Research On Oil-water Distribution Law In Ji 45 Fault Block Of Baorao Oilfield

The Ji 45 fault block in Baorao Oilfield is located in the Jiergalangtu sag of the Erlian Basin.The activity of the main fault on the north side of the sag causes the bedrock to split into blocks and causes severe tension and large tilting,resulting in the fact that the stratigraphic structure in the study area is extremely complicated.The study area is located in the sedimentary background of the large braided river delta system.During the sedimentary period of Tengger Formation,the fault activity is the strongest,the depression has the largest sinking depth,the water body is deep,the lake area is wide,and the lacustrine sedimentary reaches its peak.Sources and reservoirs of the first and second members of Tengger Formation are deposited.The study area is located in the sedimentary background of the large braided river delta system.During the sedimentary period of Tengger Formation,the fault activity is the strongest,the depression has the largest sinking depth,the water body is deep,the lake area is wide,and the lacustrine sedimentary reaches its peak.Sources and reservoirs of the first and second members of Tengger Formation are deposited.Firstly,the well logging and seismic data are combined to implement the stratification scheme and top structure of each layer,and standard wells and standard layers are selected.High-resolution sequence stratigraphy is used to establish isochronal stratigraphic framework.According to the sequence of oil formation,sand formation and sub-formation,a unified and fine stratigraphic framework of Tengger formation in Ji 45 fault block is established,and the study area is divided into 2 oil groups,11 sand groups and 50 sub-layers.Secondly,using core,logging and other geological data,combined with previous research results,determine the source direction and sedimentary system background of each stratigraphic unit during the sedimentary period,and implement the sand body connectivity,fully digest and absorb the fine anatomical results of the sand body in the study area.and summarize the distribution characteristics of the sand body in the whole area plane.For Baorao Oilfield,where oil-water distribution is extremely complicated,10 sand groups in the first and second sections of the Tengger Formation will be divided into different oil-water units by analyzing initial productivity and production dynamic data,combined with structural characteristics and oil-water distribution rules.The whole area is cut into several independent fault blocks by faults.The oil-water distribution characteristics are obviously divided by faults,and the development of sedimentary facies in the vertical and horizontal directions in the block determines the spatial variation of the sand bodies in the Tenggeer Formation of thedepression.The interlayer in the study area allows the formation of layered reservoirs and the development of multiple oil-water systems in the vertical direction.Each fault block of the study area has an independent oil-water system or multiple oil-water systems.The oil-water interface of different blocks is neither identical nor unique.Under the premise of structural control,the reservoir develops fault block reservoirs and lithologic reservoirs.The whole area is mainly controlled by structure,and the range of oil control by fault sand matching and lithology is small.The oil-rich belt of the Ji 45 fault block in Baorao Oilfield is located in the northwest of the whole area,in the high structural position of slope zone,with good oil-bearing property.By analyzing the influence of structural characteristics and sand body distribution on oil-water distribution in the study area,three main controlling factors of oil-water distribution are summarized.It is considered that the distribution of oil and water is generally affected by tectonic control,which conforms to the rule that “oil is in the upper part and water is in the lower part”;From the sedimentary microfacies of the work area,the channel sands and the mouth bars are the main bodies of sedimentation,and the distributary channel and the main body have good physical properties,which are high-quality reservoirs with oil and gas enrichment;The large-scale faults developed in the study area are basically north-north-east and north-east-east trending,mainly distributed in the central slope zone of the study area.The intersection of faults and sand bodies at high angles is conducive to oil and gas enrichment.