Abstract: During oil and gas well drilling operations, drilling fluid volume circulated per preselected vertical borehole increment drilled is continuously measured as well as the percentage by volume of hydrocarbon gas present in the return fluid. The gas is periodically sampled and analyzed to derive a relative ratio of C.sub.1 and C.sub.2 present therein. A functional relationship is then periodically computed relating the drilling fluid volume circulated per vertical increment drilled, and percentage of hydrocarbon gas therein, the rock volume of cuttings from which the gas evolved, and borehole pressure and temperature conditions at which each mud sample received respective cuttings to provide a percentage gas saturation parameter per vertical foot of reservoir. In functional response to the C.sub.1 /C.sub.

Abstract: A method for classifying kerogenous materials, e.g. materials found in raw rocks, sediments, and the like, is disclosed which comprises pyrolyzing a sample containing said materials, and analyzing the pyrolysis gases by gas chromatography and classifying the kerogen by type, i.e., oily, coaly, or mixed type, based upon selected hydrocarbon ratios.

Abstract: A method of geochemical prospecting for buried sulphur mineralization which comprises collecting relatively organic free soil samples, desorbing bound sulphur gases from the soil samples, and analyzing the sulphur gases.