THE INFLUENCE OF INTRUSIVE ROCK ON THE EVOLUTION OF HYDROCARBON SOURCE ROCKS IN SUOLUN COUNTY, INNER MONGOLIA

The Upper Permian Linxi formation in Inner Mongolia has a great potential of hydrocarbon. During the evolution of hydrocarbon source rocks, the intrusive gabbro plays a controlling role. Based on the analyses of lithology and organic geochemistry, the influence of the gabbro body on the hydrocarbon source rocks of Linxi formation is studied. It is found that in Linxi formation in Suolun area, the influencing range of gabbro intrusion to the surrounding hydrocarbon source rocks is just as wide as the width of the intrusive rock itself. Outside the intrusive body, hydrocarbon source rocks are characterized by metamorphic zonation, with low organic matter content, high maturity and developed cracks, which are caused by the high temperature and pressure when the gabbros form. The high temperature greatly accelerates the thermal evolution of the hydrocarbon source rocks, increasing the hydrocarbon generating quantity. The high pressure produces a quantity of cracks, which provide channels for the expulsion of the hydrocarbon.