A combine of Esso Australia Ltd. and BHP Petroleum Pty. Ltd. has scored a success with the final well in its 1992 exploratory/appraisal drilling program in the Bass Strait off southern Australia.
Esso-BHP's 2 Blackback step-out flowed 6,640 b/d of oil and 7.88 MMcfd of gas through a 1 in. choke from a 5 1/2 m interval at the top of the Tertiary Latrobe sandstone, the main reservoir sand in Bass Strait. The well was drilled on Vic P/24 permit in about 400 m of water 85 off Victoria state (see map, OGJ, Sept. 14, p. 43).
The combine's 1 Blackback discovery on the permit, tested in 1989, flowed 1,508 b/d of oil and 1.9 MMcfd of gas through a 42/64 in. choke.
The deepwater discovery at the time was seen as marginally commercial even if developed along with two other small discoveries nearby, Terahiki and Hapuku. Esso-BHP geologists believed the poor quality reservoir sand in 1 Blackback would improve elsewhere on the structure because better reservoir characteristics had been encountered in other wells nearby.
The 2 Blackback was sited specifically to test that belief.
The combine's 1992 Bass Strait program seemed on the verge of ending on a sour note with failures of its high risk, big prospect 1 Whaleshark wildcat and 1 Turrum wildcat this fall (OGJ, Oct. 12, p. 88).
Earlier estimates of 55 million bbl of original oil in place for Blackback are likely to be increased because of the appraisal's strong test flow.
Copyright 1992 Oil & Gas Journal. All Rights Reserved.
