Study On Digital Core And Remaining Oil In Xing-6 Area,Xingshugang Oilfield,Daqing

The Xing-6 area of the Xingshugang Oilfield has undergone several well network encryptions.The average integrated water content of the area is 91.97%.At present,the Putaohua,as the main oil layer,has undergone ASP flooding,and the degree of mining has reached 67.6%.Due to the ASP flooding,the micro-pore structure and physical properties of the reservoir are increasingly complex,resulting in unclear distribution of the remaining oil.Therefore,in this paper,based on the conventional microscopic studies of reservoirs,a digital core study based on CT scans was conducted.Through pore network modeling and seepage simulation,the micro-characteristics of reservoirs and the distribution of remaining oil before and after ASP flooding were explored.It provides a theoretical basis for the remaining oil distribution and potential exploration.The paper obtained the following research knowledge:(1)Based on CT digital core,modeling and characterization studies have been carried out on the basis of conventional reservoir microscopic studies.In the digital core modeling process,the improved NLM filtering algorithm can be filtered on the basis of structural comparison,improving the boundary recognition effect;based on multi-constraint binary segmentation and micro-pore throat identification,the pore throat boundary is accurately divided.The pore throat volume model was extracted.With the porosity and cubic length as self-constraint conditions,the REV size suitable for the study area was selected.The reliability of the data was improved while the computational efficiency was improved.(2)Based on the data of thin sections and the statistical results of digital cores,the dynamic changes of different sedimentary reservoirs before and after the ASP flooding were clarified,and the dynamic changes of the reservoirs of the point-dam reservoirs were mainly discussed.After the ASP flooding,the micro-heterogeneity of the reservoir is even more obvious.The rock particles undergo a certain degree of dissolution which results in the reduction of small particles and the unevenness of some grain surfaces.The development of large pores is more prominent,and the three-dimensional distribution of micro pores and large pores are much more uneven.(3)The micro three-dimensional displacement process of remaining oil with pore modeling and flow simulation was realized.The research made up for the insufficiency of the two-dimensional flowing study and proposed that the major reservoirs of the point-bar in the study area developed large pores five types of remaining oil,including remaining oil of large pores,oil layers,remaining oil of throat type,corner oil and isolated oil.And the remaining oil of large pores accounts for a large percentage.This paper reveals the influence of different types of pore structure on the distribution patterns of remaining oil in point-bar reservoirs.It is believed that due to the intensification of reservoir heterogeneity after ASP flooding,the distribution of remaining oil is mostly in the form of flakes and isolated.The remaining oil gathering in the large-pores and small throats is relatively high,with a certain mining potential.However,the distribution is scattered and complex,resulting in the increasing difficulty of next mining.