THE RESERVOIR MECHANISM FOR OIL GAS IN TERRESTRIAL CLASTIC ROCK IN THE CHISHUI AREA,GUIZHOU PROVINCE

Attention has not been paid for a long time to petroleum exploration in the intermediate and shallow terrestrial clastic rock layers in the Chishui area,Guizhou Province.By analysis and correlation of actual data,it is known that in the terrestrial clastic rock,there are two source rock systems of Xujiahe formation of upper Triassic and Jurassic which are of hydrocarbon potential.However gas source is from the underlying marine formation.The fracture system linking source rock and reservoir is extremely important for petroleum accumulation in this area.Gas reservoir in the intermediate and shallow terrestrial clastic rock in the Chishui area belongs to deep source-shallow accumulation type,and is characteristic of multi-stage migration and accumulation,and becoming reservoir in Himalaya stage.