Another world first wasthe subsea deploymentof the Expro CablelessTelemetry System(CaTS) on one of theClair Ridge appraisalwells. This tool providesa unique insight into thepressure across thefield, helping to give BPand its partners abetter understanding ofClair’s complexreservoir androck formations. ’’

Objectives

• The Clair Field is located 75km west ofShetland in water depths of up to 140meters. It comprises a naturally fracturedsandstone reservoir, which over the scaleof the Clair Field made reservoirconnectivity and compartmentalisation riskkey uncertainties for field developmentplanning

• The 206/8-13Y Clair Ridge appraisal wellwas located 8km from the existing Clairproduction platform and designed toconfirm the next stage of development ofthe field

• An opportunity was identified toinstrument the well with a CaTS gauge atthe time of final abandonment, thusconverting it to a long-term monitoringasset. Observing for interference effectsresulting from production or injectionevents on adjacent assets woulddemonstrate wide-scale reservoirconnectivity

Expro Excellence

• A DST was performed on the well using apermanent packer and tailpipe

• On completion of the final pressure buildup, a CaTS gauge was conveyed into thewell through-tubing and hung off below abridge plug set at the bottom of the tailpipe

• The DST string was then recovered tosurface and the well permanentlyabandoned in accordance with theapplicable UK regulations

• After installing a CaTS subsea receiveron the seabed, the rig departed theabandoned well location allowing thereservoir pressure and temperature databeing transmitted from downhole to becollected at the receiver

• Provides a unique wireless reservoirmonitoring solution in a permanentlyabandoned subsea appraisal well

Value to client

• 18 months of high quality reservoir datawas recovered from the permanentlyabandoned subsea appraisal well at lowincremental well cost

• The correlation of the reservoir pressureresponses and trends between the Clairphase 1 platform and the Clair Ridgeappraisal well provided clear evidence ofreservoir connectivity

• Cost effective Advanced Reservoir Testingin an abandoned subsea appraisal wellprovided high value data to steer thefuture development planning on Clair

The Expro CaTS wireless communications technology transmits data and controlcommands using electromagnetic (EM) communications. The EM signal uses the steelconstruction of the well, namely casing, liner or tubing as a signal conduit.

CaTS does not require a tubing string in the well and is not affected by cemented pipe,cement, plugs, or bridge plugs lending itself naturally to monitoring in abandoned orsuspended wells without compromise to the integrity of the well. The system isaddressable with up to 20 discrete zones being monitored in a single abandoned well.

Expro Exce l lence exprogroup.com Wireless Well Solutions

B.P. Champion, Expro; I.R. Seale, BP; R.K.Pollard, BP, “Clair Field: Reducing Uncertaintyin Reservoir Connectivity During ReservoirAppraisal – A First Time Application of a NewWireless Pressure Monitoring Technology in anAbandoned Subsea Appraisal Well”, SPE108435, Offshore Europe, Aberdeen, UK(September 2007)

Technical paper reference

ContactFor further information, please contact:

Brian Champion Global Sales Director,Wireless Well Solutions

brian.champion@exprogroup.comwww.exprogroup.com/wws

/ Expro Excellence

Reducing uncertainty in reservoir connectivityduring Clair Field Appraisal – CaTS™ worldfirst wireless gauge installation enables wellmonitoring to continue beyond abandonment

Wireless Well Solutions

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