised.

(4)

Checks.

PD, LI, (WD).

Lack of Integrity (1)

Components.

All.

(2)

Anomaly.

Any on caisson (C1). Missing/severed members, missing clamps (C1). Missing/loose bolts/clamps, misalignment (C2). Missing/damaged anode/anode segment, continuity cable, not associated with AW (C2).

(3)

Action.

Quantify and determine nature, i.e. missing/loose. Determine position from selected datum, take CP’s, video, digital images. For missing bolts, check size, replace if possible.

(4) 2.2.13

2.2.14

Checks.

PD.

Leaks (1)

Components.

Any.

(2)

Anomaly.

Any Leaks (C1).

(3)

Action.

As per section 2.1.3 above.

(4)

Checks.

PD, LI.

Marine Growth (1)

Components.

Steel members, Caissons and Appurtenances.

(2)

Anomaly.

NNS & CNS - Hard growth >50mm (C2) ONEgas West – Hard Growth >50mm for below –6m, >125mm for –6m and above (C2). ONEgas East – Hard Growth >50mm (C2) Exception – AME-2 300mm (C2). Soft marine growth >150mm (In the case of anemones, when not feeding/extended), and/or long filamentous growth, seaweed or kelp >1m (C2).

2.2.15

(3)

Action.

Note type of marine growth, percent cover and approximate extent (depth range), or other as specified in workscope.

(4)

Checks.

None.

Physical Damage (1)

Components.

All.

(2)

Anomaly.

Any significant impact damage to a component (C1/C2 as deemed necessary).

(3)

Action.

Determine nature i.e. abrasion/deformation/fracture. Determine position from selected datum; take dimensions (l x w x d); video and digital images.

(4)

Checks.


Am 05 03/12

2-6-9

0153-001 2.2.16

Relative Movement (1)

Components.

(a)

Clamps, (b) Conductor Guides (c) Caissons/Conductors.

(2)

Anomaly

(a)

Any movement within restraining clamp/guide (C2). Not anomalous where there is a designed gap between clamp/guide and caisson/conductor.

(b)

Any movement with associated significant PD or WT loss  20% (C2).

(c)

See Caisson anomaly criteria ‎2.2.4 for (C1) definition.

(a)

Determine range of movement relative to a fixed datum, check bolts, take CP’s, video and digital images. Clean as necessary.

(b)

Determine range of movement. Give details of WT loss. Check guide barrel, diaphragm plate and associated welds for signs of damage/cracking (Historically the bottom of the guide barrel is susceptible). Clean as specified by Shell QA/QC. Video and Digital images.

(c)

See Caisson anomaly criteria, ‎2.2.4.

(3)

(4) 2.2.17

Action

Checks.

PD, LI, WT & CP.

Scour (1)

Components.

Caisson bases, mudmats, pile cluster bases, legs.

(2)

Anomaly.

Local loss of soil-pile contact and global seabed movement 3m (SNS) (C1), 2m (CNS, NNS) (C1) Exemptions: (ONEgas East) AWG-1C

0.00 m

AWG-1 W

3.25 m

AWG-1 R

3.35 m

AME-2

5.00 m

K14-FA-1V

5.00 m

K17-FA (Monotower) 6.00 m L9-FA (Monotower) 6.00 m L9-FB (Monotower) 6.30 m L9-FF-1W

5.00 m

Exemptions: (ONEgas West) QC (Cutter - Monotower)

3.10 m

QR (Caravel - Monotower)

2.50 m

QS (Shamrock - Monotower) 2.50 m (3)

Action.

Determine extent, dimension (d x w), video and digital images, as per I-06-001.

(4)

Checks.

Extent of pile exposure; CP exposed pile & pile sleeve Note: Pile exposure on its own is not anomalous.

2-6-10

Am 05 03/12

0153-001

2.2.18

Talon Connector (1)

Components.

Relevant conductors.

(2)

Anomaly.

Any indication of rotational movement  25mm (C1) Any indication of rotational movement  12mm (C2) Any indication of cracks or damage to box (C1) Any misalignment, e.g. - visible opening of the interface of the talon joint (C1) Average readings of 4; 15-29.9 micro ohms (C2)  30 micro ohms (C1) Any indication of rotational movement  12mm and 15-29.9 micro ohms (C1)

(3)

Action.

(C1) rotational movement - measure rotation. Complete actions as per workscope & standard procedure I-49-057.

(4) 2.2.19

2.2.20

2.2.21

Checks.

RM, CR.

Variance from Specification (1)

Component.

Any.

(2)

Anomaly.

Any (C2).

(3)

Action.

Sketch accurately, measure dimensions and distance from specified datum, video, (update UMDB/COABIS onshore).

(4)

Checks.

LI.

Wall Thickness (1)

Component.

Structural members.

(2)

Anomaly.

 20% loss (C2).

(3)

Action.

Map area of low WT.

(4)

Checks.

CR, PD, FM.

Weld Defect (1)

Components.

All welds.

(2)

Anomaly.

Crack/linear indication (C1). Other defects (C2).

(3)

Action.

Crack/linear indication. Confirm length and depth of crack/linear indication using ACFM. On completion measure distance to start of defect from datum point, video and digital image. Grinding up to 5% of nominal WT (or 2mm maximum) to remove surface defects is permitted without approval. Grinding to a greater depth shall be approved by the Structural TA.

(4)

Am 05 03/12

Checks.

CR, PD and previous grinding.

2-6-11

0153-001

2.3

Anomaly Reporting and Limits – Risers, J-Tubes, Pipelines and Umbilicals

2.3.1

Index of Terms

2.3.2

2.3.3

2.3.4

C1

Category One Reporting

C2

Category Two Reporting

AW

Anode Wastage

BU

Burial

CD

Coating Damage

CP

Cathodic Protection

CR

Corrosion

DB

Debris

LI

Lack of Integrity

LK

Leak

MG

Marine Growth

PD

Physical Damage

RM

Relative Movement

SC

Scour

WT

Wall Thickness

Anode Wastage (1)

Components.

Sacrificial anodes.

(2)

Anomaly.

Wastage 90% (C2).

(3)

Action.

Take Proximity Reference CP’s at anode and protected steel near to anode. Assess wastage, video and digital images. Where possible provide dimensions of anode material (l x w x d).

(4)

Checks.

DB, CR, PD other assignable causes.

Burial (1)

Component.

Risers, J-Tubes, Pipelines and Umbilicals.

(2)

Anomaly.

Any (C2).

(3)

Action.

Record % cover. Record depth at top of burial, referenced to a known datum, and depth of burial if this can be calculated.

(4)

Checks.

DB, PD.

Cathodic Protection (1)

Component.

All risers, clamps and sacrificial anodes.

(2)

Anomaly.

On steel components  -650mV (C1). Between –650mV and –800mV (C2).  -1150mV (C2). On sacrificial anodes, outside of the range –900mV to –1150mV (C2).

2-6-12

(3)

Action.

Confirm bonding, identify anomalous reading boundaries. Look for causes, video.

(4)

Checks.

CR, DB, AW, LI, other assignable causes.

Am 05 03/12

0153-001 2.3.5

Coating Damage (1)

Components.

All.

(2)

Anomaly.

Any significant coating damage to a component (C1/C2 as deemed necessary). Bare metal exposure with significant pitting corrosion C1.

(3)

Action.

For risers, spools etc - Determine nature i.e. abrasion, coating breakdown (blistering), exposure of primer or exposure of bare metal. Where required condition of exposed bare metal i.e pitting, corrosion. Record position from selected datum; take dimensions (l x w x d); video and digital images. For concrete coated pipelines - Determine nature i.e. crack, spalling etc. exposure of rebars, underlying corrosion coating, pipe parent metal. Record position from selected feature datum; take dimensions (l x w x d); video and digital images. Note bitumen filled field joints are not to be reported as damaged unless parent pipe metal is exposed and field joint cladding is not to be reported as coating damage, although where the cladding is a ROV hazard it is to be reported under debris.

(4) 2.3.6

2.3.7

2.3.8

2.3.9

Checks.


Corrosion (1)

Components.

All riser, J-tube, pipelines, other pipework.

(2)

Anomaly.

Pitting 1mm deep (C1).

(3)

Action.

Dimension, note density of coverage, surface profile, pit gauge readings on pitting, WT readings covering area using a 25mm grid, minimum area to be inspected 100mm sq. Video and digital images.

(4)

Checks.

AW, DB, CP, WT.

Debris (1)

Components.

All.

(2)

Anomaly.

Hazardous to divers, in contact with risers/structure, causing damage, abrasion etc. (C2).

(3)

Action.

Determine type and quantity, determine position, remove as a minimum all metallic debris in contact with steelwork/anodes. Remove if a diver/ROV hazard. Video on completion of removal, checking for any associated damage.

(4)

Checks.

PD, CR, CP.

Lack of Integrity (1)

Components.

All.

(2)

Anomaly.

Missing clamps (C1). Missing loose bolts/loose clamps, misaligned (C1). Missing/damaged anode/anode segment (C2).

(3)

Action.

Determine nature i.e. missing/loose. Determine position from selected datum, tighten and/or replace bolts, check size, video, digital images.

(4)

Checks.

Any.

Leaks (1)

Components.

Any.

(2)

Anomaly.

Any leaks (C1) apart from leaks flexible end connection from vent ports. Leaks from flexible end connection vent ports, are considered ‘Not Anomalous’, unless rate is significant indicating non-designed leakage.

Am 05 03/12

2-6-13

0153-001

(3)

Action.

As per section 2.1.3 above. Where leak seen from a flexible end connection vent port, positively confirm this to be the case; clean as required. Make comment in Job Completion Report, not in anomaly report, unless rate is significant indicating nondesigned leakage. Take suitable video and digital still images (if appropriate).

(4) 2.3.10

Checks.

PD, LI.

Marine Growth (1)

Components.

Risers and J-Tubes.

(2)

Anomaly.

NNS & CNS - Hard growth >50mm (C2) ONEgas West – Hard Growth >50mm for below –6m, >125mm for –6m and above (C2). ONEgas East – Hard Growth >50mm (C2) Exception – AME-2 300mm (C2). Soft marine growth >150mm (In the case of anemones, when not feeding / extended), and/or long filamentous growth, seaweed or kelp >1m (C2).

(3)

Action.

Note type of marine growth, percent cover and approximate extent (depth range), or other as specified in workscope. Take suitable video and digital still images (if appropriate).

(4) 2.3.11

2.3.12

2.3.13

2-6-14

Checks.

None.

Physical Damage (1)

Components.

All.

(2)

Anomaly.

Any significant impact damage to a component (C1/C2 as deemed necessary).

(3)

Action.

Determine nature i.e. abrasion/deformation/fracture. Determine position from selected datum; take dimensions (l x w x d); video and digital images.

(4)

Checks.


Relative Movement (1)

Components

Risers, J-Tubes, clamps and riser elbow/pipelines; Guides.

(2)

Anomaly.

(a)

Apart from Guides (see below), Any Movement (C1).

(b)

Not anomalous where there is a designed gap between Riser/J-Tube and the guide, unless there is associated significant PD or WT loss 20% (C2).

(3)

Action.

Determine range of movement relative to a fixed datum, check bolts, take CP’s & video. Take Digital images where associated PD, WT visible. Where divers available, measure depth & area of any associated wear.

(4)

Checks.

PD, LI, CP, WT.

Scour (Pipeline) (1)

Components.

Risers, J-Tubes and Pipelines.

(2)

Anomaly.

10m of suspension from elbow/tie-in flange, or any subsequent 10m suspension (C1).

(3)

Action.

Check for possible associated damage. Measure length of suspension (position fix), obtain maximum and average suspension heights (See procedure I-60-003). If suspension at elbow/flange, obtain height of suspension and depth of seabed, relative to a known datum.

Am 05 03/12

0153-001

(4) 2.3.14

Checks.

PD, RM.

Scour (Igloos) (1)

Components.

Igloo Structure.

(2)

Anomaly.

Gaps 150mm in height, occurring within or encroaching within 1500mm of any corner (C2). Gaps 300mm in height, occurring within or encroaching within 1500mm of any corner (C1). Gaps of area (height x depth) 0.75sq.m, not extending within 1500mm of any corner (C2). Gaps of area (height x depth) 1.0sq.m, not extending within 1500mm of any corner (C1).

(3)

Action.

Check for possible associated damage. Give lengths, heights and location of scour on a suitable drawing. Take video and digital images. Block with grout bags, if the vessel has immediate remediation capability.

(4) 2.3.15

Checks.

PD, RM.

Scour (Wellheads) (1)

Components.

Wellheads.

(2)

Anomaly.

Scour 1.0m from mean seabed level (C2). Any lack of support to flowline at touchdown from as-built (C2).

(3)

Action.

Give depth and distance out from conductor of scour bowl relative to mean seabed. Supply suitable profile drawings on two 90 planes, video and digital images. Check for possible associated damage, i.e. jumper connections due to increased strain. Check any spools/jumpers for lack of support. Obtain unsupported height and length out from tie-in flange or base of gooseneck. Block with grout bags, if the vessel has immediate remediation capability.

(4) 2.3.16

Checks.

PD, LI, RM.

Wall Thickness (1)

Components.

Risers, J-Tubes, pipework & appurtenances.

(2)

Anomaly.

10-20% loss of nominal (C2). 20% loss (C1). Any lack of support to flowline at touchdown from as-built (C2).

(3)

Action.

Map area of low WT.

(4)

Checks.

CR, PD.

Am 05 03/12

2-6-15

0153-001 2.4

Critical (C1) Anomaly Process VESSEL SHELL REP

ONSHORE DATA MANAGEMENT CONTROLLER (UIE/T/PS)

INSTALLATION OIM/OS

INSPECTION DEPARTMENT (UIE/T/PS)

OTHERS (See Action)

STEP

C1 (CRITICAL ANOMALY PROCESS

1

C1 Anomaly found during Offshore Operations. Anomaly raised in COABIS

Report to Shell QA/QC. Shell QA/QC to inform Vessel Shell Rep

2

Carry out investigation and gather data to obtain full details of anomaly, as per 0153-001, Section 2, Chapter 6 and as agreed with Shell QA/QC

Clean as necessary. Obtain video clips, still images, and create sketches/drawings to fully illustrate anomaly details.

3

C1 Anomaly is leak of fluid / gas

Vessel Shell Rep to inform controlling installation OIM/OS of leak as soon as possible, providing sufficient information for installation to issue a PON1 to DECC (required within 6hrs of notification), i.e. Leak type and rate.

4

C1 Anomaly included in Vessel Daily Progress Report (DPR). (Note step 4 and 5 order may swap)

Anomalies are automatically generated within the DPR produced by COABIS. Any anomaly is to be checked for accuracy by the QA/QC prior to DPR production/distribution.

5

C1 Anomaly Reporting Onshore within 24 hours of identification (Step 1). (Note step 4 and 5 order may swap)

Vessel QA/QC e-mails C1 anomaly onshore to the following: Data management Controller (UIE/T/PS), Job Lead, Job Sponsor, U/W Inspection Department (UIE/T/PS). Vessel QA to place any video clips in designated Livelink 'Vessel Data Transfer' area

6

Data Management Controller distributes to agreed additional personnel not included in step 5.

To include Principal Well Integrity Engineer (PWIE - TA1) of any well issues. Any additional personel to be confirmed by Job Lead/Sponsor, or, responsibility of Job Lead/Sponsor to distribute as required. No request is to be made of the Vessel QA/QC to distribute.

7

Job Lead confirms C1 to sponsor, and/or asset focal point and formulates action plan

Job Lead/Sponsor to discuss with others as necessary, who may include: Subsea Assett Focal Points (UIE/T/PS), Asset Focal Point, PWIE, relevant TA, others...

8

For any additional information gathered, or follow-up actions carried out, COABIS anomaly to be updated.

Update anomaly with actions carried out and resulting outcome.

9

Repeat steps 5 and 6 if required by step 8.

Distribute anomaly as required.

Anomaly Review

COABIS Anomaly review to be overseen by relevant UIE/T/PS Inspection dept. personnel. Review to include relevant personnel, which may include the Job Lead, Job Sponsor, Subsea Asset Focal Points (UIE/T/PS), Asset Focal Point, PWIE, relevant TA, others... COABIS anomaly either Closed, or Master Anomaly created.

10

CONTRACTOR

VESSEL QA/QC

JOB LEADER

JOB SPONSOR

ACTIONS

Required action to be carried out by. Key Persons required to be included in the process step

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2.5

Leak Sample Notification and Delivery Ashore For UK related leak samples, or unless otherwise instructed for work outside the UK, the sample is to be returned to the Shell Production Chemistry Laboratory (Tullos, Aberdeen), packed in a suitable transfer case. Notification of delivery is via the Sample Analysis Request (SAR) form. An example for how to complete this form is shown below (figure 1), with a blank form provided on the next page (figure 2). Electronic versions are held Livelink, in the USC Workscope Development area, Standard Appendices, Leak Sampling folder. An electronic copy of this form is to be e-mailed to the addressees on the form (E-mail SAR to), notifying them of the delivery of the sample. A copy of the form is also to accompany the sample. Should the sample be sent ashore via an appropriate installation, prior agreement is to be made with the installation. E-mail the SAR form to the installation, notifying them of the sample contents.

Figure 1

Am 05 03/12

Example Sample Analysis Request (SAR) Form

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Figure 2

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Blank Sample Analysis Request (SAR) Form

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SECTION 2 CHAPTER 7 REPORTING CONTENTS Para

Page

1 1.1

REPORTING - MSV/DSV ACTIVITIES Reporting Requirements

3 3

2 2.1 2.1.1 2.1.2 2.1.3 2.1.4 2.1.5 2.1.6 2.1.7 2.1.8 2.1.9 2.1.10

JOB COMPLETION REPORT Report Structure Introduction Section 1 - Introduction Section 2 - Job Completion Summary Section 3 - Anomaly Summary Section 4 - Daily Summary Section 5 - Video Logs Section 6 - Digital Image Logs Section 7 - Anomaly Details Section 8 - Drawings Section 9 - Appendix (or Results)

4 4 4 4 4 5 5 6 6 6 6 7

3 3.1 3.2

ELECTRONIC FILE NUMBERING Introduction Numbering System

7 7 8

4 4.1 4.2 4.2.1 4.2.2 4.3 4.3.1 4.3.2 4.4

VIDEO RECORDINGS Introduction Recordings Standard Overlay Page 1 Standard Overlay Page 2 Overlays Diver ROV Labelling and Numbering

8 8 8 9 9 9 9 9 9

5 5.1

DIGITAL IMAGE REPORT Digital Images

10 10

6

JOB CLOSEOUT NOTE

11

FIGURES 1

Flow Chart for Work Execution Reporting

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CHAPTER 7 REPORTING 1

REPORTING - MSV/DSV ACTIVITIES Consistency, accuracy and completeness of inspection and intervention records is extremely important as the information provided will become part of the Subsea Operations Departments Component Oriented Anomaly Based Inspection System (COABIS). All irregular findings or critical anomalies are to be immediately reported. This may be either via the Shell Subsea Operations Engineer (Job Team Leader) or Shell Duty Engineer (for the sector in which operations pertain), who will inform the relevant Shell Sponsoring Engineer/Technical Authority. The specific reporting route will depend on the severity of the anomaly in question. The correct method of reporting is given in Section 2, Chapter 6 - Anomaly Reporting & Criteria, and as shown below in Figure 1 - Flow Chart for Work Execution Reporting.

1.1

Reporting Requirements Reports are to include all work carried out by the vessel. Additional reports may be requested to cover specific activities such as special projects, top side construction etc. Such reports will be defined at the time they are requested. The report shall be submitted to the Onshore Data Management Controller and Sponsors, - Northern Business Units, - Southern Business Unit, as appropriate. Interim Report

Will be compiled on all ongoing works which, due to operational requirements, have a break in the work programme exceeding 14 days, or as otherwise agreed.

Final Report

Will be compiled for all completed works, works, which are deemed complete by sponsor and at year end irrespective of work completion.

Reports are to be compiled, with one signed copy submitted to the Shell Onshore Data Management Controller within 14 days. The format to be adopted is as detailed in point 2. Where COABIS is utilised the report is automatically compiled in this format. All referencing and reporting shall follow the COABIS format, comprising Cost Code (Procedure/Workscope number - See Section 1, Chapter 1, Point 7.2), Component Task (See Section 2, Chapter 4, Point 2) and Component Numbering System (See Section 2, Chapter 5, Point 2.2). Special attention shall be paid to the final presentation of the report, its accuracy, completeness of all references within the Component Task Sheet (CTS) system and all relevant details such as job summaries, diagrams, videos, digital images, ‘As-built’ data, Procedure Changes and Sub-contractors reports. These details are to be checked by the Shell QAQC/Coordinator, prior to distribution to the Shell Offshore Operations Engineer (OOE), Contractors Offshore Construction Manager / Offshore Manager who will further check the report to confirm its completeness.

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2

JOB COMPLETION REPORT

2.1

Report Structure The Job Report is to adopt the format as specified in the sections below. This report format is to be used for all IMR and Project works carried out. Any of the sections listed below which are not required, may be omitted from the Job Report. The report is to be bound, front and back by gold card for Final reports, and by blue card for Interim reports. These covers are supplied by the Shell Onshore Data Management Controller. Interim reports are required for workscopes/procedures which have not been completed, but where further work will be carried out. If no further work is to be carried out by the vessel that last worked on the procedure, then an Interim report is required from the vessel. If a vessel is to return to carry out further works on a procedure, then the requirement for an Interim report on completion of the earlier works will depend on the time interval between the two interventions. This decision will be made by the Shell Offshore Representative, or as advised by the Job Leader. Where COABIS is utilised the Job Report is automatically generated by the COABIS System. Where this is the case, all information, with the exception of the Introduction Section, is entered into COABIS before the Report is generated. Where other electronic files are referenced in the Job Report, these files must be issued along with the Job Report. See Point 3 – Electronic File Numbering.

2.1.1

Introduction The report is sectioned as follows:

2.1.2

SECTION 1

Title Page, Contents and Introduction

SECTION 2

Job Completion Summary, by CTS number

SECTION 3

Anomaly Summary, and listing by CTS number

SECTION 4

Daily Summary, details in full by CTS number

SECTION 5

Video Logs

SECTION 6

Digital Image Logs, Digital images - colour prints

SECTION 7

Anomaly Details

SECTION 8

Drawings

SECTION 9

Appendix and/or Results

Section 1 - Introduction This should be a brief description of the work carried out. State whether the report is an Interim (blue cover) or Final (gold cover) and give the start and end dates of the work. It shall also list the following: Name of Installation, Name of Contractor(s), Name of Vessel(s), Job Title and Job Number.

2.1.3

Section 2 - Job Completion Summary This Section gives a précis job completion summary of all Workpacks (CTS’s) raised under the Job Number (Cost Code), including a brief description of any outstanding work and reason for noncompletion, including any remedial work. Any CTS not started requires to be listed, with a statement as to why.

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2.1.4

Section 3 - Anomaly Summary This section gives a complete summary listing of all anomalies, by anomaly number. Each entry is to include CTS, Anomaly number, Criticality, Anomaly Type, Component Number, Video Reference and précis description of the anomaly, i.e. 'Excessive debris & Anode wastage', 'Crack like indication'.

2.1.5

Section 4 - Daily Summary This is a daily diary of events carried out during the workscope operations. The summary is listed in order of CTS and date. References should be made to any relevant documentation raised during the operation, i.e. Change to Procedure documents, Pressure Test results raised, etc. Hard copies of any such document, including signatures, are to be included in the Appendix section of the report.

2.1.5.1

Inspection Workscopes For inspection workscopes, the daily summaries shall consist of a brief summary of the work carried out each day. A summary status of any readings taken may also be included and any other pertinent facts that may illustrate any problems encountered or achievements during the operations. Any outstanding tasks requested should be listed. A typical entry is as follows: DVI of the –20m CGF guides 35-107, 35-110 and 35-120 were completed by diver. From this survey, physical damage was identified at guide 35-107, with all other guides free from defect. For further details of the anomaly, see the referenced anomaly report. Reference

Video Tape Anomaly Report Drawing Digital Image Log

BA/VSL2004-01 BA/VSL2004-03 BA/VSL2004C101-01-01 BA/VSL2004-01, Digital Images 01, 02 & 03.

The required Wall thickness (WT) readings were outstanding and will be carried out at a later date. The ROV completed the GVI of the –20m CGF. No physical defects were identified. Scaffold debris was found during the survey, with no associated damage. Reference

Anomaly Reports

BA/VSL2004-05, 06 & 07

CP readings ranged between –950mV and –1002mV. Full details are contained within the Results section of this report. Marine growth levels were within specification. Full details are contained within the Results section of this report. Reference

Video Tape Results

BA/VSL2004-02 CP & Marine Growth Listings

Detailed results should not be entered in the summary. These should be presented, if necessary, in Section 9 (Results) and/or Section 8 (Drawings). 2.1.5.2

Construction Workscopes For construction workscopes, a detailed summary is required explaining clearly actions taken, problems encountered, remedial actions, reasons for any deviations from procedure, any relevant timings and platform assistance. The information should be succinct, with repetitive activities, i.e. bolt tensioning, described only once unless carried out in a different manner, apart from references to the likes of final tensioning pressures, and serial numbers, which may or may not differ.

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All valve and commissioning activities will be recorded, including numbers of turns and torque settings. Serial numbers and module addresses of any pertinent equipment installed, i.e. chokes, SCM’s and gaskets shall be included. 2.1.6

Section 5 - Video Logs Logs are to be listed in video log order. Each video log header should contain the Video Tape number, Platform/Facility name, Tape Title, start/end dates, and Vessel name. Operations conducted under different workscopes cannot be recorded on the same video tape. However, any combination of workscope CTS’s may be recorded on the same tape. This change in CTS must be clearly identified on the video log. Each video log line entry should include the video clip start/end times, component ident, and CTS number as a minimum. See also Point 4 – Video Recordings. For inspection workscopes, no text description (Narrative) is required for a section of video, unless the video recording is pertinent to a defect, or to highlight other relevant information such as poor visibility, restricted access, etc. For construction workscopes, the narrative should contain pertinent comments relative to the actions recorded, i.e. as-found survey, valve operations, gasket insertion, etc.

2.1.7

Section 6 - Digital Image Logs Photographic colour negatives are no longer to be used for Shell EPE operations. Digital Images/Stills is the preferred medium. For this reason one Digital Image Log is to be utilised per workscope, as opposed to a different Digital Image Log per CTS. Logs are to be listed in Digital Image Log order then image number. Each image listing is to contain the component number of the relevant subject, associated CTS and any associated anomaly number. A brief description of each image is required. The numbering system for digital images is to be adopted whereby the image is automatically associated with the Job Number, CTS and image number. This numbering system is reported under Point 3 – Electronic File Numbering. See also Point 6, Digital Image Report. Colour prints of each image are to be submitted with the issued hard copy of the report within this section of the report, following the Digital Image Log, accompanied by the relevant ident per image. A maximum two images per page are required.

2.1.8

Section 7 - Anomaly Details This Section is a detailed listing of all anomalies by CTS, then anomaly number. Details for each anomaly are to include, Criticality, Date of Identification, Component Number plus component description, Anomaly Type(s), Video and Digital Image Log Reference and a full description of the anomaly. The description of the anomaly is to include all details as required by the anomaly criteria, as specified in Section 2, Chapter 8, Points 2.2 and 2.3.

2.1.9

Section 8 - Drawings This Section should list any drawings that have been created. These can be AutoCAD drawings, or scanned sketches. All drawings / sketches must be printed and included within this section of the report.

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2.1.10

Section 9 - Appendix (or Results) This section is to include all data referenced within the Daily Summary, not included within the previous sections of the report. The title of this section can be amended as required or, additional sections created, pertinent to the documents to be contained within the report, i.e. Appendix – Pressure Test Charts, Results – PEC.

2.1.10.1 Inspection Workscopes The section should contain referenced Change Instructions and any results that have been requested in the Scope of Work, or that are required as per any Standard Procedure used. The type of results to be included are as follows:•

Marine Growth Survey Data - results listing;

•

Cathodic Protection - results listing or Standard form (See I-60-004);

•

ACFM - Listing of ACFM files and any graphical representations (See I-15-001);

•

MPI (See I-15-001);

•

PEC results (print out of PEC 2D graphics);

•

Other miscellaneous.

Alternatively, some results may be included in any drawings produced for Section 8. Where the above results are contained on an electronic file, i.e. MG, CP, PEC & ACFM, these are files are to be submitted along with the report. Where possible a system of numbering is to be adopted whereby the files are automatically associated with the Job Number and CTS. The numbering system to be adopted for these different files is reported under point 3 – Electronic File Numbering. 2.1.10.2 Construction Workscopes The section should contain hard copies (signed where applicable) of any relevant documentation raised during the operation, i.e. Change to Procedure documents, Pressure Test results raised, etc. If Shell EPE so requires, specialist sub-contractors may submit reports in addition to the computerised data. Any such reports will be summarised and referenced in the relevant summary and included in Section 9. 3

ELECTRONIC FILE NUMBERING

3.1

Introduction Where electronic files accompany a Job Report, each file requires a unique identifier. The numbering system adopted should reflect a combination of the following attributes: File Type, Platform/Facility, Vessel, Year, Job Number, CTS, then an incremental numbering system.

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3.2

Numbering System The following lists the numbering system that is to be adopted for each individual type of file: •

Job Report:

AA2005C101

(Platform/Year/Last 4 Digits of Job Number) This is the same as the job number. •

Drawing Number:

DWG-AAVSL2005C101-02-01

(File Type-Platform/Vessel Code/Year/Last 4 Digits of Job Number-CTS-Sequential Number) •

Digital Image No.:

PH-AAVSL2005C101-03-01-02

(File Type-Platform/Vessel Code/Year/Last 4 Digits of Job Number-CTS-Log No.-Image No.) •

Change Instruction:

CI-AAVSL2005C101-01

(File Type-Platform/Vessel Code/Year/Last 4 Digits of Job Number-Sequential Number) •

Closeout Report:

COR-AAVSL2005C101

(File Type-Platform/Vessel Code/Year/Last 4 Digits of Job Number) •

Miscellaneous Files:

MISC-AAVSL2005C101-01 (Other documents not covered above)

(File Type-Platform/Vessel Code/Year/Last 4 Digits of Job Number- Sequential Number) •

Cathodic Protection Results

CP-AAVSL2005C101-01

(File Type-Platform/Vessel Code/Year/Last 4 Digits of Job Number-CTS) •

Marine Growth Results

MG-AAVSL2005C101-01

(File Type-Platform/Vessel Code/Year/Last 4 Digits of Job Number-CTS) Other inspection software files, such as PEC generate their own file numbering system, which is unique. 4

VIDEO RECORDINGS

4.1

Introduction Video recordings are to be made on Super-VHS colour cassette for the original master tape. One copy is to be supplied on S-VHS. Additional copies or, compilation tapes may be required on either S-VHS or VHS, as requested, on an ad-hoc basis.

4.2

Recordings Video standards are to comply with those stated in Section 1, Chapter 3 (Equipment), Point 1.6, and as stated in the contractual agreement. The narrative is to be recorded on channel one only, leaving second channel clear for dubbing purposes. The first 45 seconds of the tape is to be left blank. Immediately after, the description of the contents of the videotape is to be verbally recorded, whilst simultaneously displayed in the form as given for page 1 shown below. Prior to operations being recorded against each new CTS, the description of the contents of the ensuing section of video tape is to be verbally recorded, whilst simultaneously displayed in the form as given for page 2 shown below.

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4.2.1

Standard Overlay Page 1 Shell Expro - Vessel (name) Contractor: Tape No: Job No: Title: Time and date to be superimposed on the video without obscuring the subject matter.

4.2.2

Standard Overlay Page 2 CTS Number: Component No: Task Description: Depth Range: Time and date to be superimposed on the video without obscuring the subject matter.

4.3

Overlays Video overlays are required for all recordings, to be superimposed without obscuring the subject matter. The content varies dependant on the spread type used for the recording, Diver or ROV.

4.3.1

Diver As a minimum, Time and Date are to be recorded as well as a brief description of task being carried out, and component where suitable, i.e. for inspection tasks.

4.3.2

ROV As a minimum, Time, Date, Bathymetric Depth and Heading are required. In addition for inspection, the component being inspected is required, or for construction purposes a brief description of the task. For seabed survey work, or as specified in the workscope, the ROV’s position is required to be permanently displayed in the format Eastings and Northings, supplied as a live feed from Survey Data.

4.4

Labelling and Numbering Shell specific Video Labels can be obtained from the Shell Onshore Data Management Controller. A Microsoft Excel form (Shell Video Label.xls) is available for the filling in of these labels. Where these labels are not supplied, the Contractors own labels may be utilised. These should clearly note the Tape Number; Location; Job Number; Relevant CTS’s; Vessel; Tape Start and End Dates; Description of Tasks covered; Contractor Name; Relevant Spreads used (ROV, SAT). Each tape, including copy, is to be supplied along with its own Video Log. The Shell Video Tape numbering system is based on the facility being worked at, Media Prefix (Vessel or Platform) which is year specific and then a sequential number starting from 01 for each Media Prefix, as follows: BA/VSL2005-01. With this numbering system it should be noted that if a vessel has worked for Shell on more than one occasion in the same year, then there is a possibility for duplication of video numbering if the vessel is to work at the same facility on those occasions. This numbering system is automatically generated by COABIS, where such duplications should not occur.

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Where COABIS is not used to control video operations, the Contractors own numbering system can be used, but this should allow no replication of tape numbers. 5

DIGITAL IMAGE REPORT Colour negative photographs are no longer to be used. Digital Images are required of any anomalies (see Section 2, Chapter 6, Points 2.2 and 2.3), where the image(s) can provide suitable illustration of the defect. Images may also be required which show aspects of a particular job and subject, relevant to a workscope. Images should be taken as a matter of course by the Data Recorder based on the above, and where specifically requested by the workscope, or Shell Offshore Representative. Where possible some form of scale should be included. As stated above for the Job Report, Point 2.1.7, Section 6 - Digital Image Logs, a Digital Image Log is required, with hard copies of each digital image to be included with the submitted Job Report. The Shell standards required for the taking of Digital Images, are specified in Section 1, Chapter 3, Point 1.7.

5.1

Digital Images Selection and editing (enhancement) of images, from those taken, will be carried out offline, with the images included within the report restricted to only the most appropriate, based on the above. All images should be supplied in .JPG format, with the file size to be kept to a minimum, without affecting the quality of the image significantly.

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6

JOB CLOSEOUT NOTE For all work completed by the Contractor, the Shell Offshore Operations Engineer, after consultation with all parties involved (Superintendent, Dive/ROV Supervisors, Project Engineers, Riggers, etc.) will complete a Job Closeout Note. The note will take the following format.

SUBSEA OPERATIONS DEPARTMENT JOB CLOSEOUT NOTE Job Number: Job Title: Execution Date: Weather Conditions:

Vessel:

Contributors: Safety: (How it was or could be made safer) •

Execution Concept: (Practicality, appropriateness, suggested alternatives for the future) •

Operational Workscope: (Clarity completeness, accuracy, timeliness, suggestions for improvements) •

Equipment: (Applicability, performance, condition, suggested modifications) •

Work times: (In Water Times not Vessel) •

Planned : hrs

•

Actual :

•

Special Circumstances :

hrs

Technical Publications: (Corrections/suggestions to UMDBs or Standard Procedures) •

Other Comments: •

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This will be submitted along with the Job Completion Report, and any other data, in both hard copy and electronic format, complete with referenced attachments, such as Change to Procedures and TRA’s. This will then be distributed to the Project Subsea Operations Engineer (Job Leader). Where COABIS is used, the electronic file will be saved within the COABIS database. EXECUTE WORK TO OPERATIONAL WORKSCOPE

RECORD DATA

PRODUCE VIDEO TAPES, DIGITAL VIDEO, AND

CRITICAL (C1) ANOMALY REPORT

DAILY PROGRESS REPORT (DPR) DATA

DATA MANAGEMENT CONTROLLER (EPE-T-PS)

COPY REPORTS TO FILES

VIDEO GRABS

PRODUCE DRAWINGS

COLLATE CHANGE TO PROCEDURES, SUB-CONTRACTOR REPORTS, ETC.

PRODUCE HARD COPY OF FINAL/INTERIM REPORT OFFSHORE SUBSEA OPERATIONS

ONSHORE SUBSEA OPERATIONS


DUTY ENGINEER

SUBSEA OPERATIONS ENGINEER (JOB LEADER)

SUBSEA OPERATIONS ENGINEER (JOB LEADER) FOR REVIEW

JOB SPONSOR

TECHNICAL AUTHORITY (If not Job Sponsor)


MASTER REPORT TO SPONSOR

Figure 1

2-7-12

COPY REPORT TO JOB FILES

COPY REPORT TO CONTRACTOR

MASTER VIDEO TO EXTERNAL ARCHIVES

COPY OF VIDEO TO LOCAL ARCHIVES (2 YEARS)

Flow Chart for Work Execution Reporting

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SECTION 3 INSPECTION PROCEDURES (EXCLUDING PIPELINES AND RISERS – SEE SECTION 5) CONTENTS STANDARD INSPECTION TASKS I 01 003

DEBRIS SURVEY AND RECOVERY

I 01 007

GENERAL VIDEO SURVEY

I 06 001

SEABED PROFILE AND SCOUR SURVEY

I 06 003

LINEAR PROFILE SCOUR SURVEY

I 10 001

DIMENSIONAL DAMAGE SURVEY TO STEEL STRUCTURES

I 15 001

WELD INSPECTION

I 15 002

WALL THICKNESS & ULTRASONIC INSPECTION - GENERAL

I 15 003

FLOODED MEMBER DETECTION

I 20 001

CONCRETE SURFACE AND DAMAGE INSPECTION

I 20 002

GENERAL CONCRETE SURFACE INSPECTION - SUBSEA AND TOPSIDE

I 30 001

SEAWATER INLET INSPECTION

I 32 001

BOAT LANDING AND BARGE BUMPER SURVEY

I 43 001

CAISSON INSPECTION

I 49 057

TALON JOINT INSPECTION

I 60 004

CATHODIC PROTECTION MONITORING

I 97 001

INSPECTION OF ABANDONED / SUSPENDED WELLHEAD

I 97 002

INSPECTION OF SUBSEA TREE (Production and Water Injection)

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PROCEDURE I 01 003 DEBRIS SURVEY AND RECOVERY CONTENTS Para

Page

1

INTRODUCTION

3

2 2.1 2.2

TASKS Standard Tasks Optional Tasks

3 3 3

3 3.1 3.2

OPERATING PROCEDURE AND SPECIFICATION Inspection Qualifications Structural Debris Survey (VD-ROV / DB-CHK)

3 3 3

4 4.1 4.2 4.3

OPTIONS Pre-Diver Intervention Survey (VI-ROV) Debris Recovery/Removal (DB-REM) Mud/Drill Cuttings Survey (DM-STD)

5 5 5 5

5 5.1

REPORTING Final Report

5 5

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PROCEDURE I 01 003 DEBRIS SURVEY AND RECOVERY 1

INTRODUCTION The work method is to be applied to a general video survey by an ROV of debris, including mud and drill cuttings, on or around a structure, pipeline or any other underwater facility, with the possible eventual removal/recovery of the debris by diver or ROV. This procedure may be applied as a ‘Pre-Diver Intervention Survey’ by ROV, to assess whether the worksite is clear from hazardous debris above and in the vicinity of the divers worksite. See 4.1.

2

TASKS

2.1

Standard Tasks The following Listed tasks are always to be invoked.

2.2

VD-ROV (DIV)

-

ROV (Diver) Video

DB-CHK

-

Visual Debris Check

Optional Tasks The following work tasks are optional and will either be explicitly called for in the Workscope, or be as dictated by diver safety. VI-ROV

-

ROV Worksite Check

DB-REM

-

Debris Removal

DM-STD

-

Standard Dimensional Survey (Mud/Drill Cuttings Survey)

Should additional activities be carried out or anomalies noted, suitable work tasks and task codes may be added to cover works. Should anomalies be noted, they are to be reported and acted upon as per Section 2, Chapter 6, ‘Anomaly Reporting & Criteria’, and as directed by the Shell Offshore Representative. 3

OPERATING PROCEDURE AND SPECIFICATION

3.1

Inspection Qualifications The inspection is to be carried out by ROV, under the guidance of a CSWIP 3.3u or 3.4u Inspection Controller. Debris clearance maybe carried out by any grade of diver or ROV Pilot. Should divers be required to investigate any identified anomaly in greater detail, and then this should be carried out by a CSWIP 3.1u/3.2u diver, under the guidance of a CSWIP 3.4u Inspection Controller. Reference Standard Procedures I-10-001 and I-20-003, ‘Dimensional Damage Surveys to Steel and Concrete Structures’, and I-90-002, ‘Pipeline Damage Inspection’.

3.2

Structural Debris Survey (VD-ROV / DB-CHK) The ROV will carry out, and fully video record, a general visual inspection of all items of debris on or within 3m of a member, i.e. on the seabed, and on or within 3m of a pipeline or subsea facility.

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The purpose of the survey is to record the following information on debris located: (1)

Location.

(2)

Description, damage if any.

(3)

Size and quantities.

(4)

Estimates of mud or drill cutting build up, where applicable.

Particular attention is to be given to large or hazardous items of debris, including notes as to where debris has come from i.e. section of caisson fallen from EL-28m. Large or hazardous items of debris are to be clearly marked on a structural layout drawing or a seabed plan. No cleaning is required. However, should an area of damage be located which may be attributable to an item of debris and is obscured by marine growth, then all marine growth is to be removed and the area fully investigated using standard anomaly reporting procedures. The survey may be conducted using SIT to establish the location of debris, or extent of mud and drill cuttings. Where items of debris are identified, colour views are required for definition, and to ascertain the presence of any associated damage. Camera movement must be slow and deliberate; lighting must be adequate to give good colour rendition. Ensure that lighting and viewing is optimised to avoid flare and flare out. Standoff and focus is to be optimised. Where possible the camera and lights are to be orientated at right angle to inspection surface to give optimum viewing, as viewing at differing angles will cause flare on screen close to subject and fade out at the far edges of the screen. The areas to be inspected should be covered in a logical order to ease subsequent topside interpretation. The video survey is to be carried out at a speed that is slow enough to allow the observer to adequately observe, comment on and note all items of debris. All route details should be mentioned i.e. moving from node ref. 15110 down diagonal bracing 13140. At anode No. 61003, large section of tubular debris lying across anode, no damage noted, length 3m by 250mm diameter approximately. Continue along member 13140 towards node ref. 15220. Components should be identified as they appear in the camera's view, not when they appear in the pilot's view unless coincident. Periodically, reference should also be made to depth and direction. The camera standoff is to be adequate so as to show the subject without loss of definition. Where necessary, the standoff distance should be increased to show an overall view of the debris and surrounding area. Other than in exceptional circumstances, the camera is to be held vertical. If the camera is rotated, the extent and direction of the rotation must be frequently mentioned on the video commentary. Any camera tilt must be described, in terms of degrees up or down, in the commentary. Reference should be made of all salient points of interest in the video narrative and on the video log. Additional findings of relevant importance must be noted and sufficient coverage made in order to assess the situation. Consideration should be given to the taking of Digital Still Images, where the image would clearly show significant, hazardous or anomaly related debris.

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4

OPTIONS

4.1

Pre-Diver Intervention Survey (VI-ROV) A Task Risk Assessment (TRA) is required to be performed prior to any diver operations. The TRA should identify those areas required to be inspected by ROV, prior to diver deployment to the worksite. The areas for inspection should be assessed based on the divers worksite in relation to the structure above, and areas where other ROV/Diver activities may be conducted at the same time as the specific diver tasks, in case these operations may cause objects to be dropped in the vicinity of the working diver below. Unless specifically requested in the workscope, these pre-diver intervention surveys are not required to be recorded on video. Where items of potentially hazardous debris, or other potential hazards are identified, then these should be recorded.

4.2

Debris Recovery/Removal (DB-REM) Unless specified in the workscope, debris will be removed from the component on which it is attached and placed on the seabed away from the structure. Attempts should be made to lay the debris in set locations, which are then to be either referenced to known points on the structure, or preferably position fixed. The debris should be laid as best as possible, to prevent it from becoming a snagging hazard. Do not relocate debris into the possible footprint areas of Jack-ups. As per debris anomaly criteria, remove only items of debris that are hazardous to diver or ROV, or with respect to risers, all contacting metallic debris is to be removed. Debris that is deemed to be causing significant physical damage to the component should only be removed after discussion with the Offshore Shell Representative, based on advice from the responsible Structural Engineer. Debris to be recovered will be specified in the workscope, designated by the Shell Offshore Representative, or as identified in the Task Risk Assessment (TRA) conducted as a result of ROV findings prior to. The debris will be recovered to the surface by whatever means is considered safe and suitable. Having removed the debris, the area of contact, if any, is to be inspected for damage. Any damage noted is to be fully reported. Depending on type of damage noted further inspection may be required, and if necessary will be detailed by the Shell Offshore Representative, acting on instructions from the sponsoring engineer.

4.3

Mud/Drill Cuttings Survey (DM-STD) For assessment of build up of mud or drill cuttings, sufficient coverage is to be made in order to assess the overall situation. If specified in the workscope, ROV bathymetric readings are to be taken to obtain a contoured profile of the extent of mud/drill cuttings. These may be obtained from spot readings using the ROV’s position, manually recorded against an as-built drawing, or position fix, or if specified in the workscope for more accurate detail by continuous survey data of ROV position, altimeter and depth. Dependant on the type of data gathered, either a representative sketch, or more detailed scaled drawings shall be produced giving a profile of the build up.

5

REPORTING

5.1

Final Report The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above. Reference section 2, Chapter 1, Section 3.1.5.

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All anomalies are to be referenced, with a general statement made concerning the types and extent of anomalies identified. Any C1 anomalies are to be commented on more specifically. Other references are to be made to any digital still images and drawings. Sketches are required, either scanned, AcadLT or other proprietary drawing format, of any major defects or debris that cannot be suitably documented by anomaly report and digital images alone. Mud/Drill Cuttings profiles are to be produced based on the type of information obtained, as discussed in 4.3.

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PROCEDURE I 01 007 GENERAL VIDEO SURVEY CONTENTS Para

Page

1

INTRODUCTION

3

2 2.1 2.2


3 3 3

3 3.1 3.2 3.2.1 3.2.2 3.2.3

OPERATING PROCEDURE AND SPECIFICATION Inspection Qualifications General Video Survey (VI-GVI / VD-ROV) General Anode Wastage (VI-AW) Steel and Concrete Structures

4 4 4 4 5 5

4 4.1 4.2

OPTIONS Cathodic Potential (CP) Monitoring Above Water Inspection

5 5 6

5 5.1


6 6

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PROCEDURE I 01 007 GENERAL VIDEO SURVEY 1

INTRODUCTION The work is to be applied to a general video survey by an ROV, of most underwater facilities such as steel and concrete structures, buoys, FPSO’s, the UMC, etc. Note: Subsea Trees, igloos and pipelines have their own procedure, see Section 5. In exceptional circumstances it may be required for divers to carry out the survey, due to access or tidal conditions. In these cases the methodology to be adopted is the same, as best as practicable. The purpose of the survey is to visually inspect a large area for possible damage, missing components, lack of component integrity, leaks, debris, anode condition, marine growth coverage and variation to specification. During the course of the general survey, Cathodic Potential (CP) data may also be gathered from components as specified in the workscope.

2

TASKS

2.1


2.2

VI-GVI

-


VD-ROV

-

ROV Video

DB-CHK

-

Visual Debris Check

MG-GEN

-


VI-AW

-


Optional Tasks The following work tasks are optional and will be explicitly called for in the Workscope. CP-PRX

-


DM-SCR

-

Scour Survey

VI-TOP

-

Topside Inspection

PH-TOP

-


Should additional activities be carried out or anomalies noted, suitable work tasks and task codes may be added to cover works. Should anomalies be noted, they are to be reported and acted upon as per Section 2, Chapter 6, ‘Anomaly Reporting & Criteria’, and as directed by the Shell Offshore Representative.

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3


3.1

Inspection Qualifications The inspection is to be carried out by ROV, under the guidance of a CSWIP 3.3u or 3.4u Inspection Controller, or CSWIP 3.1u/3.2u diver, under the guidance of a CSWIP 3.4u Inspection Controller.

3.2

General Video Survey (VI-GVI / VD-ROV)

3.2.1

General The video survey is to be taken of all components, including anodes, as specified in the Component Task Sheet (CTS) or as directed by the Shell Offshore Representative. Continuous video recording is required throughout the survey. The purpose of the survey is to check steel members/nodes and concrete surfaces for any gross damage; variation to specification; debris; lack of integrity; anode wastage; marine growth levels and any leaks. The inspection is to commence with a SIT view of the general area, to confirm the correct component has been identified, with reference to known local components, i.e. Leg B1. The remainder of the survey should be conducted in both SIT for overall coverage and colour for more detail, to give the best overall coverage of the component inspected. If visibility allows, the preference is for the more detailed colour views. Where practicable, i.e. member (excluding legs and piles), guide inspection, the full width of the component should be in view. The video survey is to be carried out at a speed that is slow enough to allow the observer to adequately observe, comment on and note the condition of the structure. Camera movement must be slow and deliberate. Lighting must be adequate to give good colour rendition. Ensure that lighting and viewing is optimised to avoid flare and fade out. Standoff light and focus is to be optimised. Where possible the camera and lights are to be orientated at right angle to inspection surface to give optimum viewing, as viewing at differing angles will cause flare on screen close to subject and fade out at the far edges of the screen. The areas to be inspected should be covered in a logical order to ease subsequent topside interpretation. All route details should be mentioned i.e. ‘Commencing survey from node 15110, down diagonal bracing 13140, on outboard side of member. Proximity reading adjacent node –920mV. Passing 1st anode which is approximately 20% depleted, active and appears secure… Continuing down diagonal bracing, now reached end node 15220. Overall marine growth cover 50% hard, 15mm thick, 10% soft, 50mm thick. No debris or anomalies observed. Survey complete.’ Describe marine growth as hard or soft, giving estimated thickness and percentage of cover of each. No removal of marine growth is required unless specified or unless on anomaly is suspected. However, should cleaning be required it should not take place prior to any CP survey, unless operational constraints dictate otherwise, and with the prior consent of the Shell Offshore Representative. Components should be identified as they appear in the camera's view, not when they appear in the pilot's view unless coincident. Periodically, reference should also be made to depth and direction. The camera standoff is to be adequate so as to show the subject, without loss of definition. Where necessary, the standoff distance should be increased to show a larger area i.e. complete node. Other than in exceptional circumstances, the camera is to be orientated in the vertical plane. If the camera is rotated, the extent and direction of the rotation must be frequently mentioned on the video commentary. Any camera tilt must be described, in terms of orientation, up or down, in the commentary. Reference should be made of all salient points of interest in the video narrative. The video log narrative should only contain references to anomalies, or other salient points, i.e. poor visibility, etc.

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Additional findings of relevant importance must be noted and sufficient coverage made in order to assess the situation. Digital Still Images (PH-DIG) are to be taken of any anomalies or other areas of interest. These may be supplemented by suitable drawings to show the location, size and details of the item of interest. 3.2.2

Anode Wastage (VI-AW) The presence and location of anodes are to be confirmed as per UMDB layout drawings. Anode attachments are to be inspected for integrity, including any bonding/earth/continuity cables. Where multiple anodes are present on a member, component, or for bracelet anodes, anode wastage estimation is to be given as an average for all individual anodes on a component. Where multiple anodes are present on a component, anomalies are only to be raised for individual anodes missing or +90% depleted anodes, unless otherwise specified in relevant Master Anomalies. A guide to estimate percentage wastage on an anode is given below: ANODE DEPLETION SCHEMATIC

3.2.3

0-5% LOSS -

ANODE AS NEW, WITH CORNERS WELL DEFINED AND NO PITTING.

6-20% LOSS -

ANODE IN GOOD CONDITION, CORNERS ROUNDED, SLIGHT PITTING.

21-50% LOSS -

ANODE DETERIORATED, LOSING SHAPE AND WITH GENERAL PITTING.

>50% LOSS -

ANODE IN VERY POOR CONDITION. METAL FROM SUPPORT BRACKET SHOWING. EXTENSIVE PITTING.

Steel and Concrete Structures For the inspection of steel and concrete structures, the recording of data will be gathered from one convenient side only for structural members up to and including 30inch (760mm) diameter. For larger members recording of data will be gathered from two opposing sides. However, on very large members, i.e. structural legs, concrete shafts etc, it may be necessary to view from several sides to fully cover all detail.

4

OPTIONS

4.1

Cathodic Potential (CP) Monitoring During the course of the General Video Survey there may be a requirement to gather CP data. The full extent and location of readings required for specific facility types will be specified in the workscope, and will be included within the COABIS task listing for each individual component. The CP probe is to be hard wired into the video overlay such that the CP readings are continuously displayed on the video screen during the ROV survey. CP readings are to be included in the video commentary. For steel structure members (component type 11, 12, 13, 14), CP readings are to be taken at both node ends and on both sides of the member. On conductor guide frame members (component types

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35, 36), on both steel and concrete structures, CP readings are to be taken both sides of the member at one location, adjacent a node, ensuring that over the complete CGF, all nodes are covered. Readings are, as best as practicable, to be taken away from anodes. All readings are to be taken prior to any cleaning that may be specified in the workscope, or required as part of an anomaly investigation. Proximity probes are the preferred method for obtaining the required readings. Contact probes shall not be used without the prior approval from the Shell Offshore Representative acting on advice from the responsible Structural Engineer. If CP readings on anodes are specifically requested in a procedure, or required as part of an anomaly investigation, then disturbance of any oxide layer on the anode is to be avoided. Calibration data is to be noted and verified before and after each dive. Reference procedure I-60 004 – Cathodic Protection Monitoring. 4.2

Above Water Inspection Topside inspection may be required to compliment platform based topside inspection. If requested in the workscope, a topside visual inspection of specified components between LAT and the under deck of the platform, paying particular attention to the region from LAT to +3m. Only gross defects (C1 category) are to be reported. Digital Images may be requested by the workscope, of the following views: (1)

Of all 4 faces from water level to under deck level.

(2)

And/or of overall views of the platform from 2 opposing faces.

These should be taken on an opportunity basis only, with no specific vessel move made to obtain these images, unless specifically requested in the workscope. 5

REPORTING

5.1

Final Report The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above. All anomalies are to be referenced, with a general statement made concerning the types and extent of anomalies identified. Any C1 anomalies are to be commented on more specifically. Other references are to be made to any digital still images and drawings. If not anomalous, reference is to be made to any marine growth results taken, confirming the location where the data can be obtained, i.e. COABIS database. The maximum and minimum of all CP readings taken are to be reported for a specific section of a survey, i.e. CTS or specific elevation, or where a section of a survey has been conducted during a specific dive. Reference should be made confirming the location where the full survey data can be obtained, i.e. COABIS database. Any other specific inspection tasks requested in the workscope are to be commented upon. If the task could not be completed, a statement is required stating reasons. Sketches are required, either scanned, AcadLT or other proprietary drawing format, of any major defects or debris that cannot be suitably documented by anomaly report and digital images alone.

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PROCEDURE I 06 001 SEABED PROFILE AND SCOUR SURVEY CONTENTS Para

Page

1

INTRODUCTION

3

2 2.1 2.2


3 3 3

3 3.1 3.2 3.2.1 3.2.2 3.2.3 3.2.4 3.2.5 3.3 3.3.1 3.3.2

OPERATING PROCEDURE AND SPECIFICATION Inspection Qualifications Scour Survey – Steel Structures Survey Datum Scour Bowls Buried Members Jacket Piles Scour Survey – Concrete Gravity Based Structures (GBS) Northern - (Brent B, Brent C, Brent D, Dunlin A & Cormorant Alpha) ONEgas - (East – F3-FB-1P)

3 3 3 3 4 5 5 5 6 6 6

4 4.1 4.2

OPTIONS ROV Seabed Mapping (DM-STD) Specialist Seabed Mapping

6 6 7

5 5.1


8 8

FIGURES No 1

Page Example of Format for Scour Survey

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PROCEDURE I 06 001 SEABED PROFILE AND SCOUR SURVEY 1

INTRODUCTION The work method is to be applied to a general video survey by ROV or Diver of scour, either around a steel or concrete structure and seabed mapping by an ROV or a specialised Imaging Tool. The work will include a general visual video survey, dimensional measurements and Cathodic Potential (CP) readings where exposed piles are identified.

2

TASKS

2.1

Standard Tasks

2.2

VD-ROV (DIV)

-

ROV (Diver) Video

DM-SCR

-

Scour Survey

-

Standard Dimensional Survey (Seabed Mapping)

Optional Tasks DM-STD



3.1

Inspection Qualifications The inspection is to be carried out by ROV, under the guidance of a CSWIP 3.3u or 3.4u Inspection Controller, or any diver, under the guidance of a CSWIP 3.4u Inspection Controller. Note: For ONEgas platforms, scour anomaly criteria may vary per jacket based on design criteria.

3.2

Scour Survey – Steel Structures

3.2.1

Survey The ROV will carry out, and fully video record, a general visual inspection of the seabed around the base of the structure for concrete platforms and around the piled legs of steel platforms, extents as specified in the workscope. Continuous video recording in SIT mode for overall coverage and colour for detailed close up work is to be conducted throughout the survey. In the event that divers are required to perform the survey, a colour camera is to be used, giving the best overall views possible. The purpose of this inspection is to record the following: (1)

Approach views of the seabed to the structure and establishment of distance out to natural seabed level.

(2)

Profile views and measurements of the depth of scour around piled legs - for steel structures.

(3)

Measurements of seabed material and or drill cuttings build up.

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Measurements of scour, and or build up of the seabed are to be supplemented by ancillary techniques, such as the use of the ROV’s calibrated bathometer, and/or a graduated/banded rule. Particular attention is to be taken where scour exceeds 0.5m in depth. Where a scour bowl exists around a leg/pile, which prevents actual readings, an estimate of depth may be given, but this must be highlighted with the results. Camera movement must be slow and deliberate. Lighting must be adequate to give good colour rendition. Ensure that lighting and viewing is optimised to avoid flare out and fade out. Standoff light focus is to be optimised. Where possible the camera and lights are to be orientated at right angle to inspection surface to give optimum viewing, as viewing at differing angles will cause flare on screen close to subject and fade out at the far edges of screen. The areas to be inspected should be covered in a logical order to ease subsequent topside interpretation. The video survey is to be carried out at a speed that is slow enough to allow the observer to adequately observe, comment on and note the condition of the structure and scour. All route details should be mentioned i.e. ‘moving east on heading 093 deg along horizontal bracing 12065, clearance to seabed approximately 0.4m at midpoint. Now approaching vertical bracing 14141, clearance to seabed at this point 0.6m. Moving in and switching to colour mode for detailed inspection’. Components should be identified as they appear in the camera's view, not when they appear in the pilot's view unless coincident. Constant reference should also be made to depth and direction. The camera standoff is to be adequate so as to show the subject, without loss of definition. Where necessary, the standoff distance should be increased to show a larger area i.e. full length of scour along a concrete face. Other than in exceptional circumstances, the camera is to be oriented in the horizontal plane. However, if necessary the camera is to be panned and tilted to fully show the extent of any scour. If the camera is rotated, the extent and direction of the rotation must be frequently mentioned on the video commentary. Any camera tilt must be described, in terms of orientation, up or down, in the commentary. Reference should be made of all salient points of interest in the video narrative and noted on the video log. Additional findings of relevant importance must be noted and sufficient coverage made in order to assess the situation. 3.2.2

Datum For steel structures, the datum for surveys shall be the underside (6 o'clock) position of the bottom elevation members. If there is no bottom framing to the jacket then the datum shall be either the underside of the mudmats (if exposed) or the underside (6 o'clock) position of a vertical diagonal member where it joins the leg. In either event the referenced datum point must be clearly defined in all produced drawings. In these cases where datum differs from the norm, the datum should be reflected on the relevant baseline drawing. Where there is doubt, datum should be confirmed by the Shell Offshore Representative (Reference Figure 1). Reference points are required to be established around the platform, to which seabed readings local to the reference point can be offset. In areas subjected to tidal variations, i.e. Central & ONEgas, frequent depth readings are required at these reference points to remove tidal errors. •

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To calculate the measurement between underside of member and seabed, take reference ROV depth reading to top of horizontal member, and deduct member diameter from seabed reading.

