The Brechin Field, Block 22/23a, UK North Sea

Abstract

Abstract The Brechin Field was discovered by Paladin Resources in 2004. The reservoir is the Paleocene Forties Sandstone Member, with oil trapped in a small dip closure. The prospect was identified as a bright anomaly on a fluid volume processed as part of a 4D survey. However, the anomaly was not consistent with rock physics modelling, and an earlier processed version of the baseline 3D survey showed the opposite response to the 4D datasets. It was established that the fluid anomaly on the 4D data resulted from constructive interference between reflections from the oil–water contact and from top reservoir. Thus, both versions of the data were responding to the presence of hydrocarbons. The discovery well, 22/23a-7, encountered 137 ft of gross oil-bearing reservoir. Without testing or further appraisal, the field was developed in 2005 with a single production well tieback to the Arbroath platform, via the production manifold at Arkwright Field. Brechin is now operated by Repsol Sinopec Resources and cumulative production to mid-2018 was 4.4 MMbbl. Seismic attributes and well-developed reservoir understanding from neighbouring analogue fields permitted the necessary de-risking of hydrocarbon presence, recovery and volumetric uncertainty, to permit the development of an otherwise economically marginal resource.