1. Well Engineering, Rig Types

MSc. Oil and Gas Enterprise Management Well Engineering Module

Day 1: Well Engineering • Introduction: – Gordon Botterill

• Well Engineering (Drilling, Completion and Well Service Engineering) • Course Deliverables – – – – –

Appreciation and knowledge of subjects. Knowledge of interfaces with other technical disciplines. Some technical/engineering calculations. Appreciation of new enabling technologies. Well design options.

Well Engineering – Course Outline •

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Drilling process, rig types and rig equipment Well design & well planning Drilling fluids & mud conditioning equipment Drillpipe & drillstring design Drilling Bits Directional Drilling

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Casing design Cementing Hole problems & stuck pipe Evaluation Well control & BOP’s Completions Complex wells Risk management Enabling technologies

Types of Drilling Rig •

Land – – – – –

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Standard derrick Portable mast Mobile Helicopter Slim Hole

Offshore – – – – – –

Platform Jack-up Semi-submersible Drill -ship Barge Tender supported

All rigs have the same purpose: • • • •

• • • •

To drill a hole of pre-determined diameter to a pre-determined depth. Evaluate the hole as required. Case the hole as required. Repeat the above process with progressively smaller hole and casing sizes until the oil or gas reservoir is drilled through. Log and test the reservoir as required. Install production casing as required. Complete the well as required. Suspend or abandon the well.

•Rigs are classified according to their depth capacity using 4.1/2” drill pipe. •Capacity depends mainly on substructure and derrick strength and drawworks HP.

The Well Construction Process

Casing Diagram for Typical Subsea Well Mud Line 30” conductor at 212 m RT

20”surface casing at 1100 m RT

13.3/8” intermediate casing at 3558 m RT

9.5/8” production casing at 4623 m RT

7” liner from 4570 m to 5450 m RT

Well TD

Land Rig

Nabors 21-E 2.5 million lb GNC Derrick, 2000 HP Drawworks, 37.5” Rotary Drilling depth 6500 metres

Helicopter Rig

• • •

Helicopter rigs are used in remote areas such as PNG. Rigs are transported in 4,000 lb loads by single or twin rotor helicopters. Helicopter shown is a Chinook.

Bottom Supported Rigs

Rowan “Gorilla” Jack-up Rig •

Rigs of this type can drill in 120 metres water during severe gale force conditions

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They are towed as a floating unit to the chosen drilling location. Once on location, the legs are first lowered to the sea bed and then the drilling platform is elevated above sea level by powerful hydromechanical jacks

Brae “B” Platform Rig •

The rig can be skidded in two directions to allow the rig to drill over multiple well slots

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The drilling rig is usually retained on the platform long after the initial directionally drilled wells have been completed to allow for later in-fill drilling and to workover existing wells

Rig Skidded Over Well Platform

Floating Rigs

Semi-submersible

Drillship

Pontoon Type Semi-Submersible Rig

Marine 700 Semisubmersible

Semi-submersible Rig “Ocean Alliance”

A dynamically positioned drilling unit capable of operating in 1500 metres water depth

Anchor Handling Vessels

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Note winch and stern roller

Piggy-back anchors on deck.

Semi-Submersible Rigs

Sedco Express, fitted with an automatic pipe handling system, can drill HPHT wells.

• • • • • •

Tank Test Model of 5th Generation Semi-Submersible Rig

Semi-submersible rigs are designed to drill in hostile environments Water depths range from less than 60 m to 3000 metres. Most buoyancy comes from pontoons below the active wave zone. Semi-submersible rigs are designed to withstand storm force winds exceeding 100 knots and storm waves over 30 metres high. Typical variable deck loads range from 2,000 to over 5,000 tons. Rigs are kept on location by anchors or dynamic positioning systems.

Drillships – Large deck load capacity. – Less stable drilling platform than a semi submersible in comparable weather conditions. – Guidelineless drilling riser/ BOP systems. – Dynamically positioned for deep water applications – Can be mobilised relatively quickly over long distances.

Drill Ships and Barges

Drill Ship •

A modern twin derrick drillship designed to permit simultaneous pipe handling operations.

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Each derrick has a crown block motion compensator.

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This drillship is maintained on station by a computer controlled dynamic positioning system.

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Drill ships have large storage capacities that make them ideally suited to operations remote from supply bases.

Swamp Barge •

These drilling units are suitable for operations in near shore, sheltered areas.

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In this case, the coastal flats have been dredged to allow the drilling barge to be positioned on location.

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Note the dumb barges moored alongside. These contain equipment for well such as casing, mud materials and cement.

Typical Rig Selection Criteria • For all rigs: – – – –

Mechanical/hydraulic capability to drill the well or wells Availability Contract rate Track record on safety and performance.

• For land rigs: – Ease of rig up/rig down – Ease of transportation to, from and within the operating area.

• For offshore rigs: – Ability to operate efficiently in the metocean conditions and water depths of the operating area – Adequacy of variable deck load (VDL) – Bulk storage and sack storage capacity – Conformance with discharge regulations