Centrica Experience with Cap Rock Barriers on Canadian Land Wells P&A Seminar 19th of October

Olav Log

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• How the IWPA barrier works

• Why and how we got involved

• Stakeholder Psychology

• Planning and preparations

• Technical issues

• Trial Well 1

• Trial Well 2

• The results

• Forward plan

Main Areas of Interest

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How the Caprock Barrier Works

The barrier is a radical approach which aims to abandon the reservoir by melting in-situ material to re-create the cap rock

Interwell video

• Non explosive

• Exothermic reaction

• Creates ≈3000 degC.

• Melts wellbore

components and

surrounding rock

Cap Rock Barrier

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• This P&A project is a JIP by Interwell P&A, BP and Statoil with the Norwegian Research Council

• The project required a test well for field trials but there were none available

• Centrica were interested in reducing abandonment liabilities

• Offered to find suitable wells in Canada which would be cheaper and easier than the North Sea

• Agreed Centrica would provide the wells, management and well engineering, Interwell P&A would cover external costs

Why and How Centrica Got Involved

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Progression from zero to 100% interest

Engagement with stakeholders early and open

Value to Centrica can only be realised if the technique is recognised as being acceptable

– Alberta Energy Regulator

– Oil & Gas UK

– Health & Safety Executive

– Oil & Gas Authority

– DECC

– Fellow engineers/Managers

– Partners/Investors

– Centrica PLC, Aberdeen, Norway, Canada

Stakeholder Psychology

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Verification – pilot wells

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• 3 Progressive risk assessments

• Workshop with stakeholders

• Local contracts in Canada

• Tool manufacture and shipping

• AER dispensation

• Programmes

Preparation & Planning

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• Shipping of tools from Norway

• Leaky bridge plug

• Tool Lifting and pre-charge

• Premature ignition

• Interface with local equipment

• Pre-charge pressure

• Verification programme

Risks & Technical Issues

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7 inch casing in well

Pull tubing

Fill or partially fill well with fresh water

Run Anchor (leaky bridge plug)

Run Heat Shield

Confirm Reservoir and barrier setting depth in communication

IWPA deployment tool

Monitor pressures

Carry out verification program

Basic Programme

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Trial Well 1 Whitehorse

• Over pressured

• Low permeability

• Sweet

• Inclination 42deg

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Whitehorse

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Trial Well 2 Benjamin

• Depleted

• H2S

• Inclination 21deg

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Benjamin

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Barrier 1 Barrier 2 Barrier 3

Well Whitehorse Whitehorse Benjamin

Depth 2157m 2150m 2132m

Pre-charge pressure 220 206 196

Tag OK OK OK

+ve Pressure Test Failed Failed OK

-ve Pressure Test Failed Failed but improving OK

CBL OK OK OK

Casing log OK OK OK

Gas Migration OK OK OK

Vent flow OK OK OK

Seismic event OK OK OK

The Results

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Pressure Graph

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Deployed the tool into the well

Ignited the tool

Operated (burn) tool

Managed pressure wave safely

Avoided cement damage

Avoided casing damage

Created solid barrier

Pressure integrity …………….third attempt OK

What have we achieved

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Both wells now on long term monitoring

Whitehorse pressure now stabilising at lower level than before barrier installed?? Requires bleed off and further monitoring.

Benjamin holding 77 bar differential pressure (inflow). Further long term monitoring.

Tool modifications to better control internal pressure

Further trials

Forward Plan