When small samples (i.e., well cuttings) of kerogen-rich rock are pyrolyzed in a test tube placed over a propane torch, oil-like material may be generated and condense as a brown residue around the walls of the tube. This simple technique may be used to identify source rocks capable of generating liquid oil. The artificial test-tube-generating process is believed to be similar to that associated with natural time- and temperature-dependent processes accompanying rock burial in depositional basins. The relative amount of oily residue pyrolytically generated in a test tube is therefore a semi-quantitative measure of the natural oil-generating capacity of the rock. Source rocks which have been subjected to advanced stages of thermal maturation are not capable of generating l quid hydrocarbons and therefore

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do not yield oily pyrolysis residues. The disappearance of pyrolysis residues from rock samples representing deep-burial and high-temperature histories relative to those which yield good residues at shallower depths and lower temperatures may be utilized to determine the depth of the oil-generating to gas-condensate-generating maturity threshold.

The technique has been utilized to map source-rock distributions and maturity thresholds in the Pennsylvanian of the western Anadarko basin.

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