US 5,055,397 A · Geomicrobiological methods of ore and petroleum exploration

Abstract

Geomicrobiological exploration method employing one or more culture, luminometry or tritiated thymidine assays of microbes (bacteria) for sensitivity, determined as survival rate in percentage, of the microbes to selected toxic materials, preferably heavy metals and/or hydrocarbons. The survival assay values are plotted as contours on a geophysical map and target areas of potential interest are identified and further evaluated by inspection or other techniques. Examples show actual use of the techniques to identify a target area in a raw prospect petroleum lease area which was drilled to successful oil discovery thus proving the method. Sensitivity test incubation ranges from 1-3 hours (preferably 2 hours) for heavy metals at 20-25 degrees C., and 3-10 min. for pentene/hexane at 15-20 degrees C. Luminometry is fastest, being run in 1.5-30 minutes and most suitable for field surveys. Toxics concentrations may range from 0.001 ug/ml to 15,000 ug/ml for heavy metals to 0.001-25 vol % for hydrocarbons.

Claims20

Dependent claims

Petroleum exploration method comprising in sequence, the steps of:

a) obtaining, at least one sample containing ambient microorganism population from an area of potential petroleum interest and recording the source location of said sample;
said sample being selected from the group consisting of soil from a B-soil horizon, and subsea sediment obtained below a depth of about 0.5 meters below the surface of the seabed;
b) dividing said sample into at least two aliquots;
c) preparing the first of said aliquots as a control, and the second of said aliquots for testing of sensitivity of said microorganism to at least one toxic material selected form the group consisting of a metal, a hydrocarbon, or combinations thereof;
d) testing said microorganism in said second aliquot for relative sensitivity to at least one of said toxic materials by subjecting said aliquot to at least one concentration of said toxic material for a period of time sufficient to determine the microbial survival rate;
and
e) assaying the remaining live microorganisms in said aliquots for the quantity of ATP or DNA, and correlating said ATP or DNA level determined in said samples to the quantities of microbes resistant to the reference concentration of heavy metal or hydrocarbon in said test sample;
and
f) correlating the microorganism sensitivity to relative presence or absence of metals or hydrocarbon products, or their relative presence or absence as a pathfinder for petroleum.

6 more elements

Dependencies are inferred from the claim text.

Geomicrobiological methods of ore and petroleum exploration

Life of this patent

Geomicrobiological methods of ore and petroleum exploration

Life of this patent

Abstract

Claims20