The Wisting Field is located offshore in the Barents Sea north of Norway.The field development requiresdrilling and completion of horizontal wells in a narrow pressure window,which is challenging forconventional technology.The Reelwell Drilling Method(RDM)provides a solution for managed pressuredrilling(MPD)to mitigate these challenges.Based on the use of dual-channel drillpipe,RDM enables thepressure gradient in the openhole section to be held constant and nearly independent of the drilling fluid flowrate.RDM provides low-energy drilling,i.e.,efficient drilling and hole cleaning when using low flow andlow-drillstring rotation speed.This allows drilling of horizontal sections within a small pressure windowand limits drillstring fatigue in high-dogleg applications.In order to start qualification of RDM for the Wisting Field,a horizontal trial well was drilled in fall2018 at the Ullrigg Drilling and Well Test Centre,located at the NORCE Norwegian Research Centre inStavanger,Norway.The goal for this trial well was to prove the dual-channel drillpipe capability to performlow-energy drilling,i.e.,low-rotary speed,low flow,and stable downhole pressure gradient.The trial wellhad a challenging geometry with up to 14°/30-m build rate,as required for the field.The 91/2-in.horizontalsection was drilled in order to check the performance of the RDM and start the qualification of the RDMfor the Wisting Field.The trial well was drilled with a low-flow motor,i.e.,with flow rates around 700 lpm.The string rotationspeed was held lower than 5 rpm to limit drillstring fatigue in the high-dogleg section of the well.Efficientdrilling and hole cleaning of the 91/2-in.horizontal hole section was demonstrated.The results from the trialconfirm the predicted performance for the RDM.The results indicate that RDM can keep well pressuregradient within the required window and mitigate the drilling challenges for the Wisting Field.The RDMarchitecture with return flow in the inner string represents a major advantage to avoid cuttings build up inthe well,challenges with laminar return flow,formation wash-outs,mechanical down hole dynamics andECD control by low energy drilling.
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