The Robert Gordon University, Aberdeen
Condition Monitoring for Remedial Sand Control
MSc Thesis by ILESANMI OLUMAKINDE
Oil & Gas Engineering
9TH SEPT. 2005 Subsea UK/OFFSHORE EUROPE 2
The Robert Gordon University, Aberdeen.
Problem Theme & Objectives
OBJECTIVES Adapt condition monitoring to sand management.
Define the failure mechanism of sand control completions.
Tools for failure diagnosis.
Options for remediation; risks, consequences and benefits.
PROBLEM THEME A systematic approach to failure diagnosis in sand control
completions using
State-of-the-art tools for effective condition monitoring.
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Fault/Failure Diagnosis Faults & Failures?
Cause & Effect Analysis A priori knowledge & Search Technique [Venkatasubramanian V., ed., 2003]
primary & secondary failures [Peter Q.H., ed., 2004]. Simultaneous failures [Wong G.K., ed., 2003] Identification of faults & diagnosis of possible sand
problems. Considerations for the effects of production problems.
CM: Diagnosis or Simulation?
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Soft & Hard Tools. Integrated Approach!
Soft Tools Description of well completion. Reservoir characteristics & Lithology. PVT data of fluids. Production Parameters/History Open-hole Logs/Offset data of typical failures.
Tools for Condition Monitoring
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Application of Production Logging & Transience Tests [Wong G.K., ed., 2004, SPE 84497] using Wireline Testing Tool. Magnetic Resonance Imager MRI or NMR (k, Φ, Sw). Floscan Multiphase Flowmeter. Electromagnetic Propagation Tool.
Permanent P/T monitoring [Acock A., ed., 2004 Slb oilfield review, Unneland T., ed., 1993 SPE Prod.& facilities ] Fiber optics?
Sand Detection Devices (Acoustic probes). [Nisbet J.W.R., ed., 2003, SPE 84494]
Fluid Sampling at Surface (Microscopic analysis, sieve analysis). [Nisbet J.W.R., ed., 2003, SPE ]
Hard Tools for Condition Monitoring
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Government Research On the average, condition monitoring achieved savings of 1.2%
on value-added output (i.e. total sales revenue minus cost of raw material and energy brought in).
Two-thirds (2/3) of savings were due to an increase in availability gained from improved shut-down performance.
There was a 75% decrease in unscheduled shutdown time.
One-thirds of savings were due to a decrease in maintenance costs gained from improved breakdown performance.
There was a 50% decrease in breakdown labour costs.
[Barron R., 1996, Neale M., 1979]
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Hypothetical Case
Case 1
Reduced productivity, No sand...Increased drawdown? Slight increase in water cut after 7days...No sand. Transient sanding after 30days? Cut back on production! Fair production rates…well sands continuously after 7days…
rapid production decline. Ran Production Logging Tools (2days). Some perf. Collapsed & Poor primary cement job. Well Shut-in, Squeeze job & pre-pack screen! (14days). Good production with slight water cut due to fingering. Subsequent gravel pack plugging.
Deviated well, cased hole, unconsolidated formation, kV/kh=1, Multiphase fluid, 5000bopd.
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Hypothetical Case -Contd-Case 2
Routine monitoring of fluid samples & Optic fibre P/T sensors…pressure spikes @ perf. & upper region? Normal temp. logs.
Production decline? No sand alarms…suspect perf./screen plugging, formation damage, possible channelling at upper region?
Run PL Tools (GR, MRI, Floscan, Noise Log, Spinner) (2days). Formation damage due to fines migration. Remedial Acid treatment, Cement & Squeeze job @ upper
region (7days). Good production & No later problems.
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Is Conditioning Monitoring worth it?
$4 603 000
$2 300 000
Pre-pack Screens
$ 80 000Misc. $ 20 000 $ 100 000
Acid Treatment $ 50 000
Sand cleaning& disposal
$3 000
$0
NPT due to cleaning of separators (12hrs: 1ce a week), Production Logging (2day), Remedial Ops. (14days) $500 000 $500 000 $3 500 000 $4 500 000 9days NPT for PL & remediation $2 250 000
Option 1
Option 2
$208 000$ 50 000
Squeeze Job $ 50 000 $ 50 000
Sandhandling $1 000 $ 0
Cut back on Production. $157 500 - 7days $ 0
Option 1Option 2
$726 000$400 000
PLT (2days)
$200 000 $400 000
water processing $1 000 $ 0
water cut @ 10% of production rates(21days) $525 000 $0
Option 1Option 2
TOTALRemedial ExpensesProcessing, Handling & Disposal Expenses
Lost Production
$ 5 537 000$ 2 750 000
Sum TotalsExcluding safety hazards & later remedial expenses for Option 1
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Risks, Consequences & Benefits Risks & Consequences? Benefits
Improved availability of downhole and surface equipments (less downtime, more production).
Improved reliability/safety of downhole and surface equipments.
Prolonged life of the reservoir for greater production-output by managing operational parameters.
Reduced workover and operational costs from catastrophic breakdown of well and/or reservoir.
Better well planning for remediation from cash flow.
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Conclusion Sand Management technique. Diagnose possible completion failures to “guarantee”
economics & safety. Cheap, effective technologies with better quality. New technologies in Fibre Optics, NMR, Flow measurements,
Acoustics, & computer-based diagnosis.
Further research Visual modelling of near-wellbore region. Computer-based diagnosis e.g. neural networks, expert
systems.
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Thank You
Q & A