Potential for the Use of Biogeochemistry in the Detection of Petroleum

KLUSMAN, RONALD W., and M. A. SAEED, Colorado School of Mines, Golden, CO, and M. A. ABU-ALI, ARAMCO, Golden, CO

Biogeochemistry was applied to the indirect detection of petroleum microseepage in the vicinity of the Eagle Springs oil field, Railroad Valley, Nevada and the Cave Canyon field, Paradox basin, Utah. Trace elements were measured in native vegetation over and surrounding areas of production at the test sites. The oxidation of microseepage in the upper part of the soil column is postulated to cause an increase in plant uptake of transition trace elements such as iron, manganese, vanadium, and a decrease in plant uptake of alkaline earth elements such as calcium, strontium, and barium.

An increase in uptake of transition trace elements and a decrease in alkaline earth elements was observed in Fourwing saltbush over the Eagle Springs field. The postulated increase in uptake of transition trace elements and decrease in alkaline earth elements was not observed in Big Sagebrush nor in Utah juniper over the Cave Canyon field.

The observation of the postulated effects at Eagle Springs may be due to the relatively large rates of microseepage independently observed using other methods, or the loss of the light hydrocarbons and extensive faulting in Railroad Valley. The apparent failure to observe the same effect at Cave Canyon may reflect the lack of faulting and the retention of light hydrocarbons in the reservoir. Another possibility is that the available plant species at Cave Canyon do not exhibit the effect at the lower soil pH measured in the area. The theory predicts that the increased uptake of transition elements and decreased uptake of alkaline earth elements will be enhanced at high soil pH.

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)