Study On Origin Of Deep Natural Gas And Gas And Source Rocks Correlation Of Gudian Depression In Songliao Basin

According to the research of sedimentary environment,organic matter and qualitative evaluation of deep hydrocarbon source rocks,it is clear that the deep hydrocarbon source rocks are mainly dark mudstone,the abundance of organic matter in the Huoshiling formation is higher than that in Shahezi formation and Yingcheng formation;The types of organic matter are mainly II2 and III,secondly II1 and no ?;The maturity of organic matter in the Huoshiling formation is from high maturity to over maturity,from mature to high maturity in the Shahezi formation;In general,the deep hydrocarbon source rocks have good hydrocarbon generation potential;The source rocks of the Huoshiling formation are best,followed by the Shahezi formation and Yingcheng formation.By studying the characteristics of deep natural gas composition,carbon isotope and light hydrocarbon,it is clear that the hydrocarbon content is the most in the Gudian depression and the deep natural gas is wet;Deep natural gas is mainly organic gas,including inorganic gas and mixed genetic gas;The deep natural gas of Huoshiling formation and Shahezi formation is mainly coal type gas.The calculation results of deep natural gas maturity and the comparison of light hydrocarbon fingerprints show that the deep natural gas in Shahezi formation mainly originated from the deep source rocks of Shahezi formation,that in Huoshiling formation mainly originated from the deep source rocks of Shahezi formation and Huoshiling formation,which has the characteristics of near source accumulation.