The Banff Field, Blocks 22/27a, 29/2a, UK North Sea

Abstract

AbstractThe Banff Field is an oil field with a small gas cap containing an estimated 300 MMB0 oil-in place. The structure straddles the boundary between blocks 22/27a and 29/2a in the West Central Graben area of UK Central North Sea. The field was discovered by well 29/2a-6 in 1991. Banff Field is a Steeply dipping raft of fractured Late Cretaceous and Danian Chalk on the flank of a salt diapir. Paleocene sands draped over the raft provide addtional reservoir potential. A vertical oil column of over 3000 ft is present within the reservoir sourced from the underlying upper jurassic Kimmeridge Formation shales. Hydrocarbon migration into the trap is believed to have started in the Eocene.The highest reservoir productivity occurs in the Late Cretaceous Tor Formation, which is expected to yield most of the field's reserves. Chalk porosity ranges from 15% to 35% but matrix permeabilities are generally less than 5 mD. Drainage is achieved through extensive faulting and fracturingInitial uncertainties over reservoir performance and connectivity led to a phased development. Phase i comprised a six month Early Production System (EPS), during which time 5 MMBo were produced and the viability of the field was confirmed. Phase 2 Production is by means of a Floating Production System and Offtake (FPSO) Vessel Named the Ramform Banff. First oil production was achieved on 30 January 1999 and ultimate reserves are expected to be in excess of 75 MMBO.