Dynamic Evolution Model Of Carboniferous Hydrocarbon Accumulation In Santanghu Basin

Santanghu Basin is an important petroliferous basin in China.Its Carboniferous volcanic reservoir has become the key target of oil field stimulation.However,due to the influence of multi-stage deformation and tectonic movement,the Carboniferous Reservoir in Malang Sag has undergone multi-stage reconstruction and adjustment,and the current research degree can not reflect the state,change and transformation process of local reservoir at the critical moment.In this study,the characteristics of source rock,fine reservoir anatomy and dynamic reservoir forming process have been analyzed to solve this problem.First of all,the geochemical evaluation of source rock has been carried out by comprehensively using logging data,seismic data and geochemical analysis test data,the main source rock and its lower inferior limit of hydrocarbon expulsion have been defined,and the thickness and distribution of high-quality source rock have been studied.And then the reservoir of block Ma 67 and block Ma 71-Ma 33 of Mazhong structural belt have dissected,the oil and gas source of the reservoir has been defined,the characteristics of volcanic rock reservoir have been summarized,and the reservoir has been divided,the source-reservoir-cap assemblage,the reservoir forming factors and the relationship between them have been recognized,and the conditions for local oil and gas enrichment have been determined.At last the dynamic geological process of the reservoir in the study area has been analyzed by integrating the hydrocarbon generation history of source rock,structural evolution history and the current thermal evolution degree of oil and gas.The results show that the Carboniferous Reservoir in the middle structure zone of Malang sag in Santanghu basin was formed in the Cretaceous period,and following the reservoir forming model of "late expulsion of lower mature source rock and early expulsion of upper low mature source rock" in Karagang Formation reservoir,the reservoir forming model of "two-stage hydrocarbon expulsion later generation self storage" and "two-stage hydrocarbon expulsion later generation main generation up storage" in Hargau Formation reservoir,it has guiding significance for the next oil and gas exploration in this area.