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The same may be applied to any other reference point of known depth, when establishing scour to the underside of a vertical diagonal or mudmat.

The standard location for scour/depth readings required for the whole of a structure are as listed, (Reference Figure 1): (1)

Adjacent the leg, or mudmat, at each of the 4 Cardinal clock positions.

(2)

2.5m out from the leg, or mudmat, at each of the 4 Cardinal clock positions.

(3)

Midway between each leg on both N-S & E-W framing elevations.

(4)

From the leg, and for midpoints between each leg, as shown by Dim ‘x’ in fig.1, identify the point where natural seabed returns. Record distance from platform and seabed depth, at each point. If natural seabed is outside 10m from platform, record seabed depth at 10m out, and report this fact.

For points (1) to (3), if prevented by clearance under member/mudmat, reading to be taken at nearest point outboard. If buried report as per 3.2.4. Partial coverage of the structure may be specified in the procedure, i.e. Northern, or Western Half, where the above positions still apply for the specified areas. Additional readings may be requested by the workscope. 3.2.3

Scour Bowls In addition to the above points, where a scour bowl exists around a leg, the bowl profile is required. Video in SIT and/or colour is required to establish the status around the leg. Actual measurements and estimates as required are to be provided with a sketch (Reference Figure 1).

3.2.4

Buried Members Where members are buried, an assessment of depth, if possible, shall be given as a positive value. At each point where a reading is taken a comment shall be made with reference to seabed composition i.e.:

3.2.5

•

Sand

•

Silt

•

Drilling Mud

•

Large Aggregate

•

Small Aggregate

•

Etc

Jacket Piles If during the course of the scour survey any jacket pile is observed as being exposed then if accessible, CP (Cathodic Potential) readings shall be taken; one reading on the exposed pile and one on the leg. This task code (CP-CON) will require to be added to the standard list of tasks, as it is not a standard task, only carried out when the above condition exists. Should it be necessary to take CP readings calibration data is to be noted and verified before and after each dive; and for diver readings before each set of readings. Refer to procedure I 60 004 – Cathodic Protection Monitoring.

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3.3

Scour Survey – Concrete Gravity Based Structures (GBS)

3.3.1

Northern - (Brent B, Brent C, Brent D, Dunlin A & Cormorant Alpha) For concrete platforms, the datum for surveys shall be the design mudline depth, as indicated on baseline drawings. The method adopted is as for steel structures. (1)

Approach views of the seabed to the structure.

(2)

Measurements of the depth of scour, at least every 2m along the survey route.

On a concrete structure base slab, if the steel skirt is visible at any point due to scour it should be inspected for corrosion and if possible a contact CP reading is to be taken. Should it be necessary to take CP readings calibration data is to be noted and verified before and after each dive; and for diver readings before each set of readings. Refer to procedure I 60 004 – Cathodic Protection Monitoring. 3.3.2

ONEgas - (East – F3-FB-1P) Platform F3-FB-1P is a Gravity Based Structure (GBS) located in the ONEgas East region. Due to its presence in a tidal environment, it has specific anti scour protection, which requires unique scour and ballast inspections. The generic scour inspection requirements for this platform will be contained in the specific workscope for the platform.

4

OPTIONS

4.1

ROV Seabed Mapping (DM-STD) Seabed mapping is generally required to ascertain the extent of drill mud build up, within and around a structure. It can however be utilised on any area of open seabed, where a contoured profile is required. The ROV will carry out and fully video record, a general visual inspection either: •

Of the seabed within a steel structure, or part thereof.

•

On the cell tops of a concrete structure, or part thereof.

•

Within any other specified area around a platform.

•

On open seabed of a specified area.

The extent of the survey area outside the platform will be 5m, unless otherwise specified in the workscope. The specific areas of inspection will be as stated in the workscope. Continuous video recording in SIT mode for overall coverage and colour for detailed close up work is to be conducted throughout the survey. There are a number of methods of obtaining the data, both with respect to seabed depth and location of the readings. Any combination of these (points 1 to 6 below) may be adopted to obtain the final results and will be influenced by: •

Availability of a Surveyor.

•

Accuracy of survey data and ROV beacon fix, due to platform interference.

•

Capabilities of ROV.

•

Visibility.

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Discussion on the method for obtaining the required data is to be conducted between all parties involved prior to the survey. These should include the Shell OOE, Shell QAQC/Coordinator, Surveyor, ROV Superintendent, ROV Supervisor and Data Recorder. Methods that may be adopted to obtain the seabed depth are: (1)

ROV bathometer, with vehicle sitting on seabed at a series of specified positions.

(2)

ROV bathometer and altimeter, with ROV passing over a set grid, with a constant string of the resultant data collected with survey positioning data.

Methods that may be adopted to obtain the position of the readings are: (3)

Grid pattern plotted by Surveyor over inspection area, of suitable grid size to be determined from pre-survey discussion, or as specified in the workscope. ROV to position over grid intersections, with fix and depth data to be gathered by Surveyor.

(4)

Use of known points within platform, i.e. conductors, nodes, legs, etc.

(5)

Use of ROV sonar to position vehicle, relative to known points on platform.

(6)

Use of ROV position fix data.

Depth calibration against a component of known depth is to be conducted prior to commencement of a survey. This should if possible be against a mud brace member of known elevation, level with its vertical midpoint, which relates to the as-built specified depth of the elevation. Alternatively, the top of the member, if the member diameter is known, which is then to be used in any calculations. The time and data of these calibrations are also to be recorded. These calibrations are to be taken: •

At the start of the survey.

•

At the start of any new dive, or vehicle used for the survey.

•

Every hour, or otherwise specified by the Surveyor, in tidal locations

Dependant on the type of survey data acquired, a contoured map is to be produced and submitted with the final report as follows. •

If accurate survey data is obtained, a scaled contoured map is required of the processed data, taking into account any tidal variations.

•

Otherwise, a drawing to as accurate a scale as possible.

The Shell Survey provided positioning platform/field layout drawing is to be used as the base drawing in both cases. The location, time and date of all calibrations are to be included on the drawing. 4.2

Specialist Seabed Mapping Should a specialist imaging tool be utilised it is to be prepared and deployed in accordance with the manufacturers operating instructions. Final positioning may require the assistance of the ROV or diver. The imaging tool is fully selfcontained, and once set up will be operated by the manufacturers personnel. The final report of finding will be the subject of a dedicated document and software data package compiled and presented by the specialist subcontractor.

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5

REPORTING

5.1

Final Report The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above. Reference section 2, Chapter 1, Section 3.1.5. All anomalies are to be referenced, with a general statement made concerning the types and extent of anomalies identified. Any C1 anomalies are to be commented on more specifically. Other references are to be made to any digital still images and drawings. Sketches are required, either scanned, AcadLT or other proprietary drawing format, of the results of the scour or seabed mapping surveys as stated above. These are to include profile drawings of any scour bowls, across two planes (12-6 & 3-9 o’clock), (Reference Figure 1). Buried members shall be indicated as such by cross-hatching on the drawings and an assessment of depth, if possible, shall be given as a positive value. At each point where a reading is taken a comment shall be made with reference to seabed composition. Seabed Mapping profiles are to be produced based on the type of information obtained, as discussed in 4.1 and 4.2.

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Figure 1

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Example of Format for Scour Survey

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PROCEDURE I 06 003 LINEAR PROFILE SCOUR SURVEY CONTENTS Para

Page

1

INTRODUCTION

3

2

TASKS

3

3 3.1 3.2

OPERATING PROCEDURE AND SPECIFICATION Inspection Qualifications Survey

3 3 3

4 4.1


4 4

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PROCEDURE I 06 003 LINEAR PROFILE SCOUR SURVEY 1

INTRODUCTION The work method to be applied will allow for an accurate measurement of the seabed profile across or adjacent to a linear feature such as a pipeline. The work will include detailed dimensional measurements, debris removal and video survey. It may be required for divers to carry out these inspections due to a number of reasons, i.e. access, or due to vehicle break down. In these cases, the methodology to be adopted is the same, as best as practicable.

2

TASKS VD-ROV

-

General ROV Video

DB-REM

-

Debris Removal

DM-STD

-


Should anomalies be noted, suitable work tasks and task codes may be added to cover works. Should anomalies be noted, they are to be reported and acted upon as per Section 2, Chapter 6, ‘Anomaly Reporting & Criteria’, and as directed by the Shell Offshore Representative. 3


3.1

Inspection Qualifications The inspection is to be carried out by ROV, under the guidance of a CSWIP 3.3u or 3.4u Inspection Controller, or any diver, under the guidance of a CSWIP 3.4u Inspection Controller.

3.2

Survey Carry out an initial survey by ROV to locate the area to be measured, reporting on any debris or other obstructions. On completion of the initial survey remove debris, if any, from the area to be inspected. The debris is to be removed by whatever means is considered suitable and that will allow safe and unrestricted access to the inspection area. On completion of debris removal establish a horizontal base line, i.e. the top of a pipeline, the underside of a structural member. If required, the depth of the baseline is noted and referred back to LAT by noting existing tidal conditions. The extent of the profile survey is to be noted i.e. between specified pipe joint numbers, where pipe spans occur or scour is evident. Vertical profile measurements are to be taken from the seabed to the horizontal baseline at specific intervals. The specified intervals are to suit local conditions and distance to be inspected, i.e. 1m, 5m, etc. Carry out a video survey of the area being profiled, which is to clearly show all reference points utilised in obtaining the profile plot of the baseline, linear feature and seabed.

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4

REPORTING

4.1

Final Report The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above. Reference section 2, Chapter 1, Section 3.1.5. All anomalies are to be referenced, with a general statement made concerning the types and extent of anomalies identified. Any C1 anomalies are to be commented on more specifically. Other references are to be made to any digital still images and drawings. Drawings are to be supplied of any data gathered.

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PROCEDURE I 10 001 DIMENSIONAL DAMAGE SURVEY TO STEEL STRUCTURES CONTENTS Para

Page

1

INTRODUCTION

3

2 2.1

TASK OPTIONS Standard Tasks

3 3

3 3.1 3.2

OPERATING PROCEDURE AND SPECIFICATION Inspection Qualifications Preliminary Works

3 3 3

4 4.1 4.2 4.3 4.3.1 4.3.2

OPTIONS Defect Profiles Ovality Measurement Straightness Measurement Straight edge measurement Taut Wire Measurement

4 4 5 5 5 5

5 5.1


6 6

FIGURES No 1 2 3 4 5

Page Example of Format for Defect Profile - Dent (Plan) Example of Format for Defect Profile - Dent (Elevation) Example of Format for Defect Profile - Dent (Data) Example of Format for Ovality Measurement Example of Format for Straightness Measurement

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PROCEDURE I 10 001 DIMENSIONAL DAMAGE SURVEY TO STEEL STRUCTURES 1

INTRODUCTION The work method is to be applied for the dimensional survey to damage located on steel structures. The work will include debris clearance, profiling, ovality and out of straightness measurements. NDT methods under Procedure I 15 001, I 15 002, I 15 003 and I 15 004 may also be required to fully investigate and report damage as found.

2

TASK OPTIONS

2.1

Standard Tasks The following Listed tasks are always to be invoked. VI-GVI

-


VD-ROV

-

ROV Video

PH-DIG

-

Digital Still Images

Optional Tasks The following work tasks are optional and will be explicitly called for in the Workscope. DB-REM

-

Debris Removal

VD-DIV

-

Diver Video

CL-INS

-


DM-STD

-


VI-DVI

-


CP-PRX (CON)

-

Proximity (Contact) CP Readings

Any number or combination of the listed work tasks, or those listed under Procedure I-15 001, I-15 002, I 15 003 and I 15 004 may be used or called for on the workscope or during the course of the inspection to fully investigate and report damage as found. 3


3.1


3.2

Preliminary Works The ROV will carry out, and fully video record, a general visual survey of the area of interest noting area of damage, item of debris which may have caused the damage or any other cause, marine growth coverage and confirm as built configuration for access and rigging for dimensional survey.

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On completion of the general visual survey the diver/ROV is to video all debris in the area as found prior to removal. Video and digital still images are to be taken of the damaged area prior to cleaning. The damaged area is to be suitably identified, with the video and digital still images to clearly show all aspects of the damage. NOTE:

Any Cathodic Protection (CP) readings requested by the procedure, are to be taken prior to any cleaning.

Deploy cleaning equipment and clean the damaged area to allow inspection. Cleaning of sites for installing dimensional survey equipment should also be undertaken at this time. At this point the damaged area should be marked up as per the requirements of the scope of work and as necessary to carry out the specified dimensional survey/and any NDT works. Prior to carrying out any further work a close visual survey is to be carried out by the diver, recorded on video. Digital Still Images (PH-DIG) are to be taken of the damaged area on completion of cleaning and diver survey. The damaged area is to be suitably identified, with the video and digital still images to clearly show all aspects of the damage. 4

OPTIONS

4.1

Defect Profiles Defect profiles are to be carried out as specified in the Workscope or as directed by the Shell Offshore Representative, acting on advice from the responsible Structural Engineer. Defect profiles of dents are normally carried out to measure significant impact damage to members. The profile measurements are to be set out as follows: (1)

Line of maximum bow visually estimated and a taut wire placed parallel to the member axis along this line, passing over stand off blocks.

(2)

A series of wires also on stand off blocks is to be placed 90 degrees to the above on a maximum spacing of 1/6th of the dent width.

(3)

A second series of taut wires is to be placed perpendicular to the ones above so as to form a grid over the dent. NOTE:

The perpendicular wires should also be spaced at a maximum of 1/6th of the dent length.

(4)

The grid is to extend across the dent and measurements taken on 'sound' areas.

(5)

The grid shall be rectangular and aligned to the member axis.

(6)

At sharply indented regions, the spacing of the grid may be reduced for more accurate plotting. NOTE:

A straight edge may be used in place of a taut wire with the agreement of the Shell Offshore Representative.

Measurements are taken from the wire to the member and noted against their grid location. The location of the dent should be referenced to the nearest node or member. Refer to Figs 1, 2 and 3.

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4.2

Ovality Measurement Ovality measurements are to be carried out as specified in the workscope, or by the Shell Offshore Representative, acting on advice from the responsible Structural Engineer. Ovality measurements are normally carried out to determine any distortion, indentation or buckling around a cylindrical element. The ovality measuring jig (Gauge) is to be constructed so as to provide a solid frame, which can be fitted round the element. This frame is to support at least 8 adjustable contact points that can be brought to bear on the surface of the element in such a way that the tips of the points are not more than 50mm apart. When fitting the gauge and adjusting the contact points care is to be taken to ensure that it is at right angles to the axis of the cylindrical element. Any local surface irregularities affecting the contact points are to be noted. The position and orientation of the measuring system relative to the member is to be defined. The stand off distances from the measuring system to the member at the contact points are to be tabulated. Should there be any deviation of straightness of the member, then profile plots are to be drawn. Refer to Fig 4.

4.3

Straightness Measurement Straightness measurements are to be carried out as specified in the workscope, or by the Shell Offshore Representative. Straightness measurements are normally carried out to check the linearity of a member by measuring from a reference datum line to the structure surface. The measurement may be carried out by either of the following: (1)

Straight edge (up to 2m).

(2)

Taut wire system.

The method used must not involve damage to the structure or its protective coating. An accuracy of 0.1% or 1mm, whichever is the least, is required for linear dimensions i.e. 1mm in 1000. The position and orientation of the measuring system relative to the member is to be defined. The stand off distances from the measuring system to the member, are to be tabulated and the datum locations referenced. Should there be any deviation of straightness of the member, then profile plots are to be drawn. 4.3.1

Straight edge measurement The areas to which measurements are being noted are cleaned to ensure the straight edge makes good contact on its support. Measurements are taken at the 12, 3, 6 and 9 o'clock positions. The distance from the bottom of the straight edge to the member is to be noted at suitable increments, as agreed with the Shell Offshore Representative, to adequately establish the extent any deflection or contours.

4.3.2

Taut Wire Measurement Clamps are installed at each end of the measurement span to hold the taut wire.

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Measurements are to be taken at the 12, 3, 6 and 9 o'clock positions around the member and along the member at intervals of 1/10 the length for members <5m long, and every 0.5m for members >5m long. A tensioning device is installed at one end of the wire that will allow the tension to be accurately measured and 'brought to'. The taut wire is run and brought to the specified tension. NOTE:

Over long distance measurements it is recommended that to reduce the problem of 'sag' in the taut wire it be replaced with 6mm diameter, 8-strand multi-filament polypropylene having a specific gravity 0.91. A jig or similar approved system is to be used to ensure that measurements between the taut wire and structure are perpendicular. Refer to Fig 5.

5

REPORTING

5.1

Final Report The Job Completion Report is to précis the results of the inspection, and any operations carried out as per the points of interest listed above. Reference section 2, Chapter 1, Section 3.1.5. Other references are to be made to any digital still images and drawings. Full results of the anomaly inspection are to be reported in the relevant anomaly report. Any specific inspection tasks requested in the workscope are to be commented upon. If the task could not be completed, a statement is required stating reasons. Sketches are required, either scanned, AcadLT or other proprietary drawing format, of any results obtained, as per the results requirements requested above.

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SHEET 1 OF 3

14112

3 MTRS

250 mm

12 O'CLOCK POSITION

A

100 mm 12142 75 mm

MEMBER 9 O'CLOCK POSITION

A

14113

ELEVATION

12 O'CLOCK

DEFECT

9 O'CLOCK

SECTION A - A

Figure 1

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Example of Format for Defect Profile - Dent (Plan)

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3m TO MEMBER

14112

SHEET 2 OF 3

9 8 GRID AT 25mm SPACING 7 6 5 4 3

9 O'CLOCK MEMBER 12124

2 1

A

B

C

D

E

F

G

H

J

K

L

M

LONGITUDINAL PROFILE

LINE 6

LINE 5

Figure 2

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Example of Format for Defect Profile - Dent (Elevation)

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LATERAL PROFILES SHEET 3 OF 3

LINE A

Figure 3

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Example of Format for Defect Profile - Dent (Data)

I 10 001 Page 9 of 11

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Figure 4

B

C

A

9

D

HINGE

CLASP

6

12

1

2

H

3

E

3

4

G

F

5

12018

6

7

9

10

47

12 13

47

11

47

48

8

10

47

7

47

49

6

9

48

5

47

48

47

A

12

43

11

4

3

2

1

10cm, DIVISIONS FROM FLANGE

8

MEASUREMENT POSITIONS AT 0.5M INTERVALS

OVALITY GAUGE LOOKING NORTH ( MEMBERS 14113, 14112 )

14112

14113

CONTINUED

57

51

57

56

56

57

58

58

57

57

57

58

B

88

65

71

54

64

86

67

67

66

66

66

86

C

72

72

72

71

70

71

73

72

72

72

72

72

D

75

74

75

74

74

75

75

75

75

75

75

79

E

73

75

75

74

73

74

74

74

73

74

73

72

F

OVALITY SCREW MEASUREMENTS

14110

14111

88

63

70

70

71

71

67

88

67

69

68

88

G

59

60

58

50

58

59

56

57

58

58

57

55

H

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Example of Format for Ovality Measurement

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14123

Figure 5 TABLE OF READINGS

DEVIATION PROFILES

ELEVATION

12

9

6

3

CLOCK POSITION

CLAMPS

12016

POSITION

MEASUREMENTS AT 0.5M MAX. INTERVALS

CLAMP

A

A

14121

14123

9

SECTION A - A

6

12

3

CLOCK POSITIONS OF MEASUREMENTS

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Example of Format for Straightness Measurement

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PROCEDURE I 15 001 WELD INSPECTION CONTENTS Para

Page

1

INTRODUCTION

3

2 2.1 2.2

TASK OPTIONS Standard Tasks Optional Tasks

3 3 3

3 3.1 3.2 3.3 3.4 3.4.1 3.4.2 3.4.3 3.4.4 3.4.5

OPERATING PROCEDURE AND SPECIFICATION Inspection Qualifications General Visual Inspection (VI-GVI / VD-ROV) Cathodic Potential Survey (CP-CON) Electromagnetic Inspection - ACFM (Alternating Current Field Measurement) Clean for Inspection (CL-INS) Close Up Detailed Visual Inspection (CU-DVI) Scope ACFM Survey and Operation (IN-ECI) Reporting of ACFM Results

4 4 4 4 4 4 5 5 6 7

4 4.1 4.2 4.3 4.4 4.5

OPTIONS Clean for MPI Inspection (CL-GRT) Close Visual Inspection (CU-CVI / VD-DIV /VD-ROV) Magnetic Particle Inspection (CU-MPI) Indication Grinding – (CN-GRD) Optional Digital Still Images (PH-DIG)

7 7 8 8 10 11

5 5.1

REPORTING Final Reporting

11 11

FIGURES No 1 2 3 4

Page Datum Marking Requirements Weld Detailed Inspection Summary Data Sheet Electro Magnetic Inspection Data Sheet Weld Inspection Magnetic Particle Data Sheet

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PROCEDURE I 15 001 WELD INSPECTION 1

INTRODUCTION The work method is to be applied to the inspection of welded steel joints to locate and size for length and depth, surface breaking defects. This method may be applied to the inspection of damage to steel members, attachments, pipelines and risers. The work carried out will include, General Visual Inspection, Cathodic Potential Survey, Cleaning, Close and Detailed Visual Inspection (CVI & DVI), Electromagnetic Inspection (ACFM) and Video/Digital Photography. If explicitly stated in the Workscope, it may also include Magnetic Particle Inspection, Ultrasonic Inspection, Remedial Grinding and Profile Measurements. Inspection methods under the following procedure are to be employed in conjunction with this Procedure. I 15 002 – Wall Thickness and Ultrasonic Inspection – General

2

TASK OPTIONS

2.1


2.2

VI-GVI

-


VD-ROV

-

ROV Video

CP-CON

-

Contact Cathodic Potential Survey

CL-INS

-

Clean For Inspection

CU-DVI

-

Close Up Detailed Visual Inspection (Weld Specific for ACFM)

IN-ECI

-

Eddy Current Inspection (Alternating Current Field Measurement – ACFM)

VD-DIV

-

Diver Video

Optional Tasks The following work tasks are optional and will be explicitly called for in the Workscope or will be required on identification of a C1 anomaly. CL-GRT

-

Clean For MPI Inspection (Air Grit Entrainment)

CU-CVI

-

Close Up Close Visual Inspection (Weld Specific for MPI)

VD-DIV (ROV)

-

Diver (ROV) Video

CU-MPI

-


CN-GRD

-

Remedial Grinding

PH-DIG

-

Digital Images

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Should anomalies be noted, they are to be reported and acted upon as per Section 2, Chapter 6, ‘Anomaly Reporting & Criteria’, and as directed by the Shell Offshore Representative. Following a 'C1' anomaly report further investigative inspection may be required. These works will be specified in the Workscope, or by the Shell Offshore Representative, acting on advice from the responsible Structural Engineer. 3


3.1

Inspection Qualifications Inspection to be carried out by CSWIP 3.1u, or 3.2u diver, CSWIP EMD Operator (ACFM Level 1/2) and CSWIP 3.4u Inspection Controller. An ACFM Level 2 operator will be required onboard during weld inspection operations to assist the level 1 as required. An ACFM Level 2 operator will be required to carry out any system reconfigurations.

3.2

General Visual Inspection (VI-GVI / VD-ROV) A general visual inspection will be carried out on the weld and surrounding area, to establish the integrity of the structure, determine the extent of cleaning required and to check that the area is safe for diver access. Marine growth will not be removed prior to this inspection. Note all debris of a hazardous nature for removal prior to the inspection. The inspection will report any obvious anomalies, e.g. missing or distorted members.

3.3

Cathodic Potential Survey (CP-CON) Contact Cathodic Potential Measurements are to be taken by diver prior to any cleaning being carried out at the selected inspection site. CP readings are to be taken at the four cardinal clock positions at the following locations: (1)

At the weld.

(2)

1m along the brace member from the weld.

(3)

2m along the brace member from the weld.

Calibration data is to be noted and verified before and after each dive and before each set of readings if the contact probe method is used. Proximity readings are the preferred option, but Contact probes may be used with prior approval of the Shell Offshore Representative, acting on advice from the Sponsoring Engineer. Reference procedure I 60 004 – Cathodic Protection Monitoring. 3.4

Electromagnetic Inspection - ACFM (Alternating Current Field Measurement)

3.4.1

Clean for Inspection (CL-INS) Excessive marine growth, corrosion and other deposits, which would inhibit the smooth probe travel along the weld toe should be removed. Loose paint coat, or paint coat in excess of 5mm, shall be removed from the weld cap and from the area within 50mm of each weld toe along the whole circumference. Cleaning shall be carried out using hand held wire brush or scrapers, or if required, low pressure air grit entrained, or high pressure water jetting. Other cleaning techniques must not be used as they can have an adverse effect on the detect ability of surface breaking defects.

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3.4.2

Close Up Detailed Visual Inspection (CU-DVI) Prior to commencing the detailed visual inspection a datum mark consisting of three vertical punch marks are to be applied to the chord member at the 12 o’clock position, starting 25mm from the weld toe. Should access be restricted, or for any other reason the 12 o’clock position cannot be used, a more suitable position may be substituted. See Fig.1. Note this may have been carried out from a previous inspection, as such the weld and/or historical data should be checked for the existence of such datum marks. Any confirmed existing datum marks should be used, to ensure consistency of results. From the datum mark the weld circumference is to be measured in a clockwise direction in 100mm increments. Each increment is to be marked with a suitably coloured oil based paint stick, or similar and numbered sequentially. Datum will always be zero. The datum mark position and total weld length are to be recorded on the Weld Inspection Data Sheet (Fig.2), the EMI Data Sheet (Fig.3), within the ACFM system software inspection log and within the COABIS Workpack Diary. The remote probe operator shall carry out a detailed visual inspection of the weld and parent material. Locate and record the position of any visible anomalies, corrosion pitting, temporary fabrication aids, geometry discontinuities, structural damage, etc.

3.4.3

Scope All Electromagnetic Inspection will be conducted using the following general rules. More specific information regarding the Shell EPE requirements for the use of ACFM are specified in points 3.4.4 and 3.4.5. (1)

This procedure is intended for the eddy current examination of nodal weldments using ACFM equipment, models U21 or U31D.

(2)

This procedure is restricted to locate and depth size surface breaking cracks in weld toe regions only.

(3)

This procedure is restricted to the use of the Standard Weld, Tight Access, Grind Repair (Pencil) and Mini probes. It is envisaged that the Standard Weld probes will be used in the main, with the other probe types used as appropriate.

(4)

The inspection principle is based on manual scanning of nodal weldments, respectively along the Chord and Brace weld-toes for either longitudinal or transverse surface breaking cracks. The possibility of interbead cracks is to be ignored.

(5)

This procedure is restricted to locating and sizing surface breaking longitudinal cracks with length exceeding 20mm and depth exceeding 2mm, and all transverse cracks with a depth exceeding 2mm.

(6)

This procedure can be applied to coated nodal weldments, but the applicability of this procedure is restricted to well adhered coating with a maximum coating thickness of <5mm.

Welded joints referred to in this procedure comprise all configurations fabricated in ferromagnetic material regardless of welding procedure or technique used. The inspection shall be carried out in the remote operator mode, utilising a remote probe operator (Diver - CSWIP 3.1u minimum) and a CSWIP EMI (ACFM Level 1) topside operator for recording and analysing of the scan data. NOTE:

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It is not envisaged that this should arise for standard weld inspections. Should a non-standard type weld be required to be inspected, this should be identified in the workscope, highlighting the requirement for a Level 2 operator. 3.4.4

ACFM Survey and Operation (IN-ECI) The ACFM equipment should be assembled with the correct probe, as identified from the GVI or DVI. This is typically the Standard Weld probe for weld toe inspection. The ACFM system does not require a calibration check. A system check should be carried out on the ACFM function test block prior to deploying the ACFM equipment to the worksite.

3.4.4.1

Diver Briefing The remote probe operator (diver) should be thoroughly briefed prior to carrying out the inspection. The briefing should include the following:

3.4.4.2

(1)

Level of cleaning required.

(2)

Marking up of the component weld prior to commencing inspection.

(3)

Reporting of visual defects and relevant features.

(4)

Dialog to be used during the inspection.

(5)

Probe selection / operation and scanning techniques.

(6)

Defect locating and visual marking of defect extents.

Topside Operation Prior to commencement of any inspection operation, the storage facility within the ACFM system software should be prepared for accurate data handling, ease of use during subsequent analysis and traceability. The emphasis is to identify a distinct inspection region. The first operation would be the choice of a suitable filename for the inspection. Due to the requirement to store the ACFM data file within the COABIS database, the filename must be unique, unrepeatable over subsequent years. To this end the following base file naming system is to be adopted, as the ACFM filing system is restricted to 8 characters. To enter the required information, proceed as follows: Enter 'FILENAME' i.e. BA040107 Where

NOTE:

BA =

Facility Code - Brent Alpha

04 =

Year (2004)

01 =

Unique Workpack Reference, relating to the last two digits of a workpack number (BA/2004/B101)

07 =

CTS Number, in this case CTS 7

For Shearwater Alpha (SWA), or Charlie (SWC), either the year or CTS (preferably CTS if single figured) should be shortened, to allow the full facility code to be entered. In cases where the above numbering system is still not appropriate, use a suitable filename, checking within historical data that such a file name has not been previously used. All ACFM files are to be saved within the COABIS database.

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The following information should be logged on the title page within the ACFM software against the initial function test scan:

3.4.5

(1)

Computer:

(6)

Weld length.

(2)

Software Version:

(7)

Direction of probe travel.

(3)

Probe type and serial no.

(8)

Probe operator.

(4)

Function check block serial no.

(9)

Topside operator.

(5)

Component under inspection

Reporting of ACFM Results All surface breaking defects located should be sized for length and depth. Defect dimensions should be recorded on the relevant title pages within the ACFM software and on the EMI Data Sheet (Fig.3). On completion of the inspection, the information (data files) should be backed up on the ACFM computer hard drive and to floppy disk. Where multiple welds are inspected, all relevant files can be saved to the same floppy disk(s) pertinent to the individual Workscope. This disk(s) should be submitted with the final Workscope report. The data files should be saved and linked within the COABIS database, and referenced within the COABIS Workpack Diary report. A screen dump showing the length and depth of all surface-breaking defects should be included in the final report, together with the relevant EMI Data Sheet (Fig.3). The completed EMI Data Sheet (Fig.3), should include the following: (1)

Clear indication of Datum location.

(2)

Distance of defect from indicated datum.

(3)

Defect length and depth.

(4)

Defect type.

(5)

A clear sketch showing component and indications.

(6)

Topside operators name.

(7)

Date of Inspection.

All findings should be reported to the Shell QAQC/Coordinator. 4

OPTIONS When specified in the Workscope or as directed by the Shell Offshore Representative or by sponsor, any of the following optional activities may be undertaken.

4.1

Clean for MPI Inspection (CL-GRT) All marine growth, protective coating, corrosion and other deposits, shall be removed from the weld itself and from areas extending 50mm from each weld edge, around the whole weld circumference, or as specified in the Workscope. Cleaning System utilised will be such that the area cleaned shall conform to Swedish Standard SIS 05 59 00 1969, Grade SA 2.5. The primary cleaning system will be a low-pressure air system with grit entrainment.

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4.2

Close Visual Inspection (CU-CVI / VD-DIV /VD-ROV) The CVI is to be carried out as for the Detailed Visual Inspection, see 3.4.2, but with the increased level of cleaning standard. The CVI will typically only be conducted where a C1 anomaly has been found as advised by the Shell Offshore Representative, based on advice from the responsible Structural Engineer, or as specified by the workscope. The survey is to be recorded on video and will take place on completion of all inspection and remedial work. The survey will start with a stand off view of the whole work site, which will clearly show the anomaly site in relation to structural members. The survey will incorporate all identification, scale, position and anomaly indication markers as used during the EMI, to allow cross-reference to a hard copy of the report data. The survey is to start at the Datum Mark - '0'mm, in all instances, and continue in a clockwise direction with the camera maintained in a vertical position until the survey ends at the Datum Mark. Care is to be taken to prevent gas bubbles obstructing the weld at any time during the survey. The stand off distance is to be so that the weld occupies the central 1/3 of the picture or the camera is at its close focus point with the weld held in focus. The survey is to be carried out at a speed that is slow enough so all anomalies are clearly observed and recorded (visual and narrative). Consideration is to be given, with the approval of the Shell Offshore Representative, to the choice of equipment depending on the circumstances where high-resolution black and white video may provide better results than colour. The orientation and position of the subject video is to be clearly identified on the Video Log.

4.3

Magnetic Particle Inspection (CU-MPI) Magnetic Particle Inspection (MPI) of the weld is to be carried out using Ardox 8560 High Ambient Light Fluorescent Ink to the following procedure: NOTE:

Due to ink concentrate dilution while carrying out MPI underwater the recommended concentration mix is to be double that specified by the manufacturer, i.e. use one Ardrox 8650 bottle of ink to one 10ltr OIS MPI Mk2 ink reservoir. This will give a 0.2% to 0.6% solids by volume when measured in a 100ml settlement flask.

(1)

Confirm light level appropriate for MPI using a photometer. Maximum light level with Ardrox 8560 is 120 Lux.

(2)

Confirm extent and standard of cleaning. Weld cap and areas extending 100mm from each weld edge.

(3)

Confirm 12 o'clock datum punch marks.

(4)

Confirm 100mm numbered increment markers are clearly visible.

(5)

Confirm only AC terminals are used for coil induced magnetic field inspection.

(6)

Install magnetising system. If coils, ensure two coils at all points around welds, with the 1st coil placed on the parent metal 25mm to 50mm from the toe of the weld under inspection. If permanent magnets or electromagnets (AC or DC) are used, ensure correct pre-dive pull off tests have been recorded. Apply inspection application for both longitudinal and transverse defect detection on weld under inspection.

(7)

Check for residual magnetism using a magnetometer. If residual magnetism confirmed, demagnetise and re-check.

(8)

Energise current. Increase until the required level is reached by checking with magnetometer (MIN 0.75 TESLA).

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(9)

Check TESLA level at a position 25mm from opposite toe of weld if using coils. NOTE:

For permanent magnet and electromagnet inspection, check magnetic field strength with Burmah - Castrol Type 2 flux indicators.

(10)

Record magnetometer and/or Burmah - Castrol indication readings on Weld Inspection Magnetic Particle Data Sheet (Fig 4).

(11)

Apply ink and view the weld and HAZ for defect indications.

(12)

Ensure angle of UV-A lamp is varied to gain maximum response. Hold lamp as close to weld as practicable. Any shading effect from the diver will enhance the viewing response.

(13)

Ensure light level is continuously checked to ensure light levels remain within parameters, less than 120 Lux, at a minimum of four cardinal clock positions, and any major change in weld geometry.

(14)

If defect indication observed - confirm by re MPI and report following: Type:

Continuous/Intermittent

Location:

HAZ/Weld Toe/Weld Cap - mm from Toe

Location:

Start/Stop position - mm from Datum Mark

Orientation:

Transverse/Longitudinal

Branching:

Location/Length/Orientation

Width:

mm - if possible

Refer to Fig 4. Report defect indications as 'defect indication' or 'intermittent defect indication' or 'severe undercut indication'. Spurious indications are not to be reported on. NOTE:

When measuring light levels, the diver is to ensure the maximum light is measured, shading from the Diver may give low readings and is to be avoided. Inspection equipment is to conform to the following standards.

BS EN ISO 9934-1/2/3:2001/2002,

:

Non-destructive testing. Magnetic particle testing. General principles (amendment AMD 14960)

:

Non-destructive testing. Penetrant testing and magnetic particle testing. Viewing conditions

:

Non-destructive testing. Magnetic particle testing. Detection media

:

Direct acting indicating analogue electrical measuring instruments and their accessories. Definitions and general requirements common to all parts

ISO 9934-1/2/3:2000/2002 (Replaces BS 6072: 1981) EN ISO 3059:2001 Identical, ISO 3059:2001 Identical (Replaces BS 4489: 1984) EN ISO 9934-2:2002 Identical, ISO 9934-2:2002 Identical (Replaces BS 4069: 1982) BS EN 60051-1:1999 Identical, IEC 60051-1:1997 Identical (Replaces BS 89-1: 1990)

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BS 667: 2005 (Replaces BS 667: 1996) 4.4

:

Illuminance meters. Requirements and test methods

Indication Grinding – (CN-GRD) Optional No grinding is to take place without the approval of the Shell Offshore Representative. Where cracks have been identified, grinding up to a depth limit of 2mm or 5% of nominal WT (which ever is the lesser value) to remove surface defects is permitted without approval from the Responsible Technical Authority (TA), as stated in the Weld Defect Anomaly Criteria actions (reference Section 2, Chapter 6, Point 2.2.19). Confirmation of the nodal nominal WT required prior to proceeding with grinding required. If the indication still remains, no further grinding shall take place unless authorised by the Shell Offshore Representative acting on advice from the responsible TA. Note that the maximum length of grinding (in excess of 2mm depth) is to be limited to 25% of the brace circumference. If the defect is greater than 75mm in length, only part of it should be ground at any one time. Removal of surface cracks by deep grinding, i.e. greater than 2mm depth or 5% of the plate thickness, shall be conducted in accordance with a procedure approved by the Responsible Shell Structural Engineer. If indications are noted check whether the area has been previously ground and report all findings to Shell Offshore Representative. All grinding shall be carried out using spherical and hemispherical tipped tungsten carbide burrs, mounted in either hydraulic or air operated pencil grinders. 12mm diameter burrs are preferred. Use of any smaller diameter burrs are only allowed after consultation and approval by the Shell Offshore Representative. NDT personnel are to familiarise themselves with the grinder on deck, or on a test piece at depth, in order to ascertain how many passes are required to remove 0.5mm of metal. Grinding will be carried out as specified in the Workscope or by the Shell Offshore Representative. (Grinding is normally carried out following the detection of indications found during MPI. It should also be carried out as a remedial measure for removing undercut and smooth contouring the surrounding steel). Where grinding, or further grinding, is to take place on a previously reported defect the NDT personnel are to refer to the previous MPI and Close Visual Inspection reports to verify the nature and extent of the indication. Indication grinding is only to be carried out whilst the grinding area is set up for MPI. The indication is to be ground in depth increments of 0.5mm, which are to be measured using a LAM gauge. Grinding depth is to be measured at maximum increments of 25mm along the indication tape datum. Before grinding, and subsequently after each grinding step, MPI is to be reapplied and the following information noted: (1)

Location of crack.

(2)

Length.

(3)

Width.

(4)

Orientation.

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(5)

Crack increase or decrease in length.

(6)

Crack increase or decrease in width.

(7)

Direction in which crack is progressing, whether defect is in weld metal, parent metal or heat affected zone.

On completion of grinding, the ground area should be smoothly contoured. The ground area shall be contoured so that its profile conforms to a circumference of a 12mm minimum diameter circle. The surrounding areas should then be ground so that no sharp edges remain which could act as stress raisers. The final grinding pass should be made at right angles to the weld's longitudinal axis. NOTES:

(1) To ensure effective removal of crack-like defects by grinding, the ground depth should continue 0.5mm deeper than the indication to remove yielded material or any burr concealing the indication. On completion of all grinding confirm as left condition ground depth with the use of the LAM gauge at maximum increments of 25mm along the ground path tape datum. (2) ECI (ACFM) inspection may also be called for to indicate crack depth and to confirm crack has been removed by grinding.

All works carried out and as left weld condition is to be recorded on the Weld inspection Magnetic Particle Data Sheet. (Ref Fig 4). 4.5

Digital Still Images (PH-DIG) If possible, digital images should be taken of any visual surface breaking cracks, or other C1 anomaly, should the video quality allow. Digital images should be taken of any subsequent grinding, with suitable indicators confirming the start and end of the grinding, with at least two 100mm increment markers included in the image.

5

REPORTING

5.1

Final Reporting The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above, referencing any ACFM files and accompanying data sheets. Reference section 2, Chapter 1, Section 3.1.5. All Weld Inspection Data Sheets (Fig.2), EMI Data Sheets (Fig.3) and MPI Data Sheets (Fig.4) are to be included with the final report, along with ACFM screen dumps of any defects identified. Any ACFM files are to be saved and linked within the COABIS database, including screen dumps of any defect. These multiple files should be zipped into a single file for each weld. Multiple zipped files, for several welds, will be required to be submitted on CD or floppy disk(s) with the final report.

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JACKET LEG (CHORD)

WELD TO BE INSPECTED

CLEANED AREA

BRACE

DATUM CENTRE PUNCHES OR MAGNETIC MARKER

CHORD

25mm

DIRECTION OF INSPECTION

BRACE

THE DATUM REFERENCE MARKS ARE TO BE CENTRE PUNCHED, WITH A ROUND POINTED PUNCH, INTO THE CHORD PARENT METAL 25mm FROM THE WELD TOE. THE CENTRE PUNCHING IS NOT TO EXCEED A DEPTH OF 2mm.

Figure 1

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Datum Marking Requirements

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Code

Figure 2

Intern/ Contin/ % Cover Max.

Chord HAZ Chord Toe Weld CAP Brace Toe Brace HAZ

Nodal Weld Inspection -

Drawing

Elevation

Workpack

Data Recorder (s)

Component

Substructure End

Structure Start

Master

WD

Anomalies

Guidance

1 2 3 4 5

Dates

VI-GVI IN-ECI CP-CON CL-GRT CU-CVI CU-MPI PH-35M CN-RIG

* + X "

No Yes No Yes No

Locations

Tape 0.0

0.000

Metres

All Tasks

No Defects Undercut >2mm D X 10mm L Undercut <2mm Deep Crack/Linear Indication Other Defects, CR, PD.

CU-CVI Weld Length

OK UC1 UC2 CR OTH

Feature

Spread

Comment

5

(Y/N)

Anom.

Length

Development - Anomalous Findings

Av.

Depth (mm)

Development - Routine Findings

Length

Shell Expro - UEIS 1.1

4

Start

Tape (mm)


3

2

1

Locn

Tape 0.0

5

4

3

2

1

Locn

Locn.

No.

Code

Feature

CU - CVI

To

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Weld Detailed Inspection Summary Data Sheet

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Figure 3

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Electro Magnetic Inspection Data Sheet

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Code

Figure 4

Intern/ Contin/ % Cover Max.

Comment

Description

Method

Demagged

Data Recorder (s)

Drawing

Elevation

Component

Substructure End

Structure

Master

WD

Anomalies

Field Check

Chord HAZ Chord Toe Weld CAP Brace Toe Brace HAZ

Workpack Nodal Weld Inspection -

5

Tape 0.0

Lux Level

Control Details

Guidance

1 2 3 4 5

Locations

Start

IN-ECI

* + X "

No Yes No Yes No

Symbol Anom

Dates

VI-GVI CP-CON CL-GRT CU-CVI CU-MPI PH-35M CN-RIG

All Tasks

Ink Type

No Defects Undercut >2mm D X 10mm L Undercut <2mm Deep Crack/Linear Indication Other Defects, CR, PD.

CU-MPI

OK UC1 UC2 CR OTH

Feature

Spread

(Y/N)

Anom.

Length

Development - Anomalous Findings

Av.

Depth (mm)

Development - Routine Findings

Length

Shell Expro - UEIS 1.1

4

Start

Tape (mm)


3

2

1

Locn

Tape 0.0

5

4

3

2

1

Locn

Locn.

No.

Code

Feature

CU - MPI

To

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Weld Inspection Magnetic Particle Data Sheet

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PROCEDURE I 15 002 WALL THICKNESS AND ULTRASONIC INSPECTION - GENERAL CONTENTS Para

Page

1

INTRODUCTION

3

2 2.1

TASKS Optional Tasks

3 3

3 3.1 3.2 3.3 3.3.1 3.3.2 3.4 3.4.1 3.4.2 3.4.3 3.4.4 3.4.5 3.4.6 3.4.7 3.5 3.5.1 3.5.2 3.5.3 3.5.4 3.6

OPERATING PROCEDURE AND SPECIFICATION Inspection Qualifications General Visual Inspection (VI-GVI / VD-ROV) Ultrasonic Digital Wall Thickness Measurements (WT-DIG) General - Diver ROV Pulsed Eddy Current (PEC) Wall Thickness Measurements (WT-PEC) WROV Dual PEC Probe Handling Frame ROV PEC Frame Obtained Caisson Readings (ONEgas / Northern) Single PEC Probe ROV Manipulator Held Calibration Readings Datum Reference Anomalous Readings Post Inspection Video (CL-INS / VI-DVI / VD-ROV) Ultrasonic `A' Scan (IN-UTA) General Surface Preparation (CL-GRT) Close Visual Inspection (VI-CVI) Inspection Method Video (VD-ROV / VD-DIV)

3 3 3 4 4 4 5 5 6 6 7 7 7 7 7 7 8 8 8 9

4 4.1


9 9

FIGURES No 1 2 3

Page Ultrasonic Inspection Report Data Sheet Dual PEC Probe Handling Frame Schematic Typical PEC Results Data Sheet Format

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10 11 12

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PROCEDURE I 15 002 WALL THICKNESS AND ULTRASONIC INSPECTION - GENERAL 1

INTRODUCTION The work method is to be applied to the Wall Thickness and Ultrasonic (UT) inspection of ferric material for the location of discontinuities within that material. The requirement for UT inspection will be specified in the Workscope. This procedure may be used in conjunction with Procedure I 15 001 to investigate anomalies.

2

TASKS

2.1

Optional Tasks The following work tasks are optional and will be explicitly called for in the Workscope. VI-GVI

-


VD-ROV

-

ROV Video

CL-INS

-

Clean For Inspection

WT-DIG

-

Ultrasonic Wall Thickness – Digital

VD-DIV

-

Diver Video

CL-GRT

-

Clean For Inspection (Air Grit Entrainment)

WT-PEC

-

Pulsed Eddy Current (PEC) Wall Thickness Measurement

IN-UTA

-

Ultrasonic 'A' Scan

Should anomalies be noted, they are to be reported and acted upon as per Section 2, Chapter 6, ‘Anomaly Reporting & Criteria’, and as directed by the Shell Offshore Representative. Following a 'C1' anomaly report further investigative inspection may be required. These works will be specified in the Workscope or by the Shell Offshore Representative acting on advice from the responsible Structural Engineer. 3


3.1

Inspection Qualifications Ultrasonic digital wall thickness inspection work is to be carried out by CSWIP 3.1u / 3.2u diver, under the guidance of a CSWIP 3.4u Inspection Controller. PEC wall thickness survey is to be carried out by a CSWIP 3.4u Inspection Controller, suitably instructed in the use of the PEC software and processes. Ultrasonic ‘A’ scan inspection work is to be carried out by suitably qualified PCN, level 2 UT Operator.

3.2

General Visual Inspection (VI-GVI / VD-ROV) A general visual inspection will be made of the inspection site and surrounding area, by ROV recorded on video, to establish the general integrity of the structure required and to check that the area is safe for diver access. Marine growth will not be removed prior to this inspection. Note all debris of a hazardous nature for removal prior to inspection.

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3.3

Ultrasonic Digital Wall Thickness Measurements (WT-DIG) The location and extent of readings will be specified in the workscope. Where these readings are not possible due to access or other factors, alternative readings may be selected after consultation with the Shell Offshore Representative, acting on advice from the responsible Structural Engineer.

3.3.1

General - Diver The ultrasonic digital inspection system to be utilised will be the Cygnus 1 Underwater Multiple Echo Ultrasonic Gauge, complete with underwater remote probe 2.25MHz 13mm. Deployment and operation of the unit will be as per the Cygnus Instruments Ltd, Operation Manual. The Inspection Diver's hat mounted TV camera is to be utilised during the ultrasonic inspection to allow the topside inspection controller to monitor the exact probe position with relationship to the inspection work site. Surface preparation prior to UT readings is to be conducted to the following levels: No intact coating is to be removed, unless previously specified in the workscope, or approved by the Shell Offshore Representative, after consultation with the responsible Structural Engineer.

3.3.2

(1)

Flaky deposits to be removed.

(2)

Marine growth to be removed.

(3)

Solid, adhering paint/protective coatings (pipe-wrap etc) can be left in place, maximum thickness 6-10mm depending on material, some glass fibre content materials are very attenuative, likewise some metal flake types. Generally it is recommended that a test be carried out to evaluate measurability.

(4)

Surface need not be ground flat or even brightened.

(5)

Ensure good application of couplant in all cases.

(6)

Neoprene/rubber protectants are only to be removed if specified in the workscope, or as advised by the Shell Offshore Representative.

ROV Wall thickness readings can be taken by WROV using a Cygnus 1 probe as employed by divers, slightly modified for use. The method of taking the readings is to follow the diver technique (3.3.1.) as best as possible. Two techniques are currently employed with Shell utilising a WROV. (1)

The main method employed is to use a suitable mounting bracket for the probe, as proposed by the contractor and agreed by Shell EPE, which is held and positioned using the vehicles manipulator. The use of this method is restricted in that generally the reading location cannot be confirmed with too great a degree of accuracy. This is as positioning the probe is influenced by access, sea conditions, current and other factors that affect the manoeuvrability of the ROV.

(2)

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A Cygnus probe is contained within the Pulsed Eddy Current (PEC) Dual Probe handling frame. This probe is fixed to the top of the PEC frame, and is used mainly for reference readings for PEC surveys, but can be used in a restricted manner for WT surveys.

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3.4

Pulsed Eddy Current (PEC) Wall Thickness Measurements (WT-PEC) Initially a topside system designed in house by Shell Global Solutions for taking wall thickness (WT) readings on coated steel components. The system uses eddy currents to determine WT, not ultrasonics. A subsea system was developed specifically for use by ROV on Firewater and Seawater lift caissons. This was to identify the existence of wall thinning due to the presence of an internal pump. It can however be used on any steel component. The method of use of the PEC wall thickness system is detailed in the current Shell Global Solutions operation manual (OG.02.20617). This system may be used by ROV, diver and topside. However, at present for this manual it is only intended for ROV use. The benefits of the PEC method are that WT readings can be obtained though coatings of most thicknesses and types, and without the need for marine growth cleaning, apart from where excessive marine growth would prevent fitment of the PEC Probe Handling frames, discussed below. There are three methods of use, which are further discussed below: (1)

WROV Dual PEC Probe Handling Frame. Two PEC probes mounted in a specifically designed frame for use by a dedicated WROV. Allows accurate positioning of the PEC probes once the frame is established around the full circumference of a vertical or caisson. Designed for use within larger structures with suitable access to components, i.e. Shell Northern Structures. This system can inspect vertical components with diameters of between 42”-22”.

(2)

ROV Mini PEC Probe Handling Frame. A dual PEC probe mounted in a specifically designed frame for use by a dedicated mid sized ROV. Allows accurate positioning of the PEC probe once the frame is established around a vertical or caisson, at two clock positions. The vehicle requires to be repositioned for further readings at different clock positions. Designed for use within smaller structures with less restricted access, i.e. Shell ONEgas Structures. This system can inspect vertical components with diameters of between 22”-16”.

(3)

Single PEC Probe ROV Manipulator Held. Use of a single probe, mounted in a bracket, held by an ROV manipulator. Designed for use where access prevents use of either of the above. Refer to 4.3.2.4.

The location and extent of readings will be specified in the workscope. Where these readings are not possible due to access or other factors, alternative readings may be selected after consultation with the Shell Offshore Representative, on advice from the responsible Structural Engineer. Two types of probes are utilised, ‘wide’ and ‘narrow’ beam. The wide beam probes allow readings over a larger footprint, where the results give an average WT over the footprint. The narrow beam gives an average WT over a smaller footprint. As a result the narrow beam probe tends to be used on smaller diameter tubulars, or where known perforations exist which may give a false indication of WT.

3.4.1

NOTE:

All PEC readings taken are subject to post processing on completion of the survey. As a result, evidence of thinning may not be fully apparent until post processing has been completed. Past history has shown that in the main, variations from the initial results are not large. However, post processing may result in readings initially not anomalous, becoming anomalous, and vice versa.

NOTE:

It has been proven that PEC cannot be used on flexible pipelines due to their method of manufacture, as is the case for UT methods also.

WROV Dual PEC Probe Handling Frame This PEC Probe handling method allows accurate positioning of two PEC Probes for WT inspection of caissons or other near vertical tubular components, over large areas. The WROV frame, designed by Sub-Atlantic, holds two standard PEC Probes diametrically opposite each other, when mounted around a tubular. The frame is permanently attached to a specifically allocated WROV, and can currently be attached to any near vertical tubular.

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Once attached the frame allows 700mm vertical and 360 degree travel of the probes, monitored by an array of cameras. The schematic Figure 2 shows the PEC frame mounted on an ROV, in position on a vertical tubular/caisson. The handling frame has the following specification, restricting its use on inclined tubulars: PEC Tool System weight (in air):

540Kg

PEC Tool System weight (in sea water):

Neutral

Pitch angle:

150 total, (7.50 either side of mid position)

Yaw angle:

300 total, (150 either side of mid position)

The extent of readings to be taken will be specified in the workscope. It is recommended that over large areas readings should be taken at 100mm or 250mm increments vertically, but readings can be taken in any increment of 50mm. Around the circumference of a tubular, readings can be taken at each of the 12 clock positions. For large inspection areas, it is recommended to take readings local to the area of interest at the 12 clock positions, and then at the 4 cardinal clock positions. It is recommended that at least 2 full passes over the 12 clock positions are taken at some point. Prior to commencement of readings in the inspection area, a calibration reading is required in an area presumed to be free from any possible thinning, on a component of the same diameter and wall thickness. This is backed up by the taking of an ultrasonic Cygnus WT reading at the same location. The PEC frame is typically mounted with wide beam PEC probes. If required these may be replaced by narrow beam probes. Where the PEC frame cannot be employed, due to either diameter size or restricted access, the ROV PEC frame (see 3.4.2) or the manipulator held PEC probe may be used (see 3.4.3). 3.4.2

ROV PEC Frame Obtained Caisson Readings (ONEgas / Northern) This PEC Probe handling method allows accurate positioning of two PEC Probes for WT inspection of caissons or other near vertical tubular components. The allowable vertical travel of the inspection probes is 300mm when the frame is in position. Subsequent readings require repositioning of the frame by the ROV. As a consequence, accurate reporting, depth monitoring and cross reference to previous readings is required. The PEC frame is typically mounted with wide beam PEC probes. If required these may be replaced by narrow beam probes.

3.4.3

Single PEC Probe ROV Manipulator Held The Single PEC probe method can be used in any location, tubular or flat, at any inclination, as access allows. Two probe types exist, providing a broad and narrow inspection beam area. The narrow beam probe should be used on tubulars of small diameter. A mounting frame has been used in the past in the form of a ‘V’, which helps to centralise and stabilise the PEC probe on the inspection area. This mounting frame must not be made from magnetic ferrous metal, or aluminium. An acceptable material is Non-magnetic Stainless Steel, or plastic. As for the taking of manipulator held Cygnus WT readings, this method is not as accurate in its positioning of the PEC probe, due to vehicle movement, and general problems regarding the correct position of the probe. However, best endeavours should be made to accurately record the locations of readings taken.

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3.4.4

Calibration Readings Prior to commencement of readings in the inspection area, a calibration reading is required in an area presumed to be free from any possible thinning. The nominal WT of the component under inspection should be known. The workscope should detail any possible change in WT within the inspection area. As a comparison with the calibration reading, ultrasonic Cygnus WT readings may additionally be required. This is catered for on the WROV PEC frame, where a Cygnus probe is mounted to the top of the frame, as well as a rotary wire brush for cleaning. This measurement is to be used as a comparison with the given nominal WT, which is a required input for the PEC software.

3.4.5

Datum Reference Readings taken should be referenced to a known datum. The most obvious reference feature is a horizontal elevation. The ‘as-built’ depths of all horizontal elevations given are based on the vertical mid point of the elevation member. To establish the position of the pump, the difference between the given pump depth and elevation depth, should be added or subtracted from the ROV (or diver) depth for the vertical mid-point of the elevation member. Where tidal variations exist, or where different vehicles, or new dives are used to continue an inspection on a specific caisson, repeat checks on the offset should be taken.

3.4.6

Anomalous Readings When using the PEC frame, where anomalous WT loss is established, to C1 level for risers ≥20%, C2 level for caissons ≥50%, and ≥20% for other steel components, PEC readings should be increased back to the workscope stated minimum vertical increment (100mm or 50mm), and at all adjacent clock positions, until WT levels are less than the above anomaly criteria, or as instructed by the Shell Offshore Representative, acting on advice from the Responsible Structural Engineer. Where manipulator held PEC survey is employed, the above criteria still applies, however it is accepted that this may not be possible. Attempts should be made to obtain the best possible results as time and operational constraints allow.

3.4.7

Post Inspection Video (CL-INS / VI-DVI / VD-ROV) The benefit of this survey is that no initial cleaning is required. Therefore any meaningful video survey post inspection would require cleaning. Video inspection should therefore be based on the results of the survey and should not be carried out unless WT loss to the anomaly levels above has been identified. Unless specified in the workscope, cleaning and DVI should be restricted to the identified areas of WT loss, or as directed by the Shell Offshore Representative, acting on advice from the Responsible Structural Engineer.

3.5

Ultrasonic ‘A’ Scan (IN-UTA)

3.5.1

General Ultrasonic Inspection Systems to be utilised will be either the Wells Krautkramer USK-7 or the Subspek SM 3, complete with surface read out (SRO) Units. Deployment and operation of the unit will be as per respective Manufacturers Operation manuals. The Inspectors Divers hat mounted TV camera is to be utilised during the Ultrasonic Inspection to allow the topside inspection controller to monitor the exact probe position with relationship to the inspection site.

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3.5.2

Surface Preparation (CL-GRT) All marine growth, protective coating, corrosion and other deposits, shall be removed from the inspection site extending 100mm beyond the area of interest, or as specified in the Workscope. The cleaning system utilised will be such that the area cleaned shall conform to Swedish Standard SIS 05 59 00 1969, Grade SA 2.5 and shall be capable of operating to a depth of at least 180 metres. The philosophy adopted is that a low-pressure air system with grit entrainment having an operating pressure of 50psi (3.5bar) over ambient pressure will be the primary method of cleaning. Additional methods of cleaning, such as rotary wire brushes and hand-held brushes, should also be available for use in appropriate situations subject to the approval of the Shell Offshore Representative.

3.5.3

Close Visual Inspection (VI-CVI) A Close Visual Inspection (CVI) will be required of the area to be inspected, to check for any defects that may affect the results of the Ultrasonic ‘A’ Scan inspection.

