Study on Hydrocarbon-Generating History of Hydrocarbon Source Rock in Upper Permain E. Sichuan Basin with Hydrocarbon-Generating Kinetics

In the Eastern Sichuan Basin the study of hydrocarbon-generating history of the Upper Permian source rocks has not well done up to now.Firstly,the hydrocarbon-generating history are not separately evaluated for Ⅰ-Ⅱ1 limestone and Ⅲ mudstone.Secondly,there are limitations in the evaluation of source rock maturity when conversing vitrinite group reflectance of marine facies to vitrinite reflectance by fitting formula.Trying to solve the problems above,we demarcated two kinds of dynamic parameters for oil-generating and gas-generating of source rocks by thermal modeling and chemical dynamic methods.Combined with thermal history and burial history of the Eastern Sichuan Basin,we fitted out a transformation ratio curve of oil-generation.The study shows that organic material from limestone and mudstone of the Upper Permian reached oil and gas threshold in 200 Ma and 109 Ma,and stopped oil-generaing in 170 Ma and 140 Ma.