Mesozoic-Cenozoic Oil And Gas Migration And Transport Systems In Yingmaili Area, Kuqa Depression

Yingmaili area in Kuqa Depression is an important oil and gas accumulation area,in which the Mesozoic and Cenozoic is rich in oil and gas resources and great exploration potential.The construction of the transport system in Yingmaili area has important guiding significance for oil and gas exploration and development in the study area.Based on the comprehensive use of drilling,logging,core and analytical data,this paper analyzes and summarizes the characteristics of sandstones,sand body transport conductor and unconformity transport conductor in Yingmaili area,and defines the dominant transport system in the study area.A fan delta-lacustrine sedimentary system is developed in the sandstones section in the Cenozoic Paleogene E_1-2km₅member in Yingmaili area,and a braided river delta sedimentary system is developed in the Mesozoic Cretaceous K₁bs formation.The lithology of the E_1-2km₅member is mainly feldspathic quartz sandstone,the K₁bs_1-2member mainly develop feldspathic lithic sandstone,and the K₁bs₃member mainly develops lithic feldspathic sandstone.In the E_1-2km₅member,Yangta area has the best physical properties,the average porosity can reach 10.32%,the permeability 104.98m D,and the Yudong formation has the best physical properties,the average porosity is 17.99%,and the permeability 551.36m D.The pore types of the Mesozoic and Cenozoic sandstones are mainly inter granular pores and inter granular solution pores,with a small amount of intragranular solution pores and microfractures.The distribution of sand body is controlled by sedimentary facies,the sand body thickness and sandstone to formation thickness ratio in the E_1-2km₅member decrease from west to east and from north to south,the connectivity of sand body weakens from northwest to southeast,and the transport capacity of sand body weakens gradually from north to south.the connecting area of oil and gas flow is mainly concentrated in Quele and Yangta area.The sand body thickness and sandstone to formation thickness ratio of K₁bs formation gradually decrease from east to west and from south to north,the connectivity of sand body weakens from southeast to northwest,the transport capacity of sand body weakens from south to north,and the oil and gas flow connection area is mainly concentrated in Yudong area.There is an angular unconformity contact between the sandstone section in the E_1-2km₅member and the K₁bs formation in the study area,and the unconformity is composed of three layers:bottom conglomerate,weathered clay layer and semi-weathered rock formation.the unconformity transport capacity is the strongest near well Quele 1,well Yangta 5 and well Yudong 710.Through the analysis of the direction of oil and gas migration,it is confirmed that the oil and gas in the south slope converges to well Yangta 5 through sand body transport and unconformity transport in the sandstone section of well Quele 1,and then continues to migrate to well Yudong 2 and well Yudong 710 through the sand body and unconformity transport of K₁bs formation,and is blocked by unconformable weathered clay layer in the sand body of K₁bs formation to form a dominant transport system in the study area.