Productivity Analysis Of Fractured Horizontal Wells Of The Oil-water Two-phase Flow Based On Finite Element Method

In recent years, with the development of horizontal well technology, some problemshave been solved that proves inefficient with straight well development, which is a technicalbreakthrough to improve the use of existing geological reserves which special and difficult touse. But the natural productivity of a lot of horizontal wells in low permeability reservoir islow, and it's impossible to obtain the ideal capacity without fracturing. Before the fracturingimplementation, engineers have to predict the production capacity program after thefracturing of the program on a variety of possible designs, for the fracturing scale andimplementation parameter optimization and fracturing equipment providing reliable data, inorder to make the fracturing effect better.Currently as to the production performance of fractured horizontal wells the maincalculation method are the analytic and numerical solutions. Because of so many assumptions,the single phase stable flow of fractured horizontal wells can only be obtained by theanalytical method, and this is far away from the actual. The numerical method for theprediction of fractured horizontal well on multiphase transit flow behavior has manyadvantages, it can consider the heterogeneity of reservoir, and oil-water relative permeabilitycan be described on the flow ability, and it can also describe the fracturing after multiplecrack interaction, and the fractured horizontal wells optimization design is mainlydetermained by the fracture parameters. Therefore, it is imperative to using numerical methodto study the production performance of the fractured horizontal wells. For the currentartificial fracturing horizontal well numerical simulation main using the finite differencemethod, and this method uses the equivalent flow resistance method to change the small sizefracture amplification into large size of the grid, this method has its limitation in the treatmentof complicated flow problem, and it did not identify specific crack grid which divided intothe extent of the results that the effect can be ignored. This article uses the finite elementnumerical method to solve the mathematical model, making the matrix cracks and the stromasystem as a whole, and uses of the convection diffusion equation thought, regarding thevertical wells as source and sink to handle.Taking the five spot horizontal wells injection-production pattern as an example, thisarticle make the study of the effect on the waterflooding for the fracture parameters of thefracture horizontal wells of Oil-water Two-phase. The factors include the half fracture length,the fracture flow capacity, the number of fractures, the non-uniform fracture spacing, the non-uniform fracture distribution, the non-uniform fracture length, and the inhomogeneousfracture conductivity. Get the pressure profile and saturation distribution map under thedifferent fracture parameters, and make the sensitivity analysis on the field of the factorsaffecting. The results indicate that: the effect of the fracture parameters on fracturinghorizontal wells parameters make great influence, but not the better. When other parametersare given, it has an optimal values. Finally, by using the orthogonal experimental designmethod and the fuzzy integral evaluation method we conduct the fracture parameters multiobjective optimal desigen which after integral fracturing for fractured horizontal wells in fivespot pattern, and finally got the group of optimal fracture parameter combination under thecondition of the well.