Optimization Of The Position Of Plugging Agents In Different Remaining Oil Distributions Of Rhythmic Formations

During the exploitation with well pattern in heterogeneous reservoirs,oil and water migration and remaining oil distribution laws are important for residual oil exploration in high water-cut stage.As a result of the heterogeneity,water channeling is easily found,and the difficulty of profile control and water shutoff increases year by year.So research on the optimum position of plugging agents in different rhythmic formations has great significance for field production.To guide the experiments of physical simulation,numerical simulations were carried out to observe the existing patterns of oil and water in different rhythm formations after primary water injection.Afterwards,explorations of effects with different plugging positions were also launched as well.Before the experiments of physical simulation,a 3D physical model was made,which can be used to observe the vertical section and horizontal section of any depth between injection and production well.With it,experiments were carried out to simulation studying the remaining oil distribution of different rhythm formations with inverted nine-spot well pattern at the high water-cut stage;and furthermore,the study of fine profile control and water plugging were carried out.Through comprehensive comparison based on the results of numerical and physical simulation,summarize the regulation of remaining oil distribution and the optimum position of plugging agents.The results showed that: in the simulated positive and reverse rhythm formation,the remaining oil is mainly distributed in the middle permeability layer between the location which is 2/4 L away from the injection well and all production wells(L is the distance between the injection and edge well),to positive rhythm formation,it's better to put plugging agents below the middle or the head end of the main remaining oil,the former is best;to reverse rhythm formation,it's better to put plugging agents above the location which is 1/4 L in front of the head end or the head end of the main remaining oil,and both effects are similar;when high permeable layer of positive rhythm only forms the effective injection-production between the injection and edge well,the main remaining oil is also distributed in the high permeability layer from the middle of the injection and angle well to the angle well,it's prior to explore the part of remaining oil,considering to put plugging agents in the middle of injection and edge well,which is aiming at forming the effective injection-production between the injection and angle well,and then explore the remaining oil of middle and low permeability layer;the simulated geological conditions of composed rhythm,because the layer thickness is reduced by half,are greatly influenced by strata distribution and gravity,should accord to the actual situation,combine with the result of positive and reverse rhythm,and gradually implement the profile control and water plugging.