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