Sedimentary Organic Facies And Distribution Features Of Lacustrine Source Rocks In Raoyang Sag

Raoyang sag located in the center of Jizhong depression is the most important oil-gas rich sag in Jizhong depression.With the degree of prospecting higher,it's of vital importance to study source rock's distribution accurately.The thesis combines sedimentary faces,the biomarker of soluble organic matter in source rock and some oil-gas geochemistry parameters to classify sedimentary organic faces types,divide single well sedimentary organic faces and depict plane sedimentary organic faces,in order to reveal spatial distribution feature of sedimentary organic faces.The article which is based on core observation and description,well-logging evaluation,geochemical analysis,sedimentary faces,includes several aspects: building logging response model of key wells to calculate total organic carbon and count the thickness of different levels of the source rocks;identifying seismic features of the source rocks,tracting seismic faces,extracting seismic attribute,defining the distribution range of source rocks;showing the distribution features of different levels of the source rocks.Three suites of lacustrine hydrocarbon are developed in Raoyang sag,which are distributed vertically,respectively,in the upper and lower of Member 3 of Shahejie Formation,in the lower of Member 1 of Shahejie Formation.The results show that the zones of source rocks of the main subsag in Shahejie Formation are distributed in B,C faces and a bit A-B faces.The development of the source rocks is controlled by sedimentary environment and stratigraphic sequences,namely,source rocks deposited in shallow to half-deep lacustrine environment,high-quality hudrocarbon source rocks of the upper and lower of Member 3 of Shahejie Formation developed in lacustrine transgressive system tracts and highstand systems tracts,high-quality hudrocarbon source rocks of lower of Member 1 of Shahejie Formation developed in lacustrine transgressive system tracts,medium-quality hydrocarbon source rocks developed in highstand system tracts.