Study On Optimization Of Temporary Plugging And Steering In Low Permeability Carbonate Reservoirs

After large clusters of acid fracturing in low-permeability carbonate reservoirs in Central Asia,the production of most horizontal wells decreases rapidly,and investment recovery is not easy.By temporary plugging and diverting acid fracturing technique,complex fracture network systems can be formed,improving oil well production and making it stabilized,so it is particularly important to study the complex fracture network formed by temporary plugging and diverting fracturing technique.Based on investigating the current research status of temporary plugging and diverting fracturing technique and fracture optimization by domestic and foreign scholars,this paper analyzes flow in porous media of low-permeability carbonate reservoirs and establishes a matrix-natural fracture-artificial fracture coupling flow numerical model suitable for low-permeability carbonate reservoirs.Using COMSOL simulate the fracture network morphology after temporary plugging and diverting fracturing,and the number of fracture network formations in fractures and fracture turning levels of horizontal wells are studied respectively,the optimal fracturing fracture parameter combination is obtained:the length of the vertical main fracture is70m,and the permeability is 60D;the number of branch fracture is 3,the length is 15m,and the permeability is 30D;the number of fracture levels is 15.Through orthogonal design experiments,the importance of the parameters is ranked using the gray correlation analysis method,and the influence of each parameter on the effect of oil well transformation is obtained in the following order:fracture levels,number of branch fractures,main fracture permeability,main fracture length,branch fracture permeability and branch fracture length.Finally,based on the fracture parameter analysis,using numerical simulation software MEYER obtain the optimal fracturing construction parameters:the optimal scale of single-stage acid fracturing is about 178m~3,the pre-fluid accounted for about 40%,and the displacement of fracturing fluid is5.5m~3/min.It can provide a reference for the design of temporary plugging and diverting fracturing of low-permeability carbonate reservoir.