Study On Hydrocarbon Source Rocks And Resource Evaluation In The Miaoxinan Sag

Papers are mainly based on the earthquake,logging and geochemical data of the study area of Miaoxinanand the distribution of hydrocarbon source rocks,the type of organic matter,the abundance of organic matter and the maturity of organic matter were analyzed.On this basis,the three-dimensional geological modeling is carried out,and the basin evolution,hydrocarbon generation and expulsion history,migration and accumulation are simulated,and the main conclusions are as follows:According to the study,four sets of relatively mature source rocks,such as the Ed3,Es1,Es2 and Es3 are developed in the Miaoxinan region.Through the analysis of parameters of source rocks,Es3 section due to the type of organic matter is good(II kerogen),higher abundance and its source rock thickness compared to other hydrocarbon source rock is thick can be seen as the main hydrocarbon source rocks.The other hydrocarbon source rocks also have a certain potential for hydrocarbon generation and are also good source rocks.According to the simulation results,hydrocarbon source rocks Es2 in Miaoxinan sag in the late 27.4Ma is already mature,now in high mature and over mature stage,Es1,Ed3 hydrocarbon source rocks are in the late Guantao formation early ripe,the overall in the middle and high mature stage.The most important inducement of hydrocarbon source rocks entering the hydrocarbon generation stage in this area is that the rapid subsidence of the basins in the large area during the deposition period of the Dongying formation resulted in the increase of formation pressure and the rise of low temperature.The oil and gas accumulation period in the Miaoxinansag is mainly from the Guantao formation to the Quaternary.The new fracture system has obvious control effect on hydrocarbon migration and accumulation,and is dominated by the stepwise migration.Through the simulation of hydrocarbon generation and expulsion in this area,it is found that a large number of stages of hydrocarbon generation and expulsion in this study area are mainly in the development period of Minghua formation and Guantao formation.The migration in the horizontal direction mainly takes the braided river delta and fan delta sedimentary facies as the channel,and the distance is relatively short.The vertical migration is the channel of long-term development fault.The combination of the main sedimentary facies,lithology,porosity and permeability and other factors may act as reservoirs are analyzed in the study area,the main study areas of Minghuazhen Group,Guantao group,Shahejie group,either from the street or from the sedimentary facies and lithology,porosity and permeability etc can be used as excellent reservoir the conditions.