Research On The Sedimentary Microfacies Of Sha1's Upper Member To Dong3 Member Of Liu485 Well Area In Dawangzhuang Oil Field

Dawangzhuang oil field belongs to Suning-Dawangzhuang structural belt in Raoyang Depression.The structural features of Dawangzhuang oil field are northwest dipping and Southeast uplifting anticlinal structures.It is one of the most favorable areas for oil and gas enrichment in Raoyang Depression.Western Dawangzhuang oil field has relatively simple reservoir structure,shallow reservoir burial and relatively concentrated reservoirs.After many years of development,some reservoirs have oil-water contradictions,ineffective injection and production,and low level of water drive control and production.The structural lithologic reservoirs in the lower part of the Dawangzhuang anticline are favorable potential areas.Based on the principles and methods of sedimentology,using the data of drilling coring,logging curves and analytical tests,combined with the regional geological background,to use the work route of point(well)-line(section)-surface(floor plan)-domain(time evolution and spatial distribution)-point(favorable area).It is of great significance to study the sedimentary microfacies of Shal's upper member to Dong3 member of Liu485 well area in Dawangzhuang oil field,and to predict the favorable potential areas,and to put forward the suggestions for the deployment adjustment.The main results and perceptions are as follows:1.According to the actual situation in dawangzhuang area,combing with seismic,well logging,drilling,logging,analysis and testing data and the principle of "standard layer control,cycle contrast",this paper makes a detailed comparison and a comprehensive analysis.Finally,Dong3 member of Liu485 well area in Dawangzhuang oil field is subdivided into 46 small layers in 5 oil groups and Shal's upper member is subdivided into 23 small layers in 4 oil groups.The stratigraphic division and correlation of 214 Wells in the study area were completed,and a complete isochronal stratigraphic framework was established.2.Based on the multivariate comprehensive analysis of the provenance of Liu485 well area in Dawangzhuang oil field,it is concluded that the main provenance in the sedimentary period of Shales upper member and Dong3 member is in the northwest direction.3.Through comprehensive analysis of sedimentary facies markers,core facies and single well facies,it is considered that the main types of sedimentary period in Dong3 member of the study area are shallow water delta facies,delta plain subfacies,distributary channel,overbank sand,crevasse fan and floodplain microfacies.The Shal'upper member belongs to delta facies,delta plain subfacies and Delta front microfacies are developed,and distributary channel,water and flood plain are developed.Microfacies such as lower distributary channel,overflow sand,crevasse fan,flood plain,estuary bar,distal bar,sheet sand and interdistributary bay.4.Sedimentary micro facies profiles and plane analysis were carried out,and the distribution characteristics of sedimentary micro facies in ShaTs upper member and Dong3 member were obtained.lt is believed that the normal delta sedimentary system is mainly developed in Shal's upper member of the study area.lt appears as a complete deltaic backwash from bottom to top:Among them,the Esl ? oil group belongs to delta front subfacies,microfacies types are underwater distributary channel,distributary bay,sand sheet and far sand bars;Esl? oil group belongs to delta front subfacies and microfacies types are underwater distributary channel,mouth bar,distributary bay,sand sheet and far sand bars;Esl ? and Esl ? oil group belong to delta plain sub facies and microfacies types are distributary channel,channel lateral margin(overflow shore sand)and flood plains;the eastern third member belongs to the sedimentary system of shallow delta,which is characterized by the distributary channel sand body as the skeleton,the deposit of estuary dam is not developed,the distributary channel sand body is thinner than that of normal delta,and the distributary channel sand body is in direct contact with lake mudstone,the color of mudstone is changeable,which shows the alternation of oxidized color and reduced color,and its vertical sequence is often incomplete.Each oil group develops the sedimentary system of shallow water delta,belonging to the subfacies of shallow water delta plain.5.According to the statistical analysis of the test data of 89 Wells in different blocks and different strata in the study area,the results show that the productivity of different sedimentary facies zones is inconsistent.The sub-facies in Dong3 member of Liu485 well area and its adjacent area of Dawangzhuang oil field are mainly shallow delta plain,and the reservoir microfacies are distributary channel,overflow bank sand and crevice fan respectively.According to the location of the well,the distributary channel is divided into two parts:main channel and river edge.The Shal's upper member of is mainly delta plain subfacies and front subfacies,and the reservoir microfacies are distributary channel,estuary sand bar,far sand bar and sheet sand bar respectively.The results show that the subaqueous distributary channel microfacies in ShaTs upper member is the main reservoir sand body with the highest productivity,followed by the sheet sand microfacies and the far sand bar sand body,and the crevasses fan sand body with certain productivity.The main channel reservoir sand body of Dong3 member has the highest productivity,generally accounting for more than 80%of the total productivity,followed by the overflow bank sand body,the edge of the river,and other microfacies such as the estuary dam only exist in a few layers in the study area.