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Centrica Experience with Cap Rock Barriers on Canadian Land Wells P&A Seminar 19th of October
Olav Log
4
• 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