3.5.4

Inspection Method It is presumed that the Ultrasonic ‘A’ Scan inspection will be conducted based on results of a previous weld survey, as per procedure I 15 001. To this end a datum mark consisting of 3 vertical punch marks should exist. From this, the weld should be marked in 100mm increments clockwise from this datum with a suitably coloured oil based paint stick or similar, and numbered sequentially. Datum will always be zero. If no punch marks exist, prior to commencing the ‘A’ scan inspection, a datum mark consisting of three vertical punch marks are to be applied to the chord member at the 12 o’clock position. Should access be restricted, or for any other reason the 12 o’clock position cannot be used, a more suitable position may be substituted. See Fig.1 for procedure I 15 001. Note this may have been carried out from a previous inspection, as such historical data, and or the diver should check for the existence of such datum marks. The datum mark position and total weld length are to be recorded on the submitted report from the UT operator, and within the COABIS Workpack Diary. Figure 1 shows an Ultrasonic Inspection Report Data Sheet which may be used should no Report Data sheets be available to the UT Operator. Where practicable, detailed special workscopes will be issued to suit individual requirements. In the absence of detailed special workscopes the procedure for carrying out ultrasonic examinations and evaluation of inclusions for Ultrasonic Technicians will comply with the following standards: (1)

Laminar defects in the parent metal.

(2)

Root area.

(3)

Sidewall lack of fusion.

(4)

Inclusions.

(5)

Shrinkage cracks.

(6)

Hydrogen sulphide cracking.

(7)

Undercut.

(8)

Wormhole and porosity

(9)

Burn-through.

(10)

Excessive weld metal.

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Any defects located are to be noted and further examination carried out to determine their size, extent and where possible, the type. The 6 dB and 20 dB drop methods are to be used as applicable. 3.6

Video (VD-ROV / VD-DIV) Video confirming the area inspected and any markings used will be required. A video survey is required to provide a supplement to the 'C1' Anomaly Report and is to provide a visual and narrative impression of the anomaly under inspection. The video survey will take place on completion of all inspection and remedial work and will start with a stand off view of the whole work site, which will clearly show the anomaly site in relation to structural members. The video survey will incorporate all identification, scale, position and anomaly indication arrows as used during the UT Inspection to allow cross-reference to hard copy report data. The survey is to start at the Datum Mark in all instances and continue in a logical sequence with the camera maintained in a vertical position until the survey ends, once more at the Datum Mark. Care is to be taken to prevent gas bubbles obstructing the weld at any time during the survey. The stand off distance is to be such that the weld occupies the central 1/3 of the picture or that the camera is at its close focus point with the weld held in focus, and that the survey is carried out at a speed that is slow enough so that all anomalies are clearly observed and recorded (visual and narrative). Consideration is to be given, with the approval of the Shell Offshore Representative, to the choice of equipment depending on the circumstances where high resolution black and white video may provide better results than colour. The orientation and position of the subject video is to be identified on the Video Log. An as left survey is required to confirm that the worksite has been left clear of all rigging & inspection equipment.

4

REPORTING

4.1

Final Report The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above, referencing any accompanying data sheets. Reference section 2, Chapter 1, Section 3.1.5. Where a large number of readings are taken, that cannot be suitably incorporated into the Workpack Diary, a drawing showing the results and the location of the readings is to be submitted. A hard copy of all PEC data results, and any associated Cygnus WT readings, are to be included in the Results/Appendix section of the final report, in a similar format to that shown in fig.3 below. This format is converted from the processed PEC data files, which is in an excel format. All PEC data files are to be saved within the COABIS database and suitably linked.

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Figure 1 I 15 002 Page 10 of 12

Ultrasonic Inspection Report Data Sheet Re-issue 04/05

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Workclass ROV

PEC Probe Handling Frame Vertical Tubular

Figure 2

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Dual PEC Probe Handling Frame Schematic

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PEC Offline Wall Thickness plot A + B (15% Smoothed + FFT filtered) Location

Nelson

Date

Saturday,12 Jun 2004

Job nr.

NELSN/2004/C101

Filenam e

RD16404C

Com ponent nr.

43-007

Description

Seaw ater caisson

Datum point

-10m

Recorded by

John Dow nes / John Knight

Diam eter

39

WT_nom

15

Grid vert.

spacing longitudinal

Vert.incr.

100

Grid. hor.

clockposi circumferential

Hor. incr.

1

[inch]

Vertical Position +1500 +1400 +1300 +1200 +1100 +1000 +900 +800 +700 +600 +500 +400 +300 +200 +100 0 -100 -200 -300 -400 -500 -600 -700 -800 -900 -1000 -1100 -1200 -1300 -1400 -1500 -1600

[mm] [mm] [hr]

Horizontal Position 1

2

3

4

5

6

7

8

9

10

11

12

14.6

14.4

14.9

14.7

14.6

15.2

15.3

15.3

14.5

13.9

13.6

19.7

13.3

13.5

14.0

13.9

14.2

14.8

14.4

14.7

14.0

11.7

12.3

19.7

11.1

13.0

13.1

13.9

13.9

13.8

13.8

13.6

13.3

11.6

11.2

18.7

11.0

12.1

11.6

12.3

13.4

13.2

13.7

12.4

11.9

10.8

10.3

18.1

9.9

11.6

10.9

11.5

12.9

13.3

13.6

12.5

12.0

11.8

9.9

17.3

9.4

12.6

11.8

13.7

14.0

13.6

13.8

12.2

12.5

11.7

10.7

17.6

11.9

13.0

12.2

13.3

14.0

14.1

14.0

12.3

12.5

12.5

10.9

16.8

11.9

12.8

11.3

13.5

13.9

13.9

13.7

12.5

13.4

12.3

12.1

18.1

12.4

15.2

15.2

15.0

13.4

11.7

15.6

15.8

15.9

15.6

14.9

14.3

13.2

15.4

15.3

14.5

15.7

15.6

16.1

15.7

15.4

15.6

15.5

15.2

14.5

15.0

16.1

14.9

15.5

14.8

15.5

15.5

15.6

16.0

16.3

15.4

15.2

15.7

15.5

15.7

15.5

15.6

15.5

15.4

15.6

16.1

16.0

15.9

15.6

15.7

15.6

15.8

15.7

14.8

15.7

15.2

15.9

16.1

15.9

16.1

16.0

15.8

15.4

15.6

15.9

15.5

15.5

15.6

15.5

15.9

16.0

16.1

15.5

15.9

15.3

15.1

15.8

15.8

15.6

15.8

15.9

15.9

16.3

16.1

16.1

16.3

16.1

16.0

15.5

18.1

15.7

15.8

15.6

15.7

16.2

16.2

16.2

16.3

15.9

15.8

14.9

18.1

15.6

15.3

15.5

15.6

15.8

16.1

16.5

15.0

14.9

15.2

14.5

18.2

16.2

16.2

15.1

15.6

15.4

16.6

15.1

15.0

15.4

17.4

15.3

15.0

15.0

17.1

15.2

14.5

14.6

16.9

15.0

14.9

14.8

16.6

15.1

15.0

15.2

16.2

15.1

14.9

15.0

15.2

15.5

14.8

15.0

14.7

14.7

16.0

14.0

15.0 14.6

14.9

15.0

15.0

14.5

14.8

15.4

14.7

14.7

14.7

15.1

14.5

14.9

14.8

14.6 13.7

13.6

14.3

14.0

13.3

14.5

14.8

14.6

12.9

14.6

14.3

10%+ (+/-) 10% 10% - 15% 15% - 20% 20% - 25% 25% - 30% 30% - 35% 35% - 40% >40% ref_value

15

margin %

10

band_min

13.5

band_ma

16.5

perc_incr

5

Figure 3

Typical PEC Results Data Sheet Format

(Produced from PEC Excel Spreadsheet Both_offl2 Corrected)

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PROCEDURE I 15 003 FLOODED MEMBER DETECTION CONTENTS Para

Page

1

INTRODUCTION

3

2 2.1 2.2

TASKS Standard Tasks Anomaly Tasks

3 3 3

3 3.1 3.2 3.3 3.4 3.5

OPERATING PROCEDURE AND SPECIFICATION Inspection Qualifications Flooded Member Detection (FMD) Systems Operational Application and Constraints (IN-FMD) Anomaly Tasks (Additional/Optional) Weld Inspection (VI-DVI)

3 3 3 4 5 5

4 4.1


5 5

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PROCEDURE I 15 003 FLOODED MEMBER DETECTION 1

INTRODUCTION Flooded Member Detection (FMD) will be employed as a first pass inspection method to inspect structural members so as to identify which, if any, are flooded. FMD will also be required to inspect members for flooding following damage, report of weld cracking or to locate blockages in pipelines, caissons, etc, and will be specified in the Offshore Workscope. This Procedure may be used in conjunction with Procedures I 15 001 and I 15 002 to investigate anomalies.

2

TASKS

2.1

Standard Tasks The following Listed tasks are always to be invoked. IN-FMD

2.2

-


Anomaly Tasks The following work tasks will be required to be conducted on finding a flooded member, as per Section 2, Chapter 6, ‘Anomaly Reporting & Criteria’, or as specified in the workscope, and /or Shell Offshore Representative, should a flooded member be suspected. VI-GVI

-


VD-ROV

-

ROV Video

CL-INS

-


3


3.1

Inspection Qualifications The inspection is to be carried out by ROV, under the guidance of a CSWIP 3.3u or 3.4u Inspection Controller. FMD System Operators will be supplied by the system's operating company. Suitably trained additional system operators may be provided by the contractor. All will be suitably qualified Radiation Protection Supervisors (RPS). The system may be employed by divers, however it is not envisaged that this option will be adopted. If used by divers, no inspection qualification is required, however suitable on site instruction into its use and risks will be provided by the FMD Operators technician.

3.2

Flooded Member Detection (FMD) Systems The Pro-Sub Services Ltd., ‘Gamm@chek’, Gamma Radiation FMD technique is the preferred method for inspecting for flooded members. The method of use will only be operated as per the latest Pro-Sub ’Gamm@chek’ Operating Procedure. The use of Gamma Radiation to detect for water within a member is based on the principle that less radiation will be able to pass through a flooded member.

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A gamma source is held at one side of the member, with a detector held diametrically opposite on the other side of the member to record the amount of passing radiation. Given the member diameter and wall thickness, it can thus be determined if the member is dry, flooded or % of partial flooding. There are other diver operated ultrasonic FMD systems available, but it is not envisaged to utilise these systems. The ‘Gamm@chek’ system can be deployed by either ROV, diver or rope access and needs no site cleaning prior to inspection being carried out. There are two forms of ‘Gamm@chek’ FMD frames that can be employed: (1)

The primary frame is a mechanical device, which allows re-configuration of the frame for different member diameters without need to recover the vehicle. This frame when employed with a rotating manipulator, removes the requirement for any recovery for reconfiguration.

(2)

The secondary frame requires recovery and reconfiguration to accommodate members of different sizes, and as such is less efficient than the mechanical frame. Its use is only allowed with approval received prior to mobilisation from the Responsible Structural Engineer. Its use therefore should only be necessary as a backup method, or where the mechanical frame is not compatible with the ROV approved for its deployment.

Pro-Sub Services Ltd. are to be supplied with full details of the members to be inspected, including location drawings, member diameter, wall thicknesses including location of WT changes and member orientation prior to mobilisation. This is to allow the data for the members to be inspected, to be preentered into the software database. This will allow pre-planning, to increase the efficiency of the survey. Local rules for handling and use of Radioactive Material apply. A Company specified Radiation Protection Supervisor (RPS) is required on site to handle the Radioactive Source. 3.3

Operational Application and Constraints (IN-FMD) Although operation of the system will be carried out by the Manufacturing Company's personnel, the following basic applications are to be carried out at inspection sites: (1)

The ROV is to inspect structural members in a logical sequence by member size and orientation, thereby minimising time spent on surface for FMD Jig reconfiguration.

(2)

Readings, where possible, are to be taken clear of any obvious disturbances such as welds, doubler plates, other appurtenances such as grout pipes, and where significant drill mud exists on members. All such items could give spurious results.

(3)

All members are to be inspected at the lowest point: (a)

Horizontal Members - 6 o'clock position (mid point of member).

(b)

Vertical members - Lowest accessible point.

(c)

Vertical Diagonal Members - Underside at lowest accessible point.

(4)

Where flooding is indicated at the base of a vertical or vertical diagonal member, no further inspection to ascertain the level of flooding is required.

(5)

Where flooding is indicated on a horizontal member, no additional readings should be required, unless it is unsure as to whether internal diaphragm plates exist. In this case additional readings may be required, unless as-built drawings are available which can confirm the member configuration. Where partial flooding of the member diameter is identified, the systems own software can be used to identify the extent of partial flooding, or failing that by use of a comparison against readings on a known dry member having the same physical attributes.

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3.4

Anomaly Tasks (Additional/Optional) Where flooding is indicated the following tasks are to be carried out; (1)

3.5

GVI of the member is to be carried out where there is no previous history of flooding, or no suspicion of a likely cause for flooding. Investigations are to be conducted for the following possible causes of flooding: (a)

Gross structural damage,

(b)

Debris which may have caused gross damage,

(c)

End weld connections

(d)

Possible flooding/grouting holes, which would be, located at the member ends, at the 12 and 6 o’clock positions.

(2)

Video is only required, should a possible cause for the flooding be identified.

(3)

Cleaning should only be carried out once a possible cause has been identified. No major cleaning program is to be commenced without consultation with Shell Offshore Representative, acting on advice from the Responsible Structural Engineer.

Weld Inspection (VI-DVI) If specified in the workscope, or advised by the Shell Offshore Representative, acting on advice from the Responsible Structural Engineer, carry out cleaning and inspection and detailed visual inspection of both end welds. Seam or Circumferential welds may also be specified. Refer to Section 1, Chapter 4 for cleaning and DVI specification.

4

REPORTING

4.1

Final Report The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above. Reference section 2, Chapter 1, Section 3.1.5. The report should list all flooded members, and any members not inspected giving reasons, i.e. restricted access. Where flooding has been identified, confirmation of the extent and results of any resultant survey, including an indication of the extent of any cleaning is required. An independent report is to be submitted by Pro-Sub Services Ltd.

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PROCEDURE I 20 001 CONCRETE SURFACE AND DAMAGE INSPECTION CONTENTS Para

Page

1

INTRODUCTION

3

2 2.1 2.2


3 3 3

3 3.1 3.2 3.2.1 3.2.2 3.2.3 3.2.4 3.2.5 3.2.6 3.3 3.4 3.5

OPERATING PROCEDURE AND SPECIFICATION Inspection Qualifications Inspection Areas Concrete Ring Beam Inspection (Reference Fig.1) CGF to Concrete Ring Beam Interface Inspection (Reference Fig. 2) Base of Leg/Shaft to Cell Top Interface Inspection (Reference Fig. 3) Star Cell / Tri-Cell Inspection (Figure 3 & 4) Outer Wall Cell Intersection Inspection (Reference Fig. 5) Cell Wall and Shaft Construction Joints Initial Survey (VI-ROV / VD-ROV) Debris (Drill Cuttings/Mud) Removal (DB-REM / CL-DRG) Inspection - Diver or ROV

4 4 4 4 4 4 4 5 5 5 5 6

4 4.1 4.2 4.3 4.3.1 4.3.2 4.4 4.4.1 4.4.2

OPTIONS Detailed Visual Inspection (IN-DVI) Close Visual Inspection (IN-CVI) Defect Mapping First Time Measurement Repeat Measurement: (Crack Monitoring) Concrete Damage Survey Preliminary Works (VD-ROV) Damage Inspection (VI-DVI)

7 7 7 7 8 8 8 8 8

5 5.1


9 9

FIGURES No 1 2 3 4

Page Concrete Ring Beam Inspection Location - Typical Leg to Cell Interface Inspection - Typical Tri-Cell / Star Cell Inspection Areas Vertical Cell Wall Interface Inspection

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10 11 13 13

I 20 001 Page 1 of 13

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PROCEDURE I 20 001 CONCRETE SURFACE AND DAMAGE INSPECTION 1

INTRODUCTION The work method is to be applied to the inspection of selected areas of the concrete structures. These areas consist of: •

Caisson roof to leg connection

•

Concrete ring beam

•

Vertical Cell/Cell, Star/Tri-Cell intersections and Concrete construction joints

•

Conductor guide frame/Leg connection

The attached sketches at the end of this procedure detail the baseline inspection required at these locations. Should the inspection areas be increased or decreased, this will be fully detailed in the workscope. In addition, the work method is to be applied for the dimensional survey of damage located on concrete structures. All works may involve debris, marine growth and mud/drill cutting removal, dimensional and video survey. Inspection may be carried out by ROV and/or diver. The method - ROV or diver and level of inspection - Close Visual Inspection (CVI) or Detailed Visual Inspection (DVI) will be clearly defined in the workscope. In the case of damage discovery during the course of a workscope, the available resource, ROV or diver, will be utilised accordingly. 2

TASKS

2.1


2.2

VI-ROV

-

ROV Worksite Check

VD-ROV (DIV)

-

ROV (Diver) Video

DB-REM (CL-DRG)

-

Debris Removal (Dredging)

CL-INS

-


DM-STD

-


Optional Tasks The following work tasks are optional and will be explicitly called for in the Workscope. VI-DVI

-


VI-CVI

-


PH-DIG

-


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Should additional activities be carried out or anomalies noted, suitable work tasks and task codes may be added to cover works. Specifically Contact CP readings (CP-CON) are required on exposed re-bar. Should any anomalies be noted they are to be reported and acted upon as per the relevant section of the 'Subsea Inspection Anomaly Reporting Requirements' Section No 2. 3


3.1


3.2

Inspection Areas Areas required to be inspected will be defined in the workscope. In the main they will be specified in the locations and to the extents as listed below, and as shown in the referenced drawings at the end of this procedure. Where inspection is not in a standard location, extents will be specified in the procedure.

3.2.1

Concrete Ring Beam Inspection (Reference Fig.1) Inspection is required of an area of the concrete ring beam, to which conductor guide frames (CGF) are secured to the platform legs/shafts. The inspection area is to the inboard, CGF, side of the leg. The extents are for 2m either side of the CGF centre line and for 300mm up the leg, and 300mm across the ring beam, from the leg/ring beam intersection.

3.2.2

CGF to Concrete Ring Beam Interface Inspection (Reference Fig. 2) Inspection is required of the interface points where the CGF steel framework penetrates the concrete ring beam. The workscope will specify if all three interface points, the central box and outboard tubular steel penetration points of the CGF framework, or individual penetration points are required for inspection. The inspection area is for 150mm out from the end of the steelwork, covering the steel/concrete interface and surrounding concrete.

3.2.3

Base of Leg/Shaft to Cell Top Interface Inspection (Reference Fig. 3) Inspection is required of the interface between the base of the leg/shaft and the cell top. A 5m arc, its position around the leg to be specified in the workscope, is to be inspected for 300mm up the leg, and out along the cell top. Where defects are found to extend outside this area, clean and inspect as required as instructed by the Shell Offshore Representative, acting on advice from the responsible structural engineer. Should mud and debris build up preclude inspection of the specified area, an alternative site may be selected, as directed by the Shell Offshore Representative, acting on advice from the responsible Project Engineer. Any alternative site, should take into account the location of previous inspections, which can be obtained from the COABIS database.

3.2.4

Star Cell / Tri-Cell Inspection (Figure 3 & 4) Inspection is required on all internal walls of selected star cell, or tri-cell, and to the top of the cell. Unless otherwise specified in the workscope, inspection is required on all internal vertical walls for 1m down. Where an overhang exists, the 1m inspection area is to be taken from the top of the vertical wall, not to include any overhang. Externally, the top of the cell is to be surveyed for 0.5m out from the Star Cell entrance, in all directions.

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Should cracks be identified, then the survey is to continue to ascertain the extent of the crack, as access/safety allows. Should, as a result, the duration of the survey become extensive, the responsible Structural Engineer/TA should be consulted on how to proceed. This inspection would normally be required to be performed by divers, due to access. However it may be possible for small ROV’s to access the sites in some cases. In both cases, the diver and ROV are to be aware of potential hazards, which may include debris. 3.2.5

Outer Wall Cell Intersection Inspection (Reference Fig. 5) Inspection is required of the intersection between two adjacent outer cell walls. The required cell wall intersections will be specified in the workscope. At the top of the cell wall intersections, the inspection area is required across the full width of the intersection, for 3m along both the horizontal ledge and vertical face. The inspection area should be increased to cover any defects extending outside this area, except where the defect extends into areas of mud and debris which will require further debris removal. In this case act as directed by the Shell Offshore Representative, based on advice from the responsible Structural Engineer/TA. (Reference Fig. 5) The workscope may specify a location lower down the cell wall on an intersection. This is usually towards the base of the cell wall intersection. In this case the inspection will be required over a 3m length of the vertical face, at a depth specified in the workscope.

3.2.6

Cell Wall and Shaft Construction Joints Individual construction joints will be specified for detailed visual inspection, typically requiring cleaning prior to inspection. Such construction joints have their own component number. Their location will be specified by depth and position on the cell wall or shaft leg. Construction Joints can typically be identified by a pronounced joint within a band of epoxy coating. Typically this inspection would be required to be performed by ROV, but may be required to be inspected by diver. If diver inspection is required, an ROV is to be employed to check above the worksite for any hazardous debris.

3.3

Initial Survey (VI-ROV / VD-ROV) Carry out an initial survey by ROV of the area to be inspected. The objective of this survey is to determine the extent of the debris and marine growth to be removed. A combination of the use of video in SIT, for general location, and colour for more detailed survey is to be used. Continuous video recording is to be taken throughout the survey. Establish that the correct worksite has been identified using location markers (i.e. Cell Wall Numbers), and other salient points of reference. This is to be recorded on video. All items of debris and mud/drill cuttings are to be noted and the following details recorded:

3.4

•

Location

•

Description

•

Size - large, small

Debris (Drill Cuttings/Mud) Removal (DB-REM / CL-DRG) On completion of the initial survey, remove debris and mud/drill cuttings from the area to be inspected.

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Mud/drill cuttings removal is likely for inspection areas at the base of the structure, or on cell top locations specified above in 3.2.3 – Base of Leg/Shaft to Cell Top Interface Inspection (Fig.3), 3.2.4 Star Cell / Tri-Cell Inspection (Figures 3 & 4), 3.2.5 – Outer Wall Cell Intersection Inspection (Fig 5). Where possible the workscope will give an indication to the extent of mud/drill cuttings to be removed. For ROV operations, a combination of ROV mounted dredge pump and water jet is to be utilised. If extensive mud/cuttings are known to be present, this will be highlighted in the workscope and suitable dredging equipment mobilised. Where extensive mud/cuttings are likely to be present, diver intervention will usually be specified. Air Lifts are the normal method for mud/cuttings removal, but where extensive mud/cuttings are known to be present, this will be highlighted in the workscope and suitable dredging equipment mobilised. If debris and mud/drill cuttings are found to be extensive, the Shell Offshore Representative is to confirm the amount of time to be spent undertaking these tasks, as advised by the responsible Project Engineer. 3.5

Inspection - Diver or ROV Cleaning will be required prior to the inspection, the levels of which are defined below, or as detailed in the workscope. Where necessary, debris removal may also be required. Should the extent of debris be prohibitive, an alternative location may be selected on consultation with the Shell Offshore Representative. Inspection may be carried out by ROV or diver or a combination of both. The extent and level of inspection shall be defined in the workscope. The level of inspection shall be defined as either a Detailed Visual Inspection (DVI) or a Close Visual Inspection (CVI) at the selected areas. (Refer to 4.1 and 4.2 below for details). The inspection (CVI or DVI) shall pay particular attention to any areas where the following occurs: (1)

Cracking or other discontinuities (excluding joints or normal discontinuities).

(2)

Swelling, lumps, popout or spalling of the concrete surface.

(3)

Change of aspect/colour of concrete.

(4)

Disbonding or separation of bitumastic or epoxy coating.

(5)

Appearance of salt secretion or chemical filtering through the skin.

(6)

Exposed rebar. Where re-bar exists, contact CP readings are required on 1-2 different exposed items, per inspection area. Specific locations have also been created for the taking of reference CP readings at areas of known cracking. These will be specified in the relevant workscope.

(7)

Evidence of Corrosion which may relate to exposed rebar, at locations of cracks or spalling.

With respect to the above defects, the description of any damage or any anomalies discovered should be reported using standard terminology in accordance with the Department of Energy, Offshore Technical Reports entitled 'Classification and Identification of Typical Blemishes Visible on the Surface of Concrete Underwater' OTH 84 206 and OTH 87 261. NOTE:

Any anomalies are to be referenced to a datum start point, accurately positioned and recorded.

Digital Still Images (PH-DIG) should be taken of any anomalies or other areas of interest. These may be supplemented by suitable drawings to show the location, size and details of the item of interest.

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4

OPTIONS

4.1

Detailed Visual Inspection (IN-DVI) This level of inspection may be carried out by ROV or divers, and is to be recorded on video. The purpose of the inspection is to establish the condition of the component, the condition of the concrete surface and any attachments, and detect defects that would be otherwise obscured by marine growth. A limited amount of cleaning will be required to carry out this inspection. Cleaning shall be carried out by either water jetting, scrapers and/or wire brushes. Soft marine growth only should be removed, the standard of cleaning shall be sufficient to enable details of the components to be seen. It will not normally be necessary to remove hard marine growth unless it obscures detail. Care to be taken during the cleaning to ensure any surface coatings are not damaged. The detailed visual inspection of the area shall be carried out looking for any defects as categorised in 3.5 above. Should any anomalies be found then they shall be referenced to a known datum point and reported for further action.

4.2

Close Visual Inspection (IN-CVI) This type of inspection may be carried out by divers or a suitably equipped ROV, and is to be recorded on video. The purpose of this inspection is to establish a Close Visual Inspection of specific areas of interest, typically concrete joints, specifically looking for any cracks in the concrete surface. Cleaning shall be carried out using medium pressure water jetting or scraper/wire brush for divers, to remove both soft and hard marine growth, taking care not to damage the surface and affect any fine cracks that may be present. Hard marine growth, in the form of worm cast stains, may be left in place unless it obscures detail. A Close Visual Inspection is to be carried out looking for defects as categorised in 3.5 above. Should any cracks be found, then additional cleaning shall be carried out to follow cracks and all branches to the full extent and until they vanish from view. Particular attention should be given to crack detection in the folds between any flat intersections and curved surfaces. The level of inspection shall be sufficient to detect cracks with a crack width opening of 1mm and above. Once detected, the inspection shall follow the crack until the width has reduced to 0.5mm or less. Where possible crack depth is to be recorded. For the ROV to carry out this level of inspection a zoom camera (preferably manipulator mounted, unless suitability can be shown otherwise) will be required, with a suitable measuring device (typically manipulator held). It is recommended that such a measuring device comprises of two rules, mounted at 90 degrees, marked in 10mm increments, length of which to be determined by the area under inspection.

4.3

Defect Mapping All defects found shall be categorised, i.e. cracks, pop-outs, spalling, etc. The location and extent shall be fully detailed in a dimensional drawing to be included in the Final Report, including any grid pattern that may have been employed.

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The description of any damage or any anomalies discovered should be reported using standard terminology in accordance with the Department of Energy, Offshore Technical Reports entitled 'Classification and Identification of Typical Blemishes Visible on the Surface of Concrete Underwater' OTH 84 206 and OTH 87 261. 4.3.1

First Time Measurement All characteristic points should be marked up in such a way that the marks or markers are visible in stand-off. Characteristic points include crack ends, branch points and points where the cracks change direction. Permanent markers should be employed where possible for cracks, for future crack propagation monitoring. This inspection is to be recorded on video, to include any markers. Where divers are employed, crack ends are to be chisel marked for permanency, and marked with black crayon. A dimensional drawing should be made of the crack pattern, noting any markers.

4.3.2

Repeat Measurement: (Crack Monitoring) Where an adequate dimensional drawing of defects/cracking exists from inspection in previous years, any repeat measurement is to be aimed at detecting extension of the crack pattern (new branches or cracks being longer) or change in crack morphology. When the crack pattern has changed, the changes should be documented as under 'first time measurement', i.e. starting with the drawing from the most recent inspection, noting any growth or changes. This inspection is to be recorded on video.

4.4

Concrete Damage Survey

4.4.1

Preliminary Works (VD-ROV) The ROV will carry out, and fully video record, a general visual survey of the area of interest noting area of damage, item of debris which may have caused the damage or any other cause, marine growth coverage and confirm as built configuration for access and rigging for dimensional survey.

4.4.2

Damage Inspection (VI-DVI) On completion of the general visual survey the diver or ROV is to carry out and video record a Detailed Visual Inspection (DVI) of the damaged area prior to cleaning. The damaged area is to be suitably identified, where possible, and is to clearly show all aspects of the damage. Any debris noted during the initial survey is to be removed by whatever means is considered suitable and that will allow safe and unrestricted access to the inspection area. Mud/drill cuttings may be removed using dredge pump or Propwash dredging equipment. Deploy cleaning equipment and clean the damaged area to allow DVI. On completion of cleaning operations, the diver is to carry out a DVI of the area, to fully describe and dimension the damage as found. The diver is to probe the area of damage with a suitable tool to establish whether the surface is loose or crumbling. Carry out a dimensional survey of the damage to define its overall dimensions and where appropriate its depth. Where surface cracks are identified their width is also to be reported. Any exposed reinforcement or aggregate where appropriate is to be inspected and reported. Dependant on size, consideration should be given to the use of a grid pattern, in which to accurately plot the defect. Where impact damage is found, a straight edge or taut wire should be used to ascertain the depth of concrete loss/damage.

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The description of any damage or any anomalies discovered should be reported using standard terminology in accordance with the Department of Energy, Offshore Technical Reports entitled 'Classification and Identification of Typical Blemishes Visible on the Surface of Concrete Underwater' OTH 84 206 and OTH 87 261. Digital Still Images (PH-DIG) are to be taken of any anomalies or other areas of interest. These may be supplemented by suitable drawings to show the location, size and details of the item of interest. 5

REPORTING

5.1

Final Report Inspection data format, video log and anomaly report format, where applicable, are to be completed for all works carried out. The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above. Reference section 2, Chapter 1, Section 3.1.5. All anomalies are to be referenced, with a general statement made concerning the types and extent of anomalies identified. Any C1 anomalies are to be commented on more specifically. Other references are to be made to any digital still images and drawings. Detailed drawings or sketches shall be produced for all anomalies found. These shall clearly show the extent of any defects found referenced to a known datum point as discussed under 3.5 and section 0. As stated above, where ‘Repeat Measurements’ are undertaken, any drawing should reference the previous results, with any propagation highlighted. Previous survey drawings are contained within the COABIS database.

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CGF-EL

2000

2000

ARC LENGTH TO BE INSPECTED

INSPECTION AREA SHOWN CROSS HATCHED.

PLAN VIEW OF RING BEAM

Figure 1

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Concrete Ring Beam Inspection Location - Typical

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CGF-EL

CONCRETE RING BEAM

CGF 150mm INSPECTION AREA ADJACENT TO CONCRETE/ STEEL AREA

LEG

INSPECTION SITE

CONCRETE STRUCTURE

STEEL/CONCRETE INTERFACE

MARINE GROWTH TO BE REMOVED OVER 150mm AREA TO ALLOW DVI OF CONCRETE SECTION. AREA HAS AN EPOXY COATING

CGF BRACING (TYPICAL)

STEEL BOXED SECTION WITH PROTECTIVE COATING

CLEANING AND INSPECTION AREA DETAIL

Figure 2

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CGF to Leg Interface Inspection – Typical

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Tri Cell / Star Cell (see fig 4)

Figure 3

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Leg to Cell Interface Inspection - Typical

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Figure 4

Figure 5

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Tri-Cell / Star Cell Inspection Areas

Vertical Cell Wall Interface Inspection

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PROCEDURE I 20 002 GENERAL CONCRETE SURFACE INSPECTION - SUBSEA AND TOPSIDE CONTENTS Para

Page

1

INTRODUCTION

3

2 2.1 2.2


3 3 3

3 3.1 3.2

OPERATING PROCEDURE AND SPECIFICATION Inspection Qualification Subsea Inspection (VI-GVI / VD-ROV)

3 3 3

4 4.1

OPTIONS Topside Inspection

5 5

5 5.1


5 5

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PROCEDURE I 20 002 GENERAL CONCRETE SURFACE INSPECTION - SUBSEA AND TOPSIDE 1

INTRODUCTION The work method is to be applied to a general video survey by an ROV of large areas on concrete structures. The purpose of the survey is to visually inspect a large area for possible damage and also to note general marine growth coverage. As an option, above water and splash zone visual inspection may be required to be carried out from the diving support vessel, including topside photographs.

2

TASKS

2.1


2.2

VI-GVI

-


VD-ROV

-

General ROV Video

DB-CHK

-

Visual Debris Check

MG-GEN

-


Optional Tasks The following work tasks are optional and will be explicitly called for in the Workscope. VI-TOP

-

Topside Inspection

PH-TOP

-


DB-REM

-

Debris Removal

CL-INS

-


Should additional activities be carried out or anomalies noted, suitable work tasks and task codes may be added to cover works. 3


3.1

Inspection Qualification The inspection is to be carried out by ROV, under the guidance of a CSWIP 3.3u, or 3.4u Inspection Controller. Topside inspection to be carried out by CSWIP 3.3u, or 3.4u Inspection Controller. Should any anomalies be noted they are to be reported and acted upon as per the relevant Section of the 'Subsea Inspection Anomaly Reporting Requirements’ Section 2.

3.2

Subsea Inspection (VI-GVI / VD-ROV) The ROV will carry out, and fully video record, a general visual inspection of all the concrete surfaces as specified in the Component Task Sheet (CTS), or as directed by the Shell Offshore Representative.

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The inspection is to commence with a SIT view of the general area, to confirm the correct component has been identified, with reference to known local components. Continuous video recording in SIT mode for overall coverage and colour for detailed close up work is to be conducted throughout the survey. The purpose of this inspection is to record the following: (1)

As-built configuration.

(2)

Any damage to concrete.

(3)

Any discolouration of the concrete i.e. rust staining.

(4)

Condition of interface of steel fixtures to concrete.

(5)

Condition of temporary opening/closures.

(6)

Any debris.

(7)

Any erosion of concrete.

(8)

Marine growth coverage. Describing marine growth as hard or soft, giving estimated thickness and percentage cover of each.

The description of any damage or any anomalies discovered should be reported using standard terminology in accordance with the Offshore Technical Reports entitled 'Classification and Identification of Typical Blemishes Visible on the Surface of Concrete Underwater' OTH 84 206, HMSO and OTH 87 261, HMSO. No cleaning is required unless specified. However, should an area of particular interest be obscured by marine growth, or if the surrounding area shows signs of damage or deterioration, then all soft marine growth and any hard marine growth, which obscures the area of interest is to be removed. Camera movement must be slow and deliberate. Lighting must be adequate to give good colour rendition. Ensure that lighting and viewing is optimised to avoid flare and fade out. Standoff light and focus is to be optimised. Where possible the camera and lights are to be orientated at right angle to inspection surface to give optimum viewing, as viewing at differing angles will cause flare on screen close to subject and fade out at the far edges of the screen. The areas to be inspected should be covered in a logical order to ease subsequent topside interpretation. The video survey is to be carried out at a speed that is slow enough to allow the observer to adequately observe, comment on and note the condition of the structure. All route details should be mentioned i.e. moving east on heading 093 degrees along horizontal construction joint cell top 8, depth -86m, now arrived at vertical intersection between cell 8 and 7, start survey following vertical intersection toward sea bed. Components should be identified as they appear in the camera's view, not when they appear in the pilot's view unless coincident. Constant reference should also be made to depth and direction. The camera standoff is to be adequate so as to show the subject, without loss off definition. Where necessary, the standoff distance should be increased to show a larger area i.e. temporary opening/closure. Other than in exceptional circumstances, the camera is to be oriented in the vertical plane. If the camera is rotated, the extent and direction of the rotation must be frequently mentioned on the video commentary. Any camera tilt must be described, in terms of orientation, up or down, in the commentary. I 20 002 Page 4 of 5

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Reference should be made of all salient points of interest in the video narrative and on the video log. Additional findings of relevant importance must be noted and sufficient coverage made in order to assess the situation. Digital Still Images (PH-DIG) should be taken of any anomalies or other areas of interest. These may be supplemented by suitable drawings to show the location, size and details of the item of interest. 4

OPTIONS

4.1

Topside Inspection Topside inspection may be required to compliment platform based topside inspection. If requested in the workscope, a topside visual inspection of specified components between LAT and the under deck of the platform, paying particular attention to the splash zone region. Only gross defects (C1 category) are to be reported. The splash zone and above water concrete inspection is to record the following: (1)

Any damage to concrete.

(2)

Any discolouration of the concrete i.e. rust staining.

(3)

Condition of interface of steel fixtures to concrete.

(4)

Any erosion of concrete.

Digital Images may be requested by the workscope, of the following views: (1)

The specified legs for inspection, between LAT and the under deck.

(2)

and/or of overall views of the platform from 2 opposing faces.

These are to be taken on an opportunity basis only, with no specific vessel move made to obtain these images, unless specifically requested in the workscope. 5

REPORTING

5.1

Final Report The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above. Reference section 2, Chapter 1, Section 3.1.5. All anomalies are to be referenced, with a general statement made concerning the types and extent of anomalies identified. Any C1 anomalies are to be commented on more specifically. Other references are to be made to any digital still images and drawings. Sketches are required, either scanned, AcadLT or other proprietary drawing format, of any major defects or debris that cannot be suitably documented by anomaly report and digital images alone.

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PROCEDURE I 30 001 SEAWATER INLET INSPECTION CONTENTS Para

Page

1

INTRODUCTION

3

2 2.1 2.2


3 3 3

3 3.1 3.2

OPERATING PROCEDURE AND SPECIFICATION Inspection Qualifications Safety

4 4 4

4 4.1 4.2 4.3 4.3.1 4.3.2 4.3.3 4.3.4 4.4

ROV CONCRETE SHAFT/LEG INLET (SEA CHEST) INSPECTION General Visual Inspection (VI-GVI / VD-ROV) Proximity (Contact) CP Readings General (CP-PRX / CP-CON) Options: Cleaning for Inspection (CL-INS) Detailed Visual Inspection (VI-DVI) Wall Thickness Measurements (WT-DIG) Diver Concrete Shaft Leg Inlet (Sea Chest) Inspection (VI-DVI) ROV FPSO Sea Chest Inspection (VI-GVI / VD-ROV)

4 4 6 6 6 6 6 6 8

5 5.1


9 9

FIGURES No 1 2 3 4 5

Page Brent Bravo Inlet 26-035, Shaft 1 Brent Bravo Inlet 26-036, 037 & 038, Shaft 1 Cormorant Alpha Typical Inlet Arrangement Dunlin Alpha Inlets 26-027 & 028 Anasuria FPSO Sea Chest Orientation and Marking

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PROCEDURE I 30 001 SEAWATER INLET INSPECTION 1

INTRODUCTION This work method is to be applied to the inspection of seawater inlets (sea chests) by both diver and ROV, on concrete structures and FPSO’s (Floating Production Storage & Offtake Tankers). Dependant on requirements of the responsible Structural Engineer, work will include; General ROV survey, ROV CP survey, external cleaning for DVI, cleaning of blockage from grille, removing and replacing the protective grille, internal cleaning of the inlet (sea chest), debris clearance, UT wall thickness measurements, Cathodic Potential (CP) measurements, anode and video survey. NDT methods under Procedure I 15 002, section 3.3, may be required to conduct UT wall thickness investigation.

2

TASKS

2.1


2.2

VI-GVI

-


VD-ROV

-

ROV Video Survey

VI-AW

-


CP-PRX (CON)

-

Proximity (Contact) CP Readings

Optional Tasks The following work tasks are optional and will be explicitly called for in the Workscope. CP-CONC

-

Proximity CP Readings for Concrete Structures

CL-INS

-


VI-ROV

-

ROV Worksite Check

CN-RGR

-

Remove Grille/Replace Grille

VI-DVI

-


WT-DIG

-

Wall Thickness Readings

VD-DIV

-

Diver Video

Any number or combination of the listed work tasks may be used or called for on the workscope, or during the course of the inspection, or to fully investigate and report damage as found.

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3


3.1

Inspection Qualifications The standard inspection is to be carried out by ROV, under the guidance of a CSWIP 3.3u or 3.4u Inspection Controller. More detailed inspections may be required to be carried out by a CSWIP 3.1u/3.2u diver, under the guidance of a CSWIP 3.4u Inspection Controller. Should anomalies be noted, they are to be reported and acted upon as per Section 2, Chapter 6, ‘Anomaly Reporting & Criteria’, and as directed by the Shell Offshore Representative.

3.2

Safety WARNING:

PRIOR TO ANY SUBSEA INSPECTION WORK ON SEAWATER INLETS, A TASK RISK ASSESSMENT (TRA) SHOULD BE CARRIED OUT. SHOULD THE TASK REQUIRE CLEANING OF THE INLET GRILLE, OR DIVER INTERVENTION, THE PLATFORM INTAKE IS TO BE ISOLATED.

Risks involved with inspection of a seawater inlet are: (1)

ROV entrapment due to inlet suction.

(2)

Diver hazard due to inlet suction.

(3)

Damage to platform internal pumps, due to marine growth/debris ingress caused by cleaning without prior isolation of the inlet and its associated pumps.

For a general ROV survey, isolation of the inlet should not be required. The rate of suction from an inlet is generally of low volume and all inlets have a grille. However, the TRA may raise an area of concern due to vehicle size. Where cleaning for inspection is required on the external components of the inlet, excluding the grille, again it is envisaged that isolation should not be required. Cleaning of the grille may be required as part of the workscope, or as a result of an anomaly raised due to marine growth or debris blockage. In this instance cleaning is not allowed without the prior approval of the platform, with all relevant isolations in place. Isolation of the inlet is required, for all diver intervention works. For platform inspections, if diver intervention is required, the TRA should take into account the possible lack of security of any work platform below the inlet. The initial ROV survey should assess the security of the platform, with further diver integrity checks made on arrival at the site. When working alongside an FPSO. An ‘FPSO Pre-Entry Checklist’ requires to be carried out by the vessel DP Operators, as part of their field entry trials. 4

ROV CONCRETE SHAFT/LEG INLET (SEA CHEST) INSPECTION

4.1

General Visual Inspection (VI-GVI / VD-ROV) Inspection activities will vary, dependant on the requirements of the workscope. Figures 1-4 show various types of seawater inlet encountered on the Shell Northern Field Platforms. Some of the drawings are platform specific, but will be relevant to other platforms such as Brent Charlie and Brent Delta.

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ONEgas East has a single concrete platform (F3-FB-1P), which has two Sea Water inlets on its central utility shaft, which differ from the Northern platform inlet designs. The inlets are in the form of large diameter short stubs, with a meshed grille. No drawings are available of these inlets, at the time of production of this procedure. Typically inspection requirements will be for ROV intervention only. Diver intervention may be required as a result of ROV findings, or for general concerns raised by the responsible Structural Engineer. The basic requirement for the inspection of an inlet (sea chest) on a concrete shaft/leg is as for a General Visual Inspection (GVI). Areas of interest are: (1)

Damage to the inlet and surrounding concrete,

(2)

Debris and other obstructions,

(3)

Integrity of any biocide pipework,

(4)

Anode integrity/wastage,

(5)

Particular attention should be paid to the inlet/shaft steel/concrete interface for any evidence of cracking or disbondment.

(6)

Inlet stub and flanges for evidence of corrosion/coating damage. See Note (1).

(7)

If a diver platform is present (below the inlet) its integrity, in particular its securing points, should be checked.

Any debris found should be removed if possible. NOTES:

(1) Past history has found severe corrosion of the stub, which has been hidden by the presence of an outer coating. To this end, the internal components of the inlet, particularly the stub walls, and the stub externally should be checked for evidence of corrosion externally and through the grille. Note WT readings required should coating damage be evident, see 4.3.3 below. (2) It is a design feature of some of the grille bolting arrangements at Dunlin Alpha that some bolts have deliberately been left slack, and therefore are not anomalous. See accompanying drawings fig.4.

Prior to commencement of the inspection, the inlet ident marker should be identified, to confirm the correct inlet. This should then be recorded at the start of the video inspection. This is typically a raised number, above the inlet, but which are not always present. Action to be taken if inlets are blocked (greater than 30%): •

Raise anomaly, take Digital Still images - Report onshore and to the platform.

•

Confirm/agree with the platform that cleaning may proceed. Isolate inlet prior to carrying out any cleaning. Do not commence cleaning without clearance from the platform, and with the correct isolation permit in place.

•

Carry out cleaning activities - video on completion and take Digital Still images.

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4.2

Proximity (Contact) CP Readings General (CP-PRX / CP-CON) Proximity probes are the preferred method for obtaining the required readings. However, with the method of use of the Shell preferred Pro-Sub CP-Chek CP system, contact readings are inevitable, but should be discussed prior to use with the Shell Offshore Representative. CP readings are to be taken prior to any cleaning. Readings should be taken at four cardinal clock positions on the inlet stub, on the grille arrangement (or blanking flange) and any anodes. Note that in some cases, the grille may be galvanized, as such no readings may be obtained. Where insufficient COABIS Workpack task boxes exist, relevant additional CP task boxes need to be raised to accommodate all readings taken. All CP readings taken by ROV (including methods discussed below) are to be hard wired into the video recorder such that the CP readings are continuously displayed on the video screen during the ROV survey. CP readings are to be included in the video commentary. CP readings are to be carried out prior to any cleaning. Calibration readings are required before and after each dive. Refer to Procedure I 60 004 – Cathodic Protection Monitoring.

4.3

Options:

4.3.1

Cleaning for Inspection (CL-INS) Cleaning may be required by the workscope, or if marine growth prevents confirmation of integrity. In particular the inlet/shaft penetration, the external flange and stub sufficient to confirm integrity. No cleaning is to be conducted without prior confirmation from the Shell Offshore Representative that it is safe to do so, with all relevant isolations in place if necessary. The ROV HP water jet is to be used for all cleaning purposes.

4.3.2

Detailed Visual Inspection (VI-DVI) On completion of cleaning, check the inlet for evidence of corrosion, damage to the stub coating and the inlet/shaft penetration for evidence of cracking or disbondment.

4.3.3

Wall Thickness Measurements (WT-DIG) WT readings taken by ROV will be required at the four cardinal clock positions on the inlet stub, or at other locations as specified in the workscope. As part of an anomaly investigation, WT readings are required to be taken on the inlet where areas of the protective coating are missing.

4.3.4

Diver Concrete Shaft Leg Inlet (Sea Chest) Inspection (VI-DVI)

4.3.4.1

Worksite Check (VI-ROV) The worksite area and areas above are to be checked for diver safety, refer to Standard Procedure I 01-003, point 4.1. Attention is also to be paid to any work platform beneath the inlet, in particular its securing points to confirm its suitability for use. A general ROV inspection of the inlet will be conducted as per 3.3.1 above.

4.3.4.2

Remove Grille (CN-RGR) Any items of debris found on the protective grille, or within the inlet are to be reported and removed.

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Remove the protective grille from the seawater inlet. It may be necessary to destroy the grille fasteners in order to remove the grille. 4.3.4.3

Clean for Inspection (CL-INS) Deploy cleaning equipment to worksite. Clean all painted surfaces within the inlet being careful not to damage or remove any paint coating. It is not necessary to remove hard stubborn growth or rust scale unless they cover an area of particular interest, if the surrounding area shows signs of damage of deterioration. However, all soft growth is to be removed.

4.3.4.4

Detailed Visual Inspection (VI-DVI / VD-DIV) Carry out a detailed visual inspection of the inlet internally. This is to be recorded on video, highlighting any anomalies noted. Particular attention should be made of any visible internal components, valve arrangement and biocide lines, and to describe any paint coating in the as viewed state. The description is to note the percent cover of the surface covered by each of the coating layers and any bare metal areas. Additionally the way in which the condition of each coating layer encountered shall be described as either: (1)

Secure - Smooth, continuous.

(2)

Blistering - Bubbles in the coating or large rounded holidays arising from blistering.

(3)

Flaking - Irregular patches of coating missing or coming off.

(4)

Eroding - Widespread thinning/deterioration of a coating layer to expose the next layer or bare metal.

(5)

Holidays - Discontinuities in coating not found as a consequence of either (2), (3) or (4).

Where blisters occur a sample of blisters shall be burst and the percentage of blisters revealing each of the other coating layers of bare metal shall be noted. Where bare metal is encountered the condition of the bare metal should be fully reported on, which shall include a full description of the surface condition i.e. dull, shiny, rough, mottled, pitted (depth and frequency) corrosion product - bare, powdery rust, scale (thickness in mm) colour of product. A video is to be taken as necessary to fully record findings. The survey may extend to the inlet externally, if requested by the workscope, or if dictated by the internal findings, as directed by the Shell Offshore representative. 4.3.4.5

CP Survey (CP-CON / VI-AW) Cathodic potential measurements are to be taken on selected areas of bare metal, which are to give a representative indication of potential level. Proximity probes are the preferred method for obtaining the required readings. Contact probes shall not be used without prior approval from the Shell Offshore Representative, acting on advice from the Responsible Structural Engineer. CP readings are to be carried out prior to any cleaning. Calibration readings are required before and after each dive, and where diver contact readings are taken before each set of readings. Refer to Procedure I 60 004 – Cathodic Protection Monitoring. Where anodes are located within the inlet, integrity of the anode, support bracket and/or earthing strap are to be reported, with an estimate of percentage wastage.

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4.3.4.6

Wall Thickness Measurements (WT-DIG) Wall thickness measurements are to be taken on the internal or external surface of the inlet, as access allows, on areas where the protective coating is missing. The location of each reading should be marked with a suitable underwater paint marker and suitably reported.

4.3.4.7

Replace Grille (CN-RGR) On completion of the inspection work replace the protective grille. If the original fasteners were destroyed during the grille removal, replacements will be supplied by Shell Expro, or sourced by the CONTRACTOR. The site is to be de-rigged, and an as-left survey to be conducted by ROV, to be recorded on video.

4.4

ROV FPSO Sea Chest Inspection (VI-GVI / VD-ROV) At the time of writing this procedure, there is presently only one FPSO requiring regular inspection, this being the Anasuria in the Central Sector. It is envisaged that FPSO Sea Chests will only be inspected by ROV. Should diver intervention be required, then follow point 4.3.4 – Diver Inlet Inspection. Prior to commencement of the inspection, the inlet ident marker should be identified, to confirm the correct inlet. This is particularly relevant for the aft sea chests, which are close together and have caused confusion in the past. The ident is marked adjacent the sea chest, with the prefix ‘S’ and then number, as listed below. This should then be recorded at the start of the video inspection. Inspection is required to check for any signs of damage, debris and in particular excessive marine growth. Proximity CP readings are to be taken on the sea chests prior to any cleaning. However, with the method of use of the Shell preferred Pro-Sub CP-Chek CP system, contact readings are inevitable, but should be discussed prior to use with the Shell Offshore Representative. The CP probe is to be hard wired into the video recorder such that the CP readings are continuously displayed on the video screen during the ROV survey. CP readings are to be included in the video commentary. Refer to Procedure I 60 004 – Cathodic Protection Monitoring. The sea chests are to be cleaned on an annual basis. Video and digital photographs are required pre and post cleaning, of each sea chest. Prior to any cleaning confirm/agree with the Anasuria that cleaning may proceed. Isolate inlet prior to carrying out any cleaning. Confirm with Shell Representative that required isolations are in place. The Anasuria has 9 Sea Chests. The Sea Chest locations are marked on the ship’s hull above the waterline, in line with the underwater location. In addition, the idents are marked with the outline of the ident number created by weld beading 100mm high, on the hull adjacent to the inlets.

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The following table gives the idents, and their relative name, location and COABIS component number Ident

Sea Chest

Location

Side

Component

S1

No 1 Fire Pump Sea Chest

Aft Machinery Space

Stbd

38-003

S2

No 1 Seawater Sea Chest

Aft Machinery Space

Stbd

38-004

S3


Aft Machinery Space

Port

38-005

S4


Aft Machinery Space

Port

38-006

S5

No 2 Fire Pump Sea Chest

Aft Machinery Space

Port

38-007

S6

Draft Gauge Sea Chest

Aft Machinery Space

Stbd

38-008

S7

W.B.P. Sea Chest

Mid Ships

Stbd

38-010

S8

W.B.P. Sea Chest

Mid Ships

Port

38-011

S9

Fwd Fire Pump Sea Chest

Fwd Machinery Space

Stbd

38-009

Sea Chest orientation and location markings (topside and Subsea) are shown on figure 5, with the locations shown in the Anasuria UMDB (2605-001), pages 3-0-13 and 3-0-14. 5

REPORTING

5.1

Final Report The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above. Reference section 2, Chapter 1, Section 3.1.5. Report the state of the inlet; any blockage found; any resultant cleaning; confirmation of isolations if any; general results of any CP and WT readings; the presence, location and number of any ident markers. Include references to all anomalies, video logs and or digital still images taken. If the full results of any CP or WT readings taken cannot be suitably entered into the COABIS database, then the full results may be entered into the Workpack Diary, or a suitable referenced drawing.

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Figure 1

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Brent Bravo Inlet 26-035, Shaft 1

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Figure 2

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Brent Bravo Inlet 26-036, 037 & 038, Shaft 1

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Figure 3

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Cormorant Alpha Typical Inlet Arrangement

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Figure 4

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Dunlin Alpha Inlets 26-027 & 028

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Note:

S3 S4 S5

S8

White Paint Mark

1. Refer to table page 6, for Sea Chest Information. S5

2. Refer to Anasuria UMDB 2605-001, drawing pages 3-0-13 and 3-0-14, for location of Sea Chests in relation to the vessel hull.

S4

S3

Double Sea Chest

S8

3. Apart from the Draft Gauge (S6), all Sea Chests are present on the underside of the flat hull section. As such these Sea Chests are viewed from below.

Sea Chest Marker Above Waterline

Handle (Eye Plate) Mid Ships 38-011 (S8)

S6

38-007 (S5)

Sea Chest Marker Above Waterline

Aft Machinery Space 38-006 (S4)

38-005 (S3)

S1 S2

S7

S9

White Paint Mark

S1

Double Sea Chest S6

Handle (Eye Plate)

Aft Machinery Space 38-004 (S2)


38-003 (S1)

Mid Ships 38-010 (S7)

S9

S7

S2

38-008 (S6)

Fwd Machinery Space 38-009 (S9)

Anasuria FPSO Sea Chest Orientation and Marking Re-issue 04/05

0153-001

PROCEDURE I 32 001 BOAT LANDING AND BARGE BUMPER SURVEY 1

INTRODUCTION The work method is to be applied to a boat landing and barge bumper survey to confirm the integrity of all landings, access ladders and barge bumpers up to and including their attachment points to the jacket structure. The work will include video survey, debris and damage inspection, dimensional survey and photography. NDT methods under Procedure I 15 001 may also be required to fully investigate and report damage as found.

2

TASKS

2.1

Standard Tasks The following Listed tasks are always to be invoked. VI-SPZ

-

Splash Zone Inspection

PH-TOP

-


VD-ROV (DIV)

-

ROV (Diver) Video

DB-CHK

-

Visual Debris Check

CL-INS

-


CH-BLT

-

Hand Bolt Check

DM-STD

-


VI-DVI

-


PH-DIG

-

Digital Photographs

Should additional activities be carried out or anomalies noted, suitable work tasks and task codes may be added to cover works. Should anomalies be noted, they are to be reported and acted upon as per Section 2, Chapter 6, ‘Anomaly Reporting & Criteria’, and as directed by the Shell Offshore Representative.

3


3.1


3.2

Boat Landing/Access Ladders Carry out, and fully video record, a general visual survey of the boat landing area and associated access ladders, up to and including the lower landing level. The purpose of this survey is to record the following: (1)

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Site conditions are currently identified in accordance with the relevant location drawings.

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Any debris or obstructions in the work area to be removed by whatever means is considered suitable to allow safe and unrestricted access to the inspection area.

(3)

Confirm integrity of all attachment points to the main structure, including the security of all bolted or clamped connections.

(4)

Any areas of damage, distortion, missing grating, ladder rungs or any other anomalies, noting the location and dimensions of each.

On completion of the general visual survey, a sequence of digital images both topside and Subsea (if visibility allows) (PH-TOP / PH-DIG) are to be taken which clearly show the as-built configuration of the complete boat landing.

3.3

Barge Bumpers Carry out and fully video record, a general visual survey of each of the barge bumpers. The purpose of this survey is to record the following: (1)

Site conditions are correctly identified in accordance with the relevant location drawings.

(2)

Any debris or obstructions in the work area is to be removed by whatever means is considered suitable to allow safe and unrestricted access to the inspection area.

(3)

Confirm integrity of all attachment points to the main structure, including the security of all bolted or clamped connections and tyres.

(4)

Any areas of damage, distortion, missing tyres or any other anomalies, noting the location and dimensions of each.

On completion of the general visual survey, topside digital images (PH-TOP) are to be taken which clearly show the Barge Bumper(s).

4

REPORTING

4.1

Final Report The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above. Reference section 2, Chapter 1, Section 3.1.5. All anomalies are to be referenced, with a general statement made concerning the types and extent of anomalies identified. Any C1 anomalies are to be commented on more specifically. Other references are to be made to any digital still images and drawings. If not anomalous, reference is to be made to any marine growth results taken, confirming the location where the data can be obtained, i.e. COABIS database. Any other specific inspection tasks requested in the workscope are to be commented upon. If the task could not be completed, a statement is required stating reasons. Sketches are required, either scanned, AcadLT or other proprietary drawing format, of any major defects or debris that cannot be suitably documented by anomaly report and digital images alone.

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PROCEDURE I 43 001 CAISSON INSPECTION CONTENTS Para

Page

1

INTRODUCTION

3

2 2.1 2.2


3 3 3

3 3.1 3.2 3.3 3.4 3.4.1 3.5

OPERATING PROCEDURE AND SPECIFICATION Inspection Qualifications Safety Above Water Inspection (VI-TOP / PH-TOP) Subsea Inspection General ROV Inspection (VD-ROV) Cathodic Protection Monitoring (CP-PRX)

4 4 4 4 5 5 5

4 4.1 4.2 4.3 4.3.1 4.3.2 4.3.3 4.3.4

INSPECTION OPTIONS Intake / Discharge Cleaning (CL-MGR) Detailed Visual Inspection (CL-INS/VI-DVI) Pump Caisson Inspections Pump Depth Location Pulsed Eddy Current (PEC) Wall Thickness Survey (WT-PEC) Cygnus Wall Thickness Survey (CL-INS / WT-DIG) Detailed Visual Inspection (CL-INS/VI-DVI)

6 6 6 6 7 7 10 10

5 5.1


11 11

FIGURES No 1 2

Page WROV PEC Inspection Area Typical PEC Results Data Sheet Format

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PROCEDURE I 43 001 CAISSON INSPECTION 1

INTRODUCTION The work method shall be applied to the integrity inspection of Cuttings Chute, Drain, Firewater suction, Seawater suction, Dump caissons and their associated fittings and attachments. The work shall include underwater inspection consisting of General Visual Inspection, including marine growth and debris surveys. Additional surveys may be required, in particular for Firewater and Seawater caissons, where a known problem exists due to internal corrosion at the location of the pump due to dissimilar metals. Above water visual inspection will also be required from the Diving/ROV Support Vessel using a digital still camera. Inspection methods under the following procedures may be employed in conjunction with this procedure. I 15 002

-

Ultrasonic Inspection -General

I 15 003

-


I 60 004

-

Cathodic Protection Monitoring – ROV

2

TASKS

2.1


2.2

VI-TOP

-

Topside Inspection

PH-TOP

-


VD-ROV

-

General ROV Video

MG-GEN

-


DB-CHK

-

Visual Debris Check

CP-PRX

-


PH-DIG

-


Optional Tasks The following work tasks are optional and will be explicitly called for in the Workscope. WT-PEC

-

Pulsed Eddy Current (PEC) Wall Thickness Survey

WT-DIG

-

Wall Thickness (WT) Readings

CL-MGR

-

Marine Growth Cleaning (General)

CL-INS

-


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VI-DVI-


IN-FMD

-


PH-DIG

-


Should anomalies be noted, they are to be reported and acted upon as per Section 2, Chapter 6, ‘Anomaly Reporting & Criteria’, and as directed by the Shell Offshore Representative. 3


3.1

Inspection Qualifications The inspection is to be carried out by ROV, under the guidance of a CSWIP 3.3u or 3.4u Inspection Controller, or CSWIP 3.1u/3.2u diver, under the guidance of a CSWIP 3.4u Inspection Controller. Topside inspection is to be carried out by a CSWIP 3.3u/3.4u Inspection Controller.

