innovative well completion design- the goldilocks completion · well completion is built from...
TRANSCRIPT
Michael Byrne
Dr Lesmana Djayapertapa
Ken Watson
Innovative Well Completion Design-The Goldilocks Completion
Lloyd’s Register
2019
Presentation Outline
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• How do we currently model wells?
• What is so different about using CFD?
• Some strange results?
• Goldilocks and the three completions
• Does this really work?
• Implications for future wells
Why Bother?Conventional Well Inflow Modelling Software Computational Fluid Dynamics (CFD)
LR - WellscopeConventional Reservoir Simulator
Numerical Method Nodal analysis 3D Numerical Method – Capturing Porous, Non-Porous, Turbulence
Darcy equation in reservoir, nodal analysis in well
Well Model Actual well completion geometry is NOT captured
Actual well completion geometry is captured
Actual well completion geometry is NOT captured
Reservoir-to-well connection Reservoir grid is imported to simulate inflow, well completion is built from library of components
Fully coupled and properly connected Reservoir-Well model
Connection factors are used to connect reservoir to well
Pressure drop / flow rate calculation
Pressure drop or flow rate is prescribed. Equations are used to determine flow rate or pressure drop
Pressure drop inside the well are the result of the actual completion geometry and flow rate from reservoir
Pressure drop between reservoir and well and the pressure within the well are determined using equation
Modelling near wellbore formation damage
Near wellbore formation damage is manifested as “skin” factor
Near wellbore formation damage can be simulated using Formation Damage lab. test results
Near wellbore formation damage is manifested as “skin” factor
Run time Fast run time Long run time, high memoryNot any more!
Moderate run time
Steady State / Transient Steady State Steady State or Transient Transient
Single Phase / Multiphase Multiphase Single Phase or Multiphase Multiphase
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3D Modelling – what is Wellscope?
● Wellscope is a patented modelling workflow to estimate well inflow and well component performance
● Based on Computational Fluid Dynamics (CFD)– Model wells and near wellbore
– Considers fluids and well geometry
● More accurate prediction of productivity benefit of different drilling and completion strategies– No “fudge” or skin factors
● Other applications– Sands and fines transport in wells– Flow into and through sand control and ICDs
– Component erosion modelling & prediction
Near wellbore pressure variation Reservoir pressure variation
VB0SQ8
• Some Strange Results!
(Restrictive ICD)
(“Goldilocks” ICD)
• Not too much restriction, not too little restriction, but just the right amount for this reservoir and this well
• The Goldilocks completion
No. Completion ICDs Nozzles PISM3/d/bar
Drawdown RateM3/d
1 SAS 0 0 30 90 2700
2 ICD 1 77 1 27 90 2430
3 ICD 2 154 4 60 90 5400
Reservoir Pressure Profile Comparison
Pressure (bar)
HeelStand Alone Screen PI: 30 (sm3/D)/bar
“Goldilocks” ICD PI: 60 (sm3/D)/bar
Restrictive ICD PI: 27 (sm3/D)/bar
Horizontal Well
Open Hole:Preferential flow at the Heel
Balanced Inflowwith Restrictions
Outlet
Outlet
Heel
Toe
Heel
Toe
Zoom in on the toe of the last Screen (nearest to the heel)
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A portion of the toe of the screen experiences “outflow”oil flows outwards from the basepipe to the annulus via the sand screen
Strong annular flowThis part of the well shows oilflows outwards towards the formation→ Inefficient completion
Some of the flow in the annulusgoes out to the formation,some goes into the basepipe, and some continues to flow along the annulus→ Inefficient completion
sandface
This part of the well is undergoing “outflow” oil flows outwards towards the formation→ Inefficient completion
Reservoir pressure contour plot is used as the background colour
Zoom in on the heel of the last Screen (nearest to the heel)
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“end of the road” for the annular flow – everything dives into the base pipe
This part of the well is experiencing “inflow”
Zoom in on the toe of ICD joint
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Annular flow is not as strong as Stand Alone Screen completionAll part of the well is flowing “inwards” from reservoir to annulus
Zoom in on the ICD
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Annular flow is not as strong as Stand Alone Screen completionAll part of the well is flowing “inwards” from reservoir to annulus
High turbulence intensity for flow through the ICD nozzles
Zoom in on the ICD
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High oil velocity through the ICD nozzles
The “Goldilocks” Completion
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Does this really work?
● Model indicated: High PI despite poor reservoir quality
● Well showed: “Best in class” PI
● Model Indicated: Flow from all sections of 2.5km horizontal well
● Well Showed: Tracers indicated clean-up from all parts of well
● Model Indicated: Well productivity more than twice best case
● Well Showed: Is the gauge broken? – “exceptional rates”
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Model versus reality
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“Grant me the serenity to accept the things I
cannot change, the courage to change the
things I can, and the wisdom to know the
difference.”
Reinhold Niebuhr
●Grant me the Serenity to accept the reservoirsI cannot change, the courage to change the wells I can and the wisdom to know the difference
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Implications for future wells
● Simple assumptions should be challenged
● Tradition and heresay are not necessarily good reasons for believing something!
● Well value will be realised
● And we’ll all live happily ever after…….
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We think…
