Optimization Of Fracturing Fluid Flowback Rules For Shale Gas Well

In recent years,because of the shortage of conventional oil and gas resources,shale gas is becoming more and more potential and noticeable.In order to acquire economic gas generation rate and gas output,shale gas reservoir need hydraulic fracture,there is a very important link after it:flowback of fracturing fluid.It may directly determine the fracture stand or fall.The passage aimed at flowback of fracturing and focused research on the two-dimensional filtration model,proppant flowback model and pseudo-three dimensional model,and computational analysis the influence factor of gas well productivity.The research results have an important practical importance for guiding fracturing fluid flowback.This thesis has completed the following work:Firstly,based on mechanics of flow through porous media,this article systematic analysis fracturing fluid flow to the layer,establish a forced fracture closure mathematical model considering the two-dimensional filtration of fracturing fluid.Because this model can give a accurate fracture close time,so it can provide reasonable scientific basis to shift choke.Secondly,this paper make an exhaustive analysis about proppant's flowback time and displacement,established the mathematical model of proppant's flowback,analysis the influence for choke and critical flw velocity of wellhead pressure,proppant's size,proppant's density and proppant's viscosity after gel breaking.Thirdly,considering the flowback of fracturing fluid and gas well productivity after hydraulic fracturing,this paper established a percolation under forced fracture closure.And after numerical difference calculation,this paper computational analysis the influence factor of flowback rate.Finally,this passage set up methods and rules used to design flow back procedures and compiled the flowback of fracturing fluid calculation software.By using this software,we can predict the time of fracture forced close and choose reasonable size of choke,so that we can make this work more scientific and quantitative.