Study On Sedimentary Microfacies And Sand Body Characterization Of Yan 10₂ Sand Formation In Z297 Well Area

The Lower Jurassic Yan'an Formation Yan10 Formation in the Z297 well area of the Longdong area in the southwest of the Ordos Basin is the main oil-bearing layer system with great development potential,but the distribution of sedimentary microfacies and sand bodies is lack of systematic understanding,and the relationship between sand body connectivity and injection production is weak.In this paper,yan102 sand formation,the main reservoir in this area,is taken as the research object.According to the methods of marker bed,sedimentary cycle and formation thickness control,fine stratigraphic division and correlation are carried out in the whole area,and the framework profile network of stratigraphic correlation is established.On this basis,it focuses on the analysis of sedimentary microfacies types and plane distribution rules of sedimentary microfacies of yan102 sand formation in the study area,describes the spatial distribution characteristics of single sand body in the study area in detail,and implements the relationship between sand body connectivity and injection production.The main work and understanding are as follows:In the braided river facies of the Yan 10₂ sand formation in the well block Z297 in the east of Gansu Province,three types of subfacies,i.e.river channel,river flood and river channel inter channel,and five types of microfacies,i.e.,central beach,river channel sand,river channel edge,river flood plain and river channel inter channel mud,have been identified.Determine the identification mark of single sand body and make a list of the genetic types of sand body;recognize that the vertical contact relationship of single sand body is mainly isolated type,superposition type and cutting superposition type,and the lateral contact relationship is mainly butt joint type and side cutting type;analyze the plane distribution law of single sand body.According to the well pattern,the injection production well group is divided,the injection production corresponding relationship between water injection well and oil well is judged,and the sand body connectivity between wells is identified.It is clear that there are three types of injection production corresponding relationship:injection production,production injection and production injection.The relationship between water absorption index,water absorption ratio and daily production of oil well is analyzed.According to the sand body connectivity,specific injection production improvement measures are proposed to adjust the oilfield in time The development plan provides reliable basis.