Deepwater Bass Strait development slated

The Esso Australia Resources Ltd./ BHP Petroleum Pty. Ltd. Bass Strait joint venture has given the go-ahead for a $220 milion (Australian) development of deepwater Blackback oil field off the southeastern coast of Australia's Victoria state.

Jan. 5, 1998

3 min read

Located 18 km southeast of the existing Mackerel platform and 92 km off the coast, the field will be developed in several phases. The first will involve three subsea wells designed to access about 18.5 million bbl of reserves along with 24 bcf of gas and associated natural gas liquids. The $220 million (Australian) development involves tying the three wells into the Mackerel system for pipeline transport to shore.

First oil is scheduled to come on stream during first half 1999, with production expected to peak at 18,000 b/d during the first 12 months of production.

Complex field

Blackback has presented a complex picture to geologists and engineers since its discovery in 1989.

Located on the steep continental slope, it lies in water depths of 300-600 m.

Five wells have been drilled to date, and although reserves are tentatively put at about 55 million bbl, there is significant uncertainty about the ultimate recovery figure.

The reservoir has an irregular distribution, and the sands are of varying quality. Because of this, Esso/BHP has decided to take the staged approach and make use of existing field infrastructure in the region.

Project details

The three wells in Phase 1, in 402 m of water, will be tied back to Mackerel platform via a single pipeline, and the Mackerel facilities-currently producing 9,200 b/d-will be expanded to handle the increased flow.

Installation work will begin in October 1998, and the estimated production life is 14 years.

Blackback development complements recent field activities elsewhere in Bass Strait, such as new developments at West Tuna, Moonfish, and Bream B and infill drilling programs in other fields.

As a result, Bass Strait activity has been the most extensive in many years-the aim being to maximize oil recovery and commercialize the significant static gas resource base.

Average total oil production for Bass Strait during November 1997 was 230,000 b/d of oil and 390 MMcfd of gas.

Activity will continue in 1998 with Esso (as operator) planning at least 40 wells for the coming year. This will be a mix of appraisal, infill, and exploration wells with four rigs active.

Esso and BHP are 50-50 partners in the region.