Study On Sedimentary Facies And Sand Body Distribution Of The Taiyuan Formation In Linxing Area

There are abundant oil and gas resources in the eastern margin of the Ordos Basin.The types of oil and gas reservoirs in the basin are mainly stratigraphic-lithologic gas reservoirs,and oil and gas reservoirs are often characterized by low porosity and permeability.The research area of this paper is located in the central part of the Linxing area on the eastern margin of the Ordos Basin.Linxing area is the main oil and gas producing area.Permian Taiyuan Formation is one of the main oil and gas producing zones.It has certain guiding significance for oil and gas exploration in this area to clarify the types of sedimentary facies,the plane distribution characteristics of sedimentary facies and the distribution law of favorable sand bodies in the study area.This paper is guided by the theories of sedimentology,sequence stratigraphy,and petroleum geology.The geological basic data such as outcrop,profile,logging data,and core are used.The Taiyuan Formation in Linxing area is taken as the research object.By identifying sedimentary facies marks such as sedimentary structure,rock type and logging curve,the sedimentary facies types and their plane distribution characteristics,the distribution range and distribution characteristics of sand bodies of Taiyuan Formation in Linxing area are studied in detail,which lays a solid foundation for oil and gas exploration and development in this area.According to the characteristics of regional marker beds,with the electric response and sedimentary cycles,and based on the principle of equal thickness of strata,the Taiyuan Formation in the study area are stratigraphically divided into Tai2 and Tai1 sections from bottom to top.The Tai 1 member is further divided into one sand group,and the Tai 2 member is divided into two sand groups.From bottom to top,they are P₁t₂-2(Tai 2²),P₁t₂-1(Tai 2¹),and P₁t₁(Tai 1¹).Six stratum skeleton profiles were established for study.It is found that the total thickness of Tai 1 formation is about 53m,that of Tai 2 formation is 60m approximately,and that of Tai 1¹,Tai 2¹ and Tai 2² are generally stable in the study area,with local changes in the thickness of small layers.