1. Introduction to Work Over Operations
Module – 13 Work Over Operations
Section – 1 Introduction Introduction to W.O.
1. Introduction to Work Over Operations •
1.
Well Intervention definition
2.
Work Over Operations
3.
Well Intervention Procedure
4.
Definition of well intervention needs
•
Definition of well intervention job
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Preparation of well intervention program
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Well Intervention Program
Types of well intervention •
Conventional operations
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Non conventional operations
•
Rig-less operations
1. Introduction to Work Over Operations 1. Well Intervention All jobs performed in a completed well any time during its productive live with the purpose of: •
Maintain or improve productivity or injection of fluids
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Conduct repairs to the surface or to the down hole equipment
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Control flow for well interventions or to recover primary well control
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Suspend the well temporarily or definitively
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Modify well function or change installations
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Etc.
1. Introduction to Work Over Operations There is a long list of work over operations that can be conducted in active or inactive wells, as follows: 1. 2. 3. 4. 5. 6. 7. 8. 9.
Repairing of down hole tools and equipment due to malfunction or damage Repairing of well head and surface installations Mechanic clean up of solid deposits Sand production control Artificial lift equipment installation and maintenance Formation stimulations Isolation of non wanted producing intervals Remedial cementing Routine well maintenance & well servicing
1. Introduction to Work Over Operations There is a long list of work over operations that can be conducted in active or inactive wells, as follows: 10. 11. 12. 13. 14. 15. 16. 17. 18.
Re-entry Well operations Formation testing Well control operations in cased hole Well re-completion Fishing operations Changes in well function or in well objectives Well suspension and temporarily abandonment Well abandonment Etc.
1. Introduction to Work Over Operations 1. Definition of Well Intervention Needs: • Evaluate well performance • Detect / Define productivity or injectivity problems • Drop of production or injection rates • Zone communication in the well bore • Reduction of ID or blockage of conduits • Leaks on connections or pipe body • Lost of integrity of down hole installations • Measurement / Evaluation of reservoir rocks properties: permeability, porosity, saturation, etc. • Adverse effect of formation fluids on well installations • Erosion, corrosion, solids build up, scaling deposits and tubing / casing bridging, etc.
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H
3.
O
4.
N
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D
6.
A
1. Introduction to Work Over Operations 2. Selection of well intervention job: • Scope and objectives of the WI job • Analysis of particular well conditions • Collecting information and well data • Work over job definition: • Basis of Design • Well service / routine maintenance • Major well intervention / complex WO • Conventional well intervention • Non Conventional Well Intervention
1. Introduction to Work Over Operations 3.Preparation of Well Intervention Program: •Well Data • Present and proposed surface and down hole installations •Well History • Summary of Drilling, Completion, work over, repairs, maintenance, etc. •Objectives of the proposed well intervention job •Reasons for the selected well intervention •List of tools and equipment required to perform the well intervention •Work Program • Detailed step by step procedure and guidelines to perform the well intervention
1. Introduction to Work Over Operations 4. The Well Intervention Program •
Step by step procedure to perform the well intervention
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Well Control: Description of equipment and procedures to keep well integrity
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Work over fluid: specification and properties of the selected fluid for well intervention
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Rig down well head installations and Recover of down hole equipment
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Analysis of present well conditions: e-logs, pressure and integrity tests, dry tests. Verification of the reported down hole installations
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Specific procedure for each intervention phase: well control, string recovery, fishing, remedial cementing, well bore clean up, stimulations, re-completion,
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Work over fluid and hydraulic requirement (if applicable)
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Flow induction / well activation procedure
1. Introduction to Work Over Operations
1.
Conventional Work Over Operations: •
Well remains static – no flow, no pressure
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Production / injection temporarily suspended
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Well is open. Annular exposed to the atmosphere
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BOP and WC equipment installed and tested
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Tubular strings can be run / retrieved with well open
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Flow induction or well activation after the intervention
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Well control and work fluids specially designed
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Installation / Rig up of the proper according to the well intervention job
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Special jobs: fishing of strings and tools, sand control, casing exits, plug backs, recompletions, replacement of ALS equipment, etc.
unit selected
1. Introduction to Work Over Operations 2.
Non – Conventional Work Over Operations: •
The well can be active or inactive: with head pressure, flowing or injecting fluids
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“Live Well” Intervention also called “Concentric Work Over” / Dynamic W.O.
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Well remains closed / annular space not exposed to the atmosphere
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Special WC equipment: BOP stack installed on the Christmas tree, concentric pipe injector head, lubricator tube with pressure head , pulleys for slick line, wire line or strand line, etc.
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Production string remains in place
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Well control fluid not required
1. Introduction to Work Over Operations 2.
Non – Conventional Work Over Operations: •
Concentric Work Over with Coiled Tubing Unit.
1. Introduction to Work Over Operations 2.
Non – Conventional Work Over Operations: •
Concentric Work Over with Snubbing Unit.
1. Introduction to Work Over Operations 2.
Non – Conventional W.O. Operations (cont.) • •
• • • •
Operations are conducted through the production or injection string in the well Some well interventions can be performed without affecting well production or injection Well continues active after the well intervention There is low risk of formation properties damage with invasion of work over fluids Operations are conducted generally with low stress but with high pressure Most of all conventional operations can be performed with non conventional rigs
1. Introduction to Work Over Operations 2.
Non – Conventional Work Over Operations (cont) •
3.
Most Units do not have mast for string running •
Coiled Tubing Unit (flexible coiled tubing)
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Snubbing Unit
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E – Line Unit / Logging Unit
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Slick Line Unit
Rig Less Operations: •
High pressure pumps / truck or skid mounted for well stimulations
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Well flow induction / solids clean up unit (Swabbing Unit / Strand Line Unit)
