THE SALADIN OIL FIELD

Abstract

The Saladin Oil Field is located immediately east of Thevenard Island, 25 km northwest of Onslow, in the Barrow Sub- basin, northwest Australia. Saladin 1, drilled in 1985 on a structure mapped from 1984 and older seismic data, tested 47° API oil at 875 kL/d (5510 B/D) from the Early Cretaceous Barrow Group. Additional shallow- water seismic was shot in 1985 and a Telseis* survey conducted in early 1986 over Thevenard Island and its fringing shoals. Saladin 2 in 1986, and Saladin 3 in 1987, tested at 1745 and 1790 kL of oil per day respectively (10 975 and 11 280 BOPD), setting successive Australian single- zone flow records. The fourth well, Saladin 7, was drilled in 1988 on a 1987 seismic line and tested at 1720 kL of oil per day (10 820 BOPD).

The oil occurs in southeast- dipping Barrow Group sands overlain by and upthrown against Muderong Shale across the northeast- trending Saladin Fault. The Barrow Group sands have porosities around 24 per cent and permeabilities averaging 5- 6 darcies. Some claystone layers are present, and carbonate cement reduces porosity but less so permeability in parts of the oil column. A bioturbated sand has low permeabilities due to clay burrow- linings.

Oil- in- place is currently estimated at 11 MkL (70 MMBBL). Field development will involve offshore platforms and deviated wells from Thevenard Island, on which oil storage and treatment facilities will be placed, and an offshore loading terminal for tanker transport. First oil production is scheduled for mid- 1989.