Research On The Sedimentary Facies Of Chang 8 Oil Formation From The Triassic YanChang Formation In The Longdong Area Of The Ordos Basin

The Triassic extension group is the most important oil-bearing strata in ordos basin and has important research value and economic value.Longdong aera is located in the southwestern ordos basin,the Chang 8 reservoir group in the region of the research is not the tip of the iceberg,but according to the basis of sedimentary system and some related research progress that contains a few new understanding and modern sedimentary notion which will play an auxiliary role from that,another excellent scene may arise from our eyes horizon.The reaearch of Longdong area has already acrossed to a new page in the resent years,combined with a large number of emerging research and a large amount of production data which will greatly improve and enrich the research on its sedimentary facies of chang 8 reservoir.Of course it will denifitely be a significant fundamental progress toward the future research assgniment.The sedimentary system of chang 8 reservoir features,and the microfacies combination,vertical evolution and different types of sand body distribution rule have been studied.The reveal of the spatial and temporal distribution of depositional systems and the aim to get a subsequent expectation for high yield are both fatal progress from that.Furthermore,the high abundance ratios of the comprehensive research of oil and gas accumulation will provide us with some important theoretical significance and practical significance in a enormous extent.In data collection,digestive and regional sedimentary evolution are all based on the analysis of the background.Through the field outcrop and core observation,as well as some large analysis contrast tests and parent rocks,it has been concluded that there are three main provenance directions: the southwest of west gansu ancient land and the qinling fold belt,la shan ancient land in northwest and north of yinshan ancient land.In addition,various sedimentary facies signs in the study area are determined,and the sedimentary system and some sedimentary facies of the research area are given by the using of some well logging data.The reaearch of some sedimentary facies and the sedimentary system showed that the Chang 8 oil layer of longdong area of ordos basin has formed a set of shallow braided river delta sedimentary system,whatsmore,it has been further divided into three main next level faces: shallow braided river delta plain,shallow braided river delta front and shallow lake.Thus,the other eight main microfacies can show some accurate details from that.The sedimentary model of this foreign minister conforms to the sedimentary characteristics of shallow water platform delta.Through the research,it has been realized that the subaqueous distributary channel sand body and shallow lake subfacies in the distributary channel sand body and shallow lake subfacies are both of the key objects in the future research and the next step of production.