3.2

Safety WARNING:

DEPENDANT ON THE RESULTS OF THE TRA, IT MAY BE REQUIRED FOR PLATFORM INTAKES OR DISCHARGES TO BE ISOLATED, PRIOR TO CARRYING OUT INSPECTIONS, PARTICULARLY FOR DIVERS AND SMALL ROV’S.

Suitable notice is to be given to the platform prior to any inspection work on a caisson, where isolations are required. ROV pilots and divers are to be aware of other caissons in the vicinity, which may be a hazard. These may be required to be isolated or idled. HOWEVER, DUE TO PLATFORM CONSTRAINTS THIS MAY NOT BE POSSIBLE. ROV For all suction caissons, generally all suctions within 5m of the radial extents of the tether may require to be idled and isolated, unless it can be demonstrated by a site TRA that there is no risk of the ROV blocking (or being sucked into) the caisson. It may be necessary for a suction caisson to be “made safe” by local platform manual over-ride control of the specific fire-water pump which would permit ROV access up to the actual specific caisson inlet in some instances. Typically, precautions for approach limits to discharges may be established in field during the TRA, giving due consideration to potential threats from loss of control, discharge medium, or visibility. Limits on the length of tether deployed, and the vehicle route to the jobsite, are to be established in advance. Divers In most cases, where diving activities are required on a caisson, the caisson will be required to be isolated. Following a TRA, if it is established that the work location is suitably distant from the intake location, with diver umbilical shorter than the termination distance, then it may be that isolations are not required. 3.3

Above Water Inspection (VI-TOP / PH-TOP) A topside visual inspection of the caisson and its associated clamps/guides is to be carried out between LAT and the under deck of the platform, paying particular attention to the region from LAT to +3m. Only gross defects (C1 category) are to be reported. Topside digital photographs are required of the above areas of the caisson from two opposite sides. These should be taken on an opportunity basis only, with no specific vessel move made to obtain these images, unless specifically requested in the workscope.

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3.4

Subsea Inspection

3.4.1

General ROV Inspection (VD-ROV) The ROV will carry out and fully record, a General Visual Inspection (GVI) of the full length of the caisson including all guides, clamps and inlet grilles/flanges. The purpose of this survey is to determine the following: The survey is to cover, as best as practicable, 360° of the circumference of the Caisson. This would generally require 2 passes. (1)

Extent of marine growth cover. Describe marine growth as hard or soft, giving estimated thickness and percentage cover of each.

(2)

Condition of welded support connections to the primary structure.

(3)

Loose or missing bolts from any of the guides, clamps or retention clamps or grille flanges.

(4)

Any debris or obstructions. Where possible debris is to be removed. The Shell Offshore Representative is to be consulted prior to removal.

(5)

Condition of any protective coatings.

(6)

Whether a grille exists at the end termination of the caisson, and what form this takes.

(7)

That suction perforation holes and inlet grilles are clear of any blockages or obstructions. (Digital Still Images to be taken of any blockage).

(8)

Anode wastage, give estimation of percentage wastage. (Note: There is not envisaged to be any anodes on caissons).

(9)

Any areas of damage or corrosion. In the case of firewater and seawater lift caissons, pay particular attention to caisson in vicinity of internal pump, depth of which should be specified in the workscope, for evidence of wall thinning in form of holes.

(10)

Evidence of caisson movement within guides. Any areas of wear or corrosion in the vicinity of guides or clamps.

(11)

Any variance to as-built specification or UMDB's.

No cleaning is to be carried out as part of this routine inspection. However, if anomalies are noted during the course of the GVI, marine growth removal may be carried out, sufficient to allow DVI of anomalous finds. Where blockage of caisson intakes are identified by any debris, or by Marine Growth (≥30%), an anomaly is to be raised. Cleaning of the grille is then required, but only with the prior approval of the platform, with all relevant isolations in place. All cleaning requirements are to be agreed and authorised by the Shell Offshore Representative, acting on advice from the responsible Structural Engineer. Digital Still Images (PH-DIG) are to be taken of any cleaned intakes, pre and post. 3.5

Cathodic Protection Monitoring (CP-PRX) Proximity CP readings are required at the mid point of each section, on both sides, and at each guide. Where the guide/clamp is bolted, where there appears to be the chance that components of the clamp may be isolated from the structure, a contact reading is required for each suspect component.

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Where insufficient COABIS Workpack task boxes exist, relevant additional CP task boxes need to be raised to accommodate all readings taken. The CP probe is to be hard wired into the video overlay such that the CP readings are continuously displayed on the video screen during the survey. CP readings are to be included in the video commentary. Readings should be taken prior to any cleaning. However, should operational constraints make this practice prohibitive, then readings can be taken post cleaning, after agreement with the Shell Offshore Representative. This fact should be clearly stated within the final report. Refer to Standard Procedure I 60 004 for taking CP measurements. 4

INSPECTION OPTIONS When specified in the Workscope, or as directed by the Shell Offshore Representative, acting on advice by the responsible Structural Engineer, any of the following optional activities may be undertaken.

4.1

Intake / Discharge Cleaning (CL-MGR) Where regular inspection of a caisson is not carried out, it may be a requirement to clean intake or discharge terminations as a matter of course during any inspection programme. Caisson terminations, including the region of any caisson intake perforations at the lower ends of the caissons, are to be cleaned of the bulk of marine growth, in particular mussels. Video (VD-ROV) and digital stills (PH-DIG) are required pre and post cleaning. The final report is to detail any areas unable to be cleaned, in particular any remaining internal marine growth, mainly with respect to mussels. Where internal marine growth could not be removed to the anomaly criteria of ≥30% at the termination, an anomaly is only required should intake perforations not exist, or where they have not have been suitably cleaned. No cleaning is to take place without prior approval of the platform, and with the necessary isolation documentation in place.

4.2

Detailed Visual Inspection (CL-INS/VI-DVI) As part of the five/ten year inspection plan for each structure, a programme of marine growth removal and Detailed Visual Inspection (DVI) of guides/clamps will be instigated. The clamps required for cleaning and DVI will be specified in the workscope. For guides/clamps, pertinent areas for cleaning and DVI are the stub/structure & stub/guide welds, all bolts, the top and bottom of the caisson guide/clamp looking for evidence of movement and associated metal loss, and the ends of any secondary clamps for evidence of movement. Levels of cleaning will require the bulk, but not all marine growth to be removed, to allow sufficient detail for DVI of the specified area to be inspected. Where defects exist a drawing should be produced, and/or digital still images taken, clearly showing the size and location of the defects. Additional cleaning and DVI may also be required during the inspection of Firewater and Seawater Lift caissons. This is discussed in section 4.3.4.

4.3

Pump Caisson Inspections The following options are envisaged to be specifically used on pump caissons, Firewater and Seawater Lift, however it may be required for some of these options to be employed on other caisson types.

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For Firewater and Seawater lift caissons, where an internal pump exists, the caissons are prone to internal corrosion at the location of the pump. This has on a number of occasions resulted in the loss of the lower section of caisson, from the pump depth down. For this reason a number of additional inspection tasks may be required to check for evidence of internal corrosion. The main method of inspection is by the use of the ‘Pulsed Eddy Current’ (PEC) Wall Thickness (WT) tool. Other techniques may also be employed, either as specified in the workscope, or based on PEC results. These techniques:- FMD, Cleaning, DVI, Digital WT and the use of PEC are discussed below. 4.3.1

Pump Depth Location Prior to carrying out any wall thickness readings, the positions of the internal pump must be located and recorded. Where known, the workscope should specify the pump depth. This should be an ‘as-built’ depth, i.e. relative to features of known depth on the structure, unless otherwise stated. The most obvious reference feature is a horizontal elevation. The ‘as-built’ depths of all horizontal elevations given are based on the vertical mid point of the elevation member. To establish the position of the pump, the difference between the given pump depth and elevation depth, should be added or subtracted from the ROV (or diver) depth for the vertical mid-point of the elevation member. Where tidal variations exist, or where different vehicles, or new dives are used to continue an inspection on a specific caisson, repeat checks on the offset should be taken.

4.3.1.1

Establishment of Pump Depth (IN-FMD) If the pump depth is not known, or is suspect, possibly due to the installation of a new caisson; new pump; altered pump depth; or otherwise, the pump depth is to be established using the Gamma FMD technique. This identifies the pump location due to its increased density. Method of use of the FMD system, is as specified in procedure I 15 003 - Flooded Member Detection, Section 3.3. Once established, the pump ‘as-built’ depth is to be calculated by measuring the offset between the located pump position and the vertical mid-point of the nearest horizontal elevation.

4.3.2

Pulsed Eddy Current (PEC) Wall Thickness Survey (WT-PEC) Operational use of three possible methods of PEC deployment and inspection, is discussed in standard procedure I 15 002 – Wall Thickness and Ultrasonic Inspection. The correct utilisation of the individual methods with respect to caissons are given below: (1)

WROV Dual PEC Probe Handling Frame. Two PEC probes mounted in a specifically designed frame for use by a dedicated WROV. Allows accurate positioning of the PEC probes once the frame is established around the full circumference of the caisson. Designed for use within larger structures with suitable access to components, i.e. Shell Northern Structures. This system can inspect caissons with diameters of between 42”-22”.

(2)

ROV PEC Probe Handling Frame. A dual PEC probe mounted in a specifically designed frame for use by a dedicated mid sized ROV. Allows accurate positioning of the PEC probe once the frame is established around the caisson, at two clock positions. The vehicle requires to be repositioned for further readings at different clock positions. Designed for use within smaller structures with less restricted access, i.e. Shell ONEgas Structures. This system can inspect caissons with diameters of between 22”-16”.

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(3)

Single PEC Probe ROV Manipulator Held. Use of a single probe, mounted in a bracket, held by an ROV manipulator. Designed for use where access prevents use of either of the above. Refer to 4.3.2.4.

No cleaning is intended to be carried out specifically for PEC readings. This is as the use of PEC allows WT readings without the requirement for cleaning, except where extensive marine growth exists which may prevent fitment of the Sub-Atlantic designed PEC handling frames. Cleaning will only be required for DVI (See 4.3.4) or where digital WT readings are required (See 4.3.3), which are optional. NOTE:

4.3.2.1

All PEC readings taken are subject to post processing on completion of the survey. As a result, evidence of thinning may not be fully apparent until post processing has been completed. Past history has shown that in the main, variations from the initial results are not large. However, post processing may result in readings initially not anomalous, becoming anomalous, and vice versa.

Calibration Reading Prior to commencement of readings in the inspection area, a calibration reading is required in an area presumed to be free from any possible thinning, away from the pump location. Such an area is more likely to be below the pump depth, outside of the inspection area. However, several caissons are comprised of tubular sections of two different wall thicknesses. To identify if this situation exists, reference to as-built drawings should be made. This should preferably have been specified in the workscope, along with the nominal WT. If not specified in the workscope, operators should be aware of this possibility, should a significant sharp step change in results occur, which may not in fact be due to internal corrosion. As a comparison with the calibration reading, ultrasonic Cygnus WT readings may additionally be required. This measurement is to be used as a comparison with the given nominal WT, which is a required input for the PEC software. For the WROV frame a Cygnus probe is mounted to the top of the frame, as well as a rotary wire brush for cleaning.

4.3.2.2

WROV PEC Frame Obtained Caisson Readings (Northern) The PEC inspection area is to be 1.5m above and below the pump depth, unless stated otherwise in the workscope, or access does not allow. Reading locations are to be reported relative to the pump depth (taken to be zero), where positive is above the datum (Less deep, i.e. less –ve), and negative is below (Deeper, i.e. more –ve). Over the inspection area, 1.5m above and below the pump depth (datum zero), PEC readings are required at datum zero, and every 100mm above and below datum for 300mm at the 12 cardinal clock positions; then every 250mm from the 500mm position, at the four cardinal clock positions. The method of use of the PEC system requires 1 or 2 further single bands of readings to be taken at each clock position, above and below datum, to act as reference readings. (See Fig.1.).

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+1500mm

Summary of PEC Locations Not To Scale +300mm Datum -300mm

-1500mm

Figure 1

WROV PEC Inspection Area

Should restricted access prevent clear access for the PEC frame, i.e. pump depth near to elevation members, consult the Shell Offshore Representative for alternative inspection locations, or method. Thought should be given to use of alternative PEC tools, ROV Frame or Manipulator held, or alternative locations above or below the restriction. Where evidence of thinning is found i.e. >25% loss, additional WT readings are to be taken at clock positions adjacent to the thinned area in 100mm vertical steps, until WT readings obtained are back to nominal WT. Inform the Shell Offshore Representative, prior to taking any readings, to confirm extent of additional readings required. Note:

Any wall thinning >50% is to be reported as a C2 anomaly. A C1 anomaly relates only to visible cracks or holes.

Where area of thinning appear to extend outside the originally specified inspection area inspection may continue outside this area until the above acceptable WT levels have been attained, as operational constraints allow, after consultation with the Shell Offshore Representative, acting on advice from the responsible Structural Engineer. 4.3.2.3

ROV PEC Frame Obtained Caisson Readings (ONEgas / Northern) The survey is initially to be restricted to four clock positions around the circumference of the caisson, as access allows, equally spaced if possible. Readings are to be taken in 100mm increments vertically. The area of inspection is to be conducted as specified in the workscope. Where evidence of thinning is found i.e. >25% loss, additional WT readings are to be taken at clock positions adjacent to the thinned area in 100mm vertical steps, until WT readings obtained are back to nominal WT. Inform the Shell Offshore Representative, prior to taking any readings, to confirm extent of additional readings required. Note:

Any wall thinning >50% is to be reported as a C2 anomaly. A C1 anomaly relates only to visible cracks or holes.

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4.3.2.4

Single PEC Probe ROV Manipulator Held Where access is restricted, or the diameter of the caisson prevents use of the PEC frame, a single PEC probe is to be used, held in the ROV manipulator. Readings are to be taken, as best as practicable, in the workscope specified locations. This method of use is not as accurate in its positioning of the PEC probe, due to vehicle movement, and general problems regarding the correct position of the probe. However, best endeavours should be made to accurately record the locations of readings taken. Use of a known depth reference is to be used (see section 4.3.1 above). Two probe types exist, providing a broad and narrow inspection beam area. The narrow beam probe should be used on tubulars of small diameter. A mounting frame has been used in the past in the form of a ‘V’, which helps to centralise and stabilise the PEC probe on the inspection area. This mounting frame must not be made from magnetic ferrous metal, or aluminium. An acceptable material is Non-magnetic Stainless Steel, or plastic. Where anomalous readings are found, increase the survey readings as per best as practicable, as per the anomaly survey requirements in 4.3.2.2 above, dependant on the originally specified survey extents.

4.3.3

Cygnus Wall Thickness Survey (CL-INS / WT-DIG) Cygnus WT readings may be required to be taken by ROV or diver, over areas either specified in the workscope, or by the Shell Offshore Representative, acting on advice from the responsible Structural Engineer based on earlier survey results. For diver inspection, where multiple readings are to be taken over an extensive area, a grid pattern should be marked on the caisson, the depth of which should be recorded relative to a known ‘as-built’ reference point. For both ROV or diver survey, a drawing and/or table of the results should accompany the final report. The method of cleaning and survey to be adopted is as specified in standard procedure I 15 002, section 3.3.

4.3.4

Detailed Visual Inspection (CL-INS/VI-DVI) Unless specified in the workscope, cleaning and DVI will only be required if the results of the Pulsed Eddy Current (PEC) wall thickness survey (see 4.3.2) indicate a wall thickness loss ≥50%, as specified in the anomaly criteria. This inspection is intended to be carried out by ROV, utilising zoom cameras for detail, to look for evidence of through wall defects and/or corrosion. The extent of the area to be cleaned and inspected is to be advised by the Shell Offshore Representative, based on the PEC results. Diver inspection may be required to further investigate defects identified by ROV. Cleaning will require the bulk, but not all, marine growth to be removed to allow sufficient detail for DVI of the area specified to be inspected. Where perforations due to thinning are visible a drawing should be produced, and/or digital still images taken (PH-DIG), clearly showing the size and location of the defects. If inspected by ROV, estimated dimensions are required as a minimum, but preferably a more accurate method of report should be utilised, i.e. a manipulator held scale. If inspected by Diver, a suitable grid should be used to plot the defects.

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5

REPORTING

5.1

Final Report The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above. Reference section 2, Chapter 1, Section 3.1.5. This should include - lack or presence of a grille and type at termination points, any blockage of the grille and any resultant cleaning activities. Where PEC readings, DVI or cleaning has taken place, all depths given should be ‘as-built’ depths, converted from actual ROV/Diver depths, which is to be clearly stated. A general statement concerning results should be made, i.e. max/min of CP, and/or WT readings. If CP readings are taken post cleaning, this should be stated. Any inspection data or PEC files are to be referenced. Where visible perforations exist due to wall thinning, a drawing and/or digital still images are to be included. Hard copies of all digital still images are to be included with the report, saved and correctly linked within the COABIS database. Where significant WT readings have been taken, that cannot be suitably represented within the COABIS results, or as a table in the Job Completion Report, a drawing should be produced. A hard copy of all PEC data results, and any associated Cygnus WT readings, are to be included in the Results/Appendix section of the final report. The PEC results are to be presented in the format shown in Fig.2 below. This format is converted from the processed PEC data files, which is in an excel format. All PEC data files are to be saved within the COABIS database and suitably linked.

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PEC Offline Wall Thickness plot A + B (15% Smoothed + FFT filtered) Location

Nelson

Date

Saturday,12 Jun 2004

Job nr.

NELSN/2004/C101

Filename

RD16404C

Component nr.

43-007

Description

Seawater caisson

Datum point

-10m

Recorded by

John Downes / John Knight

Diameter

39

Grid vert.

spacing

[inch]

Grid. hor.

clockposit circumferential

longitudinal

Vertical Position +1500 +1400 +1300 +1200 +1100 +1000 +900 +800 +700 +600 +500 +400 +300 +200 +100 0 -100 -200 -300 -400 -500 -600 -700 -800 -900 -1000 -1100 -1200 -1300 -1400 -1500 -1600

WT_nom

15

Vert.incr.

100

[mm]

Hor. incr.

1

[mm] [hr]

Horizontal Position 1

2

3

4

5

6

7

8

9

10

11

12

14.6

14.4

14.9

14.7

14.6

15.2

15.3

15.3

14.5

13.9

13.6

19.7

13.3

13.5

14.0

13.9

14.2

14.8

14.4

14.7

14.0

11.7

12.3

19.7

11.1

13.0

13.1

13.9

13.9

13.8

13.8

13.6

13.3

11.6

11.2

18.7

11.0

12.1

11.6

12.3

13.4

13.2

13.7

12.4

11.9

10.8

10.3

18.1

9.9

11.6

10.9

11.5

12.9

13.3

13.6

12.5

12.0

11.8

9.9

17.3

9.4

12.6

11.8

13.7

14.0

13.6

13.8

12.2

12.5

11.7

10.7

17.6

11.9

13.0

12.2

13.3

14.0

14.1

14.0

12.3

12.5

12.5

10.9

16.8

11.9

12.8

11.3

13.5

13.9

13.9

13.7

12.5

13.4

12.3

12.1

18.1

12.4

15.2

15.2

15.0

13.4

11.7

15.6

15.8

15.9

15.6

14.9

14.3

13.2

15.4

15.3

14.5

15.7

15.6

16.1

15.0

15.7

15.4

15.6

16.1

14.9

15.5

15.2

14.5

15.5

14.8

15.5

15.5

15.6

16.0

16.3

15.4

15.2

15.7

15.5

15.7

15.5

15.6

15.5

15.4

15.6

16.1

16.0

15.9

15.6

15.7

15.6

15.8

15.7

14.8

15.7

15.2

15.9

16.1

15.9

16.1

16.0

15.8

15.4

15.6

15.9

15.5

15.5

15.6

15.5

15.9

16.0

16.1

15.5

15.9

15.3

15.1

15.8

15.8

15.6

15.8

15.9

15.9

16.3

16.1

16.1

16.3

16.1

16.0

15.5

18.1

15.7

15.8

15.6

15.7

16.2

16.2

16.2

16.3

15.9

15.8

14.9

18.1

15.6

15.3

15.5

15.6

15.8

16.1

16.5

15.0

14.9

15.2

14.5

18.2

16.2

16.2

15.1

15.6

15.4

16.6

15.1

15.0

15.4

17.4

15.3

15.0

15.0

17.1

15.2

14.5

14.6

16.9

15.0

14.9

14.8

16.6

15.1

15.0

15.2

16.2

15.1

14.9

15.0

15.2

15.5

14.8

15.0

14.7

14.7

16.0

14.0

15.0 14.6

14.9

15.0

15.0

14.5

14.8

15.4

14.7

14.7

14.7

15.1

14.5

14.9

14.8

14.6 13.7

13.6

14.3

14.0

13.3

14.5

14.8

14.6

12.9

14.6

14.3

10%+ (+/-) 10% 10% - 15% 15% - 20% 20% - 25% 25% - 30% 30% - 35% 35% - 40% >40% ref_value

15

margin %

10

band_min

13.5

band_max

16.5

perc_incr

5

Figure 2

Typical PEC Results Data Sheet Format

(Produced from PEC Excel Spreadsheet Both_offl2 Corrected) I 43 001 Page 12 of 12

Am 01 05/05

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PROCEDURE I 49 057 TALON JOINT INSPECTION CONTENTS Para

Page

1

INTRODUCTION

3

2 2.1 2.2

TASKS ROV Survey Full Survey

3 3 3

3 3.1 3.2 3.3 3.3.1 3.3.2 3.3.3 3.3.4 3.3.5 3.3.6 3.3.7 3.3.8

OPERATING PROCEDURE AND SPECIFICATION Inspection Qualifications ROV Survey (VD-ROV) Full Survey (Including Options) Preparation Initial ROV Inspection (VD-ROV) Rigging (CN-RIG) Talon Inspection with Armawrap Deploy cleaning equipment to site and remove marine growth as follows (CL-INS): Inspection of Talon with Scalloped Sleeve Inhibitor Gel Injection (Optional) Final Inspection (VD-ROV)

4 4 4 4 4 5 5 5 5 7 7 8

4 4.1


8 8

FIGURES No 1 2 3 4 5 6

Page Installation of Digital Micro OHMS Unit on Talon Joint Probe Head Positioned on Talon Joint Armawrap Protective Sleeve Installation Tool Operation and Armawrap Protective Sleeve Installation Tool Armawrap Protective Sleeve Attachment Details Rotation Monitor Installation Talon Joint

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PROCEDURE I 49 057 TALON JOINT INSPECTION 1

INTRODUCTION The work method is to be applied to the maintenance and inspection of Talon Joints. The work will include marine growth removal, electrical resistance survey, installation of Armawrap and rotation indicators, and injection of inhibitor gel and video survey. Eddy Current Inspection (EMI) using ACFM, as per Procedure I 15 001, may be required to be employed in conjunction with this procedure.

2

TASKS

2.1

ROV Survey The following work tasks are required for an ROV only survey.

2.2

VD-ROV

-

General ROV Video

VI-ROV

-


MG-GEN

-

Marine Growth Check

CL-INS

-


VI-DVI

-


CH-FXW

-

Check Armawrap (Flexi-wrap)

Full Survey The following work tasks are required for a full Talon Joint survey, including various options. VD-ROV

-

General ROV Video

VI-GVI

-


CN-RIG

-

Rig/De-rig Equipment

CL-INS

-


CN-FXW

-

Remove/Apply Flexi-wrap

IN-ERS

-

Talon ERS Survey

VD-DIV

-

General Diver Video

VI-DVI

-


CN-STD

-

Standard Construction Task (Inject Inhibitor Gel)

VI-CVI

-

Close Visual Inspection (As per I 15 001)

IN-ECI

-

Eddy Current Inspection (As per I 15 001)

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3.1

Inspection Qualifications The inspection is to be carried out by ROV, under the guidance of a CSWIP 3.3u or 3.4u Inspection Controller. Diver intervention works may be carried out by any grade of diver. However, inspection orientated work is to be carried out by CSWIP 3.1u, CSWIP 3.2u diver, as directed by a CSWIP 3.3u/3.4u Inspection Controller.

3.2

ROV Survey (VD-ROV) The ROV will carry out, and fully video record, a visual survey of the Talon Joint. The following actions are required: (1)

Carry out an initial survey (VI-ROV) to correctly identify the joint in accordance with the given workscope location and UMDB drawings. Confirm depth of joint referenced against a known elevation. Cleaning may be required to correctly identify the joint.

(2)

Extent of marine growth (MG-GEN).

(3)

Any debris or obstructions in work area.

(4)

Clean (CL-INS) the Talon Joint.

(5)

(a)

Where no Armawrap is present clean localised to the joint, to a standard to allow a detailed visual inspection to be carried out.

(b)

Where Armawrap is present, clean sufficiently to confirm the integrity of the Armawrap seam and securing bolts. Clean above and below the Armawrap sufficient to check alignment of the rotation indicators.

Complete a detailed visual inspection (VI-DVI) of each Talon joint. The format of the survey is dependant on whether an Armawrap protection sleeve is present: (a)

If no Armawrap is present - check for any damage, corrosion staining, movement or separation of the joint. Check the status of the grease injection port to the top of the joint.

(b)

If Armawrap is present - Confirm the integrity of the Armawrap, including bolts.

(c)

Identify the presence of rotation indicators, if any, looking for evidence of rotation. Rotation indicators should be present where Armawrap is present, and should be in line with the seam of the Armawrap. (See anomaly criteria, point 2.2.16).

CP readings are not required, except as part of a relevant anomaly investigation. 3.3

Full Survey (Including Options)

3.3.1

Preparation Before work can commence on the Talon Joints carry out the following, where applicable. (1)

Marshal all necessary materials for this work on the vessel's deck.

(2)

Check off materials list.

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3.3.2

(3)

Make available inhibitor gel, in the event it is required from the inspection results, or specified in the workscope.

(4)

Pressure up digital micro OHM unit and test.

Initial ROV Inspection (VD-ROV) The ROV will carry out, and fully video record, an initial visual survey of the Talon Joint. The purpose of the survey is to record the following: (1)

An initial survey (VI-ROV) to correctly identify the joint in accordance with the given workscope location and UMDB drawings. Confirm depth of joint referenced against a known elevation. Cleaning may be required to correctly identify the joint.

(2)

Position of any rotation indicators, if any, looking for evidence of rotation.

(3)

Is Armawrap protective sleeve installed.

(4)

Extent of marine growth to be removed.

(5)


If operational constraints allow, cleaning of the joint can be carried out by the ROV, as per the requirements below. 3.3.3

Rigging (CN-RIG) Diver to establish downline to worksite. Use of a diver work stage at site may be considered, however recent inspections have not found it necessary (CN-RIG). Where rotational indicators are installed, the diver is to note and report any displacement prior to removal. If displacement is seen, record on video prior to removal. (See anomaly criteria, point 2.2.16).

3.3.4

Talon Inspection with Armawrap On Talon Joints where Armawrap protective sleeving has been installed, it will require removal to allow electrical resistance checks to be carried out (CN-FXW).

3.3.5

3.3.5.1

Deploy cleaning equipment to site and remove marine growth as follows (CL-INS): (1)

400/500mm above the Armawrap to allow it to pull up clear of the talon joint.

(2)

To remove Armawrap protective sleeve attach a span set above the Talon Joint as a rigging point, slacken off the Armawrap protective sleeve securing bolt sufficiently to allow sleeve to be pulled up clear of the Talon Joint and hang off on the span set.

(3)

With the Armawrap removed, clean the Talon Joint to allow for DVI and to allow the ‘Talon Tool’ probe assembly to make good contact with steel surface.

(4)

At the four cardinal clock positions, a vertical strip area 150mm (High) x 50mm (wide) across the joint and both rebates, must be cleaned to bright shiny metal, to allow contact of the SERIS II ‘Talon Tool’ head probes and obtain resistance readings.

On completion of cleaning, electrical resistance checks using the Talon Tool are required (IN-ERS). Assemble the probe head clamp around conductor and position the probe assembly as shown in Figs 1 and 2.

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NOTE:

When positioning the tool initially, it is essential that the four probe heads are fully retracted. Only when the tool is secure in the desired position should the probes be brought forward into contact position by operating the 'cam' lever.

(1)

Activate diver held electrical resistance tool, obtain and record a minimum of three authentic signals on monitor, calculate and record the mean value. Adjust equipment and move probe to repeat monitoring exercise at each cardinal clock position. Add the four mean values, calculate and record the overall mean.

(2)

Inform the Shell Offshore Representative of the readings obtained. Raise anomaly reports if necessary. (See anomaly criteria, point 2.2.16).

(3)

Complete a detailed visual inspection (VI-DVI), recorded on video, of the Talon joint. Check for any damage, corrosion staining, movement or separation of the joint. Check the status of the grease injection port to the top of the joint.

CP readings are not required, except as part of a relevant anomaly investigation. If required by the workscope, inject Inhibitor Gel, to the injector port found to the top of the joint, as per section 3.3.7. 3.3.5.2

3.3.5.3

Re-install Armawrap protective sleeve as follows (CN-FXW): (1)

Fit the Armawrap sleeve around the conductor and tie off so that it is positioned centrally across the joint, ensuring that the injection nipple is covered by the soft part of the wrap.

(2)

Using the Armawrap sleeve installation tool Figs. 3 and 4 in the central bolthole draw the wrap flanges together sufficiently to allow installation of two 175mm bolts, which are then used to fully close the flange faces. Finally replace the sleeve installation tool with a 175mm bolt and tighten, approx 70-80 ft lbs, fit double nylon lock nuts to all bolts. Replacement nuts and bolts should be supplied. See Fig 5.

On completion of all works rotation indicators are to be installed, ensuring correct alignment with the Armawrap flange. See Fig 6. Talon Inspection without Armawrap Where Talon Joint has not been previously inspected and/or is not protected by an Armawrap. Deploy cleaning equipment to site and remove marine growth as follows (CL-INS):

3.3.5.4

(1)

Clean the conductor 400mm either side of the Talon joint removing all marine growth and loose coating.

(2)

Clean Talon Joint at cardinal clock positions over an area 150mm (High) x 50mm (wide) to allow probe assembly to make good contact with steel surface.

On completion of cleaning, electrical resistance checks using the Talon Tool are required (IN-ERS). Assemble the probe head clamp around conductor and position the probe assembly as shown in Figs 1 and 2. NOTE:

When positioning the tool initially, it is essential that the four probe heads are fully retracted. Only when the tool is secure in the desired position should the probes be brought forward into contact position by operating the 'cam' lever.

Activate diver held electrical resistance tool, obtain and record a minimum of three authentic signals on monitor, calculate and record the mean value. Adjust equipment and move probe to repeat monitoring exercise at each cardinal clock position. Add the four mean values, calculate and record the overall mean.

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Inform the Shell Offshore Representative of the readings obtained. Raise anomaly reports if necessary. Complete a detailed visual inspection (VI-DVI), recorded on video, of the Talon joint. Check for any damage, corrosion staining, movement or separation of the joint. Check the status of the grease injection port to the top of the joint. CP readings are not required, except as part of a relevant anomaly investigation. If required by the workscope, inject Inhibitor Gel, to the injector port found to the top of the joint, as per section 3.3.7. 3.3.5.5

Install Armawrap protective sleeve as follows (CN-FXW): (1)

Fit the Armawrap sleeve around the conductor and tie off so that it is positioned centrally across the joint, ensuring that the injection nipple is covered by the soft part of the wrap.

(2)

Using the Armawrap sleeve installation tool, Figs 3 and 4, in the central bolthole draw the wrap flanges together sufficiently to allow installation of two 175mm bolts, which are then used to fully close the flange faces. Finally replace the sleeve installation tool with a 175mm bolt and tighten, approx 70-80 ft lbs, fit double nylon lock nuts to all bolts. See Fig 5.

3.3.5.6

On completion of all works, rotation indicators are to be installed, ensuring correct alignment with the Armawrap flange. See Fig 6.

3.3.6

Inspection of Talon with Scalloped Sleeve

3.3.6.1

Where Talon Joint has a scallop sleeve welded across the Talon Joint, cleaning to SA 2.5 will be necessary at the following locations: (1)

Upper 'peak' lobe at 12 o'clock position.

(2)

Upper 'trough' lobe at 3 o'clock position.

(3)

Lower 'peak' lobe at 9 o'clock position.

(4)

Lower 'trough' lobe at 6 o'clock position.

(5)

Full length of one of the vertical welds.

3.3.6.2

Talon Joints with welded scalloped sleeves are to be subjected to close visual inspection (VI-CVI), ACFM (IN-ECI) inspection and video as per Procedure I 15 001.

3.3.7

Inhibitor Gel Injection (Optional)

3.3.7.1

The joint should then be injected with inhibitor gel and Armawrap installed as follows (CN-FXW): (1)

Ensure Talon Joint and Conductor 400mm either side of Talon Joint is clean and free of marine growth cover.

(2)

Visually inspect Talon Joint, record any damage or observed movement, and photograph as necessary.

(3)

Remove the 1/2-inch NPT plug by backing out using a 1/4-inch Allen key. Ensure the Allen profile in the plug is cleaned out and the key fully home before attempting to remove the plug. In the event that the Allen head profile is deformed. Confirm with the responsible Technical Authority whether to proceed with injection operations. If confirmed, the plug is to be removed as follows:

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The plug must be drilled (1/8 inch at first) to 1/4 inch-5/16 inch and an extractor used to remove the plug. It is possible to detect when the drill has penetrated the joint interface, as an area of no resistance will be encountered immediately after drilling through plug. Use the largest size extractor suitable for 5/16-inch hole as considerable torque may be required, and removal of a sheared extractor is a laborious process. (4)

Surface preparation for inhibitor gel injection - prior to gel injection the two components of the gel must be mixed. It is vital that the container of Activator (Corexit 3328) is thoroughly agitated for 5 minutes prior to adding it to the inhibitor (Corexit 3327). The two components must then be thoroughly agitated for a further 5 minutes (add the full contents of the agitated 5 litre container to the 25 litre container). Gelling should start to take place in 1-2 hours; the mixture should not be used unless gelling has started. Transfer the gel to hydraulic pumps using 140cc syringes provided, when pump reservoir is full allow time for any air bubbles to settle out and check pump displacement per stroke (Use syringe as measure). NOTES: (1)

(2) (5)

An alternative gel may be supplied, if so, full instructions for its use will be included in the workscope. Hydraulic pump may be used both above and below water as the need arises.

Gel to be injected to a maximum pressure of 2,500psi or until 500cc (by counting pump strokes) has been injected. The latter instance would indicate that defective '0' seals are allowing the gel to pass into the annulus. Should this occur inform the Shell Offshore Representative. Also in the event of leakage of the gel being observed at the visible external Joint, inform the Shell Offshore Representative who, after consultation with the responsible Structural Engineer, will decide on the course of action to be taken. NOTE:

During pumping the pump should be slung vertically with the pump head down to avoid air being forced into the joint.

On completion of inhibitor gel injection, vent any pressure via the downstream valve (not the valve on the pump head) otherwise there is a risk of corrosion products entering the pump and damaging the seals. (6)

Disconnect hydraulic pump and fit a new 1/2-inch NPT plug. NOTE:

3.3.8

A surface GKN type hydraulic pump has been used to good effect for gel injection, in this case ensure the reservoir and umbilical are purged with inhibitor gel, and observe the same pressure/volume constraints as (5) above.

Final Inspection (VD-ROV) On completion of all diver works the ROV will carry out, and full video record, a general visual survey of each Talon Joint, paying particular attention to the final placement of the Armawrap protective sleeve and rotation indicators.

4

REPORTING

4.1

Final Report The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above. Reference section 2, Chapter 1, Section 3.1.5. This is to confirm the presence of alignment indicators; whether any misalignment was noted; the presence of Armawrap; full results of the Electrical Resistance checks; whether inhibitor gel was used;

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confirming re-instatement of Armawrap and alignment indicators. Reference any ACFM files and accompanying data sheets. Any ACFM files created are to be saved and correctly linked within COABIS. Any other specific inspection tasks requested in the workscope are to be commented upon. If the task could not be completed, a statement is required stating reasons.

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0153-001 SPANSET STRAP ASSEMBLY

HAND HELD PROBE ASSEMBLY

SPANSET OMITTED

TALON CONNECTOR

POWER LEAD

DIGITAL MICRO OHM UNIT ( DMO )

Figure 1

I 49 057 Page 10 of 15

Installation of Digital Micro OHMS Unit on Talon Joint

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0153-001

PROBE UNIT HELD ON CONDUCTOR BY RATCHET AND WEBBING STRAP ATTACHED TO UNIT

CAM LOCK ALLOWS PROBE TO RETRACT

UMBILICAL TO CONTROL

30" CONDUCTOR

>

-

+

Figure 2

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Probe Head Positioned on Talon Joint

I 49 057 Page 11 of 15

I 49 057 Page 12 of 15

Figure 3

100mm. BAR

300mm. BAR, NUT AND WASHER WELDED TOGETHER

M12 WASHER

500mm. x 20mm DIA. TUBING

1000mm. M12 THREADED BAR

M12 NUT AND WASHER WELDED TOGETHER

M12 WASHERS

M12 LOCKNUT

0153-001

Armawrap Protective Sleeve Installation Tool

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BOLT HOLES

ARMAWRAP

INNER SEAL FLAP

CLOSURE SEALS

ARMAWRAP

0153-001

Figure 4

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Operation and Armawrap Protective Sleeve Installation Tool

I 49 057 Page 13 of 15

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KEY :

Figure 5

NEOPRENE

NEOPRENE / NYLON

GRP PULTRUSION

NEOPRENE SEALS

POLYPROPENE SEAL

ANTI - FOULANT COATED POLYESTER FELT

CONDUCTOR PIPE WALL

PROTECTIVE SLEEVE CLOSURE SYSTEM

SLEEVE OVERLAP

MONEL SECURING NUT (TYP. BOTH ENDS)

NYLON LOCKING RING (TYP. BOTH ENDS)

0153-001

Armawrap Protective Sleeve Attachment Details

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CONDUCTOR

SPANSET STRAP

ALIGN MARKER WITH ARMAWRAP FLANGE

ARMAWRAP PROTECTIVE SLEEVE

750mm

ROTATION MONITOR

NOTE: Rotational monitors are to be installed at all Talon joints irrespective of Armawrap protective sleeve being fitted

Figure 6

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Rotation Monitor Installation Talon Joint

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PROCEDURE I 60 004 CATHODIC PROTECTION MONITORING CONTENTS Para

Page

1

INTRODUCTION

3

2

TASK OPTIONS

3

3 3.1 3.2 3.2.1 3.2.2 3.3 3.3.1 3.3.2 3.4 3.4.1 3.4.2

OPERATING PROCEDURE AND SPECIFICATION Inspection Qualifications CP Calibrations Calomel Cell Calibration Pre, Post and Mid Dive Calibrations Proximity CP Readings - (CP-PRX) Remote Reference CP System Direct Earthing Cable Method Contact CP Readings – (CP-CON) ROV Contact CP Readings Diver Contact CP Readings

3 3 3 4 4 4 5 6 6 6 7

4 4.1 4.1.1 4.1.2 4.2 4.2.1 4.3 4.3.1 4.4 4.4.1 4.4.2 4.4.3 4.4.4 4.5

OPTIONS Anode Inspection Anode CP Survey – (CP-AN) Detailed Anode Inspection – (VI-AWD) Cathodic Protection Potential Survey – Zonal (CP-ZON) CP Survey - Zonal Cathodic Protection Potential Survey – Nodal (CP-NOD) CP Survey - Nodal Anode Direct Current Measurement – (CP-GSC/IN-GSC) Inspection Qualifications Anode CP Survey – (CP-GSC) Anode Measurement – (IN-GSC) System Calibration Final Report

7 7 7 7 8 8 9 9 9 9 9 10 11 11

FIGURES No 1 2 3 4 5 6 7

Page Example of Format for Anode Inspection Typical Structural Cathodic Potential Reference Point Typical Anode Volumetric Measurements Example of Format for Zonal CP Survey Example of Format for Nodal CP Survey Example of Format for Anode Direct Current Measurement Monitoring- Blank Example of Format for Anode Direct Current Measurement Monitoring-Completed

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PROCEDURE I 60 004 CATHODIC PROTECTION MONITORING 1

INTRODUCTION The work method is to be applied for the inspection monitoring of structural Cathodic Protection (CP) systems. The work will include anode inspection, Cathodic Potential readings and anode direct current measurement monitoring.

2

TASK OPTIONS CP-PRX

-


CP-CON

-


MG-GEN

-


CL-INS

-


VI-AWD

-

Detailed Anode Check

CP-AN

-

Detailed Anode CP Survey

VI-AW

-


CP-ZON

-

Zonal CP Survey

CP-NOD

-

Nodal CP Survey

CP-GSC

-

G-Scan CP Survey

IN-GSC

-

G-Scan DC Measurement

VD-ROV

-

General ROV Video



3.1


3.2

CP Calibrations At the start of an inspection campaign all CP units, including all spare probes, are to be calibrated using Calomel Cells and results logged. Subsequent calibrations using Calomel cells are to be carried out or at suitable intervals over a prolonged inspection campaign, as directed by the Shell Offshore Representative, or when a probe is suspect. Subsequent calibrations pre, post and during dives (for diver inspections) are to be carried out against a zinc block.

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3.2.1

Calomel Cell Calibration Calomel cells and CP probes should be soaked in fresh salt water, for up to 2 hours prior to deployment, in a non-metallic container. The container is to be free from zinc blocks or other metallic debris. Three Calomel cells are required, each cell to be labelled 1, 2, 3 or A, B, C. Compare each calomel cell against each other using a multimeter, i.e. 1 v 2, 1 v 3 and 2 v 3. Acceptable limits are to be -4mV, +/-5mV. Select the best cell from these comparisons, closest to 0mV. The selected Calomel cell should then be read against a zinc block, and is to be within the range 1000mV to -1050mV. The selected Calomel cell number, calibration reading against both the calomel cell and zinc block are to be recorded within COABIS. Calibrate the required CP probes against the selected Calomel cell, with the Calomel cell connected to the -ve terminal of the multimeter. Acceptable readings should again be within –4mV, +/-5mV. Once proven the probe is to then be calibrated against a zinc block, and should read the same as the Calomel cell zinc block reading, plus the difference between probe and Calomel Cell. Note, when using Bathycorrometer type Calomel cells which screw directly onto the Bathycorrometer, the polarity of the acceptable readings is reversed. This is as the cell connects to the +ve terminal of the Bathycorrometer and should therefore read +4mV, +/-5mV. Note: Calomel Cells are only valid for 2 years from their production date.

3.2.2

Pre, Post and Mid Dive Calibrations CP probes should be soaked in fresh salt water, for up to 2 hours prior to deployment, in a nonmetallic container. The container is to be free from zinc blocks or other metallic debris. For ROV inspection, all systems are to be calibrated pre and post dive against a zinc block. In tidal conditions, the ROV is to be recovered once operations have been stopped due to current, to ensure post and pre-dive checks are carried out. For Diver hand held Roxby Bathycorrometers, all units are to be calibrated pre and post dive, and prior to use subsea against a zinc block. Acceptable calibrations against the zinc block are between -1000mV and -1050mV. All calibration results are to be recorded within the COABIS database. Inspection procedure and calibration of equipment is to conform to the following standard: Det Norske Veritas - Recommended Practice, Monitoring of Cathodic Protection Systems. RP B403, March 1987. In particular Sections 3 and 4, Calibration and Equipment Checks

3.3

Proximity CP Readings - (CP-PRX) NOTE:

Cathodic Potential Data, where necessary, is to be obtained prior to any marine growth removal or any site cleaning operations.

Presently there are two methods employed in the taking of Proximity CP readings. The preferred option is the use of a Remote Reference CP system. The other option is the traditional Direct Earthing Cable method. The benefits of the Remote Reference CP system, is that it allows readings without the need for permanent direct contact to the facility being inspected. The use of these methods is discussed below. Both systems are to be used by ROV, but can be used by Diver.

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The CP probe is to be hard wired into the video overlay such that the CP readings are continuously displayed on the video screen during the ROV survey. CP readings are to be included in the video commentary. 3.3.1

Remote Reference CP System There are a number of these non permanent contact proximity systems available, provided by the following companies: •

Pro-Sub Services Ltd.

•

Subspection Ltd.

•

IIcorr

The Pro-Sub Services system allows operation of the unit by any 3.3u/3.4u Inspection Controller. The other systems require specialised operators. For information on the use of these systems, refer to the relevant manual, or as instructed by the system operator. These systems use the standard philosophy of Cathodic Potential measurement but allow the taking of proximity readings without the need for a permanent contact to the facility being inspected. This is possible by means of taking an initial contact CP ‘stab’ reading on the subject to be inspected, or to another component that is directly earthed to the inspection subject, to which the CP system is calibrated. All subsequent proximity readings are taken using the same probe for the contact calibration reading in close proximity to the inspection subject, using a standard Silver/Silver Chloride (Ag/AgCl) CP probe. These systems employ a second ‘reference’ probe, which is suspended in the water away from the inspected facility. The benefits of this method are that for the inspection of platforms, no assistance is required from the platform in connecting an earthing cable. For the inspection of risers, there is no concern as to whether the risers are isolated from the remainder of the platform, and no need to obtain direct contact of the earthing cable to the riser. For subsea facilities, the proximity CP method can be employed, as opposed to direct contact. In addition the probe can also be used for contact readings during the same survey. Due to the method of calibrating the system for proximity readings, subsequent CP readings can only be taken on components earthed to the component used for the calibration reading. Therefore when inspecting a caisson, CP readings can be taken on the caisson and also on any associated guides without need for additional calibration readings. However, for risers where it is assumed, unless otherwise known, that guides/clamps are isolated from the riser by liners, a separate set of CP readings are required for the riser and for clamps/guides. In this latter case, and in other similar situations, where additional individual readings are required, contact readings would be acceptable, to remove the need to re-calibrate after each set of additional readings. When using these systems, contact calibration readings are to be taken for each new dive, for each new component type, and/or each new Component Task Sheet (CTS) worked on. Therefore new contact calibration readings are not required for each individual member to be inspected on a structure, but would be needed for a new structural elevation, caisson, riser, or any other electrically isolated component. 3.3.1.1

General CP Survey The locations for readings are specified in the relevant standard procedure, or as specified in the workscope. During a survey the distance that the CP probe is from the component is dictated by the camera view. Best endeavours should be made to keep the probe as close as possible, but out of the view of the camera as best as possible. Where a specific CP reading is requested, the CP probe should be presented to the component, but there is no need for contact.

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3.3.1.2

Riser and Other Subsea Facility Pressurised Pipework CP Survey For riser and other pressurised pipework (i.e. igloo/wellhead pipework and pipelines) inspections, direct contact CP readings are not to be carried out on the pipework itself, unless specified in the workscope or otherwise directed by the Shell Offshore Representative, acting on advice from the responsible Structural Engineer. A large proportion of risers and pressurised pipework are coated, and as such do not allow direct contact readings. To obtain a contact reading for calibration purposes either a flange, anode or other earthed appurtenance is to be used. Due to the nature of the remote reference CP system, contact readings are required to be taken on a riser clamp/guide, or other appurtenance electrically isolated from the pipework, either as part of the workscope or to investigate an anomaly. Where a clamp is comprised of a number of parts, i.e. inner and outer shell, contact CP readings are to be taken on each part. Dependant on the system used, on completion of these contact readings it should be possible to continue the riser survey, without need to re-calibrate to continue the proximity survey. If not, re-calibrate using the nearest suitable location.

3.3.2

Direct Earthing Cable Method This method of survey can only be used on manned platforms. This method requires an earthing cable to be passed to the platform to be inspected. Assistance is required of the platform to connect the earthing cable to bare steelwork, not stainless steel, i.e. not handrails. Where it is known that the platform risers are electrically isolated from the remainder of the platform, for the proximity method to work, the earthing cable requires to be connected directly to the riser to be inspected. Connection may require cleaning of the platform connection point using a wire brush. Suitable notification is required to be given to the platform, prior to vessel arrival at the platform. Due to platform manning levels, it may only be possible to make such connections during day shift. Two earthing cables are required to be passed to the platform, to check the continuity of the connection. To allow connection of the earthing cables to the platform, a ‘G-Clamp’ and/or Crocodile Clip is required to be connected to the end of each cable. Prior to connection to the ROV interface panel, the continuity between the two cables is to be checked. +/-5mV is the required tolerance.

3.4

Contact CP Readings – (CP-CON) NOTE:

Cathodic Potential Data, where necessary, is to be obtained prior to any marine growth removal or any site cleaning operations.

Contact CP readings may be taken by both ROV and diver. As discussed above, contact CP readings should not be taken on the pressurised pipework (i.e. risers, igloo/wellhead pipework and pipelines), unless specified in the workscope or otherwise directed by the Shell Offshore Representative, acting on advice from the responsible Structural Engineer. Coating may only be removed where coating damage (i.e. paint coat blistering) has occurred or suspected, unless specified in the workscope or otherwise directed by the Shell Offshore Representative, acting on advice from the responsible Structural Engineer. 3.4.1

ROV Contact CP Readings A steel tipped contact CP probe is to be used for this method of survey. This method is only to be employed where the Proximity method is not suitable, i.e. on wellheads, and other electrically isolated structures.

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The CP probe is to be hard wired into the video overlay such that the CP readings are continuously displayed on the video screen during the ROV survey. CP readings are to be included in the video commentary. The Remote Reference CP systems described above can be used in a contact CP mode. 3.4.2

Diver Contact CP Readings Bathycorrometer hand held CP meters are to be used for diver contact CP surveys. Video overlay of these readings are not possible, but where taken, best endeavours should be made to obtain video from the diver camera of the obtained readings. All readings obtained should be repeated by the inspection controller on the video commentary.

4

OPTIONS

4.1

Anode Inspection In addition to general anode wastage inspection, as specified in procedure I 01 007 – General Video Survey, other anodes may be specified for more detailed inspection, including CP. This type of survey is typical of internal igloo inspections. Anodes selected for inspection will be listed in the Workscope, or specified by the Shell Offshore Representative. The presence, location and specification of the anode is to be confirmed as per UMDB layout drawings.

4.1.1

Anode CP Survey – (CP-AN) Cathodic protection potential readings are to be taken at three positions on the anode; one on each of the two attachment stubs, and one in the centre of the anode. Proximity probes are the preferred method for obtaining the required readings. Contact probes shall not be used without the prior approval from the Shell Offshore Representative acting on advice from the responsible Structural Engineer. Calibration data is to be noted and verified before and after each dive and before each set of readings if the contact probe method is used (See 3.2).

4.1.2

Detailed Anode Inspection – (VI-AWD) Describe marine growth coverage as hard or soft, giving estimated thickness and percentage cover of each (MG-GEN). The integrity of the anode support (bracket, bracelet, earthing strap) is to be checked.

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A guide to estimate percentage wastage on an anode is given below (VI-AW): ANODE DEPLETION SCHEMATIC 0-5% LOSS -


6-20% LOSS -


21-50% LOSS -


>50% LOSS -


To obtain volumetric information on the remaining anode material it will be necessary to measure the anode for overall length, and at three positions around its perimeter, being 100mm in from each end and at the centre point of the anode, see Fig 3. ROV measurements are to be taken using a graduated, right angled, measuring stick for the three perimeter positions and a long graduated pole, or graduated marks on the manipulator, for measuring the overall length. Graduation marks to be in increments of 10mm and black/white alternatively. Diver measurements are to be taken around the perimeter using a tape measure. NOTE:

On an anode bracelet it will only be necessary to carry out the inspection on one anode segment.

On completion of the inspection the ROV is to carry out, and fully video record, a general visual survey at each anode location, which is to clearly show an overall view of the anode and attachment, brackets. The result of the inspection is to be recorded on the Anode Inspection Summary Report Format, Fig 1, and Anomaly Report Format where applicable. 4.2

Cathodic Protection Potential Survey – Zonal (CP-ZON)

4.2.1

CP Survey - Zonal Cathodic potential reference sampling points will be listed in the workscope. For the purpose of data analysis taken from structural steel jackets, the cathodic potential monitoring data is to be gathered from two zones, namely: Zone 1:

From the water level at LAT to first horizontal framing below LAT, 10 reference points to be allocated.

Zone 2:

From the first horizontal framing below LAT to the seabed. Typically 50 reference points to be allocated.

Cathodic potential reference point will be defined as: •

I 60 004 Page 8 of 15

One reading taken on each of the selected anodes either side of the mid point.

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0153-001 •

One reading taken on structural steelwork midpoint between the selected anodes.

•

Two readings, one each one metre each side of the midpoint reading location. See Fig 2.

Proximity probes are the preferred method for obtaining the required readings. Contact probes shall not be used without the prior approval from the Shell Offshore Representative acting on advice from the Sponsoring Engineer. Calibration data is to be noted and verified before and after each dive and before each set of readings if the contact probe method is used. The result of the inspection is to be recorded on the Cathodic Potential Inspection Summary Report Format, Fig. 4, which is to include make and serial number of equipment used, and Anomaly Report Format where applicable. 4.3

Cathodic Protection Potential Survey – Nodal (CP-NOD)

4.3.1

CP Survey - Nodal Cathodic potential reference sampling points will be listed in the Workscope or specified by the Shell Offshore Representative. For the purpose of data analysis taken from structural steel jackets, the cathodic potential monitoring data is to be gathered from selected nodal joints at the four cardinal clock positions at the following locations: (1)

At the Weld.

(2)

1m along the Brace Member from the Weld.

(3)

2m along the Brace Member From the Weld.

Proximity probes are the preferred method for obtaining the required readings. Contact probes shall not be used without the prior approval from the Shell Offshore Representative acting on advice from the Sponsoring Engineer. Calibration data is to be noted and verified before and after each dive and before each set of readings if the contact probe method is used (See 3.2). The result of the inspection is to be recorded on the Cathodic Potential Inspection Summary Report Format, Fig 5, which is to include make and serial number of equipment used, and Anomaly Report Format where applicable. 4.4

Anode Direct Current Measurement – (CP-GSC/IN-GSC)

4.4.1

Inspection Qualifications The gathering of G-Scan data is to be carried out by a Level II G-SCAN System Operator. Use of the Swain Sea Clip can be carried out by any topside operator.

4.4.2

Anode CP Survey – (CP-GSC) Anodes selected for inspection will be listed in the workscope, or selected by the Shell Offshore Representative. Cathodic Protection Potential readings are to be taken at three positions on the anode; one on each of the two attachment stubs and one in the centre of the anode.

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Proximity probes are the preferred method for obtaining the required readings. Contact probes shall not be used without the prior approval from the Shell Offshore Representative acting on advice from the Sponsoring Engineer. Calibration data is to be noted and verified before and after each dive and before each set of readings, if the contact probe method is used (See 3.2). 4.4.3

Anode Measurement – (IN-GSC) Measurement readings are to be taken on anode attachment brackets, and/or standoff stubs, and/or bonding cables. One reading at each position. The selected anode will be inspected and reported upon as follows, prior to carrying out the direct current measurements and any cleaning. The presence, location and specification of the anode is to be confirmed as per UMDB layout drawings. Describe Marine Growth (MG-GEN) coverage as hard or soft, giving estimated thickness and percentage cover of each. On completion of the above, the anode and attachment brackets are to be cleaned of all excessive marine growth; hard stubborn growth need not be removed. The integrity of the anode support (bracket, bracelet, earthing strap) is to be checked. A guide to estimate percentage wastage on an anode is given below (VI-AW): ANODE DEPLETION SCHEMATIC 0-5% LOSS -


6-20% LOSS -


21-50% LOSS -


>50% LOSS -


Measurements of pitting are to be carried out listing maximum and minimum depth and maximum and average diameter. The anode is to be measured for length, and at three positions for circumference being 100mm in from each end of the anode and at the centre point of the anode. To obtain volumetric information on the remaining anode material it will be necessary to measure the anode for overall length, and at three positions around its perimeter, being 100mm in from each end and at the centre point of the anode, see Fig 3. Measurements are to be taken using a graduated, right angled, measuring stick for the three perimeter positions and a long graduated pole, or graduated marks on the manipulator, for measuring the overall length. Graduation marks to be in increments of 10mm and black/white alternatively. NOTE:

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Anode direct current measurements are to be taken using the Millstrong G-Scan System, or Swain Sea Clip. The procedures to follow are as per the manufactures manual. The G-Scan unit is to be operated by a Level II G-SCAN System Operator topside. 4.4.4

System Calibration Calibration of the G-Scan System will be performed prior to each dive or planned inspection programme, but as a minimum at least every 24 hours if to be used over an extended period. Calibration of the Swain Sea Clip, is as per manufacturers instructions.

4.5

Final Report Inspection data format, CP data format, video log and anomaly report format, where applicable, are to be completed for all works carried out. Each individual CP reading taken is to be recorded within the COABIS database. Where only one CP task box is present against a component, but several readings are required, i.e. on a riser or caisson section, additional CP task boxes are to be created, and the relevant location of the reading entered, i.e. depth, along with the CP results. The COABIS Workpack Diary report is to include the maximum and minimum of all CP readings taken are to be reported for a specific section of a survey, i.e. CTS or specific elevation, or where a section of a survey has been conducted during a specific dive. Reference should be made confirming the location where the full survey data can be obtained, i.e. COABIS database. Any C1 anomalies are to be commented on more specifically. Locations of all anodes chosen for inspection are to be specified in the report. Any completed data sheets are to be included with the final report, and suitably referenced. If possible, they should be part of the final electronic COABIS Word document, not separate sheets. If created electronically they should be stored within the COABIS database and suitably linked. Where Anode Direct Current Measurements have taken place, the results of the inspection are to be recorded on the Anode Direct Current Inspection Report format, Fig 6 and 7, and Anomaly Report Format where applicable.

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Anode No

-mV

Marine Growth % Cover

Support

Wastage % and Category

Measurement (mm)

L

Figure 1

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C1

C2

Video Ref

Conditions

C3

Example of Format for Anode Inspection

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0153-001

3 1

4

5

2

62009

62010 12204

NOTE: THIS IS AN ILLUSTRATION OF THE 5 READINGS TO BE TAKEN AT EACH "REFERENCE POINT" LEG B

LEG A

Figure 2

Typical Structural Cathodic Potential Reference Point

C1

L C2

100mm C3

100mm NOTE: L = OVERALL ANODE LENGTH C1, C3 = OUTSIDE, PERIMETER MEASUREMENT, 100mm IN FROM EACH END OF ANODE. C2 = OUTSIDE, PERIMETER MEASUREMENT, MID-POINT OF ANODE THE RIGHT ANGLED MEASUREMENT AT EACH OF THE 3 LOCATIONS IS TO BE DOUBLED TO GIVE APPROXIMATE FULL OUTSIDE MEASUREMENT OF ANODE.

