Enriched Pattern And Quantitative Description Of Remaining Oil For Complex Fault Block Reservoir

Currently, complex fault block reservoirs in old oil field in eastern part of our country have entered high water cut stage. After decades of development, the underground oil ,gas and water distribution is very complex.The distribution of remaining oil is relatively enriched in most scattered parts, but the mechanism of the enriched remaing oil is still not clear. Therefore, the study of fualts and their combinations on the mechanism of the formation of the enriched remaining oil, the patterns of enriched remaining oil of different complex fault block reservoirs and their quantitative deacription is very important to improve the developing level of complex fault block reservoirs, stablize production of old oil field.According to the characteristics of complex fault block reservoir, seepage law under different combinations of faults and well patterns was studied. From the view of streamline and combining with corresponding numerical simulation results, enriched mechanism of remaining oil was analyzed during the presence of faults. Being prototype of the actual existence of complex fault block reservoirs in Dongxin oilfield, the complex fault block reservoir was classified and idealized, different types of complex fault block reservoir model were established. And on this basis, different enriched patterns of remaining oil of complex fault block reservoir were studied in using numerical simulation technique. Defining the standard of enriched remaining oil area is the oil displacement efficiency less than 20%, using enriched reserves of remaining oil per meter of single–well and enriched areas as description indexes of enriched remaining oil area, the quantitative relationship between enriched reserves of remaining oil per meter of single–well, enriched areas and oil well spacing, distances between oil well and fault, distances between water injection well and fault, production and injection well array spacing, produced fluid intension of oil well and oil viscosity was studied,and multiple regression model of different types of complex fault block reservoir was established according to that.Finally,the qualitative and quantitative system of enriched pattern of remaining oil of complex fault block reservoir was formed,which can be able to provide the basis for tapping measures of complex fault block reservoir.