L034 Surat experimental seismic reflection and refraction survey, QLD, 1958

Brief description

An experimental seismic survey was conducted at Surat, Queensland, on behalf of the Australisa Oil and Gas
Corporation Limited during a five week period from May 28th to July 2nd. 1958. The area lies within the southeastern portion of the Great Artesian. Basin on Authority to Prospect No. 36P and, sel the evidence of numerous bores near Roma, and a few other scattered bore logs, is considered to contain sediments suitable for the generation and accumulation of hydrocarbons in possible, economic vantities.

A local geological survey by the Australian Oil & Gas Corporation suggested a structure of considerable dimensions - the 'Weribone Uplift' - which, if substantiated, would provide a promising location for a stratigraphic test bore.

The experimental survey conducted by the Bureaushowed that useful results could be obtained throughout the area by conventional methods of reflection and refraction shooting. The reflection shooting indicated a fairly uniform sedimentary section with generally flat-lying beds and a probable total thickness of 7,000 to 8,000 feet. The refraction work recorded several velocities: including one near 19,000 f/s which is assumed to be a basement velocity. Depths measured to this high Velocity refractor support the estimate of the
thickness of sediments made from the reflection cross-section and indicate 4 south component of dip of about 40 ft. per mile across the area surveyed.

Neither the reflection nor the refraction work gave any evidence for the existence of the 'Weribone Uplift'.
However, the more northerly refraction traverse indicated a local component of north dip at basement depth, and a single reflection record shot along that traverse suggested a substantial thickening of the deeper sediments towards the north. Insufficient seismic work was done to estimate the northwards extent of this dip. Such limited evidence might well indicate a purely local irregularity in basement topography. On the other hand, the north dip could be extensive, and therefore structurally significant. Any further seismic work contemplated in this area should be directed, in the first instance, towards checking this possibility.

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Maintenance and Update Frequency: asNeeded

Statement: The experimental seisnic survey described in this report was underahen by the Bureau of Mineral Resources,Geology
an Geophysics at the joint request of the Queensland Mines Department and the Australian Oil and Gas Corporation Limited. The area surveyed is situated in southern Queensland in the vicinity of Surat township, and lies within the area of the Company's Queensland Authority to Prospect No. 36P.

No mineral development exists within the area. Considerable flows of natural gas, and small quantities of oil have been found since 1900 in many of the bores Which have been drilled in the .adjacent Roma area but no major commercial supplies have been developed. However, this part of the Great Artesian Basin remains an area of potential interest and the Australian Oil and Gas Corporation requested the survey on the basis of a report by their geologist, T.B.H. Jenkins, on the "Geology of the Surat Inlier and its Str,tural Significance".

The primary object of the survey was to give the Company some idea of how useful a later and more extensive seismic survey of the'Weribone Uplift' would be to determine a drilling location for an oil search bore. This involved determining the best seismic shooting technique on each of the geological formations occurring on the surface. As a secondary objective the survey might be expected to yield information on the probable thickness of the sedimentary section and, finally, it was hoped that a combination of reflection and refraction shooting might produce some evidence to support the uplift postulated by Jenkins.