Figure 3

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Typical Anode Volumetric Measurements

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Calibration: (Pre/Post, -mV) (138) 1054/1054 (141) 1052/1046 (142) 1046/1034 (145) 1034/1035 Dive

Ref No

Memb er No

Anodes

CP Readings -mV

1

2

Anode 1

1m Away

Midwa y

1m Away

Anode 2

Video Tape

Date Complet ed

ZONE 1 145

1

61001

A

B

1029

999

994

994

996

5506

12-06-96

145

2

61002

A

B

1021

1002

1001

1001

1028

5506

12-06-96

145

3

61003

A

B

1027

948

999

999

997

5506

12-06-96

145

4

61004

A

B

1026

990

940

974

981

5506

12-06-96

145

5

62101

A

B

1026

994

999

999

932

5506

12-06-96

ZONE 2 146

6

61101

A

B

1032

999

993

1025

992

5507

12-06-96

146

7

63101

A

B

1027

1000

999

1028

1004

5507

12-06-96

141

8

61102

A

B

1030

1000

1000

1000

1038

5502

11-06-06

146

9

63102

A

B

1022

996

999

1029

1001

5507

12-06-96

146

10

63103

A

B

1028

999

997

1000

1031

5507

12-06-96

142

11

61103

A

B

1032

991

993

995

1025

5503

11-06-96

142

12

63104

A

B

1033

991

991

992

1025

5503

11-06-96

142

13

61104

A

B

1026

987

998

991

1028

5503

11-06-96

141

14

62204

A

B

1037

1012

1012

1013

1036

5502

11-06-96

141

15

62208

A

B

1033

1002

1007

1008

1022

5502

11-06-96

138

16

61201

A

B

1028

996

986

999

1029

5500

10-06-96

Figure 4

Example of Format for Zonal CP Survey

Start Cal: -1027mV Location (-mV)

End Cal: -1030mV 12 O/C

3 O/C

6 O/C

9 O/C

Before

At weld

953

952

951

953

Cleaning

1m from weld

956

957

958

957

2m from weld

959

961

960

959

Figure 5

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Example of Format for Nodal CP Survey

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IN – GSC AMPS UPPER

AMPS LOWER

TOTAL AMPS

SECURE

DEPLETION

MG COVER

LENGTH

C1

C2

C3

AVERAGE PIT

MAXIMUM PIT

AVERAGE DIAMETER

MAXIMUM DIAMETER

CP - GSC (-mV) TOP STUB

ANODE

BOTTOM STUB

Figure 6

Example of Format for Anode Direct Current Measurement Monitoring- Blank

IN - GSC AMPS UPPER

AMPS LOWER

TOTAL AMPS

SECURE

DEPLETION

MG COVER

LENGTH

C1

C2

C3

AVERAGE PIT

MAXIMUM PIT

AVERAGE DIAMETER

MAXIMUM DIAMETER

0.74

0.62

1.36

YES

25

100

2430

900

980

920

15

20

80

130

CP - GSC (-mV) TOP STUB

ANODE

BOTTOM STUB

948

945

935

Figure 7

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Note 1: Total output (amps) is the sum of the GScan output (amps) from upper and lower columns

Example of Format for Anode Direct Current Measurement MonitoringCompleted

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PROCEDURE I 97 001 INSPECTION OF ABANDONED / SUSPENDED WELLHEAD CONTENTS

Para.

Page

1

INTRODUCTION

3

2 2.1 2.2


3 3 3

3 3.1 3.2 3.3 3.3.1 3.3.2 3.4 3.4.1

OPERATING PROCEDURE AND SPECIFICATION Inspection Qualifications Wellhead Identification (VI-ROV) General ROV Inspection (VD-ROV) Wellhead Survey 80m Radius survey Rig Intervention Activities Final ROV Inspection

4 4 4 4 5 5 6 6

4 4.1


7 7

FIGURES No.

Page

1

Seabed Clearance Certificate - PT1, Typical

8

2


9

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PROCEDURE I 97 001 INSPECTIONINSPECTION OF ABANDONED / SUSPENDED WELLHEAD 1

INTRODUCTION This work method is to be applied to the inspection of a wellhead, which has either been abandoned or suspended. The levels of inspection will depend upon whether the work is required to check on wells general state, or as a prelude to future rig intervention. The work shall include damage survey, video survey, debris clearance, cleaning and dimensional survey. The procedure incorporates both a general inspection of the wellhead, or inspection, cleaning and debris removal for the purposes of rig intervention. Debris removal under Procedure I 01 003 is to be employed in conjunction with this procedure.

2

TASKS

2.1


2.2

VD-ROV

-

General ROV Video

VI-ROV

-

ROV Worksite Check

DB-CHK

-

Visual Debris Check

DM-SCR

-

Scour Survey

DM-STD

-


CL-INS

-


VI-DVI

-


CH-VLV

-


PH-DIG

-


Optional Tasks The following work tasks are optional and will be explicitly called for in the Workscope. DB-REM

-

Debris Removal

Should anomalies be noted, they are to be reported and acted upon as per Section 2, Chapter 6, ‘Anomaly Reporting & Criteria’, and as directed by the Shell Offshore Representative.

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3.1

Inspection Qualifications The inspection is to be carried out by ROV, under the guidance of a CSWIP 3.3u or 3.4u Inspection Controller. There should be no requirement for a diver to conduct this survey, however if necessary inspection is to be carried out by a CSWIP 3.1u/3.2u diver, under the guidance of a CSWIP 3.4u Inspection Controller. If debris removal is required, it is intended that this should be carried out by ROV, unless survey findings establish that diver intervention will be required.

3.2

Wellhead Identification (VI-ROV) Survey data, including the position of the well to be inspected, will be provided by the Shell Survey department prior to commencement of operations. All survey data shall be based on International Spheroid, European Datum 1950 (ED50), Transverse Mercator Projection. For UK Sector Central Meridian is 0deg and for Dutch Sector Central Meridian is 5deg E. Reference Section 1, Chapter 2, Figure 1, for further datum shift parameters. On arrival at the worksite, it should be established that the correct tree has been identified, by use of suitable markings on the tree itself, or by use of the Shell survey data provided, and/or field layout drawings to provide other suitable means of confirmation. The Shell Offshore Representative is to be consulted should no markings be present, and the latter method is used to confirm that the correct tree has been identified. If doubt persists as to the correct identification of the tree, then a positional fix is to be taken of the top centre of the tree. Should this fix disagree with the workscope stated position by more than +/-5m, and then initiate checks to resolve errors. Such checks should confirm that the vessel's positioning system has been suitably calibrated. If required a spin check should be carried out to verify the USBL positioning system. If the spread of the position data is more than the accuracy of the positioning systems, (i.e. DGPS 1-3m & USBL 1% of water depth) checks should be initiated to resolve errors. Prior to this, a CTD profile of the full water column should be observed and the relevant data entered into the USBL system.

3.3

General ROV Inspection (VD-ROV) The ROV shall carry out, and fully video record, a General Visual Inspection (GVI) survey of the wellhead and the surrounding area within an 80m radius of the wellhead. For survey and video work the ROV should be positioned to maximise visibility. WARNING:

THE ROV SHOULD INITIALLY APPROACH THE WORK SITE FROM UP CURRENT TO MINIMISE THE POSSIBILITY OF ENTANGLEMENT FROM FISHING GEAR DEBRIS.

The inspection approach should be as follows: (1)

Identify wellhead position. Approach with caution as per warning above.

(2)

Once identified position fix wellhead.

(3)

Inspect wellhead as per 3.3.1.

(4)

Complete 80m radius survey as per 3.3.2.

During this survey, live Eastings and Northings are to be continuously displayed on the video overlay. I 97 001 Page 4 of 9

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0153-001 The method and results required for these surveys are as follows: 3.3.1

Wellhead Survey (1)

SIT camera video is to be recorded of the approach to the wellhead. This is to record any significant debris, which may be fouled on the wellhead.

(2)

Once the wellhead has been identified position fix the centre of the well. The position fix is to be taken by the ships surveyor, or Bridge personnel. This reading is to be noted, verbally included on the video commentary and included in the final report. If the observed position differs by more than +/-5m, initiate checks to resolve errors.

(3)

Conduct an initial survey of the wellhead using SIT camera. This is to give an overall view of the wellhead, checking for debris, gross damage and scour. Check that site conditions are correctly identified in accordance with relevant location drawings.

(4)

Using a colour camera, conduct cleaning and GVI of the wellhead checking for any obvious damage, or other anomalies. This is to include as a minimum: (a) Bullseye. Clean and inspect the bullseye level indicator, recording the position of the ball bearing on the board and give compass heading. Take digital still image. (b) Guide posts. Checking for debris (in particular at the top of the posts), damage, vertical alignment, latch profile and marine growth levels. Note:

old guide wire debris at the base of the post is not anomalous. Clean as required.

(c) All pipework and any valves. Checking integrity and for leaks. (d) Any pipeline spools or control umbilicals out to touchdown and/or the start of any mattress or grout bag protection, giving suitable views of any spools or umbilical routing away from the wellhead. (e) Corrosion Cap. Check its presence, security and extent of marine growth. (f)

Scour and seabed level around the base of the guide frame. Survey to include views of the conductor and seabed local to the well, to check for any evidence of seabed leaks.

Digital Still images are to be taken of all anomalies. Where corrosion is commonplace, representative images should be obtained. 3.3.2

80m Radius survey The 80m radius extent of the survey area is to be plotted on the vessels positioning display screen, centred on the wellhead position. Should the position fix of the wellhead identify that the given position is incorrect, and then the new position should be used. Otherwise the given position is to be used, excluding any minor deviations identified from the position fix. Unless otherwise stated in the workscope, or visibility precludes suitable visual coverage, inspection of the 80m radius survey area should be conducted using parallel grid lines spaced 10m apart. Only 1 pass is required either heading North/South, East/West, or another heading dictated by field features or constraints. Should the defined grid pattern not be suitable for any reason, this may be redefined after consultation with the Shell Offshore Representative, acting on advice from the responsible Structural Engineer.

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0153-001 The grid pattern is to be displayed within the 80m radius on the vessels positioning screen. With the ROV positioning beacon also registered. The ROV is to conduct the survey following the set grid pattern. SIT camera views are to be used for the bulk of the survey, with colour camera to be used to evaluate items of debris, and other areas of interest. Sonar is to be used set to 20m, to give suitable overlap to the SIT views, checking for debris and other seabed features. Video of the sonar display should be intermittently displayed, and where items of interest are identified. All items identified by Sonar, not previously identified visually are to be investigated and recorded on video. All items of debris or interest are to be position fixed by the ships surveyor, or Bridge personnel. This reading is to be noted, verbally included on the video commentary and included in the final report. Unless specifically requested, there is no requirement for debris removal. 3.4

Rig Intervention Activities Should the survey be required for Rig Intervention purposes, or as stated in the workscope, the following actions should be taken, either by ROV or diver: (1)

Identify wellhead position. Approach with caution as per warning above.

(2)

Complete 80m radius survey as per 3.3.2.

(3)

Recover and remove all debris within the immediate area of the wellhead and from within an 80m radius of the wellhead.

On completion of debris removal the ROV or diver shall carry out the following:

3.4.1

(4)

Clean and inspect the bullseye level indicator, recording the position of the ball bearing on the board and give compass heading. Take digital still image.

(5)

Deploy cleaning equipment to site and remove all marine growth and any corrosion product from the top 500mm of each guidepost latch profile.

(6)

Carry out a close inspection of each guidepost latch profile recording any damage or anomalies noted. Where old guide wires are located within the guideposts, these are to be removed so that there is no protrusion above the top surface of the post.

(7)

Locate and clean the corrosion cap. Care is to be taken to ensure all mating and latching profiles are thoroughly cleaned so recovery tool will engage all faces correctly. Carry out a detailed inspection of the corrosion cap recording any damage or anomalies noted.

(8)

If required, remove the corrosion cap and clean the AX/VX sealing area. The use of nylon brushes; suction or LP water jet is only permitted. Remove any silt, mud, shell or other debris from in or around the tubing hanger, control and production bores. Carry out a detailed inspection of the AX/VX sealing area recording any damage or anomalies noted. Replace corrosion cap on completion.

Final ROV Inspection Should the survey be required for Rig Intervention purposes, or as stated in the workscope, on completion of all debris removal and cleaning work the ROV shall carry out, and fully video record, a visual survey of the wellhead, paying particular attention to the following: (1)

Check each guidepost for out of vertical alignment, giving angle and direction of tilt. (Estimate from video screen).

I 97 001 Page 6 of 9

Am 02 08/05

0153-001 (2)

Check if guide base is horizontal, giving direction and degree of tilt. Bullseye reading if fitted, or estimate from screen. Give Digiquartz readings on all four faces and mid-point, if fitted.

(3)

All cleaned areas on guideposts showing detail of each guideline latch profile.

(4)

All cleaned areas on corrosion cap showing detail of all recovery tool latching faces, and fit up of corrosion cap.

(5)

Site survey of the wellhead and surrounding area within an 80m radius. Use sonar and video recording (sonar sweep to be recorded).

4

REPORTING

4.1

Final Report The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above. Reference section 2, Chapter 1, Section 3.1.5. The given and as-found position fix co-ordinates are to be stated. All anomalies are to be referenced, with a general statement made concerning the types and extent of anomalies identified. Any C1 anomalies are to be commented on more specifically. Other references are to be made to any digital still images and drawings. Forms PT1 (Fig 1) & PT2 (Fig 2) are to be completed, electronic versions saved within COABIS and hard copies submitted with the report.

Am 02 08/05

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0153-001

Seabed Clearance Certificate LOCATION / WELL:

DATE:

COORDINATES Lat:

Long:

Geodetic Datum:

METHOD OF SURVEY: TYPE OF EQUIPMENT USED:

CONTRACTOR:

RANGE OF COVERAGE:

No. OF SCANS:

VESSEL HEADING (Indicate on Diagram): POSITIONS OF VESSEL RELATIVE TO WELL DURING SCANS: HEIGHT OF SCANNING UNIT DURING SCAN: NATURE OF SEABED:

TYPE OF WELLHEAD:

TYPE OF RECORDS MADE:

0

350

0

10

20

3

30 40

32

90

270

80

280

70

290

30

60

0

31

50

0

VESSEL HEADING

30

340

260

100

250

110 0

24

0

12

0 23

13 0 14

0

0

160

0

170

180

190

200

22

21

I 97 001 Page 8 of 9

15

Figure 1

0

SPECIFY SCALE OF DIAGRAM

Seabed Clearance Certificate - PT1, Typical Am 02 08/05

0153-001 LIST OF TARGETS Position (Dist and Brg)

Approx Dimensions (m)

Description

Means of Identification

Y/N Recoverable

1 2 3 4 5 6 7 8 9 10 MEANS OF IDENTIFICATION A

SONAR SCAN

B

DIVING INSPECTION

C

ROV

REASONS FOR NOT REMOVING REMAINING DEBRIS D

VESSEL RECORDS

SIGNATORIES (1)

(2) NAME

____________________

NAME

____________________

POSITION

____________________

POSITION

____________________

COMPANY

____________________

COMPANY

____________________

GUIDANCE NOTES (1)

Survey should extend to at least 80m from the wellhead.

(2)

The first signatory should be the person responsible for the client or his representative. Second signatory should be the person supervising the seabed survey, i.e. the Sonar Operator, ROV Supervisor. Figure 2

Am 02 08/05


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0153-001

PROCEDURE I 97 002 INSPECTION OF SUBSEA TREE (PRODUCTION AND WATER INJECTION) CONTENTS Para

Page

1

INTRODUCTION

3

2 2.1

TASKS Standard Tasks

3 3

3 3.1 3.2 3.3 3.4

OPERATING PROCEDURE AND SPECIFICATION Inspection Qualifications Wellhead Identification (VI-ROV) Initial ROV Inspection (VI-ROV / VD-ROV) Visual Inspection (VD-ROV/VI-DVI)

3 3 4 4 4

4 4.1


6 6

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0153-001

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0153-001

PROCEDURE I 97 002 INSPECTION OF SUBSEA TREE 1

INTRODUCTION This work method is to be applied to the inspection of a subsea production tree. The work shall include damage and video survey. The purpose of the survey is to record the following: (1)

Any sign of debris/fishing nets.

(2)

Any sign of leaks from the wellhead conductor or from any of the tree components.

(3)

Any scour and seabed level around the perimeter of the tree.

(4)

Any obvious damage to the subsea equipment.

2

TASKS

2.1

Standard Tasks The following Listed tasks are always to be invoked. VI-ROV

-

ROV Worksite Check

VD-ROV

-

General ROV Video

DB-CHK

-

Visual Debris Check

MG-GEN

-


DM-SCR

-

Scour Survey

VI-AW -

-

Anode Wastage

VI-DVI-

-


CH-LKS

-

Check for Leaks

PH-DIG

-

Digital Photographs



3.1


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0153-001

3.2

Wellhead Identification (VI-ROV) Survey data, including the position of the well to be inspected, will be provided by the Shell Survey department prior to commencement of operations. All survey data shall be based on International Spheroid, European Datum 1950 (ED50), Transverse Mercator Projection. For UK Sector Central Meridian is 0 deg and for Dutch Sector Central Meridian is 5deg E. Reference Section 1, Chapter 2, Figure 1, for further datum shift parameters. On arrival at the worksite, it should be established that the correct tree has been identified, by use of suitable markings on the tree itself, or by use of the Shell survey data provided, and/or field layout drawings to provide other suitable means of confirmation. The Shell Offshore Representative is to be consulted should no markings be present, and the latter method is used to confirm that the correct tree has been identified. If doubt persists as to the correct identification of the tree, then a positional fix is to be taken of the top centre of the tree. Should this fix disagree with the workscope stated position by more than +/-5m, and then initiate checks to resolve errors. Such checks should confirm that the vessel's positioning system has been suitably calibrated. If required a spin check should be carried out to verify the USBL positioning system. If the spread of the position data is more than the accuracy of the positioning systems, (i.e. DGPS 1-3m & USBL 1% of water depth) checks should be initiated to resolve errors. Prior to this, a CTD profile of the full water column should be observed and the relevant data entered into the USBL system.

3.3

Initial ROV Inspection (VI-ROV / VD-ROV) The ROV shall carry out, and fully video record, an initial visual survey of the tree and the seabed area immediately around the wellhead. WARNING:

THE ROV SHOULD INITIALLY APPROACH THE WORK SITE FROM UP CURRENT TO MINIMISE THE POSSIBILITY OF ENTANGLEMENT FROM FISHING GEAR DEBRIS.

For survey and video work the ROV should be positioned to maximise visibility. Initially the ROV should position itself above the tree and, with the camera in SIT mode, carry out a full 360 degree sweep around the structure ensuring that a good video coverage of the tree and surrounding seabed is obtained. The survey is to include the flowbase and control jumper approaches. The purpose of this survey is to record the following:

3.4

(1)

Site conditions are correctly identified in accordance with relevant location drawings. This is to include that the correct tree has been identified, by suitable tree markings.

(2)


(3)

Any sign of debris/fishing nets.

(4)

Any obvious damage or anomalies. Checking for any signs of leaks from the tree conductor, seabed or from the tree components.

(5)

Any obvious areas of scour or the extent of any build up of mud around the perimeter of the base of the tree or the flowbase.

Visual Inspection (VD-ROV/VI-DVI) Although detailed in nature, no cleaning is required unless an anomaly is identified. To this extent the inspection standard required is partway between a GVI and DVI, to ensure that all tree components have been identified, and sufficient views have been obtained to confirm its integrity.

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On completion of the initial visual inspection the ROV or diver shall carry out a visual inspection of the tree flowbase checking for any signs of damage, debris, anode wastage or leaks. A seabed survey around the perimeter of the tree/flowbase is to be carried out by checking for any signs of scour/build up of mud. The survey shall include any flowlines and umbilicals from their connection points on the tree down to the seabed touchdown only, checking for any signs of leakage or damage. A detailed visual inspection is to be carried out on each of the four faces of the wellhead. The ROV/diver should set up position on each face in turn and, using the colour camera, carry out an inspection on each of the components – clearly identifying each component in turn. The video commentary is also to clearly state which face is being surveyed. The survey shall pay particular attention to the following areas: (1)

Check all major components i.e. valves, control panels, hydraulic/electrical jumpers, hydraulic connections (a common area for failure), flanges etc for any signs of leaks. Attempt to show the position of the valve indicators, although no comment is required as to the valve position. Check components for any areas of obvious damage, i.e. coating damage, blistering, corrosion etc.

(2)

Should any areas show signs of corrosion then contact CP readings should be taken.

(3)

Check under the tree cap/roof area of the tree for any signs of oil. (CH-LKS).

(4)

Check the tree cap and guide posts, in particular the Regan latches at the top of the posts, for any signs of obvious damage or debris. NOTE:

Guide wire at the base of a guidepost is not anomalous.

(5)

The serial number of any control module, where appropriate, is to be recorded.

(6)

The survey is to include any flowlines/control jumpers from their connection point on the flowbase down to the seabed touchdown. At touchdown, views are required to show the route of the flowlines/jumpers away from the tree, to confirm the presence and integrity of any supports, protection bags/mats or point of burial. Check all connections for leaks. With respect to jumpers, check the respective hose connections to the back of stab plates for any leaks or damage. For jumpers, check that there is no tension on any jumpers and their connections.

(7)

Anode wastage. (VI-AW)

(8)

ROV to move around the perimeter of the tree/flowbase reporting any scour/build up of mud on the seabed around the guide base. (DM-SCR). Note: There are specific anomaly criteria with respect to igloo scour. See Section 2, Chapter 6, Point 2.3.13.

(9)

Check for any gas bubbles emanating from the seabed area around the centre of the tree and in particular where the conductor penetrates the seabed. (CH-LKS).

Digital Still Images (PH-DIG) are to be taken of any anomalies or other areas of interest. These may be supplemented by suitable drawings to show the location, size and details of the item of interest.

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0153-001

4

REPORTING

4.1

Final Report The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above. Reference section 2, Chapter 1, Section 3.1.5. All anomalies are to be referenced, with a general statement made concerning the types and extent of anomalies identified. Any C1 anomalies are to be commented on more specifically. Other references are to be made to any digital still images and drawings. Where any problems may have arisen in confirming the correct tree identification, report on the steps taken to confirm correct identification.

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SECTION 4 CONSTRUCTION PROCEDURES CONTENTS STANDARD INSPECTION TASKS R 01 011

DREDGING

R 26 001

INSTALLATION AND REMOVAL OF CLAMPED BLANKING FLANGE

R 48 001

INSTALLATION AND REMOVAL OF BLIND FLANGE

R 48 002

INSTALLATION AND REMOVAL OF INLET BLANKING PLUG (ROV

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4-0-1

0153-001

PROCEDURE R 01 011 DREDGING

1

INTRODUCTION The work method is to be applied to the excavation of alluvial materials. Typical requirements to necessitate material removal are: (1)

Remove of excessive drilling mud and cuttings build up to permit inspection of covered members, concrete surfaces, or to reduce structural loading on cell tops.

(2)

Trenching for pipeline repair.

(3)

Clearing and levelling the seabed.

(4)

Seabed excavation during light construction operations and remedial works.

Depending on which type of dredging equipment is employed the operation can be accomplished with either ROV or diver assistance or be remotely controlled from surface.

2

TASK OPTIONS VI-ROV

-

ROV Worksite Check

DB-REM

-

Debris Removal

CL-DRG

-

Dredge Pump

3


3.1

Inspection Qualifications Work may be carried out by any grade of diver.

3.2

Dredging WARNING:

DURING THE DEPLOYMENT AND RECOVERY OF THE DREDGE PUMP THE DIVER SHOULD FOR SAFETY REASONS REMAIN INSIDE THE BELL.

Carry out an initial survey of the area to be cleared by ROV. The object of this survey is to determine the extent of the dredging operation and locate any debris that will require removal prior to deploying dredging equipment. On completion of this initial survey the diver is to remove debris, if any, from the area to be cleared. Debris is to be recovered to the surface, as is any other debris that may be uncovered during the dredging operation. Dredging equipment to be prepared and deployed ready for use in accordance with the particular manufacturers operating instructions.

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R 01 011 Page 1 of 2

0153-001

Dredge pump to be positioned at the work location in such a way as to afford the best access to the area to be dredged thereby minimising frequent movements of the pump. If a remotely operated dredge pump is being employed the diver is to withdraw from the work area prior to the commencement of dredging operations. Dredging operations will commence as per particular manufacturers operating instructions. Method of dredging is dependant on the location and the material being excavated but will generally be as follows: (1)

Soft Materials. Allow the suction head to pull itself down into the material to a depth of 2m to 3m. This method will create a self dredged crater which has been found in practice to be the most effective method for escavating soft materials. This technique reduces diver fatique when using a diver operated dredge and improves visibility around the work area.

(2)

Hard or Compacted Materials. Hard material will require to be disintegrated to assist in excavation. Most dredge pump systems have a high presure water jetting system incorporated into the suction head to accomplish this task. Jetting also serves to reduce the density of the solids/water mixture, thus easing the flow through the dredge pump system. The main disadvantage of jetting is the resultant poor visibility.

(3)

Propwash Dreging. The principle of this system is the removal of materials by directing a jet of water at the mound, liquifying it and then letting it disperse by action of tide/current. The units are remotely deployed but require the assistance of divers to remove debris as it becomes exposed and possibly prevents access to the work site. As with jet dredging a disadvantage of this method is poor visability.

Should the dredging equipment pump choke during operations the shutdown and clearing procedure as per the particular manufacturers operating instructions are to be followed. Progress during dredging operations is usually dependant on a diver assessment as the loss of visibility precludes the use of video monitoring by ROV. Where operaton allows the use of ROV mounted sonar may be used to monitor progress.

3.3

Final Report Dredging data format and video logs where applicable are to be completed for all works carried out.

R 01 011 Page 2 of 2

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0153-001

PROCEDURE R 26 001 INSTALLATION AND REMOVAL OF CLAMPED BLANKING PLATE

1

INTRODUCTION The work method is to be applied for the blanking of inlets where bolted blind flanges can not be fitted. The work will include marine growth removal, blank plate installation and removal and general visual video inspection.

2

TASK OPTIONS VI-ROV

-

V Worksite Check

VD-ROV

General ROV Video

DB-CHK

Visual Debris Check

CL-INS


CN-RBP


Should additional activities be carried out, suitable work tasks and task codes may be added to cover works.

3

OPERATING PROCEDURE AND SPECIFICATION WARNINGS:

3.1

(1)

PRIOR TO ANY SUBSEA WORK ENSURE PLATFORM INTAKE OR DISCHARGE IS ISOLATED.

(2)

THE DIVER IS TO KEEP CLEAR OF EQUALISING VALVE OPENING WHILE OPERATING THE VALVE.

Inspection Qualifications Works may be carried out by any grade of diver. However, inspection orientated work is to be carried out by CSWIP 3.1u, CSWIP 3.2u diver and CSWIP 3.3u ROV Controller.

3.2

Preparation Before work can commence on the installation of the blanking plate carry out the following, where applicable. (1)

Marshal all necessary materials for this work on the vessel's deck.

(2)


NOTE:

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Specific details of blanking plate size, neoprene gaskets, clamp type and equalising valves will be given in the Workscope. R 26 001 Page 1 of 5

0153-001

3.3

Initial ROV Inspection The ROV will carry out, and fully video record, and initial visual survey of the inlet. The purpose of this survey is to record the following:

3.4

(1)


(2)


(3)


(4)

Confirm the presence of inlet grille cage.

(5)

Any obvious damage or anomalies.

Diver Work Scope - Installation (1)

Establish downline and messenger line.

(2)

Remove marine growth and any debris as necessary to access work site.

(3)

Remove bolts, if present, from inlet grille cage, attach lift bag to lifting lug and messenger line on downline. Inflate lifting bag to lift inlet grille cage from retaining guides and recover to surface.

(4)

Clean inlet faces to receive blanking plate.

(5)

Lower blanking plate with messenger line on downline, manoeuvre into position using lift bag to assist and lower into retaining guides. Care to be taken that neoprene gasket is not damaged or misplaced.

NOTE:

(6)

Fit clamps and tighten to secure blank to inlet. Close equalising valve and fit plug.

(7)

Derig work site.

NOTE:

3.5

Prior to final tightening ensure equalising valve on blanking plate is open and plug removed.

ROV to monitor and video record the final stage of blanking plate lowering and positioning on inlet.

ROV Inspection - Post Installation On completion of diver works the ROV will carry out, and fully video record, a general visual survey of the blanking plate, paying particular attention to the final placement of the clamps, equalising valve and fit up.

3.6

Diver Work Scope - Removal

SEE WARNING (2) BEFORE COMMENCING THESE ACTIVITIES (1)

R 26 001 Page 2 of 5

Establish downline and messenger line

Re-issue 05/97

0153-001

(2)

Remove securing clamps, attach lift bag to blanking plate and messenger line on downline. Remove plug from equalising valve and open valve slowly, check for flow.

On confirmation of no flow through equalising valve, inflate bag to lift blanking plate from retaining guides and recover to surface. (3)

Lower inlet grille cage with messenger line on downline, manoeuvre into position using lift bag to assist and lower into retaining guides. Replace and tighten securing bolts if fitted.

(4)

Derig work site.

NOTE:

3.7

ROV to monitor and video record the removal of blanking plate and fitting of inlet grille cage.

ROV Inspection - Post Removal On completion of diver works the ROV will carry out, and fully video record, a general visual survey of the inlet, paying particular attention to final placement of the grille cage and fit up.

3.8

Final Report As built data format and video logs are to be completed for all works carried out.

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R 26 001 Page 3 of 5

0153-001

A

A

SHAFT 1

B

C PLAN

SECTION A - A CLAMPS

B

C SECTION B - B

SECTION C - C

GRILLE CAGE

EQUALISING VALVE

GUIDE SUPPORT

BLANKING PLATE

Fig 1 Inlet Grille Cage and Blanking Plate - General Arrangement R 26 001 Page 4 of 5

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0153-001

800mm Dia

20mm 15mm Dia BAR 3mm NEOPRENE ADHERED TO SURFACE

80mm

100mm

EQUALISING VALVE

Fig 2 Blanking Plate - Typical Re-issue 05/97

R 26 001 Page 5 of 5

0153-001

PROCEDURE R 48 001 INSTALLATION AND REMOVAL OF BLIND FLANGE

1

INTRODUCTION The work method is to be applied for the blanking of inlets where bolted blind flanges are present. The work will include marine growth removal, bland flange installation and removal and general visual video inspection.

2

TASK OPTIONS CN-DRP

-

Deck Preparation

VI-ROV

-

ROV Worksite Check

VD-ROV

-

General ROV Video

DB-CHK

-

Visual Debris Check

MG-GEN

-


CL-INS

-


CN-RBP

-


CN-RIG

-

Rig/Derig Worksite

CH-VLV

-


Should additional activities be carried out, suitable work tasks and task codes may be added to cover works. WARNING:

PRIOR TO ANY SUBSEA WORK ENSURE PLATFORM INTAKE OR DISCHARGE IS ISOLATED.

3


3.1

Inspection Qualifications Works may be carried out by any grade of diver. However, inspection orientated work is to be carried out by CSWIP 3.1u, CSWIP 3.2u diver and CSWIP 3.3u ROV Controller.

3.2

Preparation Before work can commence on the installation of the blind flange carry out the following, where applicable. (1)

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Marshal all necessary materials for this work on the vessel's deck. R 48 001 Page 1 of 9

0153-001

(2)


NOTE:

3.3

Specific details of blind flange size, studs and nuts, neoprene gasket, equalising valves and gauging tool will be given in the Workscope.

Initial ROV Inspection The ROV will carry out, and fully video record, an initial visual survey of the inlet. The purpose of this survey is to record the following: (1)


(2)


(3)


(4)


(5)

Where possible, establish internal valve status.

(6)


3.4

Diver Work Scope - Installation

3.4.1

Embedded Flange (1)


(2)


(3)

If fitted, attach lift bag to lifting lug on grille cage and messenger line on downline. Inflate lifting bag to support grille cage. Remove all bolts from around grille cage, when free, recover to surface.

(4)

Clean inlet face taking care not to damage the coating on the flange and pipe internal. Report status of bolt holes, if threaded, fixed nut or clearance.

(5)

Locate holes in embedded flange, insert gauging tool, check for thread engagement and mark positions of all accessible holes. If the number and location of usable threaded holes is within acceptable limits (Details as stated in the Workscope) then blind flange can be fitted.

(6)

Lower blind flange with messenger line on downline, manoeuvre into position using air bag to assist, care to be taken that neoprene gasket is not damaged or misplaced, insert studs in accessible holes, fit nuts and tighten up.

NOTE:

R 48 001 Page 2 of 9

Prior to final tightening ensure equalising valve on blind flange is open and plug removed.

(7)

Flog up all nuts sufficiently to ensure a good seal. Close equalising valve and fit plug.

(8)

Derig work site

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0153-001

Where it is found that there are insufficient holes within acceptable limits to fit the blind flange, then the internal diameter of the embedded flange will need cleaning and more accurate measurements taken for the purpose of making and fitting an internal plug. The following measurements, as a minimum, will be required: (a)

Accurate internal diameter of embedded pipe, checked at two positions.

(b)

Flange face diameter, checked at two positions.

(c)

Flange face thickness.

(d)

Check internal pipe clearance for a minimum distance of 1.5 times the diameter for any obstructions.

Report on any features that may restrict the fitting of an internal plug. NOTE:

3.4.2

External Spool (1)


(2)


(3)

Clean inlet face taking care not to damage the coating on the flange and spool internal. Report status of bolt holes, report any damage or corrosion.

(4)

Clean holes for studs (details of number and spacing stated in the workscope), if within acceptable limits then blind flange can be fitted.

(5)

Lower blind flange with messenger line on downline, manoeuvre into position using air bag to assist, care to be taken that neoprene gasket is not damaged or misplaced, insert studs in accessible holes, fit nuts to both sides and tighten up.

NOTE:

3.5

ROV to monitor and video record the final stage of blind flange lowering and positioning on inlet.

Prior to final tightening ensure equalising valve on blind flange is open and plug removed.

(6)

Flog up all nuts sufficiently to ensure a good seal. Close equalising valve and fit plug.

(7)

Derig work site.

ROV Inspection - Post Installation On completion of diver works the ROV will carry out, and fully video record, a general visual survey of the blind flange, paying particular attention to position of the equalising valve and fit up.

3.6

Diver Work Scope - Removal WARNING:

(1) Re-issue 05/97

THE DIVER IS TO KEEP CLEAR OF EQUALISING VALVE OPENING WHILE OPERATING THE VALVE.

Establish downline and messenger line. R 48 001 Page 3 of 9

0153-001

(2)

Attach lift bag to blind flange and messenger line on downline. Inflate bag to support blind flange, remove plug from equalising valve and open valve slowly, check for flow. On confirmation of no flow through equalising valve, remove all nuts from around blind flange, remove blind flange and recover to surface.

(3)

Remove all studs from embedded flange, or external spool.

(4)

If necessary, lower inlet grille cage with messenger line on downline, manoeuvre into position using lift bag to assist, insert bolts and tighten up.

(5)

Derig work site.

NOTE:

3.7

ROV to monitor and video record and removal of blind flange and fitting of inlet grille cage.

ROV Inspection - Post Removal On completion of diver works the ROV will carry out, and fully video record, a general visual survey of the inlet, paying particular attention to final placement of the grille cage and fit up.

3.8


R 48 001 Page 4 of 9

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0153-001 PAD EYE (LIFTING LUG) MAY BE ATTACHED TO EASE INSTALLATION

34" DIA

EQUALISING VALVE / PLUG 20 HOLES - 1 3/8" DIA AT 29.5" PCD

1 1/2" 28" Dia

25" Dia

NEOPRENE GASKET 6mm THICK

1 1/2"

Fig 1 Typical 34" Diameter Blind Flange - General Arrangement Re-issue 05/97

R 48 001 Page 5 of 9

0153-001

CAPTIVE NUTS EMBEDDED FLANGE

B7 STUDS TO SUIT LIFTING LUG

CONCRETE LEG

BLIND FLANGE

EQUALISING VALVE/PLUG

6mm NEOPRENE GASKET ADHERED TO BLIND

FIXED TOMMY BAR

WAISTED SHANK

TO SUIT

GAUGE BAR

Fig 2 Blind Flange Installation - General Arrangement - Embedded Flange R 48 001 Page 6 of 9

Re-issue 05/97

0153-001 EXTERNAL WALL NEOPRENE GASKETS CONCRETE WALL

RUBBER

NUTS WELDED

LIFTING EYE

1 1/4" DIA STUDS

Fig 3 Internal Plug Installation - General Arrangement - Embedded Flange Re-issue 05/97

R 48 001 Page 7 of 9

0153-001

32 Bolt Holes 27mm dia.

B

CL Southwest Inlets

CL A A Tower "A" Vent Valve

B View on A Grating

M24 Fastenings

A

Section on B - B 20 Bolt Holes 35mm dia. R 48 001 Page 8 of 9

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0153-001

Re-issue 05/97

R 48 001 Page 9 of 9

0153-001

Fig 4 Blind Flange Installation - General Arrangements - External Spool

R 48 001 Page 10 of 9

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0153-001

PROCEDURE R 48 002 INSTALLATION AND REMOVAL OF INLET BLANKING PLUG - ROV

1

INTRODUCTION The work method is to be applied for the blanking of inlets using blanking plugs specifically designed for ROV use. The work will include marine growth removal, blanking plug installation and removal and general visual video inspection.

2

TASK OPTIONS CN-DRP

-

Deck Preparation

VI-ROV

-

ROV Worksite Check

VD-ROV

-

General ROV

DB-CHK

-

Visual Debris Check

MG-GEN

-


CL-INS

-


CN-RBP

-

Remove/Replace Blanking Plate/plug

CN-RIG

-

Rig/Derig Worksite

CH-VLV

-


Should additional activities be carried out, suitable work tasks and task codes may be added to cover works. WARNING:

PRIOR TO ANY SUBSEA WORK ENSURE PLATFORM INTAKE OR DISCHARGE TO BE WORKED IS ISOLATED.

3


3.1

Inspection Qualifications Works may be carried out by any suitably experienced ROV pilot. However, any inspection orientated work is to be carried out by CSWIP 3.3u ROV Controller or CSWIP 3.4u Inspection Controller.

3.2

Preparation Before work can commence on the installation of the blind flange carry out the following, where applicable. (1)

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Marshal all necessary materials for this work on the vessel's deck. R 48 002 Page 1 of 4

0153-001

(2)


NOTE:

3.3

Specific details of blind flange size, studs and nuts, neoprene gasket, equalising valves and gauging tool will be given in the workscope.

Initial ROV Inspection The ROV will carry out, and fully video record, an initial visual survey of the inlet. The purpose of this survey is to record the following: (1)


(2)


(3)


(4)

Any debris or obstructions in work area, confirm the bore of the inlet is clear.

(5)

Where possible, establish internal valve status.

(6)


3.4

Installation Workscope

3.4.1

Embedded Flange (1)


(2)

If fitted, attach lift bag to lifting lug on grille cage and messenger line on dowline. inflate lifting bag to support grille cage. Remove all bolts from around grille cage by grinding or impact driver, when free, recover to surface.

(3)

Clean inlet face and bore over the length required for sealing, taking care not to damage the coating on the flange and pipe internal. Report status of bolt holes, if threaded, fixed nut or clearance.

(4)

Lower the inlet plug worksite in work basket or dummy inlet. Remove plug with the ROV and insert into the inlet, push fully home. Insert the needle valve tool (NVT) into the plug operating interface and apply the stated torque for the plug. Record number of turns necessary to seal plug.

(5)

Close equalising valve.

NOTE: 3.4.2

Prior to inserting the inlet plug, ensure that equalising valve is open.

ROV Inspection - Post Installation On completion of inlet plug installation the ROV will carry out, and fully video record, a general visual survey of the inlet plug, paying particular attention to the fit of the plug and confirming the equalising valve is closed.

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3.5

Removal Workscope

3.5.1

Embedded Flange (1)

Open the equalisation valve.

(2)

Insert the NVT into the plug interface and apply stated torque for the plug. Record number of turns necessary to unseal plug.

(3)

Remove inlet plug and recover to surface.

NOTE: (4)

Lower modified inlet grille cage in work basket frame to work site, ROV to collect grille, manoeuvre into position and install.

NOTE: 3.5.2

It will be necessary to modify grille for ROV installation.

ROV to video record removal of inlet plug and fitting of inlet grille cage.

ROV Inspection - Post Removal On completion of inlet plug removal and grille cage installation the ROV will carry out, and fully video record, a general visual survey of the inlet, paying particular attention to final placement of the grille cage and fit up.

3.6


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R 48 002 Page 3 of 4

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115

51

327

Set to 15

460 Dia

300 Dia

650 Dia

375

Fig 1 Inlet Plug - Typical R 48 002 Page 4 of 4

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SECTION 5 PIPELINE AND RISER PROCEDURES CONTENTS STANDARD INSPECTION TASKS I 41 001

RISER AND J-TUBE INSPECTION

I 90 001

VALVE ASSEMBLY SPOOL PIECE (VASP) INSPECTION

I 90 002

PIPELINE DAMAGE INSPECTION

I 91 001

IGLOO INSPECTION - FULMAR TEE SKID

I 91 002

SUBSEA INTERVENTION VALVE (SSIV) INSPECTION - NORTHERN BUSINESS UNITS

I 91 003

IGLOO INSPECTION - WELGAS NUMBER 1 AND 2

I 91 004

IGLOO INSPECTION - 20 INCH FULMAR 'A' TO ST FERGUS GAS PIPELINE

I 91 005

IGLOO INSPECTION - SUBSEA UMBILICAL SPLITTER BOX BRENT ALPHA

I 91 006

SUBSEA INTERVENTION VALVE (SSIV) INSPECTION - SOUTHERN BUSINESS UNIT (UNDER REVIEW)

I 91 007

IGLOO / MANIFOLD INSPECTION – GENERAL

I 91 008

IGLOO INSPECTION - BRENT SPAR MANIFOLD - ROV

I 91 009

IGLOO INSPECTION – OSPREY TO DUNLIN A FLOWLINE BUNDLE CARRIER PIPE

I 93 001

PIPELINE PROTECTION COVER INSPECTION

I 98 001

CONCRETE PROTECTION COVERS AND PBSJ INSPECTION

NON STANDARD TASKS R 90 003

PIPELINE SPAN STABILISATION

R 90 053

INSTALLATION OF PROTECTION MATTRESSES

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PROCEDURE I 41 001 RISER AND J-TUBE INSPECTION CONTENTS Para

Page

1

INTRODUCTION

3

2 2.1 2.2


3 3 3

3 3.1 3.2 3.3 3.3.1

OPERATING PROCEDURE AND SPECIFICATION Inspection Qualifications Above Water Inspection (VI-TOP / PH-TOP) Sub Sea Inspection (VD-ROV/VI-GVI) Cathodic Protection Monitoring (CP-PRX)

4 4 4 4 5

4 4.1 4.2 4.3 4.4 4.5

OPTIONS Detailed Visual Inspection (VI-DVI) Condition of Protection Fender in the Splash Zone (VI-GVI) Seabed Supports and Protection Frames Ultrasonic Wall Thickness Measurement (WT-DIG) Pulsed Eddy Current (PEC) Wall Thickness Measurement (WT-PEC)

6 6 6 7 7 7

5 5.1


7 7

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I 41 001 Page 2 of 8

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PROCEDURE I 41 001 RISER AND J-TUBE INSPECTION 1

INTRODUCTION The work method is to be applied to the inspection of Risers, J-Tubes and their associated components, from the underside of the deck to the seabed. Above water visual inspection will also be required from the Diving/ROV Support Vessel using a digital still camera. Underwater inspection will consist of a General Video Inspection (GVI), marine growth survey, debris survey and anode wastage measurement. If explicitly stated in the Workscope, it may also include Cathodic Potential (CP) measurement, Ultrasonic Thickness (UT) and Pulsed Eddy Current (PEC) wall thickness measurement and cleaning of specific areas such as clamps/guides, to enable Detailed Visual Inspection (DVI) to be carried out. Inspection methods under the following procedures are to be employed in conjunction with this procedure. I 15 002 - Ultrasonic Inspection - General. I 60 004 - Cathodic Protection Monitoring - ROV

2

TASKS

2.1


2.2

VI-TOP

-

Topside Inspection

PH-TOP

-


VD-ROV (VD-DIV)

-

General ROV Video

VI-GVI

-


CP-PRX

-

Proximity CP Measurements

VI-AW

-


MG-GEN

-


DB-CHK

-

Visual Debris Check

Optional Tasks The following work tasks are optional and will be explicitly called for in the Workscope. CL-INS

-

Cleaning for Inspection

VI-DVI

-


CH-BLT

-

Bolt Tightness Checks

WT-DIG

-

UT Wall Thickness Measurements

WT-PEC

-

Pulsed Eddy Current (PEC) Wall Thickness Measurements

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3.1

Inspection Qualifications The inspection is to be carried out by ROV, under the guidance of a CSWIP 3.3u or 3.4u Inspection Controller, or CSWIP 3.1u/3.2u diver, under the guidance of a CSWIP 3.4u Inspection Controller. Topside inspection is to be carried out by a CSWIP 3.3u/3.4u Inspection Controller.

3.2

Above Water Inspection (VI-TOP / PH-TOP) A topside visual inspection of the riser/J-Tube and its associated clamps/guides is to be carried out between LAT and the under deck of the platform, paying particular attention to the region from LAT to +3m. Only gross defects (C1 category) are to be reported. Topside digital photographs are required of the above areas of the riser/J-Tube from two opposite sides. These should be taken on an opportunity basis only, with no specific vessel move made to obtain these images, unless specifically requested in the workscope.

3.3

Sub Sea Inspection (VD-ROV/VI-GVI) The survey is to be carried out by ROV. Carry out, and fully video record, a GVI of the Riser or J-Tube including all guides, clamps and anodes. Unless specified by the workscope, the survey is to be performed between LAT, the seabed tie-in flange/weld or bellmouth and out for 20m from the tie-in flange/weld or bellmouth, or to touchdown point if this is further away. Should the tie-in flange/weld be greater than 20m away from the edge of the platform, then the tie-in flange/weld is to be the extent of the survey. For flexible risers and umbilicals where no tie-in flange/weld or bellmouth exist, the survey is to be taken out to touchdown or 20m out from the platform, which ever is the greater. The survey is to cover, as best as practicable, 360° of the circumference of the Riser/J-Tube. This would generally require 2 passes. The purpose of this survey is to determine the following: (1)

Obvious damage.

(2)

Corrosion in the splash zone area.

(3)

Areas of wear or corrosion in the vicinity of guides or clamps.

(4)

Condition and integrity of any intermediate flanges, guides and clamps.

(5)

Condition of protective coating checking for lack of adhesion, blistered, cracked or missing coating.

(6)

Integrity of splash zone sheathing which covers the location and condition of the Monel/Neoprene sheathing paying particular attention for any signs of splitting or bulging especially at the circumferential and longitudinal welds.

(7)

Presence of debris or obstructions (DB-CHK). As per anomaly criteria, all contacting metallic debris is to be removed. If deemed to be a Diver/ROV hazard, then attempts should be made to remove such debris.

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(8)

Extent of marine growth (MG-GEN). Describe the marine growth as hard or soft, giving estimated thickness and an estimate of the percentage of cover of each.

(9)

CP readings at the mid point of each riser section between clamps, and at each clamp. See section 3.3.1.

(10)

Anode condition and wastage (VI-AW). The integrity of the anode support (bracket, bracelet, earthing strap) is to be checked. A guide to estimate percentage wastage on an anode is given below: ANODE DEPLETION SCHEMATIC 0-5% LOSS -


6-20% LOSS -


21-50% LOSS -


>50% LOSS -


(11)

Report any differences between the Workscope drawings and the observed configuration.

(12)

Position of Seamark identification boards.

(13)

Record the distance of touchdown or burial point of the pipeline or umbilical out from the tie-in flange/weld or bellmouth.

Or

If buried record the depth at which burial occurs on the Riser or J-Tube. Where buried, complete the pipeline survey to the full extent required, to confirm that the riser or J-Tube remains in burial, or to establish re-exposure.

No cleaning is to be carried out as part of the routine inspection. If cleaning of a Riser/J-Tube subcomponent is required, these sub-components shall be clearly identified in the Workscope. However, if anomalies are noted during the course of the General Visual Survey, sufficient cleaning shall be carried out to allow a DVI and accurate description of the anomaly. Digital Still Images (PH-DIG) are to be taken of any anomalies or other areas of interest. These may be supplemented by suitable drawings to show the location, size and details of the item of interest. 3.3.1

Cathodic Protection Monitoring (CP-PRX) CP readings are required to be taken prior to any cleaning of marine growth. Proximity measurements are preferred to contact measurements. Only if unavoidable should Contact CP readings be taken on a Riser, and should only be conducted with the approval of the Shell Offshore Representative. Contact Readings are acceptable on J-Tubes, these being un-pressurised sections of pipe. Note that some J-Tubes or J-Tube Bundles terminate with emerging pressurised flexible risers. Proximity CP readings are required at the mid point of each section, on both sides, and at each guide/clamp.

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Where the guide/clamp is bolted, where there appears to be the chance that components of the clamp may be isolated from the structure, a contact reading is required for each suspect component. Where insufficient COABIS Workpack task boxes exist, relevant additional CP task boxes need to be raised to accommodate all readings taken. The CP probe is to be hard wired into the video overlay such that the CP readings are continuously displayed on the video screen during the survey. CP readings are to be included in the video commentary. Refer to Standard Procedure I 60 004 for taking CP measurements, point 3.4.1. 4

OPTIONS When specified in the Workscope or as directed by the Shell Offshore Representative or by the sponsor, any of the following optional activities may be undertaken.

4.1

Detailed Visual Inspection (VI-DVI) Areas required to be cleaned and then subjected to DVI will be specified in the workscope. The purpose of this type of inspection is to establish the condition of an area, or a component and its attachments, to detect defects that would otherwise be obscured by marine growth. A limited amount of cleaning will be required to carry out this inspection. Soft marine growth should be removed by either water jetting, scrapers and or wire brushes. The standard of cleaning shall be sufficient to enable details of the component to be seen. It will not be necessary to remove hard marine growth unless it obscures detail (CL-INS). Care is to be taken during the cleaning process to ensure any surface coatings are not damaged. On completion of the cleaning, the Detailed Visual Inspection shall consist of:

4.2

(1)

Checking the general condition of the component noting the number, alignment and condition of any securing bolts (CH-BLT) both around the Riser and back to the structure.

(2)

Checking the alignment of the component.

(3)

Reporting any movement between the Riser and the component and reporting on any wear or corrosion.

(4)

Reporting the gap between the Riser pipe and the component where appropriate.

(5)

Reporting on the presence and condition of any liners.

(6)

Checking integrity of any continuity straps or bonding cables.

Condition of Protection Fender in the Splash Zone (VI-GVI) The following areas are to be noted and fully reported on: (1)

Obvious damage or distortion.

(2)

Corrosion.

(3)

Confirm integrity and presence of any bolts (CH-BLT).

(4)

Marine growth levels. Describe growth as hard or soft, giving estimated thickness and estimate of percentage cover of each.

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4.3

(5)

Anodes. Percentage wastage is to be observed using standard depletion categories.

(6)

Pintle/fender seating.

(7)

Presence of debris. Remove by ROV if possible.

(8)

Protective coating. Lack of adhesion, blistered, cracked or missing coating, presence of corrosion product at these locations is to be noted.

Seabed Supports and Protection Frames The following areas are to be noted and fully reported on:

4.4

(1)

Obvious damage or distortion.

(2)

Corrosion.

(3)

Marine growth levels. Describe growth as hard or soft, giving estimated thickness and estimate of percentage cover of each.

(4)

Anodes. Percentage wastage is to be observed using standard depletion categories.

(5)

Presence of debris. Remove by ROV if possible.

(6)

Protective coating, lack of adhesion, blistered, cracked or missing coating, presence of corrosion product at these locations is to be noted.

(7)

Seabed condition.

(8)

Scour or build up of sediments around base of the support or protection frame is to be reported on.

Ultrasonic Wall Thickness Measurement (WT-DIG) Readings can be taken by both ROV and diver. The measurement locations shall be clearly specified in the Workscope and a final report shall clearly identify the exact location where the readings are taken. Refer to Standard Procedure I 15 002 for taking UT wall thickness measurements, section 3.3.

4.5

Pulsed Eddy Current (PEC) Wall Thickness Measurement (WT-PEC) Readings can be taken by ROV. The measurement locations shall be clearly specified in the Workscope and a final report shall clearly identify the exact location where the readings are taken. Refer to Standard Procedure I 15 002 for taking UT wall thickness measurements, section 3.4.

5

REPORTING

5.1

Final Report The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above. Reference section 2, Chapter 1, Section 3.1.5. All anomalies are to be referenced, with a general statement made concerning the types and extent of anomalies identified. Any C1 anomalies are to be commented on more specifically. Other references are to be made to any digital still images and drawings.

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If not anomalous, reference is to be made to any marine growth results taken, confirming the location where the data can be obtained, i.e. COABIS database. The maximum and minimum of all CP readings taken are to be reported for a specific section of a survey, i.e. CTS or specific elevation, or where a section of a survey has been conducted during a specific dive. Reference should be made confirming the location where the full survey data can be obtained, i.e. COABIS database. Any other specific inspection tasks requested in the workscope are to be commented upon. If the task could not be completed, a statement is required stating reasons. Sketches are required, either scanned, AcadLT or other proprietary drawing format, of any major defects or debris that cannot be suitably documented by anomaly report and digital images alone. The exact location of any WT readings taken are to be clearly identified, including any alternative locations chosen and reason. If required, a suitable drawing should be provided. Where a large number of Cygnus WT readings are taken, that cannot be suitably incorporated into the Workpack Diary, a drawing showing the results and the location of the readings is to be submitted. A hard copy of all PEC data results, and any associated Cygnus WT readings, are to be included in the Results/Appendix section of the final report. This format is converted from the processed PEC data files, which is in an excel format. All PEC data files are to be saved within the COABIS database, and suitably linked.

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PROCEDURE I 90 001 VALVE ASSEMBLY SPOOL PIECE (VASP) INSPECTION CONTENTS Para

Page

1

INTRODUCTION

3

2 2.1 2.2

TASK OPTIONS External Internal

3 3 3

3 3.1 3.2 3.2.1 3.3 3.3.1 3.3.2 3.4

OPERATING PROCEDURE AND SPECIFICATION Inspection Qualifications Location Confirmation External Survey (VD-ROV) Removable Covers (CN-RPL) Removal of Central Cover - Approximate Weight in Air 2 Tonne. Removal of End Covers - Approximate weight in air 6.5 Tonne Internal Survey (VD-DIV / VD-ROV)

4 4 4 4 5 5 5 6

4 4.1


8 8

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I 90 001 Page 2 of 14

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PROCEDURE I 90 001 VALVE ASSEMBLY SPOOL PIECE (VASP) INSPECTION 1

INTRODUCTION The work method is to be applied to the external and internal inspection of the Valve Assembly Spool Piece (VASP). The work will include damage survey, scour survey, pipeline movement monitoring, leak monitoring, Cathodic Potential (CP) measurements, UT wall thickness measurements, anode survey, video survey and photography. The VASP is situated at KP 446.860 on the Brent Alpha to St Fergus 36 inch Gas Pipeline, (Pipeline/COABIS Code N0201 (IGL03), IBIS Incident No. 99). NDT methods under Procedure I 15 001 and I 15 002 will be required to inspect lifting attachment points on removable covers and carry out UT inspection on 36 inch pipeline.

2

TASK OPTIONS

2.1

External

2.2

VI-ROV

-

ROV Worksite Check

VD-ROV

-

General ROV Video

DM-SCR

-

Scour Survey

DB-CHK

-

Visual Debris Check

-


Internal CN-RPL

VD-DIV/ROV -

General Video

CH-LKS

-

Check for Leaks

CH-VLV

-


VI-AW

-


CP-CON

-


WT-DIG

-

UT Wall Thickness Measurements

DM-STD

-


MG-GEN

-


Any number or combination of the listed work tasks, or those listed under Procedure I 15 001, may be used or called for on the workscope or during the course of the inspection to fully investigate and report damage as found. Should anomalies be noted, they are to be reported and acted upon as per Section 2, Chapter 6, ‘Anomaly Reporting & Criteria’, and as directed by the Shell Offshore Representative.

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3


3.1


3.2

Location Confirmation Survey data, including the position of the igloo/manifold to be inspected, will be provided by the Shell Survey department prior to commencement of operations. All survey data shall be based on International Spheroid, European Datum 1950 (ED50), Transverse Mercator Projection. For UK Sector Central Meridian is 0 deg and for Dutch Sector Central Meridian is 5deg E. Reference Section 1, Chapter 2, Figure 1, for further datum shift parameters. On arrival at the worksite, it should be established that the correct structure has been identified, by use of suitable markings on the SSIV itself, or by use of the Shell survey data provided, and/or field layout drawings to provide other suitable means of confirmation. The Shell Offshore Representative is to be consulted should no markings be present, and the latter method is used to confirm that the correct structure has been identified. If doubt persists as to the correct identification of the igloo/manifold, then a positional fix is to be taken of the as-built fix co-ordinate position, which may not be the centre of the igloo/manifold. Should this fix disagree with the workscope stated position by more than +/-5m, then initiate checks to resolve errors. Such checks should confirm that the vessel's positioning system has been suitably calibrated.

3.2.1

External Survey (VD-ROV) The ROV will carry out, and fully video record, a general visual survey of the VASP installation location. The purpose of this survey is to record the following: (1)

An overall view of the VASP (use of SIT camera) from all sides. This survey is to check for any gross damage or debris, and to confirm the area is safe for diver intervention. Results of this survey to be relayed to the dive supervisor (VI-ROV).

On completion of the overall view, a more detailed survey is to be carried out in colour. (2)

All side and roof panels for any evidence of impact damage. Check all hinges, paying particular attention to the central roof panel, which will be later removed. If any concerns regarding the central panel, relay this to the dive supervisor.

(3)

CP readings on four corner of the structure, proximity or contact. (CP-PRX)

(4)

The entry and exit of the pipeline to the VASP structure for any evidence of pipeline movement or door settlement.

(5)

Scour around the base of the VASP. Note: There are specific anomaly criteria with respect to igloo/manifold scour. See Section 2, Chapter 6, Point 2.3.12. (DM-SCR).

(6)

Debris (DB-CHK).

(7)

General views are required of the approaches of each pipeline out to 5m from the igloo/manifold, or to the start of protection mattresses, which ever is the lesser. The survey is to confirm the presence and integrity of any supports, protection bags/mats or point of burial.

