Study On Sedimentary Microfacies Of Dongying Formation In Ren256 Well Area,Renqiu Area

The Dongying Formation in Well Ren 256 in the Renqiu area has good accumulation conditions and huge resource reserves.As the development of Renqiu buried hill oil reservoirs has entered the middle and late stages,the Tertiary Dongying Formation in Renqiu is used as a backup successor.How to better find For large-scale reservoirs,effectively improving the production degree of sandstone reservoirs is the focus of the next stage of reservoir evaluation.With the deepening of exploration and development in recent years,more and more sedimentary phenomena of the Dongying Formation in the Ren 256 well area in the Renqiu area are difficult to explain using simple sedimentary models,and the research on the types of sedimentary facies is controversial.In addition,there has been no fine research on the sedimentary microfacies of the Dongying Formation in the Ren 256 well area in the Renqiu area,so it is urgent to carry out a fine description of the sedimentary microfacies to provide support for sedimentary characteristics for the oil and gas exploration of the Dongying Formation in the Ren 256 well area in the Renqiu area.This study mainly has the following four points of understanding.(1)In this paper,on the basis of previous strata stratification,by using the marker layer method,sedimentary cycle method,and well-seismic combination method,the strata of the Dongying Formation in the Ren 256 well area are divided and compared,and the Dongying Formation in the Ren 256 well area in the Renqiu area is divided and compared.From top to bottom,it is divided into 3 sublayers and 7 sand formations,namely,the first member of the East,the second member of the East,and the third member of the East.(2)Combined with the distribution of heavy minerals,clastic components,seismic attributes,wave impedance,thickness of small sandstone layers,sand-to-ground ratio,etc.,it is found that the main sediment source of the Dongying Formation sedimentary system is from the southwest.Combining lithological characteristics,compositional maturity and structural maturity characteristics,particle size analysis,biological characteristics,and core phase and facies signs,the sedimentary facies of the Dongying Formation in the study area are divided into shallow water delta facies and lacustrine facies,and subdivided into three subfacies And 10 microphases.(3)On the basis of the study of the sedimentary system of the Dongying Formation,combined with the single well sedimentary facies histogram and well-connected sedimentary facies,the plane sedimentary facies of the Dongying Formation in the Ren256 well area was studied,and it was confirmed that the sedimentary facies of the Dongying Formation were mainly shallow water delta and lacustrine facies,among which The shallow-water delta facies in the depositional period of the third member of the East were mainly distributed in the south and southwest,and a small shallow-water delta was developed in the northwest;the shallow-water delta facies of the second member of the east were mainly distributed in the south and southwest,and consisted of two shallow-water deltas.Delta composition;shallow water deltas in the eastern section are mainly distributed in the southeast and northeastern regions.(4)The depositional period of the Dongying Formation was a sedimentary pattern of “interaction between shallow water delta and shore-shallow lake”;vertically,the lacustrine deposits of the first and second members of the East gradually transitioned to the shallow water delta deposits of the third member of the East;During the depositional period of the formation,shallow water delta deposits gradually migrated from the south to the north and diverged.Therefore,the evolution law of shallow water delta sand bodies from south to north is clarified,which has a great guiding role in the deployment of exploration and evaluation.