Characteristics Of Sedimentary Facies And Sand Body Distribution In The Second Member Of Dongying Formation In Ying13 Fault-block Of Dongxin Oil Field

Dongxin area is a typical compound oil and gas accumulation area in China.The tectonic conditions of Ying13 Fault Block are extremely complex,where the fault blocks developed,the genetic type of the sandbody is complex,and morphology and superimposition patterns are relatively variable,which affects the efficiency of oil and gas exploration and development in the late stage.In this paper,the main object of study is the second member of the Paleogene Dongying Formation of in Dongxin oilfield.Under the guidance of the theory of sedimentary petrology and seismic sedimentology,the small layer correlation and seismic sedimentology are studied based on the three-dimensional seismic data,drilling and logging data in the study area.The fine stratigraphic framework of the study area was established,the shape and distribution of sand bodies were described,and favorable sand bodies were predicted.The study formation was divided into 4 sand groups and 25 sub-layers.By determining the color,composition,structure,sedimentary structure and logging equivalent sedimentary facies markers of core,it was clear that braided river and meandering river sediments were mainly developed in the seconod member of Dongying Formation,and the main subfacies and microfacies types were further divided.Meanwhile,it is concluded that there are three vertical superimposition patterns of sand bodies in the study area: independent,superposition and cut,and five kinds of sand body plane contact style: substitute,side cut,butt,overflow contact and flood plain contact.Finally,by combining sedimentary facies,well logging data,provenance,structure and genetic type of sand body,sandstone in second member of Dongying Formation in Ying13 Block can be subdivided into 4 reservoir types.The favorable sand body distribution of the second member of Dongying Formation in Ying13 Block is described in detail,which lays a solid foundation for later exploration,development and deployment.