L029 Heywood experimental seismic survey, Western District Basin, VIC, 1956

Brief description

An experimental seismograph survey was carried out near Heywood in the Western District Basin, south-western Victoria, during November and December, 1956 by the Bureau of Mineral Resources, Geology and Geophysics. The work was requested by Frome-Broken Hill Pty. Ltd. and was intended primarily to ascertain if reflections from deoper sediments could be recorded through a surface layer of basalt which covers considerable areas in the Western District of Victoria. Several short traverses were shot during the survey at places where a variety of surface conditions for seismic exploration could be tested. Pattern and air-shooting techniques were tried as well as the conventional single shot-hole technique. Good reflections were recorded from depths down to eleven thousand feet in areas where there was no basalt. Some apparent reflections of poor quality were recorded at times as great as 5 seconds after the shot was fired. An attempt has been made to correlate the reflections with stratigraphic horizons. Reflections were obtained from strata beneath a basalt cover in some places when explosive charges were fired in single shot holes; reflection quality was improved when pattern and air-shooting techniques were used.It was not possible to record reflections through a cover of tuff containing basalt bands on the slopes of Mt. Clay. Pattern and air-shooting were tried unsuccessfully. Sub-surface information in the Heywood area is obtainable by seismic exploration and techniques for gaining the best information from the seismic method are discussed.

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Maintenance and Update Frequency: asNeeded

Statement: Heywood is in south-western Victoria, about sixteen miles from the coast and about fifty miles from the VictoriaSouth Australia Border. It is situated in a sedimentary basin in which Tertiary marine sediments are exposed on the surface. For the purposes of this report, this basin will be called the Western District Basin. Interest in this basin as a potential oil-bearing area stems from an investigation by Dr. Wade in 1915. Since then, several petroleum geologists have investigated the area, and the most -recent geological mapping has been done by the Department of Mihes, Victoria, in collaboration with the Department of Mines, South Australia (Boutakoff and Sprigg, 1953). Geophysical work in the basin has been ce.rrieri out by Zinc Corporation Limited (airborne magnetometer survey), the Bureau of Mineral Re source s (ground magnetic and gravity surveys), the South Australian Mines Department (gravity survey), and Frome-Broken Hill Pty. Ltd. (gravity survey). An experimental seismic survey, which is the subject of this report, was made by the Bureau of Mineral Resources in November and December, 1956. The application for the survey was made by Frome_-Broken Hill Pty. Ltd., through the Department of Mines, Victoria. Frome-Broken Hill Pty. Ltd. has a Petroleum Exploration Permit (No.5) covering the HeyWood area.