Australia, Geophysical Exploration, and Great Artesian Basin: ABSTRACT

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Petroleum exploration began in the Great Artesian basin of Australia in 1900 with the recovery of a strong flow of gas from a depth of approximately 3,500 feet in a hole drilled on Hospital Hill at Roma, Queensland, in an attempt to strengthen the town's artesian water supply. Drilling, both sporadic and intense (including 20 holes in the boom exploration year of 1929), has continued in the area through the years. The lack of significant surface outcrops in much of the basin, and an unconformity at the base of the Mesozoic cover, made structural analysis by means of surface studies difficult, if not impossible. At the request of the exploration companies still operating in the Roma area in 1947, the Bureau of Mineral Resources carried out magnetic and gravity surveys and two experimental seismic surveys from 1947 to 1953. Electric logging of test wells was begun in 1954 but, by the mid-1950s, few of the basin's structural or stratigraphic problems had been solved. Encouraged by liberal concession terms and government subsidies, serious geophysical exploration was started by the Australian-owned Associated Group in 1959. Major world oil firms joined the search in 1960 and the exploration techniques developed in other parts of the world were brought to bear on the problems of the basin. Geophysical data, augmented by information from many test wells, have made it possible to strip the Mesozoic mantle from the basin and have disclosed not a single large basin but many basins. The commercial return from a large exploration investment has been disappointing to date but the chapter is not yet complete. Gas has been found in abundance, yet the Moonie field remains the only oil field of consequence. Moonie and Alton oil are reaching the market but gas still awaits a gathering network of pipelines. The structural and stratigraphic framework of this great basin is still being drawn from a decelerated program of geophysical exploration. Somewhere within the assemblage of data probably lies the key to discovery of a major oil field which, when found, will provide the impetus for completion of the geophysical-geological mapping job. End_of_Article - Last_Page 483------------