DIVERSITY IN THE THERMAL EVOLUTION AND HYDROCARBON GENERATION OF SOURCE SOCKS IN DIFFERENT SUB-DEPRESSIONS OF RICH OIL DEPRESSION

Every rich oil depression in the Bohai Bay Basin generally consists of several sub-depressions which are commonly independent hydrocarbon-generating centers.Due to the differences in sedimentary-burial history of these sub-depressions,there are obvious differences in thermal evolution and hydrocarbon generation of source rocks between different sub-depressions and their different structural positions.Taking the main source rocks of Paleogene Shahejie Formation in Dongpu Depression and Dongying Depression of the Bohai Bay Basin for example,the article demonstrated a comparative analysis in the thermal history and hydrocarbon generation history of source rock between major sub-depressions in two depressions,and the control effects on the reservoir formation and distribution were illustrated in detail.The result shows that,in rich oil depression which consists of several hydrocarbon generation sub-depressions,the source rock in the most deep buried sub-depression adjacent to fault in steep slop is the best,which is widely distributed with high thermal evolution degree,great hydrocarbon generation potential and rich resources.Because of the distinction of the conditions of source rock and burial-thermal history,the hydrocarbon-generating cha-racteristics of source rock in different members of the same strata series and different structural positions in the same sub-depression show relatively large diversity.There are obvious diversities in hydrocarbon generation of source rock in different rich oil depressions.