Study On Hydrocarbon Migration And Accumulation Model In The Western Section Of South Slope In Kuqa Depression

The south slope in Kuqa Depression in Tarim Basin is located in the south margin of Kuqa Depression,which is rich in oil and gas resources,and it is an important oil and gas exploration field.The south slope in Kuqa Depression is characterized by the vertical superposition of marine cratonic structure layer and continental foreland structure layer.At present,oil and gas exploration have been found in both marine and continental strata,mainly continental oil and gas.Complicated geological setting,multi-source mixing,multi-stage accumulation and strong tectonic thrusting deformation make the process and model of hydrocarbon accumulation unclear.Based on seismic data,physical property test data,geochemical test data,combined with oil and gas reservoir analysis,this paper carried out a detailed study on the oil and gas source,hydrocarbon accumulation period,transport system structure and evolution characteristics,hydrocarbon migration characteristics and hydrocarbon accumulation types in the western section of the south slope in Kuqa Depression,finally defined the hydrocarbon accumulation process in the study area,and established the hydrocarbon accumulation model in the study area.The results show that the crude oil in Yudong-Quele-Yangtake area in the western section of the south slope in Kuqa Depression is mainly from the source rocks of the Middle Jurassic Qiakemake Formation,the crude oil in Yingmaili area is mainly from the source rocks of the Upper Triassic Huangshanjie Formation,and the natural gas is mainly from the coal measure source rocks of Kuqa depression.Since Cenozoic,three stages of hydrocarbon accumulation events have occurred in the study area,and the characteristics of hydrocarbon source,hydrocarbon transport system and hydrocarbon migration are obviously different in different accumulation periods.According to the above differences,three hydrocarbon accumulation modes are established in the study area: They are the early unconformity lateral transport buried hill accumulation mode,the early oil source fault-unconformity-middle-shallow fault transport accumulation model,and the late oil source fault-unconformity-sand body-middle-shallow fault transport accumulation model.Based on the established oil and gas accumulation model,the buried hill in the third row of the south slope in Kuqa Depression is predicted to be a new field of oil and gas exploration in the future.