West Australian Petroleum Pty. Ltd. (Wapet) has added Roller and Skate oil fields to its inventory of producing fields off Western Australia.
Elsewhere off Australia, main Bass Strait producers Esso Australia Ltd. and BHP Petroleum Pty. Ltd. are likely to develop the small Moonfish oil and gas field with a monopod similar to those used in the strait's Dolphin and Perch fields.
ROLLER, SKATE DEVELOPMENT
Production started from Roller at a rate of 5,000 b/d of oil, 1 month ahead of schedule and under budget.
When details were disclosed about 2 years ago, project cost was estimated at $150 million (OGJ, Aug. 17,1992, p. 29).
Discovered in 1990 and 1991, respectively, Roller and Skate fields lie 20 km off the coastal town of Onslow.
The two fields are expected to ramp up oil production to a combined peak in August-September of 35,000 b/d. Total liquids output, including water, will be 68,000 b/d. The fields are being developed with horizontal wells drilled from four unmanned monopod platforms, which have no separation facilities. The monopods were fabricated entirely at Perth. Roller C monopod went on stream May 23. Roller A and B monopods are expected to start up in mid-June. Skate's lone monopod is expected to start up by the end of June.
Production from Roller/Skate will be from eight wells. The 6 Roller well has a 1,125 m horizontal section that was completed open hole in permeable sandstone.
Oil moves via 27 km pipeline to Wapet's oil and gas processing plant on Thevenard Island about 10 km north of the fields. There, Roller and Skate oil and gas output comingles with production from the area's mainstay producer, Saladin field, as well as satellites Yammaderry and Cowle.
Previously, gas from Saladin, Yammaderry, and Cowle fields had been flared because the volumes were too small to transport.
However, Roller and Skate have economic reserves of associated gas. Their gas production, pegged at about 20 MMcfd, will be added to volumes from the other fields and transported from Thevenard to Western Australia's onshore gas trunk pipeline via a spur to onshore Tubridgi field. Wapet's Thevenard gas system productive capacity is about 21 Mmcfd.
If needed, Thevanard gas can be stored in Wapet's onshore Dongara and Mondarra fields farther south, although Wapet hopes to secure a gas supply deal soon.
Combined oil reserves in Roller and Skate fields are estimated at 40 million bbl, good for about 12 year life.
Partners in Wapet are Ampolex Ltd., Chevron Asiatic Ltd., Shell Australia Ltd., Texaco Inc., and Western Mining Corp. Ltd.
BASS STRAIT
Esso/BHP's Moonfish proposal, still incomplete, is part of a major new assessment of remaining oil and gas reserves in Bass Strait production licenses.
Moonfish, closer to shore than Marlin and Snapper fields, holds about 20 million bbl of oil and 19 bcf of gas.
Elsewhere in the Bass Strait, Esso/BHP will begin a major infill drilling program in nearby Fortescue oil field following completion of a successful infill program in West Kingfish and more recently Mackerel field. Fortescue infill work could add 43 million bbl to the field's estimated reserves.
The infill program will continue with work in Tuna and Flounder fields.
Thus far, infill drilling has arrested the decline in Bass Strait oil production, keeping production steady at about 300,000 b/d. Industry officials hope the new infill program will maintain production at that level for several more years.
The Bass Strait combine also is conducting a concentrated 3D seismic survey over Turrum and Marlin fields. It is part of an effort to increase gas reserves in the region to compete for new domestic supply contracts when the current contracts expire in 2000.
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