GEOCHEMICAL EFFECT AND EXPULSION TYPE OF PRIMARY MIGRATION OF OIL
Tian Shicheng ( China University of Geosciences, Wuhan 430074 ) Sun Shangru ( Henan Oil Field College )
Based on the systematic organic geochemical analysis of continuous sampling in source rocks of different thickness, the paper discusses the geochemical effect of primary migration of oil and concludes that there are two apparent effects. The first is depletive effect, and the second is chromatographic effect. So the expulsion from source rocks of different compenents is various. Generally, hydrocarbon is easier to expelled than non-hydrocarbon. So does saturated HC than aromatic HC, chain alkane than cycloalkane, normal alkane than branched ones, and HC with low carbon number than that with high carbon number. According to the compac-tion and geochemical effect, the source rocks are classified into five types: fully expelled, expelled, with hydrocarbon stagnation,lateraly expelled and expelled throu-gh pressure fracture at the same time their characters and distribution are descri-bed.