After crude oil has been biodegraded, the parameters of saturated hydrocarbon in GC analysis should be changed.

The biodegradation of regular sterane and rearranged sterane in crude oil was studied on the basis of simulated biodegradation experiment to the crude oil.

Steranes and terpanes exist in saturated hydrocarbon component of oil and source rock, and they are usually identified by gas chromatogram-mass spectrum.