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ABSTRACT: Petroleum Exploration Using Available Aerial Gamma-Ray Data in Australia

THOMPSON, C. KEITH, and DONALD F. SAUNDERS, Recon Exploration, Inc., Dallas, TX

RECON Exploration Pty. Ltd. has completed initial successful testing of a new method for processing and interpretation of aerial gamma-ray spectrometer data for petroleum exploration in Australia. Test areas included portions of the following 1:250,000 scale quadrangles: Derby (Canning Basin), Colac and Portland (Otway Basin). The Derby test area included Blina, Lloyd, West Terrace and Sundown oil fields. The Colac test area included commercial gas production in PPL-1, and Portland test area contained Windermere wells.

Each sample count rate data for potassium and uranium were normalized to the thorium count rate to suppress unwanted effects of variations in surface lithology or soil type and soil moisture.

The commercially producing fields in the test areas showed characteristic radiometric anomalies similar to those found over 72.7% of 706 oil and gas fields in the U.S. These include low normalized potassium and higher normalized uranium values.. This type of petroleum-related anomaly can be explained in terms of hydrocarbon microseepage-related microbial alterations in overlying sediments.

In addition to existing production-related anomalies, there are groupings of untested similar anomalies in each test area that suggest additional potential for petroleum production. The distribution of anomalies and areas devoid of anomalies appear to clearly define regions with best petroleum potential.

This new methods appears to be effective in all parts of the test areas except salt flats in Portland and Colac test areas. There, radiometric properties of recent surface salt accumulations mask any

petroleum-related gamma radiation anomalies emanating from bedrock sediments.


AAPG Search and Discovery Article #91015©1992 AAPG International Conference, Sydney, N.S.W., Australia, August 2-5, 1992 (2009)