Digital Still Images (PH-DIG) are to be taken of any anomalies or other areas of interest. These may be supplemented by suitable drawings to show the location, size and details of the item of interest. Note: I 90 001 Page 4 of 14

A redundant pipeline movement-monitoring device exists on the North side of the VASP. Am 03 04/06

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3.3

Removable Covers (CN-RPL) For the diver or ROV to gain access to the VASP, it will be necessary to remove one or more of the three top covers. CAUTION

3.3.1

(1)

The centre end panels.

panel

(2)

End cover removal of the central cover.

has

to

must

be

only

removed

be

before

either

of

the

undertaken

after

removal

Removal of Central Cover - Approximate Weight in Air 2 Tonne. Prior to attaching lifting strops the 4 extension horn lifting points are to be subjected to a close visual inspection. Only after the inspection confirms no anomalies is the central cover to be removed (see Fig 2). The Lifting Strop: 1 x Four Leg Sling complete with frame type link made up as follows: 3/4 inch - 6 x 19 galvanized IWRC slings 5m long. Each leg tested to 3.25T SWL. Hard eyes both ends each leg. 6.5T SWL G2150 shackles at free ends. 6 x Crosby Type G2150 bolt type anchor shackles. Attach lifting strop and remove central cover with vessel crane or lifting bags and place cover on seabed adjacent to VASP Igloo and clear of any pipelines. Disconnect crane or deflate lift bags. See Fig 3 for typical slinging arrangement. WARNING:

3.3.2

IF LIFTING BAGS ARE USED, HOLD BACK STROPS MUST BE ATTACHED PRIOR TO INFLATION OF LIFT BAGS TO PREVENT ACCIDENTAL BLOW UP AND POSSIBLE UNCONTROLLED ASCENT OF COVER.

Removal of End Covers - Approximate weight in air 6.5 Tonne Diver to visually inspect the 4 extension horn lifting points on each cover for damage prior to attaching the lifting strop. (Fig 2). The Lifting Strop: 1 x Four-leg sling complete with frame type link made up as follows: 3/4 inch - 6 x 19 galvanised IWRC slings 5m long. Each leg tested to 3.25T SWL. Hard eyes both ends each leg. 6.5T SWL G2150 shackles at free ends. 8 x Crosby type G2150 bolt type anchor shackles. Identify the southern end cover, which is situated over the ball valve and actuator assembly. Disconnect the holding down strops on the Southern end cover, See Figs 4 and 5. Check that there are no other obstructions to the lifting of the end cover. The end cover is lifted with the two sling legs nearest the centre of the VASP having two extra Crosby type G2150 bolt type anchor shackles on each leg. This arrangement is designed so they become 2 inch to make cover sit level. Attach lifting strop and remove southern end cover with vessel crane or lifting bags and place cover on seabed adjacent to VASP and clear of any pipelines. Disconnect crane or deflate lift bags. See Fig 3 for typical slinging arrangement. Repeat the above steps for the northern end cover. On completion of cover removal diver is to disconnect the ends of the safety strops, coil back and stow them out of the way. See Fig 5. Note:

Am 01 05/05

ROV to monitor and video record the cover removal operations.

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3.4

Internal Survey (VD-DIV / VD-ROV) When a diver enters the VASP Igloo, a second diver must remain at the entrance and act as tender. On gaining entry to the interior of the VASP the diver or ROV, as access allows, will carry out and fully video record, a general visual survey of the VASP installation and internal walls of the Igloo. The purpose of this survey is to record the following: (1)

Pipework. All pipe work for corrosion and leaks. Particular attention is to be given to the three pipe guides supports paying particular attention to any evidence of pipe movement through the guide and any corrosion.

(2)

36 inch Check Valve. Inspect the various vent connection on the body of the 36-inch check valve for any evidence of gas leaks (CH-VLV / CH-LKS). Note:

An injection clamp and cylinder from a previous operation have been left in place on vent connection 7C. Under no circumstances is the diver to interfere with this assembly. (Date of installation 1984).

(3)

4 inch Ball Valve Assembly. Inspect for any evidence of gas leaks(CH-VLV / CH-LKS).

(4)

36 inch Ball Valve. Inspect for any evidence of gas leaks (CH-VLV / CH-LKS).

(5)

Hoses. Inspect any hydraulic hoses, paying particular attention to the end fittings and hose ends for evidence of deterioration.

CAUTION:

IN THE EVENT OF A LEAK BEING DISCOVERED, IF DEEMED SAFE TO DO SO AN INSPECTION SHOULD BE CARRIED OUT TO IDENTIFY THE LEAK SOURCE, THE RATE OF LEAKAGE AND DAMAGE ASSOCIATED WITH THE LEAK. IF UNSAFE, DIVERS ARE TO BE RECOVERED, WITH THE SURVEY CARRIED OUT BY ROV IF POSSIBLE. ALL LEAKS ARE TO BE TREATED AS 'C1' ANOMALIES AND IMMEDIATELY REPORTED TO THE SHELL OFFSHORE REPRESENTATIVE.

(6)

ANODES. Carry out an anode inspection (VI-AW) of the anodes, which are located on the sidewall panels, under the roof panels, on the igloo/manifold sub-frame and on the pipeline manifold (VI-AW). The inspection is to record the following: (a)

The presence and location of the anodes are to be confirmed as per as-built layout drawings and are to be confirmed as specified. Give an estimated average range of the anode wastage. Not all anodes are expected to be identified. The survey is to confirm all pipework related anodes. The presence of structure anodes is to be confirmed as best a possible, confirming that there are no obvious missing or severely depleted anodes.

I 90 001 Page 6 of 14

(b)

Describe marine growth as hard or soft, giving estimated thickness and percentage cover of each anode.

(c)

The integrity of the anode support (bracket, bracelet, earthing strap) is to be checked.

(d)

Estimate percentage wastage on each anode using one of the following categories:

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ANODE DEPLETION SCHEMATIC

(7)

0-5% LOSS -


6-20% LOSS -


21-50% LOSS -


>50% LOSS -


CP Readings. Proximity readings are the preferred method. Contact readings are only to be taken where a suitable proximity system is not available. Refer to the workscope for qualification on the method to use, and if in doubt refer to the Shell Offshore Representative for advice, based on recommendations from the relevant Sponsoring Engineer (CP-PRX). Where Reference Proximity readings are taken, an initial contact reading is required. All subsequent readings are to be proximity, unless doubts exist as to the electrical continuity of the locations of the subsequent readings. During the internal survey of the VASP, should significant areas of bare metal or corrosion be noted, CP readings are to be taken and recorded. Where these areas occur, readings to be restricted to one CP per component. In addition, CP readings are to be taken on two vertical (including diagonals) and two horizontal tubulars. Positions of any bare metal, tubular and pipework CP readings obtained are to be clearly shown on structural drawings.

(8)

The diver is to take CP (CP-CON) readings and UT (WT-DIG) wall thickness measurements at four locations on the underside of the 36-inch pipeline. See Fig 6 for positions. Paint coating is not to be removed for UT Wall Thickness measurements and areas where readings are taken are to be permanently marked.

(9)

On completion of all internal inspection work the top covers are to be replaced in reverse order to removal procedure ensuring all hold down strops are correctly reinstalled (CN-RPL).

Note: (10)

ROV to monitor and video record the cover replacement operation. Prior to leaving location the ROV will carry out and fully video record, a general visual survey of the VASP paying particular attention to the final placement of top covers and fit up.


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0153-001

4

REPORTING

4.1

Final Report The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above. Reference section 2, Chapter 1, Section 3.1.5. All anomalies are to be referenced, with a general statement made concerning the types and extent of anomalies identified. Any C1 anomalies are to be commented on more specifically. Other references are to be made to any digital still images and drawings. CP and UT readings obtained at the four designated locations, and measurement ‘X’ are to be included on the drawing fig.6. Maximum and minimum range for all other CP readings taken are to be stated, with the readings and their locations clearly shown on structural drawings. The average anode wastage range estimate for all anodes is to be included. Sketches are required, either scanned, AcadLT or other proprietary drawing format, of any major defects or debris that cannot be suitably documented by anomaly report and digital images alone.

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0153-001

4.26m

14.6m

2

1

A

B

C

D

E

ELEVATION

END VIEW ( PROTECTIVE CANOPY OMITTED )

( PROTECTIVE CANOPY OMITTED ) REMOVABLE COVER PLATES ( 3 PANELS ) HINGED PANEL

HINGED PANEL

ST. FERGUS

BRENT 'A'

36" BALL VALVE AND ACTUATOR

SECTIONAL ELEVATION 4" BALL VALVE VALVE SPINDLE

36" CHECK VALVE

A

B

C

D

E

1 2

KEY PLAN

Figure 1

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VASP - General Arrangements

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0153-001

PLAN VIEW

OUTER CORNER OF END COVER

HORN

SHACKLE

ELEVATION VIEW ENSURE HORN IS NOT BENT ABOVE THIS LEVEL

DIMENSION +/- 0.5O

GUIDE CONE

Figure 2

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Removable Cover Lifting Point - Typical

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0153-001

HINGED ACCESS PANELS NOTE CENTRE PANEL HAS TO BE REMOVED BEFORE EITHER END PANEL. END COVER

A

CENTRE COVER

END COVER

NOTE EXTENSION HORNS WHICH PROJECT UNDER THE CENTRE COVER. SEE DETAIL 'A' FOR TYPICAL HORN Detail 'A'

Figure 3

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Slinging Arrangement Central Cover - Typical

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0153-001 PLAN VIEW

COVER LOCATING STROPS

OUTER HORN

FOR DETAIL SEE FIGURE 6

A

A

INNER HORN

EXISTING CENTRE COVER

SECTION ELEVATION IN DIRECTION A-A

COVER LOCATING STROPS

ROOF PANEL

PROTECTION APRON

SAFETY STROPS

Figure 4

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Plan and Section Elevation of VASP

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0153-001

COVER

MOUSE HARD EYE TO SHACKLE IN THIS POSITION

3 " x 3 " ANODE 5.65 "

1 ' 10 "

TOP BEAM OF PROTECTION APRON

INSERT EXTRA SHACKLE HERE IF REQUIRED

TO CORRESPONDING PADEYE ON OTHER SIDE OF VASP SECTION

2.5 " SAFETY STROP

COVER LOCATING

1.5 " DIA. HOLE 1 " PLATE

2.5 "

COVER PADEYE 1.125 " DIA. HOLE 2.5 " RAD. CENTRE PLATE EDGE 4.25 " PLATE

Figure 5

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Detail of Shackle Arrangement and Padeye on Protection Apro

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0153-001

Figure 6

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Location of Inspection Areas

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0153-001

PROCEDURE I 90 002 PIPELINE DAMAGE INSPECTION CONTENTS Para

Page

1

INTRODUCTION

3

2 2.1

TASKS Standard Tasks

3 3

3 3.1 3.2 3.3 3.3.1 3.3.2 3.3.3 3.4

OPERATING PROCEDURE AND SPECIFICATION Inspection Qualifications Pre-Inspection (VI-ROV) Damage Inspection (PI-DAM) No Bare Metal Exposed No Metal Loss Pipe Grooved Final Survey

3 3 3 4 4 4 5 5

4 4.1


5 5

FIGURES Figure 1 2 3 4 5 6 7

Page Damaged Area Markings - Typical Dimensional Survey - No Metal Damage Dimensional Survey - of Damaged Metal Ultrasonic Measurements on Bare Metal/Grooved Areas - Typical Ultrasonic Measurement Positions on Groove - Typical Blank Pipeline Datasheet Example Completed Pipeline Datasheet

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7 7 8 8 9 11 13

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0153-001

PROCEDURE I 90 002 PIPELINE DAMAGE INSPECTION 1

INTRODUCTION The work method is to be applied to the detailed inspection of a damaged area on a submarine pipeline caused by impact, anchor wires, anchors, trawl boards, etc. The work will include Cathodic potential (CP) measurements, cleaning, UT wall thickness measurements, dimensional survey, video survey and Digital Still Images. Inspection methods under the following procedures may be employed in conjunction with this procedure. I 15 001 – Weld Inspection I 15 002 – Ultrasonic Inspection – General I 60 004 – Cathodic Protection Monitoring

2

TASKS

2.1

Standard Tasks VI-ROV

-

ROV Worksite Check

PI-DAM

-

Bare Metal Incident

VD-ROV

-

General ROV Video

PH-DIG

-


Any number or combination of the listed work tasks, or those listed under Procedure I 15 001 and I 15 002, may be used or called for on the workscope or during the course of the inspection. 3


3.1


3.2

Pre-Inspection (VI-ROV) Prior to starting the inspection, the ROV (or diver) is to ensure that the incident has been correctly identified as indicated in the workscope. Should investigation of the incident site identify no damage as detailed in the procedure, then it should be considered that the inspection is being undertaken at an incorrect location. If this occurs, a ten (10)-metre search either side of the reported location should be undertaken to locate the correct damage incident. In addition, a second independent check should be carried out using the vessel positioning system. The workscope may identify the distance between the incident and nearest pipeline feature i.e. field joint or anode. This distance should also be checked to confirm that the correct incident has been located.

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0153-001 If any doubt exists, or where in close proximity to another similar defect, the problem should be referred to the Shell Offshore Representative for clarification. 3.3

Damage Inspection (PI-DAM) On completion of the pre-inspection, the ROV will carry out an initial general visual inspection of the defect area, recorded on video (VD-ROV), viewing both sides of the pipeline. This inspection is not to be restricted to the localised area of damage, but will cover an area sufficient to highlight the area of damage, any items of debris, and/or any other item, which may have caused the damage. Where field joints are present, the inspection is to show the anomaly relative to the two end field joints on the pipe section that the damage is located, and/or any other pertinent fixed reference point, i.e. anode. The survey is to reference the direction of associated installations. The confirmed position of the incident, and any other items of note i.e. field joint, anode and debris, are to be position fixed. These fixes are to be recorded on video. Where taken by ROV the fix position is to be displayed on the video overlay in Eastings and Northings. At least two contact CP readings are to be taken on the incident prior to any cleaning by either ROV or diver. Calibration data is to be noted and verified before and after each dive and before each set of readings. Refer to Standard Procedure I 60 004 for taking CP measurements, point 3.4. The incident is to be cleaned either by ROV water jet, or by diver with wire brush and scraper. If bare metal is present it must be established if there has been metal loss, i.e. grooved pipe. The following gives the three methods of inspection to be conducted, dependant on the extent of damage encountered.

3.3.1

No Bare Metal Exposed Mark the damaged area with the four cardinal clock positions with the 6 o'clock position being the downstream side of the damage as shown in Figure 1. Carry out a dimensional survey of the damaged area. Record the following dimensions as shown in Figure 2.

3.3.2

(1)

Length and breadth of the damaged concrete weight coat.

(2)

Length and breadth of exposed bitumen.

No Metal Loss If the pipeline surface is scored but there is no visible groove(s) in the marked area, carry out the following measurements in addition to those measurements in 3.3.1 above. Dimensions to be recorded as shown in Figure 3. (1)

Length and breadth of exposed bare metal.

(2)

Length and breadth of any damaged metal. If there is more than one damaged area within the incident, record the overall dimensions of the damage.

(3)

Length and breadth of damaged area(s) measured along the axis of the damage.

(4)

Take wall thickness readings on the scored area. Readings should be taken at intervals of 20% of the length of the scored area (See Figure 4). For example, if the scored area is 200mm long, measured along the axis of the score, then take readings every 40mm. The frequency should be increased if low readings are obtained. At least four further readings should be obtained on undamaged metal.

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0153-001 3.3.3

Pipe Grooved If the pipeline is grooved then carry out the following tasks in addition to those described in 3.3.1 and 3.3.2 above. (1)

For concrete coated pipe, if required, additional concrete and bitumen coating may be removed back to bare metal, to allow suitable access for inspection of the damaged pipe. This may need to be sufficient to allow Pit or Linear Angular Measurement (LAM) gauge measurements. For other forms of coating, i.e. paint, neoprene, polyurethane, the thickness of the coating should not prevent the use of these gauges. Further coating removal is allowable to obtain comparison WT readings on undamaged pipe. Unless specified in the workscope, removal of coating requires approval of the Shell Offshore Representative, as advised by the relevant sponsoring engineer.

(2)

Clean the exposed area. For concrete coated pipe, if required, hydraulic wire brush or low pressure grit cleaning systems are acceptable. For other forms of coating, scouring pads and or wire brush may be employed, but not to the further detriment of the remaining coating.

(3)

Locate the deepest point of the damage and draw a line through the axis, and a second line across the axis of the damage. Mark lines in 10mm increments. See Fig 5.

(4)

Measure the length and breadth of each individual groove along its axis.

(5)

Take a digital wall thickness measurement at each 10mm increment. In addition two readings are to be taken on undamaged parent metal on each axis to provide datum. Should WT readings not be possible due to the contours of the groove then Pit or LAM gauge readings are to be taken to complete the required metal loss readings.

(6)

Carry out a detailed visual inspection using the divers hat mounted camera. The video survey should show views from the various sides and angles to allow digital images to be obtained. Suitable close up images to be obtained from divers hat mounted camera source direct, and from video source, not tape.

The damage may be such that ACFM (preferred) or MPI inspection of the area is necessary to quantify any surface/subsurface cracks detected/suspected. Such inspections are to be conducted as per relevant sections of procedure I 15 001, after agreement with the Shell Offshore Representative. 3.4

Final Survey The ROV will carry out, and fully video record (VD-ROV), a general visual survey of the damaged area. During the survey, particular attention is to be given to areas of interest identified during the diver inspection works. The ROV (or diver) is to obtain stand off digital images (PH-DIG) of the incident from at least two sides and a plan view. Images are to be obtained from video source, not tape.

4

REPORTING

4.1

Final Report The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above. Reference Section 2, Chapter 1, Section 3.1.5.

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0153-001 Where dimensions have been taken by ROV, the method employed and levels of accuracy expected of the survey, are to be fully documented in the final report. Maximum and minimum range for all CP readings taken are to be stated. Other references are to be made to any digital still images, drawings and Pipeline Fix Data Sheets included in the report. Raise an anomaly for the defect as found. Anomaly to highlight the results found, making reference to the report. A C1 anomaly is based on a WT loss ≥ 20% WT loss, or for any other significant integrity issue. See Anomaly Criteria, Section 2, Chapter 6, Section 2.3. All data is to be recorded on a Pipeline Datasheet, including a suitable sketch of the damaged area. For the pipeline datasheet, WT reading locations entered are to be numbered 0 upwards. Along the length of the pipe, 0 is to be upstream (12 o’clock). Across the breadth of the pipe, 0 is to the left (9 o’clock) looking upstream. See Figures 1 and 5, and Pipeline Datasheets Figures 6 and 7. The Pipeline Datasheet (Figure 6) is to be completed and included in the results section of the report, along with suitable schematic dimensional drawings to include details required as indicated in Figures 1 to 5. An example of a completed Pipeline Datasheet, including defect sketch are shown in Figure 7. Additional sketch boxes, measurement boxes, LAM / Pit Gauge boxes to be added to the example Pipeline Datasheets to suit. The data does not have to be restricted to the 1 page shown.

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0153-001

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Figure 1

Damaged Area Markings - Typical

Figure 2

Dimensional Survey - No Metal Damage

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0153-001

Figure 3

Figure 4

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Dimensional Survey - of Damaged Metal

Ultrasonic Measurements on Bare Metal/Grooved Areas - Typical

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0153-001

Figure 5

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Ultrasonic Measurement Positions on Groove – Typical

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Figure 6 Am 03 04/06

Blank Pipeline Timesheet I 90 002 Page 11 of 13

0153-001

I 90 002 Page 12 of 13

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Example Completed Pipeline Datasheet I 90 002 Page 13 of 13

0153-001

PROCEDURE I 91 001 IGLOO INSPECTION – FULMAR TEE SKID CONTENTS Para

Page

1

INTRODUCTION

3

2 2.1 2.2 2.3

TASK OPTIONS External Internal Optional Tasks

3 3 3 3

3 3.1 3.2 3.3 3.4

OPERATING PROCEDURE AND SPECIFICATION Inspection Qualifications Location Confirmation External Survey (VD-ROV) Internal Survey (VD-DIV / VD-ROV)

4 4 4 4 5

4 4.1

OPTIONS Wall Thickness Readings (WT-DIG)

7 7

5 5.1


7 7

FIGURES Figure

Page

1

Fulmar Tee Skid Igloo Field Layout

8

2

Tee Skid Plan Arrangement

9

3

GA of Tee Piece Skid Frame

10

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0153-001

PROCEDURE I 91 001 IGLOO INSPECTION - FULMAR TEE SKID 1

INTRODUCTION The work method is to be applied to the external and internal inspection of the Fulmar Tee Skid Igloo on the 16 inch Fulmar AD to new SALM Base Oil Loading Pipeline. The work will include damage survey, scour survey, leak monitoring, anode survey and video survey. The Fulmar Tee Skid Igloo is situated at KP 2.238 on the 16 inch Fulmar AD to new SALM Base Oil Loading Pipeline, at position E631260 N626101 (Pipeline Code N0307, IBIS Incident No. 426, COABIS Code IGL19/220-001). (See Figure 1) Inspection methods under the following procedures may be employed in conjunction with this procedure. I 15 002 – Ultrasonic Inspection – General I 60 004 – Cathodic Protection Monitoring

2

TASK OPTIONS

2.1

External

2.2

VI-ROV

-

ROV Worksite Check

VD-ROV

-

General ROV

DM-SCR

-

Scour Survey

DB-CHK

-

Visual Debris Check

CP-PRX

-


-

ROV Worksite Check

Internal VI-ROV

2.3

VD-DIV/ROV -

General Video

CH-LKS

-

Check for Leaks

CH-VLV

-


VI-AW

-


MG-GEN

-


CP-PRX

-


Optional Tasks The following work tasks are optional and will be explicitly called for in the Workscope, or as a result of finding an anomaly.

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0153-001 WT-DIG

-


PH-DIG

-


Any number or combination of the listed work tasks may be used or called for in the workscope or during the course of the inspection to fully investigate and report damage as found. Should anomalies be noted, they are to be reported and acted upon as per Section 2, Chapter 6, ‘Anomaly Reporting & Criteria’, and as directed by the Shell Offshore Representative. 3


3.1


3.2

Location Confirmation Survey data, including the position of the igloo, will be provided by the Shell Survey department prior to commencement of operations. All survey data shall be based on International Spheroid, European Datum 1950 (ED50), Transverse Mercator Projection. For UK Sector Central Meridian is 0 degrees East. Reference Section 1, Chapter 2, Figure 1, for further datum shift parameters. On arrival at the worksite, it should be established that the correct structure has been identified, by use of suitable markings on the igloo, or by use of the Shell survey data provided, and/or field layout drawings to provide other suitable means of confirmation. The Shell Offshore Representative is to be consulted should no markings be present, and the latter method is used to confirm that the correct structure has been identified. If doubt persists as to the correct identification of the igloo, then a positional fix is to be taken of the asbuilt fix co-ordinate position, which may not be the centre of the igloo. Should this fix disagree with the workscope stated position by more than +/-5m, then initiate checks to resolve errors. Such checks should confirm that the vessel's positioning system has been suitably calibrated.

3.3

External Survey (VD-ROV) The ROV will carry out, and fully video record, a general visual survey of the Tee-Skid Igloo installation location. The purpose of this survey is to record the following: (1)

An overall view of the igloo (use of SIT camera) from all sides. This survey is to check for any gross damage or debris, and to confirm the area is safe for diver intervention. Results of this survey to be relayed to the dive supervisor (VI-ROV).


Structure for any evidence of impact damage (concrete & pipework protection frame).

NOTE:

Protection panels originally installed to cover the Tee-Skid pipework have been removed. Three concrete protection structures remain around the Tee. See Figure 2.

(3)

Check for Leaks.

(4)

Proximity (preferred) or contact CP readings on the three ends of the pipework protection frame (CP-PRX).

(5)

The entry and exit of the pipelines to the structure (3), for any evidence of pipeline movement or settlement.

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0153-001 (6)

Scour around the base of the structure. Note: There are specific anomaly criteria with respect to igloo scour. See Section 2, Chapter 6, Point 2.3.12. (DM-SCR).

(7)

Debris (DB-CHK).

(8)

General views are required of the approaches of each pipeline out to 5m from the Tee-Skid, or to the start of protection mattresses, which ever is the lesser. The survey is to confirm the presence and integrity of any supports, protection bags/mats or point of burial. Comment on any pipeline anodes seen within this region.

Digital Still Images (PH-DIG) are to be taken of any anomalies or other areas of interest. These may be supplemented by suitable drawings to show the location, size and details of the item of interest. 3.4

Internal Survey (VD-DIV / VD-ROV) The internal survey may be conducted by either diver or ROV. Original steel panels have been removed and not replaced. Diver access is possible through the open pipework protection structure. When a diver enters the igloo, a second diver must remain at the entrance and act as tender. On gaining entry to the interior of the igloo the diver or ROV, as access allows, will carry out and fully video record, a general visual survey of the Tee Skid Igloo installation and internal framework of the igloo. The purpose of this survey is to record the following: (1)

Pipework. All pipe work for corrosion and leaks. Particular attention is to be given to the pipe guides and clamps with any evidence of pipe movement to be reported. Pipework schematics are shown on Figures 2 & 3.

(2)

Valves. Each of the four 16 inch and two 2 inch valves, as shown on Figure 3, are to be visually inspected. Any leaks or evidence of leaks are to be reported. Where visible, all valve positions are to be noted on video. However, these are not required to be recorded in the job Completion Report.

(3)

Flanges. Each of the twelve flanges are to be visually inspected. Any leaks or evidence of leaks is to be reported. All blind flanges are to be similarly checked. CAUTION:

IN THE EVENT OF A LEAK BEING DISCOVERED, DIVERS SHOULD BE WITHDRAWN FROM THE AREA AND AN ROV INSPECTION SHOULD BE CARRIED OUT TO IDENTIFY THE LEAK SOURCE, THE RATE OF LEAKAGE AND DAMAGE ASSOCIATED WITH THE LEAK. ALL LEAKS ARE TO BE TREATED AS 'C1' ANOMALIES AND IMMEDIATELY REPORTED TO THE SHELL OFFSHORE REPRESENTATIVE.

(4)

Igloo Framework. Inspect the protection structure for evidence of damage and corrosion. Inspect the igloo to Tee Skid securing clamps for any evidence of movement and security.

(5)

Anodes. Carry out an inspection of the anodes (VI-AW) that are located on the igloo subframe and on the Tee Skid. The inspection is to record the following: (a)

The presence and location of the anodes are to be confirmed as per as-built layout drawings, and are to be confirmed as specified. Give an estimated average range of the anode wastage. Not all anodes are expected to be identified. The survey is to confirm all pipework related anodes. The presence of structure anodes is to be confirmed as best a possible, confirming that there are no obvious missing or severely depleted anodes.

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0153-001 (b)


(c)


(d)



(6)

0-5% LOSS -


6-20% LOSS -


21-50% LOSS -


>50% LOSS -


CP Readings. Proximity readings (CP-PRX) are the preferred method. Contact readings are only to be taken where a suitable proximity system is not available. Refer to the workscope for qualification on the method to use, and if in doubt refer to the Shell Offshore Representative for advice, based on recommendations from the relevant Sponsoring Engineer. Where Reference Proximity readings are taken, an initial contact reading is required. All subsequent readings are to be proximity, unless doubts exist as to the electrical continuity of the locations of the subsequent readings. During the internal survey of the Tee-Skid, should significant areas of bare metal or corrosion be noted, CP readings are to be taken and recorded. Where these areas occur, readings to be restricted to one CP per component. Where no areas of bare metal are evident, or where the inspection is to be conducted by ROV, one CP reading is required on a typical area of major pipework (preferably a flange) and a valve. Locations of these readings are to be recorded, and used for repeat readings in future years. In addition, CP readings are to be taken on two vertical (including diagonals) and two horizontal tubulars. With respect to igloo inspection by ROV, where the internal framework is the same as the external framework, these readings are not required, as they have been covered by the CP’s taken as part of the external survey. Positions of bare metal, pipework and framework CP readings obtained are to be clearly shown on structural drawings.

(7)

Prior to leaving location the ROV will carry out, and fully video record, a general visual survey of the igloo, confirming that all diver equipment has been removed.


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0153-001 4

OPTIONS

4.1

Wall Thickness Readings (WT-DIG) Wall thickness (WT) readings may be requested on specific areas of pipework to check for internal corrosion/erosion. The location, extent and areas of readings to be taken will be specified in the workscope. Method for taking WT readings are as per the standard procedure I-15-002, Point 3.3.

5

REPORTING

5.1

Final Report The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above. Reference section 2, Chapter 1, Section 3.1.5. All anomalies are to be referenced, with a general statement made concerning the types and extent of anomalies identified. Any C1 anomalies are to be commented on more specifically. Other references are to be made to any digital still images and drawings. Maximum and minimum range for all other CP readings taken are to be stated, with the readings and their locations clearly shown on structural drawings. The average anode wastage range estimate for all anodes is to be included. Sketches are required, either scanned, AcadLT or other proprietary drawing format, of any major defects or debris that cannot be suitably documented by anomaly report and digital images alone.

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Fulmar Tee Skid Igloo Field Layout Am 03 04/06

0153-001

Figure 2

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Tee Skid Plan Arrangement

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GA of Tee Piece Skid Frame Am 03 04/06

0153-001

PROCEDURE I 91 002 SUBSEA INTERVENTION VALVE (SSIV) INSPECTION NORTHERN BUSINESS UNIT CONTENTS Para.

Page

1

INTRODUCTION

3

2 2.1 2.2 2.3

TASK OPTIONS External Internal Optional Tasks

3 3 3 4

3 3.1 3.2 3.3 3.4 3.5 3.5.1 3.5.2 3.5.3

OPERATING PROCEDURE AND SPECIFICATION Inspection Qualifications External Survey (VD-ROV) External Survey (Reference Figs 2, 3 & 4) Hinged Access Panel ‘D’ - Approximate Weight in Air 3360 kg (CN-RPL) Internal Survey (VD-DIV / VD-ROV) Brent A SSIV Igloo Cormorant A SSIV Igloo North Cormorant SSIV Igloo

4 4 4 4 5 5 6 8 10

4 4.1


12 12

5 5.1


12 12

FIGURES No 1 2 3 4 5 6 7 8 9 10 11

Page SSIV Field Location General Layout of Brent A SSIV Igloo General Layout of Cormorant A SSIV Igloo General Layout of North Cormorant SSIV Igloo Hinged Access Panel - General Arrangements Brent A SSIV Igloo - Piping Schematic and Valves Cormorant A SSIV Igloo - Piping Schematic and Valves North Cormorant SSIV Igloo - Piping Schematic and Valves SSIV Assembly Anode Locations – Typical Subsea Control Skid – General Arrangements Subsea Control Skid – General Arrangements

Am 01 05/05

13 14 15 16 17 18 19 20 21 22 23

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0153-001

PROCEDURE I 91 002 SUBSEA INTERVENTION VALVE (SSIV) INSPECTION NORTHERN BUSINESS UNITS 1

INTRODUCTION The work method is to be applied to the external and internal inspection of Subsea Intervention Valves (SSIV). The work will include damage survey; scour survey, pipeline movement monitoring, leak monitoring, Cathodic potential (CP) measurements, anode survey and video survey. The Brent A SSIV is situated at KP 41.176 on the 16 inch Cormorant A to Brent A (Western Leg, WELGAS) gas pipeline, (Pipeline/COABIS Code N0601 (IGL09), IBIS Incident No. 13) at position E591893 N6767949. The Cormorant A SSIV is situated at KP 0.404 on the 16 inch Cormorant A to Brent A (Western Leg, WELGAS) gas pipeline, (Pipeline/COABIS Code N0601 (IGL10), IBIS Incident No. 14) at position E557834 N6774448. The North Cormorant SSIV is situated at KP 0.225 on the 10-inch North Cormorant to Western Leg gas pipeline, (Pipeline/COABIS Code N0602 (IGL01), IBIS Incident No. 5) at position E561938 N6790157. NDT methods under Procedure I 15 001 may be employed in conjunction with this procedure.

2

TASK OPTIONS

2.1

External

2.2

VI-ROV

-

ROV Worksite Check

VD-ROV

-

General ROV Video

DM-SCR

-

Scour Survey

DB-CHK

-

Visual Debris Check

CP-PRX

-


Internal VD-DIV/ROV -

General Video

CN-RPL

-


CP-PRX

-


VI-AW -

-


MG-GEN

-


CH-LKS

-

Check for Leaks

CH-VLV

-


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0153-001

2.3

Optional Tasks The following work tasks are optional and will be explicitly called for in the Workscope, or as a result of finding an anomaly. WT-DIG

-


PH-DIG

-


Any number or combination of the listed work tasks, or those listed under Procedure I 15 002 and I 90 002, may be used or called for on the workscope or during the course of the inspection. Should anomalies be noted, they are to be reported and acted upon as per Section 2, Chapter 6, ‘Anomaly Reporting & Criteria’, and as directed by the Shell Offshore Representative. 3


3.1


3.2

External Survey (VD-ROV) Survey data, including the position of the igloo/manifold to be inspected, will be provided by the Shell Survey department prior to commencement of operations. All survey data shall be based on International Spheroid, European Datum 1950 (ED50), Transverse Mercator Projection. For UK Sector Central Meridian is 0 deg and for Dutch Sector Central Meridian is 5deg E. Reference Section 1, Chapter 2, Figure 1, for further datum shift parameters. On arrival at the worksite, it should be established that the correct structure has been identified, by use of suitable markings on the SSIV itself, or by use of the Shell survey data provided, and/or field layout drawings to provide other suitable means of confirmation. The Shell Offshore Representative is to be consulted should no markings be present, and the latter method is used to confirm that the correct structure has been identified. If doubt persists as to the correct identification of the igloo/manifold, then a positional fix is to be taken of the as-built fix co-ordinate position, which may not be the centre of the igloo/manifold. Should this fix disagree with the workscope stated position by more than +/-5m, then initiate checks to resolve errors. Such checks should confirm that the vessel's positioning system has been suitably calibrated.

3.3

External Survey (Reference Figs 2, 3 & 4) The ROV will carry out, and fully video record, a general visual survey of the igloo installation location. The purpose of this survey is to record the following: (1)

An overall view of the Igloo/manifold (use of SIT camera) from all sides. This survey is to check for any gross damage or debris, and to confirm the area is safe for diver intervention. Results of this survey to be relayed to the dive supervisor. (VI-ROV)


Structure for any evidence of impact damage. Check for leaks.

(3)

Loose or displaced panels paying particular attention to the seating of panels at the roof interface. Check all hinges.

(4)


I 91 002 Page 4 of 23

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0153-001

(5)

Anode condition if visible.

(6)

The entry and exit of the pipelines and umbilical to the structure, for any evidence of movement or door settlement.

(7)

Check the external umbilical anchor points (Figs2, 3 & 4).

(8)

Scour around the base of the structure. Note: There are specific anomaly criteria with respect to igloo/manifold scour. See Section 2, Chapter 6, Point 2.3.12.

(9)

Debris.

(10)



Hinged Access Panel ‘D’ - Approximate Weight in Air 3360 kg (CN-RPL) It is possible for divers to enter all three igloos, and possibly small ROV’s, through the umbilical access port. If however at the discretion of the divers, dive supervisor or ROV supervisor that this practice is unsafe it will be necessary for the hinged access door panel on the roof of the igloo to be opened. Typical door positions as shown on Fig 5. WARNING:

PRIOR TO ATTEMPTING TO OPEN THE HINGED ACCESS PANEL DOOR, A CLOSE VISUAL AND ELECTROMAGNETIC INSPECTION OF ALL PADEYES ON THE DOOR AND AS NECESSARY FOR TIRFOR AND TIE BACK ATTACHMENT IS TO BE CARRIED OUT. SHOULD THE INSPECTION REVEAL ANY ANOMALIES OR DAMAGE THEN THE PADEYE IS NOT TO BE USED. VISUALLY INSPECT BOTH HINGE ARRANGEMENTS FOR SECURITY, PAYING PARTICULAR ATTENTION TO THE ‘U’ BOLT FASTENINGS. RE-TIGHTEN ALL BOLTS AS NECESSARY. SHOULD THERE BE EVIDENCE OF DAMAGE TO THE HINGE ARRANGEMENT, CARRY OUT A CLOSE VISUAL AND ELECTROMAGNETIC INSPECTION.

On completion of the padeye and hinge inspection the diver is to open the hinged access door panel using the following method: (1)

Install two Tirfor (T516) between the padeyes on the hinged panel (opposite side to the hinges) and padeyes on panel C (refer to Fig 5).

(2)

Using 2000 kg webbing strops, choked around hinged panel frame members, attach two 500 kg lifting bags on the hinged panel (refer to Fig 5). Inflate the bags slowly until the panel opens.

(3)

When the hinged panel is open and vertical, tighten the Tirfors to pull panel past the vertical and secure. Slowly deflate bags and lower door to lay flat on top of igloo panel C. NOTE:

3.5

ROV to monitor and video record the door opening operation.

Internal Survey (VD-DIV / VD-ROV) When a diver enters the igloo, a second diver must remain at the entrance and act as tender. NOTE:

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Divers and ROV to take care of hydraulic hoses when manoeuvring inside the igloo, as damage has been caused in the past, resulting in shutting in of the SSIV.

I 91 002 Page 5 of 23

0153-001

3.5.1

Brent A SSIV Igloo (Pipeline/COABIS Code N0601 (IGL09), IBIS Incident No. 13) In the past diver access has been gained to the igloo through the Control Umbilical opening, on the north side of the igloo. On gaining entry to the interior of the igloo the diver or ROV, as access allows, will carry out and fully video record, a general visual survey of the manifold installation and internal walls of the igloo. The purpose of this survey is to record the following: (1)

PIPEWORK. All pipe work for corrosion and leaks. Particular attention is to be given to the pipe guides and clamps with any evidence of pipe movement to be reported. Pipework schematic is shown on Fig 6.

(2)

VALVES. All valves (16 off, See fig.6) are to be visually inspected. Any leaks or evidence of leaks is to be reported (CH-VLV). Where visible, all valve positions are to be noted on video. These however are not required to be recorded in the job Completion Report.

(3)

ACCUMULATOR MODULES. Each of the three accumulator modules as shown on Figs 10 and 11 are to be visually inspected. Any leaks or evidence of leaks is to be reported. Check for continuity straps.

(4)

CONTROL MODULE. The Control Module as shown on Figs 10 and 11 is to be visually inspected. Any leaks or evidence of leaks is to be reported. Check for continuity straps.

(5)

HYDRAULIC DISTRIBUTION MANIFOLDS. Each of the three hydraulic distribution manifolds as shown on Fig 11 are to be visually inspected. Any leaks or evidence of leaks are to be reported. Check connection points, condition of hoses i.e. blistering and cracking and for general deterioration. Check for continuity straps.

(6)

UMBILICAL TERMINATION MODULE. The Umbilical Termination Module as shown in Fig 10 is to be visually inspected. Any leaks or evidence of leaks is to be reported. The module’s support cradle is to be checked for security, as is the umbilical support ramp, bend restrictor and attachments. Check for continuity straps.

(7)

HYDRAULIC HOSES. All hydraulic hoses are to be inspected, paying particular attention to the end fittings and hose ends for evidence of deterioration. These have failed in the past.

(8)

FLANGES. Each of the flanges as shown in Fig 6 are to be visually inspected. Any leaks or evidence of leaks is to be reported.

CAUTION:


(9)


I 91 002 Page 6 of 23

The presence and location of the anodes are to be confirmed as per as-built layout drawings and are to be confirmed as specified. Give an estimated average range of the anode wastage.

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0153-001

Not all anodes are expected to be identified. The survey is to confirm all pipework related anodes. The presence of structure anodes is to be confirmed as best a possible, confirming that there are no obvious missing or severely depleted anodes. (b)


(c)


(d)

Estimate percentage wastage on each anode using one of the following categories: ANODE DEPLETION SCHEMATIC

(10)

0-5% LOSS -


6-20% LOSS -


21-50% LOSS -


>50% LOSS -


CP READINGS. Proximity readings are the preferred method. Contact readings are only to be taken where a suitable proximity system is not available. Refer to the workscope for qualification on the method to use, and if in doubt refer to the Shell Offshore Representative for advice, based on recommendations from the relevant Sponsoring Engineer (CP-PRX). Where Reference Proximity readings are taken, an initial contact reading is required. All subsequent readings are to be proximity, unless doubts exist as to the electrical continuity of the locations of the subsequent readings. During the internal survey of the igloo/manifold, should significant areas of bare metal or corrosion be noted, CP readings are to be taken and recorded. Where these areas occur, readings to be restricted to one CP per component. Where no areas of bare metal are evident, or where the inspection is to be conducted by ROV, one CP reading is required on a typical area of major pipework (preferably a flange) and a valve. Locations of these readings are to be recorded, and used for repeat readings in future years. In addition, CP readings are to be taken on two vertical (including diagonals) and two horizontal tubulars. With respect to manifold inspection by ROV, where the internal framework is the same as the external framework, these readings are not required, as they have been covered by the CP’s taken as part of the external survey. Positions of bare metal, tubular and pipework CP readings obtained are to be clearly shown on structural drawings.

(11)

On completion of all internal inspection work the hinged access panel is to be closed in reverse order to opening procedure. Ensure all diving umbilicals and ROV tether cable are clear of the panel before closing (CN-RPL). NOTE:

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ROV to monitor and video record the panel closing operation. I 91 002 Page 7 of 23

0153-001

(12)

Prior to leaving location the ROV will carry out, and fully video record, a general visual survey of the igloo, paying particular attention to the final placement of top panels and fit up. Digital Still Images (PH-DIG) are to be taken of any anomalies or other areas of interest. These may be supplemented by suitable drawings to show the location, size and details of the item of interest.

3.5.2

Cormorant A SSIV Igloo (Pipeline/COABIS Code N0601 (IGL10), IBIS Incident No. 14) In the past diver access has been gained to the igloo through the Control Umbilical opening, on the west side of the igloo. On gaining entry to the interior of the igloo the diver or ROV, as access allows, will carry out and fully video record, a general visual survey of the manifold installation and internal walls of the igloo. The purpose of this survey is to record the following: (1)


(2)


(3)


(4)


(5)


(6)


(7)


(8)


CAUTION:


I 91 002 Page 8 of 23

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0153-001

(9)



(b)

Not all anodes are expected to be identified. The survey is to confirm all pipework related anodes. The presence of structure anodes is to be confirmed as best a possible, confirming that there are no obvious missing or severely depleted anodes.

(c)


(d)


(e)


(10)

0-5% LOSS -


6-20% LOSS -


21-50% LOSS -


>50% LOSS -


CP READINGS. Proximity readings are the preferred method. Contact readings are only to be taken where a suitable proximity system is not available. Refer to the workscope for qualification on the method to use, and if in doubt refer to the Shell Offshore Representative for advice, based on recommendations from the relevant Sponsoring Engineer (CP-PRX). Where Reference Proximity readings are taken, an initial contact reading is required. All subsequent readings are to be proximity, unless doubts exist as to the electrical continuity of the locations of the subsequent readings. During the internal survey of the igloo/manifold, should significant areas of bare metal or corrosion be noted, CP readings are to be taken and recorded. Where these areas occur, readings to be restricted to one CP per component. Where no areas of bare metal are evident, or where the inspection is to be conducted by ROV, one CP reading is required on a typical area of major pipework (preferably a flange) and a valve. Locations of these readings are to be recorded, and used for repeat readings in future years. In addition, CP readings are to be taken on two vertical (including diagonals) and two horizontal tubulars. With respect to manifold inspection by ROV, where the internal framework is the same as the external framework, these readings are not required, as they have been covered by the CP’s taken as part of the external survey.

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I 91 002 Page 9 of 23

0153-001

Positions of bare metal, tubular and pipework CP readings obtained are to be clearly shown on structural drawings. (11)


(12)

ROV to monitor and video record the panel closing operation.

Prior to leaving location the ROV will carry out, and fully video record, a general visual survey of the igloo, paying particular attention to the final placement of top panels and fit up. Digital Still Images (PH-DIG) are to be taken of any anomalies or other areas of interest. These may be supplemented by suitable drawings to show the location, size and details of the item of interest.

3.5.3

North Cormorant SSIV Igloo (Pipeline/COABIS Code N0602 (IGL01), IBIS Incident No. 5) In the past diver access has been gained to the igloo through the Control Umbilical opening, on the north side of the igloo. On gaining entry to the interior of the igloo the diver or ROV, as access allows, will carry out and fully video record, a general visual survey of the manifold installation and internal walls of the igloo. The purpose of this survey is to record the following: (1)


(2)


(3)


(4)


(5)


(6)


(7)


(8)


CAUTION:

I 91 002 Page 10 of 23

IN THE EVENT OF A LEAK BEING DISCOVERED, IF DEEMED SAFE TO DO SO AN INSPECTION SHOULD BE CARRIED OUT TO IDENTIFY THE LEAK SOURCE, Am 01 05/05

0153-001

THE RATE OF LEAKAGE AND DAMAGE ASSOCIATED WITH THE LEAK. IF UNSAFE, DIVERS ARE TO BE RECOVERED, WITH THE SURVEY CARRIED OUT BY ROV IF POSSIBLE. ALL LEAKS ARE TO BE TREATED AS 'C1' ANOMALIES AND IMMEDIATELY REPORTED TO THE SHELL OFFSHORE REPRESENTATIVE. (9)


The presence and location of the anodes are to be confirmed as per as-built layout drawings and are to be confirmed as specified. Give an estimated average range of the anode wastage. Not all anodes are expected to be identified. The survey is to confirm all pipework related anodes. The presence of structure anodes is to be confirmed as best a possible, confirming that there are no obvious missing or severely depleted anodes.

(b)


(c)


(d)


(10)

0-5% LOSS -


6-20% LOSS -


21-50% LOSS -


>50% LOSS -


CP READINGS. Proximity readings are the preferred method. Contact readings are only to be taken where a suitable proximity system is not available. Refer to the workscope for qualification on the method to use, and if in doubt refer to the Shell Offshore Representative for advice, based on recommendations from the relevant Sponsoring Engineer (CP-PRX). During the internal survey of the igloo/manifold, should significant areas of bare metal or corrosion be noted, CP readings are to be taken and recorded. Where these areas occur, readings to be restricted to one CP per component. If no bare metal areas are present, take one set of readings on both sides of a flange, and on a typical valve. In addition, CP readings are to be taken on two vertical (including diagonals) and two horizontal tubulars. With respect to manifold inspection by ROV, where the internal framework is the same as the external framework, these readings are not required, as they have been covered by the CP’s taken as part of the external survey.

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I 91 002 Page 11 of 23

0153-001

Positions of bare metal and tubular CP readings obtained are to be clearly shown on structural drawings. (11)


(12)

ROV to monitor and video record the panel closing operation.

Prior to leaving location the ROV will carry out, and fully video record, a general visual survey of the igloo, paying particular attention to the final placement of top panels and fit up.

Digital Still Images (PH-DIG) are to be taken of any anomalies or other areas of interest. These may be supplemented by suitable drawings to show the location, size and details of the item of interest. 4

OPTIONS

4.1

Wall Thickness Readings (WT-DIG) Wall thickness (WT) readings may be requested on specific areas of pipework to check for internal corrosion/erosion. The location, extent and areas of readings to be taken will be specified in the workscope. Method for taking WT readings are as per the standard procedure I-15-002.

5

REPORTING

5.1

Final Report The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above. Reference section 2, Chapter 1, Section 3.1.5. All anomalies are to be referenced, with a general statement made concerning the types and extent of anomalies identified. Any C1 anomalies are to be commented on more specifically. Other references are to be made to any digital still images and drawings. Maximum and minimum range for all other CP readings taken are to be stated, with the readings and their locations clearly shown on structural drawings. The average anode wastage range estimate for all anodes is to be included. Sketches are required, either scanned, AcadLT or other proprietary drawing format, of any major defects or debris that cannot be suitably documented by anomaly report and digital images alone.

I 91 002 Page 12 of 23

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0153-001

KEY: WESTERN LEG GAS 16inch LINE

NORTH CORMORANT

SSIV IGLOO

10inch GAS LINE NW HUTTON

CORMORANT A

PROTECTION COVER E561446 N6769400

SSIV IGLOO E591923 N6767927 STRATHSPEY TIE-IN IGLOO

SSIV IGLOO

WELGAS TEE IGLOO No.2 (8inch AND 10inch)

SPLITTER BOX IGLOO

BRENT A WELGAS TEE IGLOO No.1

NORTH NINIAN

HEATHER

NORTH CENTRAL (STRATHSPEY)

Figure 1

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SSIV Field Location

I 91 002 Page 13 of 23

I 91 002 Page 14 of 23

Figure 2

TO BRENT A

16 INCH GAS PIPELINE

FROM CORMORANT A

9

8

7

6

9

A2

A1

1

A

D

A

1

2

C

2

A

A

A

A

1

1

B2

B1

9

5

4

3

9

UMBILICAL

ANCHOR POINT

12 INCH GAS PIPELINE FROM STRATHSPEY TIE-IN IGLOO

0153-001

General Layout of Brent A SSIV Igloo

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Figure 3

FROM CORMORANT A


TO BRENT A

9

8

7

6

9

A2

A1

1

A

D

A

1

2

C

2

A

A

A

A

1

1

B2

B1

9

5

4

3

9

UMBILICAL

ANCHOR POINT

0153-001

General Layout of Cormorant A SSIV Igloo

I 91 002 Page 15 of 23

I 91 002 Page 16 of 23

Figure 4

TO WELGAS TEE IGLOO No 2


FROM NORTH CORMORANT

9

8

7

6

9

A2

A1

1

A

D

A

1

2

C

2

A

A

A

A

1

1

B2

B1

9

5

4

3

9

UMBILICAL

ANCHOR POINT

0153-001

General Layout of North Cormorant SSIV Igloo

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0153-001

Figure 5

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Hinged Access Panel - General Arrangements

I 91 002 Page 17 of 23

0153-001

Figure 6

I 91 002 Page 18 of 23

Brent A SSIV Igloo - Piping Schematic and Valves

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0153-001

Figure 7

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Cormorant A SSIV Igloo - Piping Schematic and Valves

I 91 002 Page 19 of 23

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Figure 8

I 91 002 Page 20 of 23

North Cormorant SSIV Igloo - Piping Schematic and Valves

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0153-001 A

B

A

B

1 A

A

A

1

D

C

B

PLAN OF SIDE PANELS (ANODE TYPE A)

2 A

A

A

PROTECTION HOUSING ROOF - PANELS (ANODE TYPES A & B)

A

---

2 1

1 B

B

---

---

2

SECTION

SUBSEA SUPPORT FRAME (ANODE TYPE A)

A

---

B

--(ANODE TYPE A)

2 SECTION

A

--(ANODE TYPE A)

PROTECTION HOUSING ROOF SUPPORT FRAME (ANODE TYPE A) 1640 150 ANODE TYPE A 1850

SSIV CONTROL SKID (ANODE TYPE C) ANODES QUANTITIES TYPE A 44 OFF TYPE B 3 OFF TYPE C 5 OFF

VALVE SKID & SPOOL SKID (ANODE TYPE C) 2 NO. ARRANGEMENTS THUS

ANODE TYPE B 1620 120 ANODE TYPE C

Figure 9

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220

SSIV Assembly Anode Locations – Typical

I 91 002 Page 21 of 23

0153-001

A UMBILICAL SUBSEA B TERMINATION CONTROL SKID

KEY PLAN

UMBILICAL TERMINATION TERMINATION SUPPORT CRADLE

PADEYE

B

TIE-BACK BAR BEND RESTRICTOR

OUTER EDGE OF SIDE PANEL CONTROL UMBILICAL SUPPORT RAMP

SECTION A ---

NOTE : FOR DETAILS OF CONTROL PANELS No's 1, 2, 3 REFER TO FIG 11

SUBSEA CONTROL MODULE

(SIDE PANELS REMOVED)

ACCUMULATOR MODULE No 1

B 1

A

3

B

4

UMBILICAL

UMBILICAL SUBSEA TERMINATION

A ---

A ---

A ACCUMULATOR MODULE No 2

UMBILICAL TIEBACK

5 ANCHORTECH PILE

ACCUMULATOR MODULE No 3

2

PART ROOF PLAN SHOWING UMBILICAL ANCHOR POINT PLAN VIEW

Figure 10 Subsea Control Skid – General Arrangements I 91 002 Page 22 of 23

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0153-001 PANEL (2A)

06

ACC. 1

ACC. 3

UST

OPEN

CLOSE

ACTUATOR ACC. 2

SCM.

KEY PLAN SUBSEA CONTROL SKID

SPARE

SUPPLY

PANEL 3

PANEL (2B) PANEL 1

SCM DIRECT

SCM BLEED

SPARE SCM DIRECT

RETURN FUTURE

VENT SUPPLY

SUPPLY FUTURE

ACC 1

X OVER SPARE SUPPLY

FROM PANEL 1

PANEL 1

PANEL 3

VENT

VENT

RETURN

RETURN VENT

VENT SUPPLY

SUPPLY ACC 2

ACC 3

RETURN SUPPLY

RETURN SUPPLY

FROM PANEL 1 PANEL 2(B)

PANEL 2(A)

Figure 11 Subsea Control Skid – General Arrangements

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I 91 002 Page 23 of 23

0153-001

PROCEDURE I 91 003 IGLOO INSPECTION – WELGAS NUMBER 1 AND 2 CONTENTS Para

Page

1

INTRODUCTION

3

2 2.1 2.1.1 2.1.2 2.2

TASK OPTIONS Standard Tasks External Internal Optional Tasks

3 3 3 3 4

3 3.1 3.2 3.3 3.4 3.5

OPERATING PROCEDURE AND SPECIFICATION Inspection Qualifications Location Confirmation External Inspection (VD-ROV / VD-DIV) Roof Access Doors (CN-RPL) Internal Inspection (VD-DIV / VD-ROV)

4 4 4 4 5 6

4 4.1


8 8

FIGURES Figure 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Page Igloo Field Location WELGAS Tee Igloo No 2 (NCHIG) - General Layout WELGAS Tee Igloo No 1 (NHUIG) - General Layout External Anode Positions (both Igloos) Location of External Valve and Control Panels Typical Control Box Layout WELGAS Igloo No 2 (NCHIG) Modified CBIE, CB2E Actuator/Control Box Jumper Typical Arrangement for Valve Actuation of the WELGAS Igloo No 2 (NCHIG) Valves Using Diver Deployed Cross Over Panel Igloo Door Positions and Lifting Points - Typical Lifting Point Hole Dimensions Lifting Point General Arrangement Rigging for Door Opening - Typical WELGAS Igloo No 1 (NHUIG) – Pipework Schematic and Valve Status WELGAS Igloo No 2 (NCHIG) – Pipework Schematic and Valve Status Location of Jacks and CP Readings (both Igloos) Location of CP Readings (both Igloos) Location of Wall Thickness Readings (both Igloos)

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9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25

I 91 003 Page 1 of 25

0153-001

I 91 003 Page 2 of 25

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0153-001

PROCEDURE I 91 003 IGLOO INSPECTION - WELGAS NUMBER 1 AND 2 1

INTRODUCTION The work method is to be applied to the external and internal inspection of the two igloos on the 16 inch Western Leg Gas Pipeline. The work will include damage survey, scour survey, pipeline movement monitoring, leak monitoring, cathodic potential measurements, wall thickness readings, anode survey, video survey and photography. Welgas igloo, number 1, is situated at KP 24.02 on the 16 inch Western Leg Gas Pipeline (UPIS Incident No 798) at position E575699 N6763761. (Pipeline Code N0601, IBIS Incident No. 798, COABIS Code NHUIG, IGL11 / 220-001). (See figure 1). Welgas igloo, number 2, is situated at KP7.171 on the 16 inch Western Leg Gas Pipeline (UPIS Incident No 1034) at position E561417 N6769351. (Pipeline Code N0601, IBIS Incident No. 1034, COABIS Code NCHIG, IGL12 / 220-001). (See figure 1). NDT methods under Procedures I 15 001 and I 15 002 are to be employed in conjunction with this procedure.

2

TASK OPTIONS

2.1

Standard Tasks

2.1.1

External VI-ROV

2.1.2

-

ROV Worksite Check

VD-ROV/DIV -

General Video

DM-SCR

-

Scour Inspection

DB-CHK

-

Visual Debris Check

VI-AW

-


CP-PRX

-

Cathodic Potential Measurements

VI-DVI

-


-


Internal CN-RPL

VD-DIV/ROV -

General Video

CH-VLV

-


CH-LKS

-

Check for Leaks

CP-PRX/CON -


WT-DIG

Ultrasonic Wall Thickness - Digital

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-

I 91 003 Page 3 of 25

0153-001

2.2

VI-AW

-


MG-GEN

-

Marine Growth Inspection

Optional Tasks The following work tasks are optional and will be explicitly called for in the Workscopes, or as a result of finding an anomaly. PH-DIG

-


Any number of combination of the listed work tasks, or those listed under Procedure I 15 001 and I 15 002, may be used or called for on the workscope or during the course of the inspection. Should anomalies be noted, they are to be reported and acted upon as per Section 2, Chapter 6, ‘Anomaly Reporting & Criteria’, and as directed by the Shell Offshore Representative. 3


3.1


3.2

Location Confirmation Inspection data, including the position of the igloo/manifold to be inspected, will be provided by the Shell Inspection department prior to commencement of operations. All inspection data shall be based on International Spheroid, European Datum 1950 (ED50), Transverse Mercator Projection. For the UK Sector, Central Meridian is 0 degrees East. Refer to Section 1, Chapter 2, Figure 1 for further datum shift parameters. On arrival at the worksite, it should be established that the correct structure has been identified, by use of suitable markings on the igloo, or by use of the Shell inspection data provided, and/or field layout drawings to provide other suitable means of confirmation. The Shell Offshore Representative is to be consulted should no markings be present, and the latter method is used to confirm that the correct structure has been identified. If doubt persists as to the correct identification of the igloo/manifold, then a positional fix is to be taken of the as-built fix co-ordinate position, which may not be the centre of the igloo/manifold. Should this fix disagree with the workscope stated position by more than +/-5m, then initiate checks to resolve errors. Such checks should confirm that the vessel's positioning system has been suitably calibrated.

3.3

External Inspection (VD-ROV / VD-DIV) The ROV will carry out, and fully video record, a general visual survey of the igloo installation location. The purpose of this survey is to record the following: (1)

An overall view of the igloo (use of SIT camera) from all sides. This inspection is to check for any gross damage or debris, and to confirm the area is safe for diver intervention. Results of this inspection to be relayed to the dive supervisor (VI-ROV).

On completion of the overall view, a more detailed inspection is to be carried out in colour. (2)

All side and roof panels for any evidence of impact damage. Check all hinges, paying particular attention to the central roof panel which will be later removed. If any concerns regarding the central panel, relay this to the dive supervisor.

(3)

Report on external anode wastage levels, as shown on Figure 4. (VI-AW).

I 91 003 Page 4 of 25

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0153-001 (4)

CP readings on four corner of the structure, proximity or contact. (CP-PRX).

(5)

The entry and exit of the pipelines to the structure, for any evidence of pipeline movement or settlement.

(6)

Scour around the base of the Igloo. Note: There are specific anomaly criteria with respect to igloo/manifold scour. See Section 2, Chapter 6, Point 2.3.12. (DM-SCR).

(7)

Debris (DB-CHK).

(8)

General views are required of the approaches of each pipeline out to 5m from the igloo/manifold, or to the start of protection mattresses or supports, which ever is the lesser. The inspection is to confirm the presence and integrity of any supports, protection bags/mats or point of burial.

On completion of the ROV inspection, the diver is to carry out the following inspections: (9)

Inspect the four external valve remote control panels on the igloo roof. These are located as shown on Figures 4, 5 & 6. (VI-DVI). Clear any debris off the hatch which is made up of two half doors. Open the hatch and visually inspect the control panel. Clear any silt off the control panel. Note any damage or deterioration of the control panel particularly to connections, valves and labels. The pressure gauges are known to be in poor condition and further reporting is not required. For details of the control box layout see Fig 7.

