Abstract: Combining Gamma Radiation and Multi-Element Chemical Surveys For Detection of Hydrocarbons
Roger M. McCoy, Jason Blake
The translocation of chemical elements in the rock and soil overlying an oil field has been explained by several alternative mechanisms. Although the theory is not yet proven, the electro-chemical concepts proposed by Pirson and elaborated by Tompkins offers plausible explanations for phenomena observed in the field. In the oil environment, certain mobile elements, such as uranium, may be detected by gamma radiation counters. Gamma radiation anomalies by themselves may not be reliable due to various radiation influences not related to oil deposits. Hence, a quick and inexpensive follow-up procedure that can help verify a radiation anomaly is needed. For this purpose, analysis of plant and/or soil samples provides a means of direct observation of the translocation of chemical elements hich may be indicative of oil in the subsurface.
A test of the combination of these two techniques was done on the Salt Wash oil field in Utah and the Blackburn field in Nevada. A positive radiation response is present in each case. The soils in and near the fields were then surveyed, and analysed by discriminate analysis. Maps showing the probability that each soil sample point has an anomalous concentration of a suite of chemical elements was produced from the discriminate analysis. The result of the study is that there is strong evidence from two inexpensive lines of evidence that significant translocation of elements in the soil has created anomalous chemical concentrations in patterns that coincide with the locations of the oil fields.
AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994