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MSc.

Oil and Gas EnterpriseManagement

Well Engineering Module

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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.

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Well Engineering Course Outline

Drilling process, rigtypes and rigequipment

Well design & wellplanning

Drilling fluids & mudconditioning equipment

Drillpipe & drillstring

design Drilling Bits

Directional Drilling

Casing design

Cementing Hole problems & stuckpipe

Evaluation

Well control & BOPs

Completions

Complex wells

Risk management

Enabling technologies

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Types of Drilling Rig

Land 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-determineddiameter to a pre-determined depth.

Evaluate the hole as required.

Case the hole as required.

Repeat the above process withprogressively smaller hole and casingsizes until the oil or gas reservoir isdrilled 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.

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The Well Construction Process

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Casing Diagram for Typical SubseaWell

30 conductor at 212 m RT

20surface 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

Mud Line

Well TD

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Land Rig

Nabors 21-E

2.5 million lb GNC Derrick, 2000 HP Drawworks, 37.5 Rotary

Drilling depth 6500 metres

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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.

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Bottom Supported Rigs

Rowan Gorilla Jack-up Rig

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

They are towed as a floating unit to thechosen drilling location. Once on location,the legs are first lowered to the sea bed

and then the drilling platform is elevatedabove sea level by powerful hydro-mechanical jacks

Brae B Platform Rig

The rig can be skidded in two directionsto allow the rig to drill over multiple wellslots

The drilling rig is usually retained on theplatform long after the initial directionally

drilled wells have been completed toallow for later in-fill drilling and toworkover existing wells

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Rig Skidded Over Well Platform

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Floating Rigs

DrillshipSemi-submersible

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Anchor Handling Vessels

Note winch and stern roller

Piggy-back anchors on deck.

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Semi-Submersible Rigs

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 windsexceeding 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.

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

Tank Test Model of 5th GenerationSemi-Submersible Rig

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Drillships

Large deck load capacity.

Less stable drilling platformthan a semi submersible in

comparable weatherconditions.

Guidelineless drilling riser/BOP systems.

Dynamically positioned fordeep water applications

Can be mobilised relativelyquickly over long distances.

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Drill Ships and Barges

Drill Ship

A modern twin derrick drillship designed topermit simultaneous pipe handlingoperations.

Each derrick has a crown block motioncompensator.

This drillship is maintained on station by acomputer controlled dynamic positioningsystem.

Drill ships have large storage capacitiesthat make them ideally suited to operationsremote from supply bases.

Swamp Barge

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

In this case, the coastal flats have been

dredged to allow the drilling barge to bepositioned on location.

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

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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