Petroleum Developments in Western Australia

Abstract

Abstract From relatively humble beginnings to its world class billion dollar projects, Western Australia has become the focal point of Australian oil and gas production. Currently it is the nation's largest producer of hydrocarbons and ranks fourth in world LNG production. The rapidly expanding oil and gasindustryl is the State's fastest-growing economic sector with output totalling about US$3.4 billion per annum. This paper is one of three which review opportunities and growth in the petroleum industry in Western Australia. In the 1970's exploration drilling on the North West Shelf yielded the giant Scott Reef, North Rankin, Goodwyn, Angel and Scarborough gas-condensate fields. The giant Gorgon gas discovery was made in 1981. The perception of the NorthWest Shelf being gas-prone changed in the 1980's with major oil discoveries at Wanaea, Cossack and Griffin. Since then numerous oil discoveries have been made in other areas of offshore Western Australia including Wandoo, Stag, Laminaria, Buffalo and Cornea (Fig. 1 and 2). Infrastructure continues to grow with further field developments on the North West Shelf. The presence of facilities and pipelines will facilitate production from existing oil and gas ields, and the development of other fields and discoveries. Production facilities used now include conventional platforms, mini platforms, concrete gravity structures, automated buoys, monopods, subsea completions and tiebacks to FPSO's. In 1997, 28 North West Shelf oil and gas fields produced some 64 million barrels of oil, 40 million barrels of condensate and 803 BCF gas, A synopsis follows. Oil and Gas Developments Barrow Island (WAPET). The onshore Barrow Island oil field was discovered in 1964 and is the largest oil field discovered to date in Western Australia - over 1 billion barrels in place2 Production commenced in 1967 and peak production of 50,000 barrels per day was reached in 1971. In excess of 800 wells have been drilled on the island, including 440 oil production wells, 240 water injection wells, and various gas producer and water disposal wells. Infill development drillingphases are underway. The majority of producing wells use beam pumps to pump oil to the surface. The remaining producersuse gas-lift or are on natural flow. Produced fluids are piped from each well to one of ten separator stations. Clean oilis pumped to the main oil storage facility, comprising five 200,000 barrel tanks. The oil is then piped through a 6 mile long submarine pipeline to an offshore mooring system where tankers are berthed. WAPET comprises Chevron, Texaco, Mobil and Shell. Offshore Airlie Island (Novus). The South Pepper oil field was discovered in 1982, North Herald and Chervil in 1983. In order to improve oil recovery from thin oil sands and decreaseproject costs, alternative development approaches were considered3. Rather than constructing a high capital cost productionplatform, the Vicksburg jackup rig was modified with the addition of on board production processing equipment andused over the South Pepper field.