The Study On Architecture Analysis And Remaining Oil Of Large Scale Overlap Channles

Since 1971,basic well pattern was developed in the Saertu and Putaohua layer in Xing 12 Area in Xingshugang oilfield.After the basic well pattern,Xing 12 area successively experienced three adjustments.Until now,there were four sets of well pattern in Xing 12 area.In order to provide technical reserves and practical basis for the tertiary recovery,Xing 12 Area in Xingshugang oilfield carried out alkaline-surfactant-polymer flooding field test in 2005 and made it industrialized.However,after a long time of alkaline-surfactant-polymer flooding,the cognition of the reservoir producing situation,the change of physical property,the connectivity of sand body and the distribution of the remaining oil are still not sufficient enough.Especially through the transgression regression transgression cycle,the sedimentary environment of deposition units was changed greatly and the reservoirs were Serious heterogeneity.Layers were cut and overlapped seriously which made the distribution of remaining oil was more fragmented,groundwater was more complex after the oil ASP Flooding.All above made the recognization is more difficult.Therefore it is necessary to systematically evaluate the change of sand body inner architectural structure and the distribution of remaining oil of the main reservoir(PI Formation)which have been carried out alkaline-surfactant-polymer flooding.In this paper,taking the Xing 12 alkaline-surfactantpolymer flooding test area which located in the south of the Xingshugang oilfield as an example,using logging data,through high resolution fine fluvial stratigraphic correlation,compound sand body anatomy,microfacies fine analysis and point bar sand body fine modeling,the meticulous stratigraphic correlation of the whole area was realized,and the distribution of microfacies and single sand body and the inner architectural structure of point bar were revealed accurately and delicately.In this paper,the PI3 layer in Xing 12 test area is fine contrasted and the high resolution stratigraphic framework is established under the condition of dense well pattern.Using the key technology of the combination of large overlap river facies high-resolution sequence comparison and practice,namely distinguishing single period channel vertically,contrasting the thick layer of cutting and stacking sand body,identifying river cutting and stacking surface using single well,from division to combination in space,contrasting interface firstly,and then contrasting causative interface,the contrasting problem of PI3 reservoir with very complex cutting and stacking sand body and straddle river channel is commendably resolved,which made a solid foundation for the research of time unit plane sedimentary microfacies,single sand body and meander point bar recognition and the prediction of lateral accretion body and lateral accretion interlayer.The six depositional time unit plane sedimentary microfacies and single fine sand body distribution maps show that the reservoir types are of various kinds of channel sands,such as distributary channel,small crevasse channel,abandoned channel and underwater distributary channel.River channels were cut and overlapped seriously.Edge sedimentation of some river channel is not complete,and interspersed with some abandoned channel and discontinuous interchannel deposition.The inner heterogeneities of river channel were revealed,especially the distribution of abandoned channel.The abandoned channel and discontinuous interchannel deposition play a role of shielder and flow resistance in the single channel sand body,and control the water flooding,the formation and distribution of remaining oil and layer potential.Through the calculation of the internal configuration parameters of the overlap channels sand body,the spatial distribution pattern of the thin layer is established,which provides a theoretical basis for the establishment of the geological model of the fine configuration of the point bar.Lateral accretion layer in the point bar as an impermeable barrier layer has a direct impact on the sand body inner connectivity status and injection production,and controls the distribution of the remaining oil.Influenced by the shield of lateral accretion interlayer,the water flooded thickness is small along the lateral accretion direction and the bottom is flooded seriously,and the remaining oil is mainly concentrated in the middle and upper part of the point bar.Overlap sand body architecture,which has profound significance on further tapping the potential of remaining oil and determine the injection-production relationship.