Numerical Simulation Of Rupture Fluid Rupture

In the field of engineering practice, the engineering technical personnel often control the settling and spread state in cracks through controlling the nozzle size and flowback velocity, but the nozzle size to be selected often rely on limited operating experience or subjective awareness of decision-makers, to some extent, this will affect the flowback effect and the fracturing effect. Therefore, some scholars study flowback at home and abroad, through the literature survey, The author find that the research of fracturing fluid flowback existing the following two problems:First, the existing theory of fracturing fluid flowback is mostly based on the conventional sandstone reservoir, and without considering the effects of natural fracture. To some extent, the way simplifies the complexity of the modeling and calculation difficulty. At the same time, it makes the model limited, which cannot be used to guide the fractured reservoir pressure flowback; Second, the study of proppant backflow is not enough in-depth, and without given the operated standard and basis of changing nozzle size on the basis of analysis of the backflow and settlement of proppant.According to the above problem, the paper deeply analyzes the fracturing fluid flowback of the fractured reservoir. First of all, the paper establish the fractured reservoir fracturing fluid loss model, through analyzing the fluid loss mechanism of fractured reservoir during the period of flowback; Secondly, according to the principle of volume balance, the paper establishes and solves the fractured reservoir fracturing flowback model, combining with the fracturing fluid return discharge calculation model and the crack volume change rate calculation model, and the model proved to be rationality and scientific through the application instance analysis. In addition, the paper establishes the proppant subsidence model with the influence of proppant backflow, the roughness of fracture surface, the friction, and collision between the proppant and cracks in the wall, considering the actual fracturing proppant settlement will be influenced by fracturing fluid properties and the proppant particles interacting with each other, Then, the nozzle size of the dynamic optimization are analyzed according to the backflow of proppant flowback, and the paper give the combination of choke size in different wellhead pressure through instance.The paper compiles the fractured reservoir fracturing flowback simulation software, which can analyze proppant the traffic of proppant flowback, proppant settlement characteristics and wellhead pressure change rule, on the basis of the above theoretical research. Finally, the paper calculates examples of the well by using the software, which has an important reference value and guiding significance to the fracturing flowback.