The Main Controlling Factors And Models Of Hydrocarbon Migration And Accumulation Of The Jurassic To Paleogene Strata In Sarybulak,Zaysan Basin

Starting from the basic geological conditions and tectonic background of the Zaysan basin,based on the comprehensive utilization the data of the geology,seism,geochemistry,under the guidance of multi-disciplinary theories such as petroleum system,hydrocarbon pool forming dynamics,associated with petroleum accumulation modeling and geologic analogy,this paper studies firstly the element of hydrocarbon accumulations such as rock,reservoir,seal rock,source-reservoir-seal assemblage,trap.Then,the accumulation progress is established,the accumulation mechanism is illuminated,and through anatomy of hydrocarbon reservoir type,the main controlling factors of petroleum accumulation are discussed,the models of oil and gas accumulation are establishedand the distribution of oil and gas is analyzed.The results are as follows:Petroleum accumulation,being predominated by structural reservoirs,is mainly located to the foreland zones of the Zaysan basin,accompanied by the well growth of faults.Natural gas is mainly contained in shallower reservoirs,and deep reservoirs are characterized by the heavy crude oil enrichment.The difference enrichment is dominated by multifactor functioning of the faults and seal rock.Faults help to form a variety of structural traps,the later formed faults could be used as the oil and gas migration channel,the seal rocks play an important role in the accumulation of Paleogene gas reservoirs.Combined with the characteristics of tectonic and sedimentary,based on the analysis of accumulation conditions and accumulation features,accompanied with the process of oil and gas migration and accumulation,the accumulation models of the Jurassic to Paleogene strata in Zaysan Basin can be divided into three types: the model A controlled directly by the fracture conducting system,the model B controlled by the conducting system of the faults and connecting sand combination,the model C which is managed by the combination of the connecting sand,faults and the surface of unconformity,what's more,the model B can be divided into B1 that connecting sand is prior to the faults and B2 that the faults are prior to the connecting sand.