The Fine Characterization Of Single Sand Body Of Yan9 Reservoir In HZ Well Area,Ordos Basin

The study area is located in the middle of Ordos Basin.Yan9 reservoir is the main development layer in the area,which is characterized by small reservoir area and poor contiguity,but good reservoir physical property,high output of single well.At present,the general water injection method can no longer meet the needs of efficient production of oil fields,and it is necessary to adopt the layered water injection method for development,so the fine characterization of single sand body for development layers has become the key.To solve this problem,this paper uses sedimentology principle and reservoir architecture principle to carried out fine characterization and internal configuration research of single sand body in the study area,and establishes a three-dimensional reservoir geological model to realize quantitative research and visual prediction of single sand body in Yan9 reservoir.In the sedimentary period of Yan9,the provenance in the study area mainly came from the direction of north and northeast,and developed delta plain subfacies,including distributary channel,interdistributary bay,natural levee and crevasses splay.The single sand body is mainly distributary channel sand body and develope three vertical superimposition patterns,including isolated type,overlap-type and o-verlay type,and three lateral contact patterns,including interdistributary contact,butt-joint and side shear type.The overlap-type,o-verlay type and side shear type have batter connectivity,while butt-joint take second phase.The sand body of isolated type and interdistributary contact are connected to each other.Through the analysis of distribution characteristics of the single sand body in the two areas of HZ3-01 and HZ8-01,there are 7 periods of channel deposition in the well area of HZ3-01 and5 periods of channel deposition in the well area of HZ8-01.The channels are composed of several single zonal or netted single channel.Among them,the sand bodies of Yan9^2-2 sub-layers and Yan9³ subgroups have a large scale and good connectivity.The thickness of single channel sandbody is in the range from 2～11m and their width range from 150～960m,and the width to thickness ratio is about 106.24.The quantitative relationship between the width and thickness of the single sand body is established,and the fitting formula is obtained,which can provide guidance for the identification and distribution prediction of the single sand body in the area with sparse well pattern.Based on single sand body features,establishing the 3D construct model,facies model and reservoir property model in the two typical wellblock.The geological model directly shows the distribution characteristics of reservoir sand body,physical property and oil-bearing in three-dimensional space,which is more consistent with the geological situation of the study area,and provides guidance for subsequent layering water injection.