NOTE:

Control panels CB1E and CB2E are redundant on both igloos.

On completion of the visual inspection of each control panel close the two half doors. Digital Still Images (PH-DIG) are to be taken of any anomalies or other areas of interest. These may be supplemented by suitable drawings to show the location, size and details of the item of interest. 3.4

Roof Access Doors (CN-RPL) WARNING:

NOTE:

PRIOR TO ATTEMPTING TO OPEN ANY OF THE FOUR ACCESS DOORS A CLOSE VISUAL AND ELECTROMAGNETIC INSPECTION OF ALL PADEYES ON THE ACCESS DOORS AND ON THE IGLOO STRUCTURE (TIRFOR ATTACHMENT POINTS) IS TO BE CARRIED OUT. SHOULD THE INSPECTION REVEAL ANY ANOMALIES OR DAMAGE THEN THE PADEYE IS NOT TO BE USED, BUT IS TO BE REPLACED WITH A 'U' BOLT LIFTING ARRANGEMENT, REFER TO FIGS 10 AND 11. Where 'u' bolt lifting arrangements are fitted, check security of nuts prior to attaching lifting bag.

On completion of the padeye inspection the diver is to open the access door using the following method: (1)

Install two Tirfors (T516) between the padeyes on the door and at the base of the side panel. Leave the Tirfors loose. See Fig 12.

(2)

Install two 2 ton lift bags on the inboard side of the door. Inflate the bags slowly until the door opens. See Figure 12.

(3)

When the door is open, tighten the restraining Tirfors. At the start of each dive, the lift bags are to be checked and reinflated as necessary.

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ROV to monitor and video record the door opening operation. I 91 003 Page 5 of 25

0153-001 3.5

Internal Inspection (VD-DIV / VD-ROV) Diver access in the past has been gained for both igloos from the pipeline entrance/exit on the Brent Alpha side of the igloo. When a diver enters the igloo, a second diver must remain at the entrance and act as tender. On gaining entry to the interior of the igloo the diver or ROV, as access allows, will carry out and fully video record, a general visual inspection of the manifold installation and internal walls of the igloo. The purpose of this inspection is to record the following: (1)

Pipework. All pipe work and flanges for corrosion and leaks. Particular attention is to be given to the three pipe guides supports, for any evidence of pipe movement through the guide and any corrosion. Pipework schematic is shown on Figure 13 for WELGAS Igloo No 1 (NHUIG) and Figure 14 for WELGAS Igloo No 2 (NCHIG).

(2)

Valves. Each of the 10 valves as shown on Figures 13 and 14 are to be visually inspected. Any leaks or evidence of leaks is to be reported. Where visible, all valve positions are to be noted on video and recorded in the job Completion Report. Figure 13 shows WELGAS 1, Figure 14 shows WELGAS 2.

(3)

Hoses. The two flexible hydraulic hoses between each external control panel and valve actuator are to be visually inspected. (Total 8 hoses). Check connection points, condition of hoses i.e. blistering and cracking. Check for general deterioration.

NOTE:

CAUTION:

(4)

I 91 003 Page 6 of 25

Control boxes CB1E and CB2E are redundant on both WELGAS 1 & 2. As a result at WELGAS 1 (NHUIG), hoses from CB1E and CB2E to valves 10V1 and 10V2 respectively, have been disconnected and blanked off at the valves. IN THE EVENT OF A LEAK BEING DISCOVERED, DIVERS SHOULD BE WITHDRAWN FROM THE AREA AND AN ROV INSPECTION SHOULD BE CARRIED OUT TO IDENTIFY THE LEAK SOURCE, THE RATE OF LEAKAGE AND ANY DAMAGE ASSOCIATED WITH THE LEAK. ALL LEAKS ARE TO BE TREATED AS 'C1' ANOMALIES AND IMMEDIATELY REPORTED TO THE SHELL OFFSHORE OPERATIONS ENGINEER.

Anodes. Carry out an inspection (VI-AW) of the anodes located on the side wall panels, under the roof panels, on the igloo/manifold sub-frame and on the pipeline manifold (VI-AW). The inspection is to record the following: (a)


(b)

The inspection is to confirm all pipework related anodes. The presence of structure anodes is to be confirmed as best a possible, confirming that there are no obvious missing or severely depleted anodes.

(c)


(d)


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0153-001 (e)



(5)

0-5% LOSS -


6-20% LOSS -


21-50% LOSS -


>50% LOSS -


CP Readings. Proximity readings are the preferred method. Contact readings are only to be taken where a suitable proximity system is not available. Refer to the workscope for qualification on the method to use, and if in doubt refer to the Shell Offshore Representative for advice, based on recommendations from the relevant Sponsoring Engineer (CP-PRX). Where Reference Proximity readings are taken, an initial contact reading is required. All subsequent readings are to be proximity, unless doubts exist as to the electrical continuity of the locations of the subsequent readings. During the internal inspection of the igloo/manifold, should significant areas of bare metal or corrosion be noted, CP readings are to be taken and recorded. Where these areas occur, readings to be restricted to one CP per component. In addition, CP readings are to be taken on two vertical (including diagonals) and two horizontal tubulars. Positions of any bare metal, tubular and pipework CP readings obtained are to be clearly shown on structural drawings.

(6)

Contact CP readings are also to be taken on the six clamp support screw jacks (Figure 15) and on valve flanges (Figure 16). Data Sheets are provided within the COABIS database for these results. (CP-CON).

(7)

The diver is to check that the six clamp support screw jacks are not loose, and report any adjustment to be carried out. Location of jacks are as shown on Figure 15. Comment on any pipe clamps which show signs of corrosion. Wire brush any areas where build up of rust would prevent assessment of clamp condition. On completion of inspection and/or adjustment, carry out a video inspection of each clamp support screw jack from all sides to clearly show their condition.

(8)

Ultrasonic wall thickness readings are to be taken at eight locations at both WELGAS 1 and 2, as shown on Figure 17. The areas have had the bitumen coating removed to allow probe access and metal contact. Data Sheets are provided within the COABIS database for these results. (WT-DIG)

(9)

Complete the internal inspection of the igloo structure and walls.

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0153-001 (10)

If access was gained through the roof access doors, on completion of all internal inspection work the doors are to be closed in reverse order to opening procedure. Ensure all diving umbilicals and ROV tether are clear of the door before closing. (CN-RPL).

NOTE: (11)

ROV to monitor and video record the door closing operation.

Prior to leaving location the ROV will carry out, and fully video record, a general visual inspection of the igloo, paying particular attention to the final placement of top covers and fit up.


REPORTING

4.1

Final Report The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above. Reference section 2, Chapter 1, Section 3.1.5. All anomalies are to be referenced, with a general statement made concerning the types and extent of anomalies identified. Any C1 anomalies are to be commented on more specifically. Other references are to be made to any digital still images and drawings. Record the CP and WT readings as required Figures 15, 16 & 17. These are to be completed and included with the final report. Templates for which are contained within the COABIS database. Maximum and minimum range for all other CP readings taken are to be stated, with the readings and their locations clearly shown on structural drawings. The average anode wastage range estimate for all anodes is to be included. Record the position of all valves where identified. Sketches are required, either scanned, AcadLT or other proprietary drawing format, of any major defects or debris that cannot be suitably documented by anomaly report and digital images alone.

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0153-001

Figure 1

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Igloo Field Location

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Figure 2

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WELGAS Tee Igloo No 2 (NCHIG) - General Layout

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Figure 3

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WELGAS Tee Igloo No 1 (NHUIG) - General Layout

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Figure 4

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External Anode Positions (both Igloos)

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0153-001


Location of External Valve and Control Panels I 91 003 Page 13 of 25

0153-001

Figure 6

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Typical Control Box Layout

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0153-001

Figure 7

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WELGAS Igloo No 2 (NCHIG) Modified CBIE, CB2E Actuator/Control Box Jumper Arrangement I 91 003 Page 15 of 25

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Figure 8

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Typical Arrangement for Valve Actuation of the WELGAS Igloo No 2 (NCHIG) Valves Using Diver Deployed Cross Over Panel Am 03 04/06

0153-001

Figure 9

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Igloo Door Positions and Lifting Points - Typical

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Figure 10 Lifting Point Hole Dimensions I 91 003 Page 18 of 25

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0153-001

Figure 11

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Lifting Point General Arrangement

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Figure 12 Rigging for Door Opening - Typical

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0153-001

Figure 13

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WELGAS Igloo No 1 (NHUIG) – Pipework Schematic and Valve Status

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Figure 14 WELGAS Igloo No 2 (NCHIG) – Pipework Schematic and Valve Status I 91 003 Page 22 of 25

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0153-001

Figure 15

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Location of Jacks and CP Readings (both Igloos)

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Figure 16 Location of CP Readings (both Igloos) I 91 003 Page 24 of 25

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0153-001

Figure 17 Location of Wall Thickness Readings (both Igloos)

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0153-001

PROCEDURE I 91 004 IGLOO INSPECTION – 20 INCH FULMAR A TO ST FERGUS GAS PIPELINE CONTENTS Para

Page

1

INTRODUCTION

3

2 2.1 2.1.1 2.1.2 2.2


3 3 3 4 4

3 3.1 3.2 3.3 3.4 3.4.1 3.4.2 3.5 3.5.1 3.5.2 3.5.3 3.5.4 3.5.5 3.5.6 3.5.7

OPERATING PROCEDURE AND SPECIFICATION Inspection Qualification Location Confirmation External Survey (VD-ROV) Diver Access Doors and Roof Panel Doors (CN-RPL) Diver Access Door - Approximate Weight in Air 500 KG Roof Panels - Approximate Weight in Air 4100 KG Internal Survey (VD-ROV / VD-DIV) Kittiwake/Nelson Receiver Tee (KRT) Igloo (Pipeline Code N0202) Gannet Diverter Igloo (Pipeline Code N0202) Deep Gas Diverter Igloo (Pipeline N0202) Emergency Shutdown (ESD) Valve Assembly Igloo (Pipeline N0202) Alternative Gannet Diverter Igloo (Pipeline N0204) Gannet Subsea Isolation Valve (SSIV) Igloo (Pipeline N0204) Anasuria/Gannet Diverter Tie-in Igloo (Pipeline N0205)

4 4 4 5 5 6 6 6 7 9 11 13 15 17 19

4 4.1


21 21

5 5.1


21 21

FIGURES Figure

Page

1

20 inch Fulmar Gas Pipeline Igloo Field Location

22

2

Kittiwake/Nelson Receiver Tee Igloo Site Location

23

3

Gannet Diverter, Alternative Diverter & Diverter Tie-in Igloo Site Layout

24

4

Gannet SSIV Igloo Site Layout

25

5

Deep Gas Diverter Igloo Site Layout

26

6

Fulmar ESDV Igloo Site Layout

27

7

General Layout of Kittiwake Receiver Tee Igloo

28

8

General Layout of Gannet Diverter Igloo

29

9

General Layout of Deep Gas Diverter Igloo

30

10

General Layout of ESD Valve Assembly Igloo

31

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0153-001 11

General Layout of Alternative Gannet Diverter Igloo

32

12

General Layout of Gannet SSIV Igloo

33

13

Anasuria/Gannet Diverter Tie-in Igloo

34

14

Lifting Point General Arrangement - Typical

35

15

Lifting Point Hole Dimensions - Typical

36

16

Kittiwake/Nelson Receiver Tee Igloo - Pipework Schematic and Valve Status

37

17

Gannet Diverter Igloo - Pipework Schematic and Valve Status

39

18

Deep Gas Diverter Igloo - Pipework Schematic and Valve Status

40

19

ESD Valve Assembly Igloo - Pipework Schematic and Valves Status

41

20

Alternative Gannet Diverter Igloo - Pipework Schematic and Valve Status

42

21

Gannet SSIV Igloo - Pipework Schematic and Valves Status

43

22

Anasuria/Gannet Diverter Tie-in Igloo - Pipework Schematic and Valve Status

44

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0153-001

PROCEDURE I 91 004 IGLOO INSPECTION - 20 INCH FULMAR A TO ST FERGUS GAS PIPELINE 1

INTRODUCTION The work method is to be applied to the external and internal inspection of the igloos listed below, which are associated with the 20 inch Fulmar A to the St.Fergus Gas Pipeline, N0202 (See Figure 1). The work will include damage, debris, scour and anode wastage surveys, leak monitoring and Cathodic Potential (CP) measurements. These surveys are to be recorded on video. The following igloos covered under this procedure are: Pipeline N0202:

20 inch Fulmar Alpha to St Fergus Gas Pipeline.

The Kittiwake/Nelson Receiver Tee (KRT) igloo is situated at KP 140.315 at position E529698721 N6367901N6367882 (IBIS Incident No. 3093, COABIS Code - IGL07 / 220-004). (See figure 2) The Gannet Diverter igloo is situated at KP 181.880 at position E558539 N6338251 (IBIS Incident No. 5069, COABIS Code - IGL06 / 220-003). (See figure 3) The Deep Gas Diverter igloo is situated at KP 250.890 at position E605066 N6288311 (IBIS Incident No. 4952, COABIS Code - IGL05 / 220-002). (See figure 5) The Emergency Shutdown (ESD) Valve Assembly igloo is situated at KP 288.080 at position E632225 N6264240 (IBIS Incident No. 4188, COABIS Code - IGL04 / 220-001). (See figure 6) Pipeline N0204:

20 inch Gannet Alpha to Fulmar Alpha Gas Pipeline.

The Alternative Gannet Diverter igloo is situated at KP 1.906 at E558502 N6338215 (IBIS Incident No. 73, COABIS Code - IGL14 / 220-002). (See figure 3)

position

The Gannet SSIV igloo is situated at KP 0.400 at E560045 N6338545 (IBIS Incident No. 27, COABIS Code - IGL13 / 220-001). (See figure 4)

position

Pipeline N0205:

8 inch FPSO Anasuria to Fulmar Alpha Gas Pipeline.

The Anasuria/Gannet Diverter Tie-in Igloo is situated at KP 12.753 at E558476 N6338240 (IBIS Incident No. 02, COABIS Code N0205 / 220-001). (See figure 3) NOTE:

position

The Triton Gas Export Pipeline PLEM (Figure 3) and Deep Gas Diverter Pigging Skid (Figure 5), are not required for inspection under this procedure.

NDT methods under Procedure I 15 001 may be employed in conjunction with this procedure. 2

TASK OPTIONS

2.1


2.1.1

External VI-ROV

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-

ROV Worksite Check

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0153-001

2.1.2

VD-ROV

-

General ROV Video

DM-SCR

-

Scour Survey

DB-CHK

-

Visual Debris Check

CP-PRX

-


Internal VI-ROV

2.2

-

ROV Worksite Check

VD-DIV/ROV -

General ROV Video

CN-RPL

-


CH-VLV

-

Valve Position Checks

CH-LKS

-

Check for Leaks

CP-PRX/CON -


VI-AW

-


MG-GEN

-


Optional Tasks The following work tasks are optional and will be explicitly called for in the Workscopes, or as a result of finding an anomaly. WT-DIG

-


PH-DIG

-


Any number or combination of the listed work tasks, or those listed under Procedure I 15 001, may be used or called for on the workscope or during the course of the inspection. Should anomalies be noted, they are to be reported and acted upon as per Section 2, Chapter 6, ‘Anomaly Reporting & Criteria’, and as directed by the Shell Offshore Representative. 3


3.1

Inspection Qualification The inspection is to be carried out by ROV, under the guidance of a CSWIP 3.3u or 3.4u Inspection Controller, or CSWIP 3.1u/3.2u diver, under the guidance of a CSWIP 3.4u Inspection Controller.

3.2

Location Confirmation Survey data, including the position of the igloo/manifold to be inspected, will be provided by the Shell Survey department prior to commencement of operations. All survey data shall be based on International Spheroid, European Datum 1950 (ED50), Transverse Mercator Projection. For UK Sector Central Meridian is 0 degrees East. Reference Section 1, Chapter 2, Figure 1, for further datum shift parameters. On ROV arrival at the worksite, it should be established that the correct igloo/manifold has been identified, by use of suitable markings on the igloo/manifold itself, or by use of the Shell survey data provided, and/or field layout drawings to provide other suitable means of confirmation. The Shell

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0153-001 Offshore Representative is to be consulted should no markings be present, and the latter method is used to confirm that the correct igloo/manifold has been identified. If doubt persists as to the correct identification of the igloo/manifold, then a positional fix is to be taken of the as-built fix co-ordinate position, which may not be the centre of the igloo/manifold. Should this fix disagree with the workscope stated position by more than +/-5m, then initiate checks to resolve errors. Such checks should confirm that the vessel's positioning system has been suitably calibrated. If required a spin check should be carried out to verify the USBL positioning system. If the spread of the position data is more than the accuracy of the positioning systems, (i.e. DGPS 1-3m & USBL 1% of water depth) checks should be initiated to resolve errors. Prior to this, a CTD profile of the full water column should be observed and the relevant data entered into the USBL system. 3.3

External Survey (VD-ROV) The ROV will carry out, and fully video record, a general visual survey of the igloo/manifold installation location. The purpose of this survey is to record the following: (1)

Confirm igloo/manifold identification if present.

(2)




(4)

Loose or displaced panels paying particular attention to the seating of panels. Check all hinges.

(5)


(6)


(7)


(8)

Debris.

(9)



Diver Access Doors and Roof Panel Doors (CN-RPL) It may be possible for divers and possibly small ROV’s, to enter the igloos through the pipeline entrance/exit ports. If however at the discretion of the divers, dive supervisor or ROV supervisor that this practice is unsafe, it will be necessary to gain access to any of the seven igloos via one of the diver access or door panels on the roof of the igloos to be opened. Door positions are shown in Figures. 7 to 13. NOTE:

Where access has in the past been gained without cause to remove an access panel or door, this is stated at the start of the relevant internal inspection instructions below. For the Alternate Gannet Diverter Igloo and Gannet SSIV, panels have been removed for diver access.

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0153-001 WARNING:

3.4.1

PRIOR TO ATTEMPTING TO OPEN ANY OF THE DIVER ACCESS OR ROOF PANEL DOORS, A CLOSE VISUAL AND ELECTROMAGNETIC INSPECTION OF ALL PADEYES ON THE DOORS AND AS NECESSARY FOR TIRFOR AND TIE BACK ATTACHMENT IS TO BE CARRIED OUT. SHOULD THE INSPECTION REVEAL ANY ANOMALIES OR DAMAGE THEN THE PADEYE IS NOT TO BE USED. REFER TO ALTERNATIVE LIFTING ARRANGEMENTS, FIGS 9 AND 10.

Diver Access Door - Approximate Weight in Air 500 KG WARNING:

PRIOR TO INFLATION OF LIFT BAG, HOLD BACK STROPS MUST BE ATTACHED TO PREVENT ACCIDENTAL BLOW UP AND POSSIBLE UNCONTROLLED ASCENT OF COVER.

On completion of the padeye inspection the diver is to open the diver access door using the following method:

3.4.2

(1)

The Lifting Strop. 1 x Four Leg Sling complete with 4T SWL Master Link assembly made up as follows: 12mm dia. 6x36 galvanized IWRC slings 2.2m long. Each leg tested to 1T SWL. Hard eyes both ends each leg. 3.25T SWL Safety Anchor Shackles at free ends,

(2)

Attach lifting strop to padeyes and using a 500kg lifting bag remove the diver access door and place cover on igloo roof clear of opening. Deflate lift bag.

Roof Panels - Approximate Weight in Air 4100 KG Should it be necessary to open roof panels for access the following procedure is to be carried out: (1)

Install a Tifor (T516) between one of the padeyes on the roof panel (opposite side to the hinges) and a padeye on the igloo top. Leave the Tirfor loose.

(2)

Install two 1000 kg lifting bags on the roof panel padeyes. Inflate the bags slowly until the door opens.

(3)

When the roof panel is open and vertical, tighten the Tirfor to pull panel past the vertical and secure. Slowly deflate bag and lower door to lay flat on top of igloo.

NOTE: 3.5


Internal Survey (VD-ROV / VD-DIV) When a diver enters the igloo, a second diver must remain at the entrance and act as tender.

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0153-001

3.5.1

Kittiwake/Nelson Receiver Tee (KRT) Igloo (Pipeline Code N0202) NOTE:

Diver access has in the past been gained via a roof access hatch. See Figure 7.

On gaining entry to the interior of the igloo the diver or ROV, as access allows, will carry out, and fully video record, a general visual survey of the manifold installation and internal walls of the igloo. The purpose of this survey is to record the following: CAUTION:


(1)

Pipework. All pipework for corrosion and leaks. Particular attention is to be given to the pipe guides and clamps, with any evidence of pipe movement to be reported. The pipework schematic is shown on Figure 16.

(2)

Valves. Each of the 39 valves as shown on Figure 16 are to be visually inspected. Any leaks or evidence of leaks are to be reported (CH-VLV). Where visible, the status (Open or Closed) of all valve positions is to be noted on video. These however are not required to be recorded in the Job Completion Report.

(3)

Blind Flanges. The flanges at the end of the valve manifolds are to be inspected for any evidence of gas leaks.

(4)

Anodes. Carry out an anode inspection (VI-AW) of the anodes which are located on the side wall panels, under the roof panels, on the igloo sub-frame and on the pipeline manifold. The inspection is to record the following: (a) The presence and location of the anodes are to be confirmed as per as-built layout drawings and are to be confirmed as specified. Give an estimated average range of the anode wastage. Refer to Procedure I 60 004 – Cathodic Protection Monitoring, in particular section 4.1.2. (b) Describe marine growth as hard or soft, giving estimated thickness and percentage cover of each anode. (c) The integrity of the anode support (bracket, bracelet, earthing strap) is to be checked. (d) Estimate percentage wastage on each anode using one of the following categories: ANODE DEPLETION SCHEMATIC

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21-50% LOSS -


>50% LOSS -


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0153-001 (5)

Proximity readings are the preferred method. Contact readings are only to be taken where a suitable proximity system is not available. Refer to the workscope for qualification on the method to use, and if in doubt refer to the Shell Offshore Representative for advice, based on recommendations from the relevant Sponsoring Engineer (CP-PRX). During the internal survey of the igloo/manifold, should significant areas of bare metal or corrosion be noted, CP readings are to be taken and recorded. Where these areas occur, readings to be restricted to one CP per component. In addition, CP readings are to be taken on two vertical (including diagonals) and two horizontal tubulars. With respect to manifold inspection by ROV, where the internal framework is the same as the external framework, these readings are not required, as they have been covered by the CPs taken as part of the external survey. Positions of bare metal and tubular CP readings obtained are to be clearly shown on structural drawings.

(6)

On completion of all internal inspection work the panels are to be closed in reverse order to opening procedures. Ensure all diving umbilicals and ROV tether cable are clear of the door before closing (CN-RPL).

NOTE: (7)

ROV to monitor and video record any panel closing operation.

Prior to leaving location the ROV will carry out, and fully video record, a general visual survey of the igloo, paying particular attention to the final placement of top covers and fit up.


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0153-001

3.5.2

Gannet Diverter Igloo (Pipeline Code N0202) NOTE:

Diver access has in the past been gained via a roof access hatch. There is no access through pipeline entrance/exits. See Figure 8.

On gaining entry to the interior of the igloo the diver or ROV, as access allows, will carry out and fully video record, a general visual survey of the manifold installation and internal walls of the igloo. The purpose of this survey is to record the following: CAUTION:

IN THE EVENT OF A LEAK BEING DISCOVERED, DIVERS SHOULD BE WITHDRAWN FROM THE AREA AND AN ROV INSPECTION SHOULD BE CARRIED OUT TO IDENTIFY THE LEAK SOURCE, THE RATE OF LEAKAGE AND DAMAGE ASSOCIATED WITH THE LEAK. ALL LEAKS ARE TO BE TREATED AS 'C1' ANOMALIES AND IMMEDIATELY REPORTED TO THE SHELL OFFSHORE OPERATIONS REPRESENTATIVE.

(1)

Pipework. All pipe work for corrosion and leaks. Particular attention is to be given to the pipe guides and clamps, with any evidence of pipe movement to be reported. The pipework schematic is shown on Fig 17.

(2)

Valves. Each of the 16 valves as shown on Fig 17 are to be visually inspected. Any leaks or evidence of leaks are to be reported (CH-VLV). Where visible, the status (Open or Closed) of all valve positions are to be noted on video. These however are not required to be recorded in the Job Completion Report.

(3)


(4)


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0153-001 (5)

Proximity readings are the preferred method. Contact readings are only to be taken where a suitable proximity system is not available. Refer to the workscope for qualification on the method to use, and if in doubt refer to the Shell Offshore Representative for advice, based on recommendations from the relevant Sponsoring Engineer (CP-PRX). During the internal survey of the igloo/manifold, should significant areas of bare metal or corrosion be noted, CP readings are to be taken and recorded. Where these areas occur, readings to be restricted to one CP per component. In addition, CP readings are to be taken on two vertical (including diagonals) and two horizontal tubulars. With respect to manifold inspection by ROV, where the internal framework is the same as the external framework, these readings are not required, as they have been covered by the CP’s taken as part of the external survey. Positions of bare metal and tubular CP readings obtained are to be clearly shown on structural drawings.

(6)

On completion of all internal inspection work the panels are to be closed in reverse order to opening procedures. Ensure all diving umbilicals and ROV tether cable are clear of the door before closing (CN-RPL). NOTE:

(7)




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0153-001

3.5.3

Deep Gas Diverter Igloo (Pipeline N0202) NOTE:

Diver access has in the past been gained via a roof access hatch. See Figure 9.



(1)

Pipework. All pipework for corrosion and leaks. Particular attention is to be given to the pipe guides and clamps, with any evidence of pipe movement to be reported. The pipework schematic is shown on Fig 18.

(2)

Valves. Each of the 16 valves as shown on Fig 18 are to be visually inspected. Any leaks or evidence of leaks are to be reported (CH-VLV). Where visible, the status (Open or Closed) of all valve positions are to be noted on video. These however are not required to be recorded in the Job Completion Report.

(3)


(4)


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(6)


(7)




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0153-001

3.5.4

Emergency Shutdown (ESD) Valve Assembly Igloo (Pipeline N0202) NOTE:

Diver access has in the past been gained via the Southern pipeline entrance. Access has also been gained by removal of the Northern roof access panel. See Figure 10.



(1)


(2)

Valves. Each of the 8 valves as shown on Fig 19 are to be visually inspected. Any leaks or evidence of leaks are to be reported (CH-VLV). Where visible, the status (Open or Closed) of all valve positions are to be noted on video. These however are not required to be recorded in the job Completion Report.

(3)


(4)


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6-20% LOSS -


21-50% LOSS -


>50% LOSS -


I 91 004 Page 13 of 44

0153-001 (5)


(6)


(7)




I 91 004 Page 14 of 44

Am 03 04/06

0153-001

3.5.5

Alternative Gannet Diverter Igloo (Pipeline N0204) NOTE:

Access has been gained to this igloo via removed roof panel ‘D’. See Figure 11.

NOTE:

The Pipeline entering the Igloo from the North-East (N0202) from the Gannet Diverter is under tension. The pipeline has been rock dumped and a sign exists over its entrance stating this. (See Figures 3, 11 and 20)



(1)

Pipework. All pipe work for corrosion and leaks. Particular attention is to be given to the pipe guides and clamps, with any evidence of pipe movement to be reported. The pipework schematic is shown on Figure 20.

(2)

Valves. Each of the 15 valves as shown on Figure 20 are to be visually inspected. Any leaks or evidence of leaks are to be reported (CH-VLV). Where visible, the status (Open or Closed) of all valve positions are to be noted on video. These however are not required to be recorded in the job Completion Report.

(3)


(4)


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6-20% LOSS -


21-50% LOSS -


>50% LOSS -


I 91 004 Page 15 of 44

0153-001 (5)


(6)


NOTE: (7)




I 91 004 Page 16 of 44

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0153-001

3.5.6

Gannet Subsea Isolation Valve (SSIV) Igloo (Pipeline N0204) NOTE:

Access can be gained to this igloo via a removed panel ‘K’ at the East end. See Figure 12.



(1)


(2)

Valves. The valve as shown on Fig 21 is to be visually inspected. Any leaks or evidence of leaks are to be reported. If visible, the status (Open or Closed) of the valve position is to be noted on video. This however is not required to be recorded in the job Completion Report.

(3)

Hydraulics. All subsea control box-interfaces and controls from the umbilical termination, accumulator bank and EIV actuator, along with hydraulic accumulator, electro/hydraulic cables/tubing are to be inspected and checked for leakage, damage, corrosion and signs of movement. Check connection points, condition of hoses i.e. blistering and cracking and for general deterioration. Check any continuity straps.

(4)

Umbilical Termination Unit. The unit is to be inspected for damage and any sign of movement. Check any continuity straps.

(5)


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6-20% LOSS -


21-50% LOSS -


>50% LOSS -


I 91 004 Page 17 of 44

0153-001 (6)


(7)


NOTE: (8)




I 91 004 Page 18 of 44

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0153-001

3.5.7

Anasuria/Gannet Diverter Tie-in Igloo (Pipeline N0205) NOTE:

Diver access has in the past been gained via the Northern roof panel. See Figure 13.



(1)


(2)

Valves. Each of the 24 valves as shown on Fig 22 are to be visually inspected. Any leaks or evidence of leaks are to be reported. Where visible, the status (Open or Closed) of all valve positions are to be noted on video. These however are not required to be recorded in the job Completion Report.

(3)


(4)

Non Return Valve. The non return valve (TDCV-01) as shown in Fig 22 is to be visually inspected for any evidence of gas leaks.

(5)

Anodes. Carry out an anode inspection (VI-AW) of the anodes which are located on the side wall panels, under the roof panels, on the igloo sub-frame and on the pipeline manifold. The inspection is to record the following: (a) The presence and location of the anodes are to be confirmed as per as built layout drawings and are to be confirmed as specified. Give an estimated average range of the anode wastage. Refer to Procedure I 60 004 – Cathodic Protection Monitoring, in particular section 4.1.2. (b) Describe marine growth as hard or soft, giving estimated thickness and percentage cover of each anode. (c) The integrity of the anode support (bracket, bracelet, earthing strap) is to be checked.

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I 91 004 Page 19 of 44

0153-001 (d) Estimate percentage wastage on each anode using one of the following categories: ANODE DEPLETION SCHEMATIC

(6)

0-5% LOSS -


6-20% LOSS -


21-50% LOSS -


>50% LOSS -



(7)


NOTE: (8)




I 91 004 Page 20 of 44

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0153-001

4

OPTIONS

4.1


5

REPORTING

5.1

Final Report The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above. Reference Section 2, Chapter 1, Section 3.1.5. All anomalies are to be referenced, with a general statement made concerning the types and extent of anomalies identified. Any C1 anomalies are to be commented on more specifically. Other references are to be made to any digital still images and drawings. Maximum and minimum range for all other CP readings taken are to be stated, with the readings and their locations clearly shown on structural drawings. The average anode wastage range estimate for all anodes is to be included. Sketches are required, either scanned, AcadLT or other proprietary drawing format, of any major defects or debris that cannot be suitably documented by anomaly report and digital images alone.

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I 91 004 Page 21 of 44

0153-001

Figure 1

I 91 004 Page 22 of 44

20 inch Fulmar Gas Pipeline Igloo Field Location

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0153-001

Figure 2

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Kittiwake/Nelson Receiver Tee Igloo Site Location

I 91 004 Page 23 of 44

0153-001

Figure 3

I 91 004 Page 24 of 44

Gannet Diverter, Alternative Diverter & Diverter Tie-in Igloo Site Layout

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0153-001

Figure 4

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Gannet SSIV Igloo Site Layout

I 91 004 Page 25 of 44

0153-001


Deep Gas Diverter Igloo Site Layout Am 03 04/06

0153-001

Figure 6

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Fulmar ESDV Igloo Site Layout

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0153-001

Figure 7

I 91 004 Page 28 of 44

General Layout of Kittiwake Receiver Tee Igloo

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0153-001

Figure 8

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General Layout of Gannet Diverter Igloo

I 91 004 Page 29 of 44

0153-001

Figure 9

I 91 004 Page 30 of 44

General Layout of Deep Gas Diverter Igloo

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0153-001

Figure 10 Am 03 04/06

General Layout of ESD Valve Assembly Igloo I 91 004 Page 31 of 44

0153-001

Figure 11 General Layout of Alternative Gannet Diverter Igloo I 91 004 Page 32 of 44

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0153-001

Figure 12 Am 03 04/06

General Layout of Gannet SSIV Igloo I 91 004 Page 33 of 44

0153-001

B2

From Triton PLEM

A2

A1

B1

To Alternative Gannet Diverter

N From Anasuria PLEM

Figure 13 Anasuria/Gannet Diverter Tie-in Igloo

I 91 004 Page 34 of 44

Am 03 04/06

DIVERS HATCH (TYPICAL)

ROOF PANEL (TYPICAL)

HINGE (TYPICAL)

SLING ACCESS HOLES CUT IN GRATING (TYPICAL)

0153-001

Figure 14 Lifting Point General Arrangement - Typical

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I 91 004 Page 35 of 44

Hole cut in grate

I 91 004 Page 36 of 44

Detail 'A'

Detail at 'A'

12mm DIA. (6x36 galvanized IWRC) Strop 2m long Tested to 1T SWL with soft eye each end

Igloo (Typical)

Hinges

Roof Panel (Typical)

1000KG Lift Bags

0153-001

Figure 15 Lifting Point Hole Dimensions - Typical

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0153-001

Figure 16 Kittiwake/Nelson Receiver Tee Igloo - Pipework Schematic and Valve Status

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I 91 004 Page 37 of 44

0153-001

I 91 004 Page 38 of 44

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0153-001

Figure 17 Gannet Diverter Igloo - Pipework Schematic and Valve Status Am 03 04/06

I 91 004 Page 39 of 44

0153-001

Figure 18

I 91 004 Page 40 of 44

Deep Gas Diverter Igloo - Pipework Schematic and Valve Status

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0153-001

Figure 19 Am 03 04/06

ESD Valve Assembly Igloo - Pipework Schematic and Valves Status I 91 004 Page 41 of 44

0153-001


Alternative Gannet Diverter Igloo - Pipework Schematic and Valve Status Am 03 04/06

0153-001

Figure 21 Gannet SSIV Igloo - Pipework Schematic and Valves Status

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I 91 004 Page 43 of 44

0153-001

Figure 22

I 91 004 Page 44 of 44

Anasuria/Gannet Diverter Tie-in Igloo - Pipework Schematic and Valve Status

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0153-001

PROCEDURE I 91 005 IGLOO INSPECTION - SUBSEA UMBILICAL SPLITTER BOX BRENT ALPHA 1

INTRODUCTION The work method is to be applied to the external and internal inspection of the Brent Alpha Subsea Umbilical Splitter Box Igloo. The work will include damage survey, scour survey, umbilical movement monitoring, leak monitoring, Cathodic Potential (CP) measurements, anode survey and video survey. The arrangement of the Splitter Box protection structure allows for easy internal access by ROV. As such this procedure assumes that the inspection will be carried out by ROV only, however should it be necessary then the inspection can be carried out by diver. The Brent Alpha Subsea Umbilical Splitter Box Igloo is situated at KP 0.0 on the control umbilical for the Brent A SSIV (Pipeline/COABIS Codes - N0830/IGL08), at position E592060 N6768087 (See Fig 01).

2

TASK OPTIONS

2.1

External

2.2

VI-ROV

-

ROV Worksite Check

VI-GVI

-


CP-PRX

-

Cathodic Potential Proximity Measurements

DM-SCR

-

Scour Survey

DB-CHK

-

Visual Debris Check

VI-GVI

-


CH-LKS

-

Check for Leaks

CP-PRX/CON

-


VI-AW

-


MG-GEN

-


Internal

Should additional activities be carried out or incidents noted, suitable work tasks and task codes may be added to cover works. Should anomalies be noted, they are to be reported and acted upon as per Section 2, Chapter 6, ‘Anomaly Reporting & Criteria’, and as directed by the Shell Offshore Representative. 3

OPERATING PROCEDURE AND SPECIFICATION Note:

Am 04 04/08

Refer to figures below and to the Igloos and Subsea Facilities UMDB (0144-001), Section 5 for drawings and component numbering details relevant to the Subsea Umbilical Splitter Box.

I 91 005 Page 1 of 8

0153-001

3.1


3.2

Location Confirmation Survey data, including the position of the Subsea Umbilical Splitter Box, will be provided by the Shell Survey department prior to commencement of operations. All survey data shall be based on International Spheroid, European Datum 1950 (ED50), Transverse Mercator Projection. For UK Sector Central Meridian is 0 degrees East. Reference Section 1, Chapter 2, Figure 1, for further datum shift parameters. On ROV arrival at the worksite, it should be established that the correct igloo has been identified, by use of suitable markings on the igloo itself, or by use of the Shell survey data provided, and/or field layout drawings to provide other suitable means of confirmation. The Shell Offshore Representative is to be consulted should no markings be present, and the latter method is used to confirm that the correct igloo has been identified. If doubt persists as to the correct identification of the igloo, then a positional fix is to be taken of the asbuilt fix co-ordinate position, which may not be the centre of the igloo. Should this fix disagree with the workscope stated position by more than +/-5m, then initiate checks to resolve errors. Such checks should confirm that the vessel's positioning system has been suitably calibrated. If required a spin check should be carried out to verify the USBL positioning system. If the spread of the position data is more than the accuracy of the positioning systems, (i.e. DGPS 1-3m & USBL 1% of water depth) checks should be initiated to resolve errors. Prior to this, a CTD profile of the full water column should be observed and the relevant data entered into the USBL system.

3.3

External Survey (VI-GVI) The ROV will carry out, and fully video record, a general visual inspection of the splitter box igloo protection structure location (See Fig. 2). The purpose of this inspection is to record the following: (1)

Confirm igloo identification if present.

(2)

An overall view of the igloo (use of SIT camera) from all sides. This inspection is to check for any gross damage or debris, and to confirm the area is safe for further intervention (VI-ROV). Results of this inspection are to be relayed to the diver supervisor as required. On completion of the overall view, a more detailed inspection is to be carried out in colour.

(3)


(4)

Security of the roof panel.

(5)

The entry and exit of the umbilicals to the structure for any evidence of movement.

(6)

Scour around the base of the structure (DM-SCR). Note: There are specific anomaly criteria with respect to igloo scour. See Section 2, Chapter 6, Point 2.3.12.

(7)

CP readings on four corners of the structure and the roof panel, proximity or contact (CP-PRX).

(8)

Debris (DB-CHK). Structure and adjacent seabed.

(9)

General views are required of the approaches of each umbilical out to 5m from the igloo, or to the start of protection mattresses, which ever is the lesser. The inspection is to confirm the presence and integrity of any supports, protection bags/mats or point of burial.

I 91 005 Page 2 of 8

Am 04 04/08

0153-001

Digital Still Images are to be taken of any anomalies or other areas of interest. These may be supplemented by suitable drawings to show the location, size and details of the item of interest. 3.3.1

Internal Survey (VI-GVI) The igloo is of an open design with only a roof panel for protection of the Subsea Umbilical Splitter Box, therefore it is not necessary to remove any panels for diver or ROV to gain access. Refer to Fig 2 for igloo general arrangements. On gaining entry to the interior of the igloo the diver or ROV, as access allows, will carry out and fully video record, a general visual inspection of the Subsea Umbilical Splitter Box and igloo subframe (See Figs. 2, 3 and 4). The purpose of this inspection is to record the following: CAUTION:

In the event of a leak being discovered, divers should be withdrawn from the area and an ROV inspection should be carried out to identify the leak source, the rate of leakage and any damage associated with the leak. All leaks are to be treated as ‘C1’ anomalies and immediately reported to the Shell Offshore Representative.

(1)

Subsea Umbilical Splitter Box. The splitter box as shown on Fig 4 is to be visually inspected. Any leaks or evidence of leaks is to be reported.

(2)

Umbilical Terminations. The three umbilical termination blocks are to be visually inspected. Any leaks or evidence of leaks are to be reported. Check connection points, condition of hoses i.e. blistering and cracking and for general deterioration.

(3)

Anodes (VI-AW). Carry out an anode inspection of the anodes which are located under the roof panel, on the igloo subframe and on the splitter box frame assembly, (Refer to Figs 2, 3 and 4). The inspection is to record the following: (a)

The presence and location of the anodes are to be confirmed as per as-built layout drawings and are to be confirmed as specified. Give an estimated average range of the anode wastage. Refer to Procedure I 60 004 – Cathodic Protection Monitoring, in particular section 4.1.2.

(b)


(c)


(d)


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>50% LOSS -


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0153-001

(4)

CP Readings (CP-PRX/CON). Proximity readings are the preferred method. Contact readings are only to be taken where a suitable proximity system is not available. Refer to the workscope for qualification on the method to use, and if in doubt refer to the Shell Offshore Representative for advice, based on recommendations from the relevant Sponsoring Engineer. Where Reference Proximity readings are taken, an initial contact reading is required. All subsequent readings are to be proximity, unless doubts exist as to the electrical continuity of the locations of the subsequent readings. A CP reading is required of the Splitter Box itself (Figs. 2 and 4). During the internal inspection of the igloo, should significant areas of bare metal or corrosion be noted, CP readings are to be taken and recorded. Where these areas occur, readings to be restricted to one CP per component. Where no areas of bare metal are evident, one CP reading is required on a typical area of major pipework (preferably a flange) and on the splitter box base. Locations of these readings are to be recorded and used for repeat readings in future years. In addition, CP readings are to be taken on two vertical (including diagonals) and two horizontal tubulars. With respect to igloo inspection by ROV, where the internal framework is the same as the external framework, these readings are not required, as they have been covered by the CPs taken as part of the external inspection. Positions where readings are obtained, including bare metal and tubular CPs are to be clearly shown on structural drawings.

(5)

If diver intervention has occurred, prior to leaving location the ROV will carry out, and fully video record, a general visual inspection of the igloo and subsea umbilical splitter box to show that no diver tools/rigging has been left.

Digital Still Images are to be taken of any anomalies or other areas of interest. These may be supplemented by suitable drawings to show the location, size and details of the item of interest. 3.4

Final Report The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above. Reference Section 2, Chapter 7. All anomalies are to be referenced, with a general statement made concerning the types and extent of anomalies identified. Any C1 anomalies are to be commented on more specifically. Other references are to be made to any digital still images and drawings. Maximum and minimum range for all other CP readings taken are to be stated, with the readings and their locations clearly shown on structural drawings. The average anode wastage range estimate for all anodes is to be included. Sketches are required, either scanned, AcadLT or other proprietary drawing format, of any major defects or debris that cannot be suitably documented by anomaly report and digital images alone.

I 91 005 Page 4 of 8

Am 04 04/08

0153-001 591750E

592000E

592250E

N 16 O "T BR EN T

6768250N

AR SP

SUBSEA UMBILICAL SPLITTER BOX IGLOO E592060 N6768087

20" GAS FROM MAGNUS (BP)

BRENT 'A' /BP UMBILICAL L

CA

I IL

B

NT

' 'A

UM

O ST GA ARE " 8 2 FL NT RE

E BR

BRENT 'A' J-TUBE UMBILICAL BRENT 'A' SSIV

B

6768000N BRENT 'A'

'A

36" GAS

6767750N

CO

N CE

RM

OR

AN

NINIA

T

ROM

'

AS F

16" G

TO ST F E

RGUS

STRATHSPEY TIE-IN IGLOO

FR

OM

NTRA

16

"G

AS

P ATHS L (ST EY)

Figure 1

Am 04 04/08

Subsea Umbilical Splitter Box Igloo Field Location

I 91 005 Page 5 of 8

0153-001

ANODE DETAIL 001 - 002 - 009 TO 014 SEE FIG 3 4

010

ANODE DETAIL 003 TO 008 SEE FIG 3

6 5 009 005 2

004

008 003 007 3

006 2 1 BASE

L

ICA

2 M30 BOLTS C/W No SPACERS WASHERS & 1 No NUT

IL MB

'U

T 'A

L

ICA

N RE

B

BP

3 FRAME

'/ T 'A

IL MB

U

EN

4 COVER RETAINING PIN

BR

7

5 RETAINING PL C/W 2 No SCREWS 6 COVER

001

012

011

7 SPLITTER BOX BE

TU

T

EN

J'A'

BR

L

CA

I BIL

1

UM

002

014

013


Umbilical Junction Protection Frame - General Arrangement Am 04 04/08

0153-001

ANODE DETAIL 001 - 002 - 009 - 010 1580 (MODIFIED ANODE) 009 & 010 1370 (MODIFIED ANODE) 001 & 002

235

ANODE DETAIL 003 TO 008

1775

230

Figure 3

Am 04 04/08

Anode Dimensions

I 91 005 Page 7 of 8

0153-001

SIDE VIEW ANODE (TYP) BRENT 'A' UMBILICAL

BRENT 'A'/BP UMBILICAL

PLAN VIEW

BRENT 'A' J-TUBE UMBILICAL

FRONT VIEW

Figure 4

I 91 005 Page 8 of 8

Splitter Box

Am 04 04/08

0153-001

PROCEDURE I 91 007 IGLOO / MANIFOLD INSPECTION - GENERAL CONTENTS Para.

Page

1

INTRODUCTION

3

2 2.1 2.1.1 2.1.2 2.2


3 3 3 3 4

3 3.1 3.2 3.3

OPERATING PROCEDURE AND SPECIFICATION Inspection Qualifications External Survey (VD-ROV) Internal Survey (VD-ROV / VD-DIV)

4 4 4 5

4 4.1


7 7

5 5.1


7 7

Am 01 05/05

I 91 007 Page 1 of 8

0153-001

I 91 007 Page 2 of 8

Am 01 05/05

0153-001

PROCEDURE I 91 007 IGLOO / MANIFOLD INSPECTION - GENERAL 1

INTRODUCTION The work method is to be applied to the external and internal inspection of an igloo/manifold, and of submarine pipelines and umbilicals, which converge at an igloo/manifold. The work will include damage survey, Cathodic Potential measurements, and anode survey; scour survey and general video survey. Intervention under Procedure I 90 002 may be employed in conjunction with this procedure. NDT methods under Procedure I 15 001 and I 15 002 may be employed in conjunction with this procedure.

2

TASK OPTIONS

2.1


2.1.1

2.1.2

External VI-ROV

-

ROV Worksite Check

VD-ROV

-

General ROV Video

DM-SCR

-

Scour Survey

DB-CHK

-

Visual Debris Check

CP-PRX

-

Proximity CP Readings

VI-ROV

-

ROV Worksite Check

VD-DIV/ROV

-

General Video

CN-RPL

-


VI-AW

-


MG-GEN

-


CP-PRX

-

Proximity CP Readings

CH-LKS

-

Check For Leaks

CH-VLV

-

Valve Status Checks

Internal

Am 01 05/05

I 91 007 Page 3 of 8

0153-001

2.2

Optional Tasks The following work tasks are optional and will be explicitly called for in the Workscope, or as a result of finding an anomaly. WT-DIG

-


PH-DIG

-


Any number or combination of the listed work tasks, or those listed under Procedures I 15 001, I 15 002 and I 90 002, may be used or called for on the workscope or during the course of the inspection. Should anomalies be noted, they are to be reported and acted upon as per Section 2, Chapter 6, ‘Anomaly Reporting & Criteria’, and as directed by the Shell Offshore Representative. 3


3.1


3.2

External Survey (VD-ROV) Survey data, including the position of the igloo/manifold to be inspected, will be provided by the Shell Survey department prior to commencement of operations. All survey data shall be based on International Spheroid, European Datum 1950 (ED50), Transverse Mercator Projection. For UK Sector Central Meridian is 0 deg and for Dutch Sector Central Meridian is 5deg E. Reference Section 1, Chapter 2, Figure 1, for further datum shift parameters. On arrival at the worksite, it should be established that the correct igloo/manifold has been identified, by use of suitable markings on the igloo/manifold itself, or by use of the Shell survey data provided, and/or field layout drawings to provide other suitable means of confirmation. The Shell Offshore Representative is to be consulted should no markings be present, and the latter method is used to confirm that the correct igloo/manifold has been identified. If doubt persists as to the correct identification of the igloo/manifold, then a positional fix is to be taken of the as-built fix co-ordinate position, which may not be the centre of the igloo/manifold. Should this fix disagree with the workscope stated position by more than +/-5m, then initiate checks to resolve errors. Such checks should confirm that the vessel's positioning system has been suitably calibrated. If required a spin check should be carried out to verify the USBL positioning system. If the spread of the position data is more than the accuracy of the positioning systems, (i.e. DGPS 1-3m & USBL 1% of water depth) checks should be initiated to resolve errors. Prior to this, a CTD profile of the full water column should be observed and the relevant data entered into the USBL system. The ROV will carry out, and fully video record, a general visual survey of the igloo/manifold installation location. The purpose of this survey is to record the following: (1)

Confirm igloo/manifold identification if present.

(2)


On completion of the overall view, a more detailed survey is to be carried out in colour. (3) I 91 007 Page 4 of 8

Structure for any evidence of impact damage. Check for leaks. Am 01 05/05

0153-001

(4)

Loose or displaced panels paying particular attention to the seating of panels at the roof interface. Check all hinges.

(5)


(6)

Anode condition if visible.

(7)


(8)


(9)

Debris.

(10)



Internal Survey (VD-ROV / VD-DIV) WARNING:

PRIOR TO ATTEMPTING TO OPEN ANY ACCESS DOORS OR PANELS A CLOSE VISUAL AND/OR ELECTROMAGNETIC INSPECTION OF ALL PADEYES ON THE DOORS AND PANELS, AS NECESSARY FOR TIRFOR AND TIE BACK ATTACHMENT, IS TO BE CARRIED OUT. SHOULD THE INSPECTION REVEAL ANY ANOMALIES OR DAMAGE THEN THE PADEYE IS NOT TO BE USED. VISUALLY INSPECT ANY HINGE ARRANGEMENTS FOR SECURITY, RETIGHTEN ALL BOLTS AS NECESSARY. SHOULD THERE BE EVIDENCE OF DAMAGE TO THE HINGE ARRANGEMENT, CARRY OUT A CLOSE VISUAL AND/OR ELECTROMAGNETIC INSPECTION. REPORT ALL ANOMALIES NOTED TO THE SHELL OFFSHORE REPRESENTATIVE. SPECIFIC ENTRY PROCEDURES WILL BE ISSUED BY THE RESPONSIBLE STRUCTURAL ENGINEER PRIOR TO COMMENCEMENT OF WORKS.

When a diver enters an igloo/manifold, a second diver must remain at the entrance and act as tender. On gaining entry to the interior of the igloo/manifold, consisting of in part or all, the following items, the diver or ROV, as access allows, will carry out and fully video record, a general visual survey of the manifold installation and internal framework of the igloo/manifold. The purpose of this survey is to record the following, where the relevant components listed below exist: CAUTION:

In the event of a leak being discovered, divers should be withdrawn from the area and an ROV inspection should be carried out to identify the leak source, the rate of leakage and damage associated with the leak. All leaks are to be treated as 'C1' anomalies and immediately reported to the Shell Offshore Representative.

(1)

PIPEWORK. All pipe work for corrosion and leaks. Particular attention is to be given to the pipe guides and clamps with any evidence of pipe movement to be reported.

(2)

VALVES. All valves are to be visually inspected. Any leaks or evidence of leaks is to be reported (CH-VLV). Where visible, all valve positions are to be noted on video. These however are not required to be recorded in the job Completion Report.

(3)

ACCUMULATOR MODULES. All accumulator modules are to be visually inspected. Any leaks or evidence of leaks is to be reported. Check continuity Straps.

Am 01 05/05

I 91 007 Page 5 of 8

0153-001

(4)

CONTROL MODULE. All Control Modules are to be visually inspected. Any leaks or evidence is to be reported. Check continuity Straps.

(5)

HOSES. Check connection points, condition of hoses i.e. blistering and cracking and for general deterioration.

(6)

HYDRAULIC DISTRIBUTION MANIFOLDS. All hydraulic distribution manifolds are to be visually inspected. Any leaks or evidence of leaks are to be reported.

(7)

UMBILICAL TERMINATION MODULE/ASSEMBLY. All Umbilical Termination Modules/ Assemblies (UTM / UTA / BUTA) are to be visually inspected. Any leaks or evidence of leaks are to be reported. Where necessary the module's support cradle is to be checked for security, as is the umbilical support ramp, bend restrictor and attachments.

(8)

FLANGES. All flanges are to be visually inspected. Any leaks or evidence of leaks are to be reported.

(9)

Check for the presence and integrity of all continuity Straps. These are usually to be found at clamps, and appurtenances such as modules, UTM/UTA/BUTA’s. Anomalies are only to be generated should it be obvious that the straps are missing from as designed, or if there are Cathodic Potential concerns.

(10)

Anodes. Carry out an anode inspection (VI-AW) of the anodes, which are located on the sidewall panels, under the roof panels, on the igloo/manifold sub-frame and on the pipeline manifold (VI-AW). The inspection is to record the following: (a)


(b)

Refer to Procedure I 60 004 – Cathodic Protection Monitoring, in particular section 4.1.2.

(c)


(d)


(e)

(Estimate percentage wastage on each anode using one of the following categories: ANODE DEPLETION SCHEMATIC

I 91 007 Page 6 of 8

0-5% LOSS -


6-20% LOSS -


21-50% LOSS -


>50% LOSS -


Am 01 05/05

0153-001

(11)

Proximity readings are the preferred method. Contact readings are only to be taken where a suitable proximity system is not available. Refer to the workscope for qualification on the method to use, and if in doubt refer to the Shell Offshore Representative for advice, based on recommendations from the relevant Sponsoring Engineer (CP-PRX). Where Reference Proximity readings are taken, an initial contact reading is required. All subsequent readings are to be proximity, unless doubts exist as to the electrical continuity of the locations of the subsequent readings. During the internal survey of the igloo/manifold, should significant areas of bare metal or corrosion be noted, CP readings are to be taken and recorded. Where these areas occur, readings to be restricted to one CP per component. Where no areas of bare metal are evident, or where the inspection is to be conducted by ROV, one CP reading is required on a typical area of major pipework (preferably a flange) and a valve. Locations of these readings are to be recorded, and used for repeat readings in future years. In addition, CP readings are to be taken on two vertical (including diagonals) and two horizontal tubulars. With respect to manifold inspection by ROV, where the internal framework is the same as the external framework, these readings are not required, as they have been covered by the CP’s taken as part of the external survey. Positions of bare metal, tubular and pipework CP readings obtained are to be clearly shown on structural drawings.

(12)

On completion of all internal inspection work the doors are to be closed in reverse order to opening procedures. Ensure all diving umbilicals and ROV tether cable are clear of the door before closing (CN-RPL). NOTE:

(13)

ROV to monitor and video record the door closing operation.

Prior to leaving location the ROV will carry out, and fully video record, a general visual survey of the igloo/manifold, paying particular attention to the final placement of top covers and fit up.


OPTIONS

4.1


5

REPORTING

5.1

Final Report The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above. Reference section 2, Chapter 1, Section 3.1.5. All anomalies are to be referenced, with a general statement made concerning the types and extent of anomalies identified. Any C1 anomalies are to be commented on more specifically. Other references are to be made to any digital still images and drawings.

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Maximum and minimum range for all other CP readings taken are to be stated, with the readings and their locations clearly shown on structural drawings. The average anode wastage range estimate for all anodes is to be included. Sketches are required, either scanned, AcadLT or other proprietary drawing format, of any major defects or debris that cannot be suitably documented by anomaly report and digital images alone.

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0153-001

PROCEDURE I 91 008 IGLOO INSPECTION - BRENT SPAR MANIFOLD - ROV 1

INTRODUCTION The work method is to be applied to the external and internal inspection of the Brent Spar manifold protection cover igloo and the original Brent Spar base, manifold and pipework. The work will include damage survey, scour survey, leak monitoring, Cathodic Potential (CP) measurements, anode survey and general video survey. The arrangement of the Brent Spar Manifold allows for easy internal access by ROV. As such this procedure assumes that the inspection will be carried out by ROV only, however should it be necessary then the inspection can be carried out by diver. The Brent Spar Igloo (Pipeline/COABIS Codes - N0301/IGL719) is situated at KP2.910, being the joining point of the 16 inch Oil Pipelines from Brent A (N0301) and Brent B (N0302) at position E 590047 N 6770105 (See Fig 1). NOTE:

These lines are now used as a Drains Export from Brent Alpha to Brent Bravo. As such the pipeline is at low pressure and contains predominantly water, which may contain traces of oil.

2

TASK OPTIONS

2.1

External

2.2

VI-ROV

-

ROV Worksite Check

VI-GVI

-


CP-PRX

-


DM-SCR

-

Scour Survey

DB-CHK

-

Visual Debris Check

VI-GVI

-


CH-LKS

-

Check for Leaks

CH-VLV

-

Valve Status Checks

Internal

CP-PRX/CON -


VI-AW -


MG-GEN

-


Should additional activities be carried out or incidents noted, suitable work tasks and task codes may be added to cover works. Should anomalies be noted, they are to be reported and acted upon as per Section 2, Chapter 6, ‘Anomaly Reporting & Criteria’, and as directed by the Shell Offshore Representative.

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0153-001

3

OPERATING PROCEDURE AND SPECIFICATION NOTE:

3.1

Refer to figures below and to the Igloos and Subsea Facilities UMDB (0144-001), Section 10 for drawings and component numbering details relevant to the Brent Spar Manifold.

Inspection Qualification The inspection is to be carried out by ROV, under the guidance of a CSWIP 3.3u or 3.4u Inspection Controller, or CSWIP 3.1u/3.2u diver, under the guidance of a CSWIP 3.4u Inspection Controller.

3.2

Location Confirmation Survey data, including the position of the Brent Spar manifold, will be provided by the Shell Survey department prior to commencement of operations. All survey data shall be based on International Spheroid, European Datum 1950 (ED50), Transverse Mercator Projection. For UK Sector Central Meridian is 0 degrees East. Reference Section 1, Chapter 2, Figure 1, for further datum shift parameters. On ROV arrival at the worksite, it should be established that the correct manifold has been identified, by use of suitable markings on the manifold itself, or by use of the Shell survey data provided, and/or field layout drawings to provide other suitable means of confirmation. The Shell Offshore Representative is to be consulted should no markings be present, and the latter method is used to confirm that the correct manifold has been identified. If doubt persists as to the correct identification of the manifold, then a positional fix is to be taken of the as-built fix co-ordinate position, which may not be the centre of the manifold. Should this fix disagree with the workscope stated position by more than +/-5m, then initiate checks to resolve errors. Such checks should confirm that the vessel's positioning system has been suitably calibrated. If required a spin check should be carried out to verify the USBL positioning system. If the spread of the position data is more than the accuracy of the positioning systems (i.e. DGPS 1-3m & USBL 1% of water depth) checks should be initiated to resolve errors. Prior to this, a CTD profile of the full water column should be observed and the relevant data entered into the USBL system.

3.3

External Survey (VI-GVI) The ROV will carry out, and fully video record, a general visual inspection of the manifold igloo protection structure location (See Fig.2). The purpose of this inspection is to record the following: (1)


(2)

An overall view of the igloo (use of SIT camera) from all sides. This inspection is to check for any gross damage or debris, and to confirm the area is safe for further intervention (VI-ROV). On completion of the overall view, a more detailed inspection is to be carried out in colour.

