Delivering BP North Sea's Longest OHGP Completion in the Harsh Environment Deepwater West of Shetlands

Abstract

The BP Operated Foinaven, Schiehallion and Loyal fields, located West ofShetland (WoS) in the UKCS, are a highly challenging environment to work in.The three deepwater fields are drilled and completed utilising 4th generationsemisubmersible rigs and the harsh marine environment can severely impactoperations. Although standalone screen completions have been used successfully in themajority of the wells, premature sanding problems have been experienced, potentially jeopardizing project economics due to prohibitively high cost ofremediation. To improve this situation, alternative means of sand controlcompletions have therefore been sought. There are now four Open Hole Gavel Pack(OHGP) completions in the fields, all of which are performing well with highproductivities and no sand production. In this paper, we present a case history on the application of thecirculating water pack in the Foinaven field. The P11 sidetrack is the thirdgravel pack completion in this deepwater environment, and the first to becompleted with a water pack. The subject well is the longest OHGP in BP's NorthSea portfolio with a 3,345 ft open hole, penetrating through two sand bodiesand multiple shale and mudstone packages. The well was designed with a long horizontal open hole section tocost-effectively access multiple sand bodies and maximise productivity whileminimising drawdown across the sandface. Baker Oil Tools BetaBreaker technologywas utilised for the completion to maintain the treatment pressure below thereservoir fracture gradient during the gravel pack. The well was completed witha +110% packing efficiency, has an early time mechanical skin of +2 based onpressure buildup testing and was delivered safely 5 days ahead of target atP(10) production expectations. Introduction The Foinaven P11 sidetrack (204/24a-A16z) was planned to replace theoriginal A04z production bore which had watered out and suffered from excessivelevels of sand production. The original P11 well (A04z) was completed withnon-compliantly expanded 5–1/2" expandable sand screens. The sidetrack wasdesigned with a long horizontal open hole section to cost-effectively accessmultiple sand bodies and maximise productivity while minimising drawdown acrossthe sandface. It was planned to access the reserves left behind in theabandoned motherbore as well as accessing new reserves to the East of theoriginal well location.