Simulation Analysis Of Dominant Seepage Channels In Sandstone Reservoirs With Water Injection Development

Sandstone reservoirs are widely distributed and abundant in reserves.However,in the process of water injection development,most of the oilfields have entered a high water cut period.Prolonged waterflood development aggravated the heterogeneity of oil layer and the inner contradictions.The pore radius and permeability gradually become larger.The percolation channel is formed between water injection well and oil well.Injected water preferentially flows along the high permeability channel,The existence of high permeability channel leads to low efficiency or invalid cycle of injected water.If injection water does not work,it will seriously affect the efficiency of water flooding development.Therefore,if we can accurately describe the percolation channel and high permeability channel,calculate their pore size,pore volume,and the ratio of pore volume to the total pore volume,we can determine strength and dosage of plugging agent according to these parameters.Finally,it will be beneficial to improve the effect of water injection and improve the oil recovery.For a long time,the identification methods of dominant seepage channels are mainly qualitative identification.Due to the influence of borehole environment factors,there are still many uncertainties in the identification of dominant seepage channel by using logging data.Therefore,it is necessary to make a further research on how to accurately calculate the parameters of dominant seepage channel and judge the development of seepage channel.In this paper,taking C fault block in Wangguantun oilfield as an example,according to the geological survey and reservoir characteristics,the distribution area of seepage channel in flooding unit is determined,I also study the calculation method of pore size distribution and pore volume.According to the actual situation,the pore size is divided into four levels:super large pore,large pore,middle pore and small pore.Based on the analysis of the original data of oil field,the distribution of pore channels and the parameters of the channel are simulated.According to the results of tracer monitoring,the development of seepage channel between injection and production units is verified and qualitative judgment.In addition,By comparing and analyzing the relationship between oil layer and oil-water layer,the pore size and volume parameters of the oil-water layer are simulated.At the same time,I also propose a new method to design the plugging agent according to the minimum pore radius.These research results can provide an accurate basis for the oil field plugging construction.