(3)


(4)

Loose or displaced panels paying particular attention of the seating of panels at the roof interface.

(5)

The entry and exit of the pipelines to the structure, for any evidence of pipeline movement or panel settlement.

(6)


(7)

Location and condition of any concrete covers, submats or grout bag supports.

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0153-001

(8)

CP readings on four corners of the structure, proximity or contact, and of the roof and four side panels. (CP-PRX).

(9)

Debris (DB-CHK).

(10)

General views are required of the approaches of each pipeline out to 5m from the igloo, or to the start of protection mattresses, which ever is the lesser. The inspection is to confirm the presence and integrity of any supports, protection bags/mats or point of burial.


Internal Survey (VI-GVI) The igloo structure has been fabricated to allow easy access for ROV intervention and therefore will not necessitate diver assistance with opening access panels. On gaining entry to the interior of the igloo the ROV will carry out and fully video record, a general visual inspection of the original Spar manifold and internal walls of the protection igloo (See Figs 3 and 4). The purpose of this inspection is to record the following: CAUTION:

In the event of a leak being discovered, the ROV is to identify the leak source, the rate of leakage and any damage associated with the leak. All leaks are to be treated as ‘C1’ anomalies and immediately reported to the Shell Offshore Representative.

(1)

Pipework. All pipework for corrosion and leaks. Particular attention is to be given to the pipe guides with any evidence of pipe movement to be reported. Pipework schematic is shown on Fig. 3.

(2)

Valves (CH-VLV). Each of the 6 external valves (Fig. 3) are to be visually inspected. Any leaks or evidence of leaks is to be reported. Where visible, all valve positions are to be noted on video. These however are not required to be recorded in the Job Completion report.

(3)

Blind Flange. The flanges on the 2 x 16” and 4 x 4” valves are to be inspected for any evidence of oil leaks.

(4)

Anodes (VI-AW). An inspection of all anodes located on the original spar manifold cover and on protection cover igloo frame work is to be carried out (Fig.4). The inspection is to record the following: (a)

The presence and location of the anodes are to be confirmed as per as-built layout drawings and are to be confirmed as specified. Give an estimated average range of the anode wastage. Refer to Procedure I 60 004 – Cathodic Protection Monitoring, in particular section 4.1.2.

Am 04 04/08

(b)


(c)


(d)


I 91 008 Page 3 of 8

0153-001


(5)

0-5% LOSS -


6-20% LOSS -


21-50% LOSS -


>50% LOSS -


CP Readings (CP-PRX/CON). Proximity readings are the preferred method. Contact readings are only to be taken where a suitable proximity system is not available. Refer to the workscope for qualification on the method to use, and if in doubt refer to the Shell Offshore Representative for advice, based on recommendations from the relevant Sponsoring Engineer. Where Reference Proximity readings are taken, an initial contact reading is required. All subsequent readings are to be proximity, unless doubts exist as to the electrical continuity of the locations of the subsequent readings. A CP reading is required of the pipework cover (Fig.3). During the internal inspection of the igloo, should significant areas of bare metal or corrosion be noted, CP readings are to be taken and recorded. Where these areas occur, readings to be restricted to one CP per component. Where no areas of bare metal are evident, one CP reading is required on a typical area of major pipework (preferably a flange) and a valve. Locations of these readings are to be recorded and used for repeat readings in future years. In addition, CP readings are to be taken on two vertical (including diagonals) and two horizontal tubulars. With respect to igloo inspection by ROV, where the internal framework is the same as the external framework, these readings are not required, as they have been covered by the CPs taken as part of the external inspection. Positions where readings are obtained, including bare metal and tubular CPs are to be clearly shown on structural drawings. Refer to Procedure I 60 004 – Cathodic Protection Monitoring, in particular section 4.1.2.



I 91 008 Page 4 of 8

Am 04 04/08

Figure 1

591 000 E M MAGNUS 20" GAS PIPELINE FRO

1 FR 6" O O IL M P BR IP EN ELI T NE 'A '

P S PI U AS S) RG G E " G F 36 FLA ST ( O T

E IN EL

30" GAS PIPE FROM BREN LINE T 'C'

BRENT 'A'

36" GAS TO BRE PIPELINE NT 'A'

Am 04 04/08 BRENT SPAR BASE PROTECTION COVER E590047 N6770105

N

16" OIL PIPELINE FROM BRENT 'B'

24" OIL TO/FR PIPELINE OM BR ENT 'C ' BRENT 'B'

594 000 E

6 768 000 N

E LIN E IPELAR P F AS T " G EN 28 BR O T

6 769 000 N

36 TO " GAS BR PIP EN T F ELIN LAR E E 6 770 000 N

6 771 000 N

0153-001

Brent Spar Manifold Igloo Field Location

I 91 008 Page 5 of 8

593 000 E

592 000 E

590 000 E

589 000 E

Figure 2

I 91 008 Page 6 of 8

MANIFOLD COVER

ROOF PANEL

WEST FACE PANEL WEST FACE PANEL

N

A1

B1

NORTH FACE PANEL

SOUTH FACE PANEL

16" OIL LINE FROM BRENT BRAVO

A2

B2 EAST FACE PANEL

16" OIL LINE FROM BRENT ALPHA

0153-001

General Layout of Brent Spar Manifold Igloo

Am 04 04/08

Am 04 04/08

Figure 3

FROM BRENT ALPHA

VALVE E

4" 300# BALL VALVE

4" 300# BALL VALVE

V-H

4" 300# BALL VALVE

V-E

4" 300# BALL VALVE

16" BALL VALVE

V-D

V-F

16" BALL VALVE

V-C

V-G

16" BALL VALVE 16" BALL VALVE

V-A

VALVE DESCRIPTION

VALVE TYPE

CAMERON/SHAFER ACTUATOR

CAMERON/SHAFER ACTUATOR

CAMERO

CAMERO

COVER CUTAWAY FOR CLARITY

VALVE B

V-B

VALVE No.

VALVE F

BLIND FLANGES

VALVE D

N

CLOSE

CLOSE

CLOSE

CLOSE

CLOSE

CLOSE

OPE

OPE

NORMAL OPERATING STATUS

AS FOUND STATUS

VALVE G

BRENT BRAVO

FROM

VALVE H

BLIND FLANGES

VALVE A

VALVE C

BLIND FLANGES

0153-001

Brent Spar Manifold - Pipework Schematic and Valve Status

I 91 008 Page 7 of 8

WEST FACE PANEL

I 91 008 Page 8 of 8

A1

B1

Figure 4

A

B

2

A2

B2

PLAN ON ROOF SUPPORT FRAME

1

PLAN ON PROTECTION COVER ANODE ON UNDERSIDE OF MEMBER

SOUTH FACE PANEL

MANIFOLD COVER

NORTH FACE PANEL

EAST FACE PANEL

1

2

B

A

(LOOKING NORTH)

SECTION ALONG GRIDLINE B

(LOOKING SOUTH)

SECTION ALONG GRIDLINE A

(LOOKING EAST)

SECTION ALONG GRIDLINE 2

B

(LOOKING WEST)

SECTION ALONG GRIDLINE 1

A

2

1

0153-001

Brent Spar Manifold Igloo - Anode Locations

Am 04 04/08

0153-001

PROCEDURE I 91 009 IGLOO INSPECTION – OSPREY TO DUNLIN A FLOWLINE BUNDLE CARRIER PIPE 1

INTRODUCTION The work method is to be applied to the external and internal inspection of the towheads, intermediate towhead and trailheads on the 31.5”/38” Osprey to Dunlin A flowline bundle carrier pipe (N0904). The work will include damage inspection, scour inspection, leak monitoring, Cathodic Potential measurements, anode inspection and video inspection. Midpoint Trailhead No 3 is situated at KP3.330 on the 38inch Osprey to Dunlin A flowline bundle carrier pipe No 1 (COABIS Code and IBIS Incident No 246) at position E583966 N6797398. Production Towhead No 4 is situated at KP6.192 on the 31.5/38 inch Osprey to Dunlin A flowline bundle carrier pipe No 1 (COABIS Code and IBIS Incident No 476), to the west of the Osprey production cluster, at position E582779 N6799984. Water Injection Towhead No 5 is situated at KP6.559 on the 31.5 inch Osprey to Dunlin A flowline bundle carrier pipe No 1 (COABIS Code and IBIS Incident No 511), to the west of the Osprey Water Injection cluster, at position E582779 N6800342. Trailhead No 6 at Dunlin Alpha is situated at KP0.049 on the 38 inch Osprey to Dunlin A flowline bundle carrier pipe No 2 (COABIS Code and IBIS Incident No 1) at position E585573 N6794559. Midpoint Towhead No 7 is situated at KP3.290 on the 38 inch Osprey to Dunlin A flowline bundle carrier pipe No 2 (COABIS Code and IBIS Incident No 244) at position E583972 N6797357. Reference Figure Number 1 for Trailhead and Towhead Locations. NOTE:

Due to their configuration, all of the above towheads/trailheads may be inspected by ROV.

Towheads 4 and 5 are open structures, which allow for internal ROV inspection. There may however be a requirement for closer diver inspection, including wall thickness readings. Trailhead 6 is also an open structure, which allows for ROV inspection, but with restricted internal views due to its size. Diver internal inspection is preferred. Towheads 3 and 7 are enclosed structures, and are typically restricted to ROV external inspection. Internal specific points of interest are pipework and flanges only. These items would not warrant internal inspection of their own accord. Diver internal inspection would only be required for pipework WT readings. Diver access panels have been cut into the roof of these protection structures, but previous interventions have proposed that these hatches be enlarged prior to future diver intervention. NDT methods under Procedures 15 002 may be employed in conjunction with this procedure. 2

TASK OPTIONS

2.1


2.2

External VI-ROV

Am 04 04/08

-

ROV Worksite Check

I 91 009 Page 1 of 22

0153-001

2.3

VI-GVI

-


CP-PRX

-

Cathodic Potential Proximity Measurements

DM-SCR

-

Scour Inspection

DB-CHK

-

Visual Debris Check

CN-RPL

-


VI-GVI

-


CH-LKS

-

Check for Leaks

Internal

CP-PRX/CON -


VI-AW -


MG-GEN

-

Marine Growth Inspection

Should additional activities be carried out or incidents noted, suitable work tasks and task codes may be added to cover works. 2.4

Optional Tasks The following work tasks are optional and will be explicitly called for in the Workscopes, or as a result of finding an anomaly. WT-DIG

-




Refer to figures below and to the Igloos and Subsea Facilities UMDB (0144-001), Section 16 for drawings and component numbering details relevant to the Osprey Towheads. For Towheads 4 and 5 also refer to the Osprey/Merlin Subsea Facilities UMDB (5014-001), Part 2 for drawings and component numbering.

3.1


3.2

Location Confirmation Survey data, including the position of the igloo to be inspected, will be provided by the Shell Survey department prior to commencement of operations. All survey data shall be based on International Spheroid, European Datum 1950 (ED50), Transverse Mercator Projection. For UK Sector Central Meridian is 0 degrees East. Reference Section 1, Chapter 2, Figure 1, for further datum shift parameters. On ROV arrival at the worksite, it should be established that the correct igloo has been identified, by use of suitable markings on the igloo itself, or by use of the Shell survey data provided, and/or field layout drawings to provide other suitable means of confirmation. The Shell Offshore Representative is

I 91 009 Page 2 of 22

Am 04 04/08

0153-001

to be consulted should no markings be present, and the latter method is used to confirm that the correct igloo has been identified. If doubt persists as to the correct identification of the igloo, then a positional fix is to be taken of the asbuilt fix co-ordinate position, which may not be the centre of the igloo. Should this fix disagree with the workscope stated position by more than +/-5m, then initiate checks to resolve errors. Such checks should confirm that the vessel's positioning system has been suitably calibrated. If required a spin check should be carried out to verify the USBL positioning system. If the spread of the position data is more than the accuracy of the positioning systems, (i.e. DGPS 1-3m & USBL 1% of water depth) checks should be initiated to resolve errors. Prior to this, a CTD profile of the full water column should be observed and the relevant data entered into the USBL system. 3.3

External Inspection (VI-GVI) The ROV will carry out, and fully video record, a general visual inspection at the workscope specified towhead or trailhead location. The purpose of this inspection is to record the following: (1)


(2)

An overall view of the igloo (use of SIT camera) from all sides. This inspection is to check for any gross damage or debris, and to confirm the area is safe for further intervention (VI-ROV). If further diver intervention is planned, results of this inspection are to be relayed to the diver supervisor as required. On completion of the overall view, a more detailed survey is to be carried out in colour.

(3)


(4)

Loose or displaced panels paying particular attention to the seating of panels. Check all hinges.

NOTE:

Trailhead 3: In 2006 displaced panels to the South end were replaced with one panel. This panel and the East and West sides were extensively protected by mattresses (See Fig. 2). Towhead 7: In 2006 displaced panels to the North end were replaced with one panel, as was the SW panel No.6. Protection mattresses were also installed (See Fig. 3).

(5)

CP readings on four corners of the structure, proximity or contact (CP-PRX).

(6)

The entry and exit of the pipelines, Coflexip lines and umbilical to the structures, for any evidence of movement or door settlement.

(7)


(8)


(9)

General views are required of the approaches of each pipeline out to 5m from the igloo, or to the start of protection mattresses, which ever is the lesser. The survey is to confirm the presence and integrity of any supports, protection bags/mats or point of burial.


Internal Inspection (VI-GVI) When a diver enters the structure, a second diver must remain at the entrance and act as tender.

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0153-001

3.4.1

Trailhead No 3 (Incident No. 246) The buoyancy tanks have been removed from this trailhead and a protective structure fitted over the structure and as a result access inside the igloo is severely restricted (See Fig. 4). Internal inspection should normally not be specified for this trailhead due to restricted access problems. However if internal inspection is specified in the workscope, this would require diver intervention, and the following applies. A panel, 700mm x 600mm, has been cut in the roof panel to allow diver access. This panel can be removed by diver without the aid of lift bags (CN-RPL). The panel has previously been secured by TyWraps. However, previous attempts to enter through this panel was dismissed as too restrictive and the suggestion made that this hole be enlarged. An assessment as to whether safe to enter, needs to be made on site. It may be that an alternative to access through the roof panel is to remove some of the protection panels and mattresses. In 2006 displaced panels to the South end were replaced with one panel. This panel and the East and West sides were extensively protected by mattresses (See Fig. 2). The method for removing panels and mattresses will be specified in the workscope. On gaining entry to the interior of the structure the diver will carry out and fully video record, a general visual inspection of the pipework installation and internal framework of the structure. The purpose of this inspection is to record the following: CAUTION:


(1)

PIPEWORK. All pipe work for corrosion and leaks. Particular attention is to be given to the pipe supports with any evidence of pipe movement to be reported.

(2)

FLANGES. Each of the flanges is to be visually inspected. Any leaks or evidence of leaks are to be reported.

(3)

Anodes (VI-AW). Carry out an inspection of any anodes which may be located on the side wall panels and under the roof panels of the protection structure (See Fig. 9). The inspection is to record the following: (a)

The presence and location of the anodes are to be confirmed as per as-built layout drawings, and are to be confirmed as specified. Give an estimated average range of the anode wastage. Refer to Procedure I 60 004 – Cathodic Protection Monitoring, in particular section 4.1.2

I 91 009 Page 4 of 22

(b)


(c)


(d)


Am 04 04/08

0153-001


(4)

0-5% LOSS -


6-20% LOSS -


21-50% LOSS -


>50% LOSS -


CP Readings (CP-PRX/CON). Proximity readings are the preferred method. Contact readings are only to be taken where a suitable proximity system is not available. Refer to the workscope for qualification on the method to use, and if in doubt refer to the Shell Offshore Representative for advice, based on recommendations from the relevant Sponsoring Engineer. Where Reference Proximity readings are taken, an initial contact reading is required. All subsequent readings are to be proximity, unless doubts exist as to the electrical continuity of the locations of the subsequent readings. During the internal inspection of the igloo, should significant areas of bare metal or corrosion be noted, CP readings are to be taken and recorded. Where these areas occur, readings to be restricted to one CP per component. Where no areas of bare metal are evident, one CP reading is required on a typical area of major pipework (preferably a flange) and on the towhead structure. Locations of these readings are to be recorded and used for repeat readings in future years. Positions where readings are obtained, including bare metal and tubular CP’s are to be clearly shown on structural drawings. Refer to Procedure I 60 004 – Cathodic Protection Monitoring, in particular section 4.1.2.


Intermediate Towhead No 4 (Incident No. 476) Intermediate towhead No 4 is an open structure with no protection covers fitted and still has its buoyancy structures attached. There is relatively unrestricted access to all the components inside this structure (See Fig. 5). On gaining entry to the interior of the structure the diver or ROV, as access allows, will carry out and fully video record, a general visual inspection of the pipework installation and internal walls of the structure. The purpose of this inspection is to record the following: CAUTION:

(1)

Am 04 04/08


PIPEWORK. All pipe work for corrosion and leaks. Particular attention is to be given to the pipe supports with any evidence of pipe movement to be reported. I 91 009 Page 5 of 22

0153-001

(2)

FLANGES. Each of the flanges is to be visually inspected. Any leaks or evidence of leaks is to be reported.

(3)

PRODUCTION JUNCTION BOX (PJB). The PJB is to be visually inspected. Any leaks, evidence of leaks or any damage to be reported.

(4)

UMBILICAL EXTENSION TERMINATION ASSEMBLY PRODUCTION (UETAP). The UETAP is to be visually inspected. Any leaks or evidence of leaks is to be reported. The module’s attachment to the production guidebase is to be checked for security as is the umbilical attachment to the module and its seal at the 31.5” flowline bundle carrier pipe. All attachments and connections with the UTA are to be checked for security.

(5)

UMBILICAL TERMINATION ASSEMBLY (UTA). The UTA is to be visually inspected. Any leaks or evidence of leaks are to be reported. The module's support cradle is to be checked for security as is the umbilical support ramp, bend restrictor, weaklink anchor assembly and attachments.

(6)

HUB CONNECTORS. Check the hub connectors between the PJB, UETAP and UTA to check on their integrity and for leaks.

(7)

UMBILICAL. Check the umbilical between the bundle and UETAP, for integrity and for leaks.

(8)

Anodes (VI-AW). Carry out an anode inspection of the anodes located on two sides of the base supporting the PJB, UETAP and UTA (See Figure 5) and on the remainder of the structure. The inspection is to record the following: (a)


(b)


(c)


(d)


(9)

I 91 009 Page 6 of 22

0-5% LOSS -


6-20% LOSS -


21-50% LOSS -


>50% LOSS -


CP Readings (CP-PRX/CON). Proximity readings are the preferred method. Contact readings are only to be taken where a suitable proximity system is not available. Refer to the workscope for qualification on the method to use, and if in doubt refer to the Shell Offshore Representative for advice, based on recommendations from the relevant Sponsoring Engineer. Am 04 04/08

0153-001

Where Reference Proximity readings are taken, an initial contact reading is required. All subsequent readings are to be proximity, unless doubts exist as to the electrical continuity of the locations of the subsequent readings. A CP reading is required of each of the major internal components PJB, UETAP and UTA. During the internal inspection of the igloo, should significant areas of bare metal or corrosion be noted, CP readings are to be taken and recorded. Where these areas occur, readings to be restricted to one CP per component. Where no areas of bare metal are evident, one CP reading is required on a typical area of major pipework (preferably a flange) and on the towhead base. Locations of these readings are to be recorded and used for repeat readings in future years. Positions where readings are obtained, including bare metal and tubular CP’s are to be clearly shown on structural drawings. Refer to Procedure I 60 004 – Cathodic Protection Monitoring, in particular section 4.1.2. Digital Still Images are to be taken of any anomalies or other areas of interest. These may be supplemented by suitable drawings to show the location, size and details of the item of interest. 3.4.3

Towhead No 5 (Incident No. 511) Towhead No 5 is an open structure with no protection covers fitted and still has its buoyancy structures attached. There is relatively unrestricted access to all the components inside this structure (See Fig. 6). On gaining entry to the interior of the structure the diver or ROV, as access allows, will carry out and fully video record, a general visual inspection of the pipework installation and internal framework of the structure. The purpose of this inspection is to record the following: CAUTION:


(1)


(2)


(3)

WATER INJECTION JUNCTION BOX (WIJB). The WIJB is to be visually inspected. Any leaks, evidence of leaks or any damage is to be reported.

(4)

UMBILICAL EXTENSION TERMINATION ASSEMBLY WATER INJECTION (UETAW). The UETAW is to be visually inspected. Any leaks or evidence of leaks is to be reported. The module’s attachment to the water injection guidebase is to be checked for security as is the umbilical attachment to the module and its seal at the 31.5” flowline bundle carrier pipe.

(5)

HUB CONNECTOR. Check the hub connectors between the WIJB and UETAW to check on its integrity and for leaks.

(6)

UMBILICAL. Check the umbilical between the bundle and UETAW, for integrity and for leaks.

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I 91 009 Page 7 of 22

0153-001

(7)

Anodes (VI-AW). Carry out an anode inspection of the 4 anodes located on two sides of the base supporting the WIJB and UETAW (See Figure 6) and on the remainder of the structure. The inspection is to record the following: (a)


(b)


(c)


(d)


(8)

0-5% LOSS -


6-20% LOSS -


21-50% LOSS -


>50% LOSS -


CP Readings (CP-PRX/CON). Proximity readings are the preferred method. Contact readings are only to be taken where a suitable proximity system is not available. Refer to the workscope for qualification on the method to use, and if in doubt refer to the Shell Offshore Representative for advice, based on recommendations from the relevant Sponsoring Engineer. Where Reference Proximity readings are taken, an initial contact reading is required. All subsequent readings are to be proximity, unless doubts exist as to the electrical continuity of the locations of the subsequent readings. A CP reading is required of each of the major internal components WIJB and UETAW. During the internal inspection of the igloo, should significant areas of bare metal or corrosion be noted, CP readings are to be taken and recorded. Where these areas occur, readings to be restricted to one CP per component. Where no areas of bare metal are evident, one CP reading is required on a typical area of major pipework (preferably a flange) and on the towhead base. Locations of these readings are to be recorded and used for repeat readings in future years. Positions where readings are obtained, including bare metal and tubular CP’s are to be clearly shown on structural drawings. Refer to Procedure I 60 004 – Cathodic Protection Monitoring, in particular section 4.1.2.

Digital Still Images are to be taken of any anomalies or other areas of interest. These may be supplemented by suitable drawings to show the location, size and details of the item of interest. I 91 009 Page 8 of 22

Am 04 04/08

0153-001

3.4.4

Trailhead No 6 (Incident No. 1) Trailhead No 6 is an open structure with no protection covers fitted and still has its buoyancy structures attached (See Fig. 7). Views of the internal components are restricted to those obtained from outside by ROV. Divers will have better access for more detailed inspection. On gaining entry to the interior of the structure the diver or ROV, as access allows, will carry out and fully video record, a general visual inspection of the pipework installation and internal walls of the structure. The purpose of this inspection is to record the following: CAUTION:


(1)

PIPEWORK. All pipe work for corrosion and leaks. Particular attention is to be given to the pipe supports with any evidence of pipe movement to be reported. Pipework schematic is shown in Figure 7.

(2)

FLANGES: Each of the flanges is to be visually inspected. Any leaks or evidence of leaks is to be reported.

(3)

Anodes (VI-AW). Carry out an anode inspection of the structure. The inspection is to record the following: (a)


(b)


(c)


(d)


Am 04 04/08

0-5% LOSS -


6-20% LOSS -


21-50% LOSS -


>50% LOSS -


I 91 009 Page 9 of 22

0153-001

(4)

CP Readings (CP-PRX/CON). Proximity readings are the preferred method. Contact readings are only to be taken where a suitable proximity system is not available. Refer to the workscope for qualification on the method to use, and if in doubt refer to the Shell Offshore Representative for advice, based on recommendations from the relevant Sponsoring Engineer. Where Reference Proximity readings are taken, an initial contact reading is required. All subsequent readings are to be proximity, unless doubts exist as to the electrical continuity of the locations of the subsequent readings. During the internal inspection of the igloo, should significant areas of bare metal or corrosion be noted, CP readings are to be taken and recorded. Where these areas occur, readings to be restricted to one CP per component. Where no areas of bare metal are evident, one CP reading is required on a typical area of major pipework (preferably a flange) and on the towhead base. Locations of these readings are to be recorded and used for repeat readings in future years. Positions where readings are obtained, including bare metal and tubular CP’s are to be clearly shown on structural drawings. Refer to Procedure I 60 004 – Cathodic Protection Monitoring, in particular section 4.1.2.


Towhead No 7 (Incident No. 244) The buoyancy tanks have been removed from this trailhead and a protective structure fitted over the structure and as a result access inside the igloo is severely restricted (See Fig. 8). Internal inspection should normally not be specified for this trailhead due to restricted access problems. However if internal inspection is specified in the workscope, this would require diver intervention, and the following applies. A panel, 700mm x 600mm, has been cut in the roof panel to allow diver access. This panel can be removed by diver without the aid of lift bags (CN-RPL). The panel has previously been secured by TyWraps. However, previous attempts to enter through this panel was dismissed as too restrictive and the suggestion made that this hole be enlarged. An assessment as to whether safe to enter, needs to be made on site. It may be that an alternative to access through the roof panel is to remove some of the protection panels and mattresses. In 2006 displaced panels to the North end were replaced with one panel, as was the SW panel No.6. Protection mattresses were also installed (See Fig. 3). The method for removing panels and mattresses will be specified in the workscope. On gaining entry to the interior of the structure the diver will carry out and fully video record, a general visual inspection of the pipework installation and internal framework of the structure. The purpose of this inspection is to record the following: CAUTION:

(1)

I 91 009 Page 10 of 22



Am 04 04/08

0153-001

(2)


(3)

Anodes (VI-AW). Carry out an inspection of any anodes which may be located on the side wall panels and under the roof panels of the protection structure (See Fig. 10). The inspection is to record the following: (a)


(b)


(c)


(d)


(4)

0-5% LOSS -


6-20% LOSS -


21-50% LOSS -


>50% LOSS -


CP Readings (CP-PRX/CON). Proximity readings are the preferred method. Contact readings are only to be taken where a suitable proximity system is not available. Refer to the workscope for qualification on the method to use, and if in doubt refer to the Shell Offshore Representative for advice, based on recommendations from the relevant Sponsoring Engineer. Where Reference Proximity readings are taken, an initial contact reading is required. All subsequent readings are to be proximity, unless doubts exist as to the electrical continuity of the locations of the subsequent readings. During the internal inspection of the igloo, should significant areas of bare metal or corrosion be noted, CP readings are to be taken and recorded. Where these areas occur, readings to be restricted to one CP per component. Where no areas of bare metal are evident, one CP reading is required on a typical area of major pipework (preferably a flange) and on the towhead structure. Locations of these readings are to be recorded and used for repeat readings in future years. Positions where readings are obtained, including bare metal and tubular CP’s are to be clearly shown on structural drawings. Refer to Procedure I 60 004 – Cathodic Protection Monitoring, in particular section 4.1.2.

Digital Still Images are to be taken of any anomalies or other areas of interest. These may be supplemented by suitable drawings to show the location, size and details of the item of interest. Am 04 04/08

I 91 009 Page 11 of 22

0153-001

3.4.6


I 91 009 Page 12 of 22

Am 04 04/08

Am 04 04/08

Figure 1

W2

W3

WATER INJECTION LINEAR BLOCK MANIFOLD

P8

W4

W1 P6

P2

P3

TOWHEAD No. 5 (For Details See 0144-001)

P4

P7

P1 (Disconnected)

PRODUCTION LINEAR BLOCK MANIFOLD

10" WATER INJECTION (Redundant)

OSPREY

P5

INTERMEDIATE TOWHEAD No. 4 (For Details See 0144-001)

10" WATER INJECTION

TRAILHEAD No. 3 (For Details See 0144-001)

MID LINE CONNECTION

TOWHEAD No. 7 (For Details See 0144-001)

W11

D RO P 8"

TE WA 8"

TIO

N

N

P12

P11

UC

EC NJ RI

MERLIN

TIO

8" WATER INJECTION 2 x 8" PRODUCTION

OSPREY REPLACEMENT UMBILICAL

OSPREY UMBILICAL (ABANDONED)

TRAILHEAD No.6 (For Details See 0144-001)

P13

UTA/SAM

CONTROL UMBILICAL

CROSSOVER MANIFOLD

Y SPOOL PIECE (For Details See 0144-001) CONTROL UMBILICAL

DUNLIN 'A'

0153-001

Osprey General Arrangement

I 91 009 Page 13 of 22

I 91 009 Page 14 of 22

Figure 2

38 FLOWLINE BUNDLE CARRIER PIPE No 1 TO/FROM INTERMEDIATE TOWHEAD No 4

5

MATTRESSES

7

6

NOTE: PANELS Nos 8 AND 9 HAVE BEEN REMOVED

3

1

2 4

SINGLE PANEL INSTALLED 2006

TO/FROM TOWHEAD No 7

8 COFLEXIP JUMPER

10 COFLEXIP JUMPER

8 COFLEXIP JUMPER

0153-001

General Layout of Trailhead No 3 Igloo

Am 04 04/08

Figure 3

Am 04 04/08

TO/FROM TRAILHEAD No 3

8 COFLEXIP JUMPER

10 COFLEXIP JUMPER

8 COFLEXIP JUMPER

GROUT BAGS

SINGLE PROTECTION UNIT INSTALLED 2006

4

MATTRESS

2

1

3

PANEL 6 INSTALLED 2006

6

5

7

38 FLOWLINE BUNDLE CARRIER PIPE No 2 TO/FROM INTERMEDIATE TRAILHEAD No 6

0153-001

General Layout of Towhead No 7 Igloo

I 91 009 Page 15 of 22

0153-001

A

A

SIDE VIEW

38" FLOWLINE BUNDLE CARRIER PIPE No 2 TO INTERMEDIATE TOW END No 4

8" COFLEXIP JUMPER TO TOWHEAD No 7

PLAN VIEW 10" COFLEXIP JUMPER FROM TOWHEAD No 7

VIEW AT A-A

Figure 4

I 91 009 Page 16 of 22

Trailhead Number 3 – Pipework Schematic

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0153-001

A

A SIDE VIEW 8" OIL PRODUCTION LINES FROM PLBM

38" FLOWLINE BUNDLE CARRIER PIPE No 1 FROM TRAILHEAD No 3

31.5" FLOWLINE BUNDLE CARRIER PIPE No 1 TO TOWHEAD No 5

CONTROL UMBILICAL FROM DUNLIN A PLAN VIEW (BUOYANCY TANKS OMITTED FOR CLARITY)

ANODE (TYPICAL)

VIEW AT A-A

Figure 5

Am 04 04/08

Intermediate Towhead Number 4 – Pipework Schematic

I 91 009 Page 17 of 22

0153-001

A

U.E.T.A.W. W.U.B.

A SIDE VIEW

31.5 FLOWLINE BUNDLE CARRIER PIPE No 1 FROM INTERMEDIATE TOWHEAD No 4

10 WATER INJECTION LINE TO WILBM

W.U.B.

U.E.T.A.W. PLAN VIEW (BUOYANCY TANKS OMITTED FOR CLARITY)

ANODE (TYPICAL)

VIEW AT AA

Figure 6

I 91 009 Page 18 of 22

Towhead Number 5 – Pipework Schematic

Am 04 04/08

0153-001

A

A SIDE VIEW

10" WATER INJECTION LINE FROM DUNLIN A

38" FLOWLINE BUNDLE CARRIER PIPE No 2 TO TOWHEAD No 7

8" OIL PRODUCTION LINE FROM MERLIN (COFLEXIP)

8" OIL PRODUCTION LINE TO DUNLIN A

PLAN VIEW (BUOYANCY TANKS OMITTED FOR CLARITY)

VIEW AT A-A

Figure 7

Am 04 04/08

Trailhead Number 6 – Pipework Schematic

I 91 009 Page 19 of 22

0153-001

A

A

SIDE VIEW

8" COFLEXIP JUMPER FROM TRAILHEAD No 3

38" FLOWLINE BUNDLE CARRIER PIPE No 1 FROM TRAILHEAD No 6

PLAN VIEW 10" COFLEXIP JUMPER TO TRAILHEAD No 3

VIEW AT A-A

NOTE: PROTECTION STRUCTURE HAS BEEN OMITTED FOR CLARITY

Figure 8

I 91 009 Page 20 of 22

Towhead Number 7 – Pipework Schematic

Am 04 04/08

Figure 9

Am 04 04/08

7 3

1

NOTE: 1. PANELS Nos 8 AND 9 HAVE BEEN REMOVED 2. ALL ANODES ARE ON UNDERSIDE OF PANELS

38 FLOWLINE BUNDLE CARRIER PIPE No 1 TO/FROM INTERMEDIATE TOWHEAD No 4

5

6

2

4

TO/FROM TOWHEAD No 7

8 COFLEXIP JUMPER

10 COFLEXIP JUMPER

8 COFLEXIP JUMPER

INSTALLED 2006 NO ANODES FITTED

0153-001

Trailhead Number 3 – Anode Distribution

I 91 009 Page 21 of 22

Figure 10

I 91 009 Page 22 of 22

TO/FROM TRAILHEAD No 3

INSTALLED 2006 NO ANODES

8 COFLEXIP JUMPER

10 COFLEXIP JUMPER

8 COFLEXIP JUMPER

4

1

NOTE: ALL ANODES ARE ON UNDERSIDE OF PANELS

2

3

6

5

7

38 FLOWLINE BUNDLE CARRIER PIPE No 2 TO/FROM INTERMEDIATE TRAILHEAD No 6

0153-001

Towhead Number 7 – Anode Distribution

Am 04 04/08

0153-001

PROCEDURE I 93 001 PIPELINE PROTECTION FRAME INSPECTION 1

INTRODUCTION The work is to be applied to the external and internal inspection of the Gas Pipeline Protection Frame on the 10 inch North Cormorant to Western Leg Gas Pipeline and the associated pipeline flange. The Protection Frame was installed to protect a repaired flange on this line. The work will include damage survey, Cathodic Potential (CP) measurements, anode survey and video survey. The pipeline protection frame is situated at KP 22.132 on the 10 inch North Cormorant to Western Leg Gas Pipeline (Pipeline/COABIS - Code N0602/IGL02 (IBIS Incident No 30005)) at position E561443 N6769378.

2

TASK OPTIONS

2.1

External

2.2

VI-ROV

-

ROV Worksite Check

VI-GVI

-


CP-PRX

-


DM-SCR

-

Scour Survey

DB-CHK

-

Visual Debris Check

VI-ROV

-

ROV Worksite Check

CN-RPL

-


VI-GVI

-


CH-LKS

-

Check for Leaks

CP-PRX/CON

-


VI-AW

-


MG-GEN

-


Internal

Should additional activities be carried out or incidents noted, suitable work tasks and task codes may be added to cover works. Should anomalies be noted, they are to be reported and acted upon as per Section 2, Chapter 6, ‘Anomaly Reporting & Criteria’, and as directed by the Shell Offshore Representative. 3

OPERATING PROCEDURE AND SPECIFICATION Note:

Am 04 04/08

Refer to figures below and to the Igloos and Subsea Facilities UMDB (0144-001), Section 2 for drawings and component numbering details relevant to the Western Leg Protection Frame.

I 93 001 Page 1 of 7

0153-001

3.1


3.2

Location Confirmation Survey data, including the position of the Protection Frame, will be provided by the Shell Survey department prior to commencement of operations. All survey data shall be based on International Spheroid, European Datum 1950 (ED50), Transverse Mercator Projection. For UK Sector Central Meridian is 0 degrees East. Reference Section 1, Chapter 2, Figure 1, for further datum shift parameters. On ROV arrival at the worksite, it should be established that the correct igloo has been identified, by use of suitable markings on the igloo itself, or by use of the Shell survey data provided, and/or field layout drawings to provide other suitable means of confirmation. The Shell Offshore Representative is to be consulted should no markings be present, and the latter method is used to confirm that the correct igloo has been identified. If doubt persists as to the correct identification of the igloo, then a positional fix is to be taken of the asbuilt fix co-ordinate position, which may not be the centre of the igloo. Should this fix disagree with the workscope stated position by more than +/-5m, then initiate checks to resolve errors. Such checks should confirm that the vessel's positioning system has been suitably calibrated. If required a spin check should be carried out to verify the USBL positioning system. If the spread of the position data is more than the accuracy of the positioning systems, (i.e. DGPS 1-3m & USBL 1% of water depth) checks should be initiated to resolve errors. Prior to this, a CTD profile of the full water column should be observed and the relevant data entered into the USBL system.

3.3

External Survey (VI-GVI) The ROV will carry out, and fully video record, a general visual survey of the pipeline Protection Frame. The purpose of this survey is to record the following: (1)


(2)

An overall view of the igloo (use of SIT camera) from all sides. This inspection is to check for any gross damage or debris, and to confirm the area is safe for further intervention (VI-ROV). Results of this inspection are to be relayed to the diver supervisor.

On completion of the overall view, a more detailed inspection is to be carried out in colour. (3)

Structure and Expamet (Concrete side/seabed panels) for any evidence of impact damage. Check for leaks.

(4)

Pile attachment hold down points.

(5)

The entry and exit of the pipeline to the Protection Frame for evidence of pipeline movement or cover settlement.

(6)

Scour around the base of the Protection Frame (DM-SCR). Note: There are specific anomaly criteria with respect to igloo scour. See Section 2, Chapter 6, Point 2.3.12.

(7)

CP readings on four corners of the two Protection Frames, and a typical access panel/door for each frame, proximity or contact (CP-PRX).

(8)


I 93 001 Page 2 of 7

Am 04 04/08

0153-001

(9)

General views are required of the approaches of the pipelines out to 5m from the igloo, or to the start of protection mattresses, which ever is the lesser. The inspection is to confirm the presence and integrity of any supports, protection bags/mats or point of burial.


Access Hatches and Doors (CN-RPL) WARNING:

PRIOR TO ATTEMPTING TO OPEN ANY OF THE FOUR DOORS OR TWELVE HATCHES A CLOSE VISUAL INSPECTION OF ALL LIFTING POINTS IS TO BE CARRIED OUT. SHOULD THE INSPECTION REVEAL ANY ANOMALIES OR DAMAGE THEN AN ALTERNATIVE LIFTING POINT IS TO BE USED.

For the ROV and diver to gain access to the Protection Frame, it will be necessary for one of the twelve hatches or four doors to be opened. Hatch and door positions are shown on Fig 2. On completion of the lifting point inspection the diver is to open the access doors or hatches. In the past access has been gained through hatch W7, which is open, or hatch E4 which could be removed by diver without the aid of rigging or lift bags. Alternatively, the doors or hatches are to be removed using either of the methods described below. 3.4.1

3.4.2

Access Door E1, E8, W1 and W8 (1)

Install a 250kg lift bag to the door. Use necessary hold back, inversion and dump lines. Inflate bag slowly until door opens.

(2)

When door is open, secure to Protection Frame with 1 inch diameter polypropylene rope to prevent door accidentally closing. At the start of each dive, the lift bag is to be checked and reinflated as necessary.

Access Hatch E2-E7 and W2-W7 (1)

Install a 100kg lift bag to the upper section of the hatch. Use necessary hold back, inversion and dump lines. Inflate bag slowly until hatch opens.

(2)

When hatch is open, secure to Protection Frame with 1 inch diameter polypropylene rope to prevent hatch accidentally closing.

(3)

Repeat (1) and (2) for lower hatch. At the start of each dive, the lift bags are to be checked and re-inflated as necessary.

NOTE: 3.5

ROV to monitor and video record the door opening operation (VI-ROV).

Internal Survey (VI-GVI) When a diver enters the Protection Frame, a second diver must remain at the entrance and act as tender. On gaining entry to the interior of the Protection Frame, the diver or ROV, as access allows, will carry out and fully video record, a general visual survey of the pipeline, flange and internal walls of the Protection Frame. The purpose of this survey is to record the following: CAUTION:

Am 04 04/08

In the event of a leak being discovered, divers should be withdrawn from the area and an ROV inspection should be carried out to identify the leak source, the rate of leakage and any damage associated with the leak. All leaks are to be treated as 'C1' anomalies and immediately reported to the Shell Offshore Representative.

I 93 001 Page 3 of 7

0153-001

(1)

Pipework. Pipework for corrosion and leaks. Check pipeline is fully supported by grout bag supports.

(2)

Flange. The repaired flange for evidence of gas leaks.

(3)

Anodes (VI-AW). Carry out an anode inspection on the anodes which are located on the side wall panels and under the roof panels. The inspection is to record the following: (a)

The presence and location of the anodes are to be identified, and any indication of missing anodes to be reported. Give an estimated average range of the anode wastage. Refer to Procedure I 60 004 – Cathodic Protection Monitoring, in particular section 4.1.2.

(b)


(c)


(d)


(4)

0-5% LOSS -


6-20% LOSS -


21-50% LOSS -


>50% LOSS -


CP Readings (CP-PRX/CON). Proximity readings are the preferred method. Contact readings are only to be taken where a suitable proximity system is not available. Refer to the workscope for qualification on the method to use, and if in doubt refer to the Shell Offshore Representative for advice, based on recommendations from the relevant Sponsoring Engineer. Where Reference Proximity readings are taken, an initial contact reading is required. All subsequent readings are to be proximity, unless doubts exist as to the electrical continuity of the locations of the subsequent readings. During the internal inspection of the protection cover internal wall and piles, should significant areas of bare metal or corrosion be noted cathodic potential readings are to be recorded. Where these areas occur, readings to be restricted to one CP per component. Where no areas of bare metal are evident, one CP reading is required on a typical area of major pipework (preferably a flange) and on the protection structure. Locations of these readings are to be recorded and used for repeat readings in future years. Positions where readings are obtained, including bare metal and tubular CP’s are to be clearly shown on structural drawings.

(5)

I 93 001 Page 4 of 7

Close Hatch (CN-RPL). On completion of all internal inspection work the doors and hatches are to be closed in reverse order to opening procedure. Ensure all diving umbilicals and ROV tether are clear of the door or hatch before closing. Am 04 04/08

0153-001

Hatch W7 is to be left open. NOTE: (6)

ROV to monitor and video record the door or hatch closing operation.

The ROV will carry out, and fully video record, a general visual survey of the Protection Frame, paying particular attention to the final placement of doors and hatches and fit up. Digital Still Images are to be taken of any anomalies or other areas of interest. These may be supplemented by suitable drawings to show the location, size and details of the item of interest.

3.6


Am 04 04/08

I 93 001 Page 5 of 7

0153-001

NORTH CORMORANT

SSIV IGLOO

10inch GAS LINE NW HUTTON

CORMORANT A

PROTECTION COVER E561446 N6769400 SSIV IGLOO

SSIV IGLOO

SPLITTER BOX IGLOO

STRATHSPEY TIE-IN IGLOO WELGAS TEE IGLOO No.2 (8inch AND 10inch)

BRENT A WELGAS TEE IGLOO No.1

NORTH NINIAN

HEATHER

NORTH CENTRAL (STRATHSPEY)

Figure 1

I 93 001 Page 6 of 7

Pipeline Protection Frame Field Location

Am 04 04/08

TO NORTH CORMORANT

Am 04 04/08

Figure 2 PILES

W8

E8

W7

E7

W5

E5

W4

E4

W3

FRAME NO. 2

E3

VIEW LOOKING EAST

PLAN ON PROTECTION NOTE : W7 HATCH LEFT OPEN FOR ACCESS

W6

FRAME NO. 1

E6

W2

E2

W1

E1

WELGAS TEE IGLOO No. 2

SECTION LOOKING NORTH

10inch GAS LINE

0153-001

General Arrangement of Pipeline Protection Frame

I 93 001 Page 7 of 7

0153-001

PROCEDURE I 98 001 CONCRETE PROTECTION COVERS AND PBSJ INSPECTION 1

INTRODUCTION The work method is to be applied to the external and internal inspection of concrete protection covers and the inspection of the Pressure Balanced Safety Joint (PBSJ) and tie-in flanges within the concrete protection covers. The work will include damage survey, scour survey, pipeline movement monitoring, leak monitoring, Cathodic Potential (CP) measurements and video survey. PBSJ's are installed at the Northern and Southern ends of the two 8” oil pipelines, N 0705 and N 0706, KP 0.080 and 6.800, 0.180 and 6.917 respectively and at the Northern and Southern ends of the TFL lines, N 0703/N 0704, KP 0.115 and 6.763, between the Underwater Manifold Centre (UMC) and the Cormorant A Platform. N0703 and N0704 are twinned, with the PBSJ’s for each line within the same protection cover. The positions and IBIS incident (anomaly) numbers of these PBSJ’s are as follows (as reported from the 2005 pipeline inspection): NOTE:

The TFL lines are at present redundant.

N0703/N0704 – Cormorant ‘A’ to UMC 3” TFL

(Both PBSJ’s are reported under N0703)

Incident No.

K.P.

Depth

Description

Co-ordinates

IN551

0.115

149m

PBSJ at CA End

E 557976 N 6774907

IN234

3.422

154m

Mid Line Tie-In CA End

E 558598 N 6778153

IN232

3.457

155m

Mid Line Tie-In UMC End

E 558610 N 6778186

IN635

6.763

153m

PBSJ at UMC End

E 559685 N 6781312

N0705 – Cormorant ‘A’ to UMC 8” OFL East Incident No.

K.P.

Depth

Description

Co-ordinates

IN316

0.080

150m

PBSJ at CA End

E 557952 N 6774914

IN554

3.420

155m


E 558557 N 6778197

IN558

3.456

155m


E 558553 N 6778235

IN867

6.800

153m

PBSJ at UMC End

E 559682 N 6781380

N0706 – Cormorant ‘A’ to UMC 8” OFL West

Incident No.

K.P.

Depth

Description

Co-ordinates

IN009

0.180

149m

PBSJ at CA End

E 557789 N 6774970

IN222

3.520

155m


E 558517 N 6778213

IN225

3.576

155m


E 558503 N 6778247

IN424

6.917

153m

PBSJ at UMC End

E 559662 N 6781379

The coordinates are as observed from the 2005 ROV inspection, and will have a nominal tolerance of approximately +/- 5m.

Am 04 04/08

I 98 001 Page 1 of 12

0153-001

2

TASK OPTIONS

2.1

External

2.2

VI-ROV

-

ROV Worksite Check

VI-GVI

-


DM-SCR

-

Scour Survey

DB-CHK

-

Visual Debris Check

VI-ROV

-

ROV Worksite Check

CN-RPL

-


VI-GVI

-


CH-LKS

-

Check for Leaks

Internal

CP-PRX/CON -

Contact Cathodic Potential Measurements

MG-GEN


-

Any number or combination of the listed work tasks, or those listed under Procedure I 15 001, may be used or called for on the workscope or during the course of the inspection. Should additional activities be carried out or incidents noted, suitable work tasks and task codes may be added to cover works. Should anomalies be noted, they are to be reported and acted upon as per Section 2, Chapter 6, ‘Anomaly Reporting & Criteria’, and as directed by the Shell Offshore Representative. 3


3.1

Refer to figures below and to the Igloos and Subsea Facilities UMDB (0144-001), Sections 11, 12 and 13 for drawings and component numbering details relevant to the Covers and PBSJ’s.


3.2

Location Confirmation Survey data, including the position of the covers and PBSJ’s, will be provided by the Shell Survey department prior to commencement of operations. All survey data shall be based on International Spheroid, European Datum 1950 (ED50), Transverse Mercator Projection. For UK Sector Central Meridian is 0 degrees East. Reference Section 1, Chapter 2, Figure 1, for further datum shift parameters. On ROV arrival at the worksite, it should be established that the correct cover has been identified, by use of suitable markings on the cover itself, or by use of the Shell survey data provided, and/or field layout drawings to provide other suitable means of confirmation. The Shell Offshore Representative is to be consulted should no markings be present, and the latter method is used to confirm that the correct cover has been identified.

I 98 001 Page 2 of 12

Am 04 04/08

0153-001

If doubt persists as to the correct identification of the cover, then a positional fix is to be taken of the as-built fix co-ordinate position, which may not be the centre of the cover. Should this fix disagree with the workscope stated position by more than +/-5m, then initiate checks to resolve errors. Such checks should confirm that the vessel's positioning system has been suitably calibrated. If required a spin check should be carried out to verify the USBL positioning system. If the spread of the position data is more than the accuracy of the positioning systems, (i.e. DGPS 1-3m & USBL 1% of water depth) checks should be initiated to resolve errors. Prior to this, a CTD profile of the full water column should be observed and the relevant data entered into the USBL system. 3.3

External Survey (VI-GVI) The ROV will carry out, and fully video record, a general visual survey of the concrete protection cover location. The purpose of this survey is to record the following: (1)

Confirm cover identification if present.

(2)

An overall view of the cover (use of SIT camera) from all sides. This inspection is to check for any gross damage or debris, and to confirm the area is safe for further intervention (VI-ROV). Results of this inspection are to be relayed to the diver supervisor. On completion of the overall view, a more detailed inspection is to be carried out in colour.

(3)

Concrete covers for any evidence of impact damage, loose gravel or rocks.

NOTE:

The description of any concrete damage or any anomalies discovered should be reported using standard terminology in accordance with the Department of Energy, Offshore Technical Reports entitled 'Classification and Identification of Typical Blemishes Visible on the Surface of Concrete Underwater' - OTH 84 206 and OTH 87 261.

(4)

Lifting bars and 'U' shaped link bars on concrete covers for damage and corrosion.

(5)

The entry and exit of the pipeline to the concrete covers for evidence of pipeline movement or covers touching the pipelines.

(6)

Scour around concrete cover skirts (DM-SCR).

(7)


(8)

General views are required of the approaches of the pipelines out to 5m from the cover, or to the start of protection mattresses/rock dump, which ever is the lesser. The inspection is to confirm the presence and integrity of any supports, protection bags/mats or point of burial. Digital Still Images are to be taken of any anomalies or other areas of interest. These may be supplemented by suitable drawings to show the location, size and details of the item of interest.

3.4

Access Doors (CN-RPL) WARNING:

PRIOR TO ATTEMPTING TO OPEN THE ACCESS DOOR A CLOSE VISUAL AND ELECTROMAGNETIC INSPECTION OF THE LIFTING BAR AND HINGE PINS ON THE ACCESS DOOR AND THE LIFTING PADEYES ON CONCRETE COVER (C2), TIRFOR ATTACHMENT POINTS, IS TO BE CARRIED OUT. SHOULD THE INSPECTION REVEAL ANY ANOMALIES OR DAMAGE THEN THE ATTACHMENT POINT IS NOT TO BE USED, BUT IS TO BE REPLACED WITH A 'U' BOLT LIFTING ARRANGEMENT. REFERENCE FIGS 4 AND 5.

For the ROV and diver to gain access to the concrete covers it will be necessary for the access door on the end closure unit to be opened. Door position and detail are shown on Figs 2, 3 & 4. Am 04 04/08

I 98 001 Page 3 of 12

0153-001

(1)

On completion of the inspection the diver is to open the access door using the following method: (a)

Install a Tirfor (T508) between the lifting bar on the door and a padeye on the concrete cover. Leave the Tirfors loose.

(b)

Install one 250 kg lift bag on the door lifting bar. Inflate the bag slowly until the door opens.

(c)

When the door is open and vertical, tighten the Tirfor to pull door past the vertical and secure. Slowly deflate bag and lower door to lay flat on top of concrete cover.

NOTE: 3.5


Internal Survey (VI-GVI) When a diver enters the concrete cover, a second diver must remain at the entrance and act as tender. On gaining entry to the interior of the concrete cover the diver or ROV, as access allows, will carry out and fully video record, a general visual survey of the PBSJ installation, or the mid-point Tie-In flanges, and internal walls of the concrete covers. The purpose of this survey is to record the following: CAUTION:

In the event of a leak being discovered, divers should be withdrawn from the area and an ROV inspection should be carried out to identify the leak source, the rate of leakage and any damage associated with the leak. All leaks are to be treated as 'C1' anomalies and immediately reported to the Shell Offshore Representative.

(1)

Pipework. Pipework for corrosion and leaks. Particular attention is to be given to the flanged connections of the PBSJ, or the mid-point Tie-In flanges for signs of leaks. Leaks may be detected by looking for deposits of hydrocarbons on the flanges and on the surrounding fittings, refer to Fig 6 for typical arrangement.

(2)

Measure the distance between the PBSJ flanges. Refer to Fig 7 for typical values recorded.

(3)

Indications of pipe movement.

(4)

Internal damage to the concrete covers.

(5)

CP Readings (CP-PRX/CON). Proximity readings are the preferred method. Contact readings are only to be taken where a suitable proximity system is not available. Refer to the workscope for qualification on the method to use, and if in doubt refer to the Shell Offshore Representative for advice, based on recommendations from the relevant Sponsoring Engineer. Where Reference Proximity readings are taken, an initial contact reading is required. All subsequent readings are to be proximity, unless doubts exist as to the electrical continuity of the locations of the subsequent readings. A CP reading is required on each PBSJ arrangement (Fig. 6). During the internal inspection of the cover, should significant areas of bare metal or corrosion be noted, CP readings are to be taken and recorded. Where these areas occur, readings to be restricted to one CP per component. Where no areas of bare metal are evident, one CP reading is required on a typical area of major pipework (preferably a flange). Locations of these readings are to be recorded and used for repeat readings in future years. Refer to Procedure I 60 004 – Cathodic Protection Monitoring, in particular section 4.1.2.

I 98 001 Page 4 of 12

Am 04 04/08

0153-001

(6)

Close Hatch (CN-RPL). On completion of all internal inspection work the door is to be closed in reverse order to opening procedure. Ensure all diving umbilicals and ROV tether are clear of the door before closing. NOTE: ROV to monitor and video record the door closing operation.

(7)

The ROV will carry out, and fully video record, a general visual survey of the concrete covers, paying particular attention to the final placement of the door and fit up.


Final Report The Job Completion Report is to précis the results of the inspection, and any subsequent actions as per the points of interest listed above. Reference Section 2, Chapter 7. All anomalies are to be referenced, with a general statement made concerning the types and extent of anomalies identified. Any C1 anomalies are to be commented on more specifically. Other references are to be made to any digital still images and drawings. Maximum and minimum range for all other CP readings taken are to be stated, with the readings and their locations clearly shown on structural drawings. Sketches are required, either scanned, AcadLT or other proprietary drawing format, of any major defects or debris that cannot be suitably documented by anomaly report and digital images alone.

Am 04 04/08

I 98 001 Page 5 of 12

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Pressure Balanced Safety Joint (PBSJ) Field Location I 98 001 Page 6 of 12

B

X X

DIVER ACCESS DOOR ( SEE FIG. 3 )

VIEW ON ARROW A

A

SECTION X - X

VIEW ON ARROW B

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General Layout of Concrete Protection Covers and PBSJ Pipework I 98 001 Page 7 of 12

Figure 3

SECTION A - A

12mm THICK GALVANISED MILD STEEL PLATE

10mm 1329mm

I 98 001 Page 8 of 12 15mm

200mm LONG EYE - BOLTS CAST INTO CONCRETE

165mm

130mm

80mm

40mm

A

A

650mm

M20 BAR

130mm

M20 MILD STEEL BAR, 200mm LONG WELDED TO 12 THICK MILD STEEL PLATE USING 6 THICK CONTINUOUS FILLET WELD

15mm

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Access Door Arrangement and Details

Am 04 04/08

80mm

A

Figure 4

10mm THICK COVER PLATE

o

45

VIEW ON ' A - A '

PLAN

EDGES GROUND

75mm 75mm

Am 04 04/08 37mm

75mm

25mm DIA. TYP.

A

0153-001

Lifting Point Hole Dimensions

I 98 001 Page 9 of 12

10mm

R

40

m m

0153-001

20mm DIA. BAR FORMED TO U

EDGES GROUND TO ALLOW EYE TO LOWER

EXISTING DOOR 5mm

70mm

10mm

80mm

2 OFF M20 NUT AND WASHER

PEEN OVER 140mm ( x 60mm )

Figure 5

I 98 001 Page 10 of 12

Lifting Point General Arrangement

Am 04 04/08

Am 04 04/08

END FITTING 3" 10000 PSI

500mm

675mm

276mm

Figure 6

BREAKAWAY JOINT

1384mm

2734mm

675mm

END FITTING 3"

500mm

0153-001

Pressure Balanced Safety Joint (PBSJ) Typical Arrangement

I 98 001 Page 11 of 12

13mm 15mm

PIPELINE

WELLHEAD

480mm

88mm

15mm

1130mm

954mm

15mm

88mm

470mm

COFLEX

0153-001

Figure 7

I 98 001 Page 12 of 12

PBSJ and Flange Measurements - Typical

Am 04 04/08

0153-001

APPENDIX 1 REFERENCES

BS EN ISO 99341/2/3:2001/2002 Identical,

Non-destructive testing. (amendment AMD 14960)

Magnetic

particle

testing.

General

principle

ISO 9934-1/2/3:2000/2002 Identical EN ISO 3059:2001 Identical, ISO 3059:2001 Identical EN ISO 9934-2:2002 Identical,

Non-destructive testing. Penetrant testing and magnetic particle testing. Viewing conditions Non-destructive testing. Magnetic particle testing. Detection media

ISO 9934-2:2002 Identical BS EN 60051-1:1999 Identical, IEC 60051-1:1997 Identical BS 667: 2005

Direct acting indicating analogue electrical measuring instruments and their accessories. Definitions and general requirements common to all parts Illuminance meters. Requirements and test methods

(Replaces BS 667: 1996) BS 4331 Pt. 1, 2, 3

Methods for assessing performance and 1972, 1974, 1978 characteristics of ultrasonic flaw detection equipment. Amended 1987 and 1989.

BS 3923 Pt. 1

Methods for manual examination of fusion welds in 1986 ferritic steels

ASME V

Ultrasonic examination

ASME VIII

Evaluation of inclusions

SI 1988 No. 1657

The Control of Substances Hazardous to Health (COSHH)

SI 1985 No. 1333

The Ionising Radiations Regulations

SI 1974 No. 1735

The Radioactive Substances (Carried By Road) (Great Britain) Regulations The Radioactive Substances Act 1960 Approved code of practice for the protection of persons against ionising radiation arising from any work activity. Radiation safety for site radiography. Radiation safety in underwater radiography guidance notes GS 41 (HSE). IMCO International Maritime Dangerous Goods Code (Class 7). The International Air Transport Association Restricted Articles Regulations.

SIS 05 59 00-1969

Swedish standards for cleaning.

OTH 84 206

The classification and identification of typical blemishes visible on the surface of concrete underwater.

OTH 87 261

Typical blemishes visible on the surface of concrete underwater. A supplementary classification and identification.

AODC

Code of practice for the safe use of electricity underwater

AODC

Code of Practice for the safe use of high-pressure water jetting techniques.

Det Norske Veritas

Recommended Practice, Monitoring of Cathodic Protection Systems.

Re-issue 04/05

App 1 Page 1 of 2

0153-001

RP B403, March 1987 Shell Standard Procedure for Video Assessment OP-01: Revision 10: Jan 2003

Pro-Sub, Gamma@chek FMD Procedure

OG.02.20617

Shell Global Solutions – User Manual for the Pulsed Eddy Current (PEC) inspection tool deployed by a Remotely Operated Vehicle (ROV)

SHELL Doc. No. UEIM4/IUSC/TS01

Technical Specification for Survey & Positioning & As-Built Reporting. IUSC Contract

App 1 Page 2 of 2

Re-issue 04/05

Standard Procedures for Underwater Engineering Operations

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