A group led by BHP Petroleum Pty. Ltd., Melbourne, plans a $600 million (Australian) development of Griffin oil field, a 1989 discovery in the Carnarvon basin off Western Australia.
The field, along with nearby smaller Chinook and Scindian oil fields, will be developed using a purpose built, disconnectable, floating production, storage, and offloading (FPSO) vessel. First oil is expected in March 1994.
The Griffin production system will be similar in concept to BHP's systems in Jabiru and Skua oil fields in the Timor Sea. However, it will feature significant enhancements in scope and design.
The 1 million bbl FPSO vessel will accommodate 11 wells, nine of which will be producers and two injectors. Peak flow is expected to be 80,000 b/d. There will be spare capacity for connection of four more wells if needed.
A major element in the Griffin development is that no associated gas will be flared.
Although treated mainly as an oil development project, provision will be made to ship 40 MMcfd of gas ashore by pipeline to buyers with whom contract talks are under way. Gas also will be reinjected for pressure maintenance. BHP estimates gas handling facilities will cost $60 million within the total project outlay.
A $100 million contract to build the production/storage vessel has been let to Samsung Co. Ltd. and Samsung Heavy Industries Co. Ltd. of South Korea. However, 40% of the total project value will be of Australian origin.
RESERVES, RESERVOIRS
The three fields hold an estimated 115-130 million bbl of recoverable oil. Of that, 60-70 million bbl are proved. Life expectancy is 13 years.
The oil lies mainly in the Cretaceous Barrow group sands, which have excellent reservoir characteristics. A recovery factor of 50-60% is expected.
Some oil also is to be produced from the overlying Cretaceous Mardie Greensand, which is less pristine although of greater areal extent. Recovery in the Mardie may be as low as 20%. Gas reinjection will be into the Mardie reservoir only.
First phase of the development will involve completion of five existing exploration/appraisal wells and drilling of four more wells, including three horizontal wells in the Mardie. BHP will use permanent downhole pressure gauges to monitor the early response of this reservoir.
The fields lie in 130 m of water about 70 km west of Onslow on the Western Australian coast.
The development plan has been submitted to the Western Australian government for consideration.
BHP, with a 45% interest in Permit WA-210-P on which all three fields lie, operates on behalf of itself, Mobil Exploration & Producing Australia Pty. Ltd. 35%, and Inpex Alpha Ltd. of Japan 20%.
Copyright 1992 Oil & Gas Journal. All Rights Reserved.
