Recent production and drilling success of the Stag oil field from multidisciplinary evaluation of OBC seismic data

Abstract

Originally discovered in 1993, the Stag oil field, on the North West Shelf of Western Australia, has proven to be both a prolific and complicated reservoir since production began in 1998. To date, more than 56 million barrels have been produced, in addition to significant volumes of water and glauconite, which has resulted in complex changes to the reservoir over time as the field has produced. Because the reservoir is shallow, at 680 m true vertical depth subsea (TVDSS) with shallow carbonates causing noise issues and imaging challenges, Stag Field remained largely invisible on seismic data. To address these issues, a 220-[Formula: see text] 4C-3D ocean-bottom cable survey (OBC) was acquired in early 2008. Subsequent processing and interpretation of these data, including a joint multicomponent inversion, have resulted in drilling six successful new wells with additional wells currently underway and planned in the near future.