Fracturing Back Row Optimization Theory And Application Technology Research

For low permeability tight reservoirs, often use fracturing fluid forcing flowback technologyafter the Fracturing. Among them, the length and short of the crack closuretime and displacement, whetherproppant reflux, is the key factor of the success of this technique,affecting the well normal production and the effect of fracturing, directly deciding fracturing fluid flowback rate.The fracture closure time and displacement will directly affect fracture conductivity after fracturing, thus it will be studied through 3 part. Firstly, to simulate the loss calculation of fracturing fluid during fracture closure process better, considering the two-dimensional fracturing fluid filtration, the material balance equation to establish a fracturing fluid filtration model during mandatory closure of cracks are used; secondly, using the material balance principle, fluid dynamics and other related knowledge, mandatory closure model for gas after fracturing are built well, and the trend of wellhead pressure with time after fracturing with different nozzle sizes will be obtained, so do the calculation of fracture closure time and displacement; at last, fracture closure time and displacement factor are analyzed.Contrary toproppantreflux mechanism research, the physical process of proppant transport backflow is analyzed. Through the single-particle proppant stress analysis of the last paragraph of proppant injected, proppant flowback motion model and starting model is established. Because proppant occurs reflux, depends on whether the fracturing fluid will startthe final period of a single particle and the blowoutnozzle size about proppant backflow.According to the special physical process of fracturing fluid flowback,establishs two-dimensional two-phase flow model about water and oil after the crack plane forced closure, solve displacement backafter fracture closure according to the numerical difference solving, combined with forced closure of cracks, that calculating the return displacement before fracture closure, solve the flowbackrate and influencing factors of fracturing fluid.On the basis of theoretical models, make fracturing fluid flowback rate optimization softwareand examples of calculations have been worked out.