The Sedimentary Environment and Molecular Geochemical Characteristics of Jurassic Source Rock in Central and Southern Junggar Basin

In central and southern Junggar basin,Jurassic source rock is characterized by the large thickness,widespread,whose partial interval have well potential hydrocarbon and exploration.Based on the former study,according to the organic geochemistry and organic petrology experiment analysis method,the distribution characteristics,hydrocarbon potential,biomarker geochemistry and sedimentary environment have been investigated.The results indicate that in western Well Pen 1 depression,the Jurassic formation source rock has worse hydrocarbon potential,in Shawan depression,the Badaowan Formation and Xishanyao Formation have better hydrocarbon potential,but Sangonghe Formation source rock is worse.In Sikeshu depression,Badaowan Formation source rock has better hydrocarbon potential.Additionally,in earlier sedimentary period of Badaowan Formation,the research area developed delta front sub-facies and shore shallow lake facies.In Shawan depression,the formation developed shore shallow facies and limnetic facies with much organic matter input.The source rock is formed in weak oxidation-strong weak sedimentary environment with high plant input.In Sangonghe Formation sedimentary period,the study area distributed shore shallow lake faices,whose source rock is formed in strong oxidation environment with lacustrine high plant input.In Xishanyao Formation sedimentary period,in Mahu depression,Luliang uplift,and Western Well Pen 1 depression distributed delta plain facies and front plain facies.The sedimentary centre moved to eastern and southern depression with sub-deep lake facies,whose source rock is formed in weak oxidation-strong oxidation environment with high lacustrine plant input.