Remaining Oil In The High Water-Cut Period Of Complex Fault-Block Oilfields Quantitative Characterization Studies

Block F of X oilfield is currently in the"double-high"stage of"high water cut and high oil recovery".The reservoir has significant fault blocks,and the distribution of remaining oil is complex.It is difficult to stabilize and increase oil production.Therefore,it is very essential to characterize and evaluate the remaining oil in the high water cut stage.In view of the change of reservoir parameters of coring wells before and after water flooding in Block F of X Oilfield,a sand-packing tube flooding experiment was carried out.Then,the reasons for the index changes caused by the washing of the reservoir with water were analyzed,and according to the experimental results,the functional relationship between the water passing multiple and the physical properties of the reservoir was carried out,and the corresponding numerical simulation method was implemented,which solved the problem that the traditional reservoir numerical simulation software could not consider the reservoir.Time-varying defects in layer physical properties.The time-varying variation of the parameters will also affect the production and water cut.Combining the remaining oil dominant potential abundance and the over-water multiple two parameters,the remaining oil dominant potential abundance is used to characterize the remaining oil dominant potential abundance value and the over-water multiple.To characterize the remaining oil fluidity,superimpose the two parameter fields into a new remaining oil potential evaluation field,and divide the high and low boundary values to establish a complete remaining oil evaluation system.Afterwards,the history matching of the whole area and single well of Block F of X oilfield was carried out,the differences of various indicators considering time-varying and not considering time-varying were analyzed,the distribution pattern of remaining oil was analyzed,and the potential of remaining oil was evaluated.On the basis of the clear development potential of the target oilfield,a variety of measures to tap the remaining oil were proposed,including:well pattern shutting off,well pattern infilling,increasing of fluid delivery and other measures.The results show that:the results of the oil flooding experiment show that the permeability of the core is generally increasing,and the increasing trend of the permeability is first increasing quickly and then tending to be slow;The calculation results of the theoretical model show that the greater the increase in permeability,the lower the yield and the higher the rise in water content.The comprehensive analysis results of remaining oil potential show that measures such as well pattern shutting off,increasing of fluid delivery,and well pattern infilling can effectively suppress the ineffective circulation of injected water and improve the utilization rate of injected water.Among all the measures,the well pattern infilling measure has the best oil increasing effect,with a cumulative increase of 4.198×10~4m~3.The remaining oil with the dominant potential abundance of remaining oil is effectively produced,and it has a good effect of increasing and stabilizing production.