Establishing and Solving a Model for Matching Fracturing Fluid Flowback

Abstract

Fracturing flowback rate is one of the most important parameters to evaluate fracturing effects. While calculation of fracturing flowback rate is always lack of theoretical model to predict, it is always been solved by accumulation of filed fluid after fracturing finished in oil filed. In order to tackle this problem, a great deal of work has been done to establish a model for solving fracturing flowback rate, in which procedures like fracture closing, fluid loss, formation fluid flows and well bore flow are entirely considered. Based on comprehensive procedures, a few functions are established in this model. The average fracture pressure was calculated by adjusting time that might affect fracture closure degrees. According to wellhead pressure, bottom hole flowing pressure and average fracture pressure which was used to calculate flowback quantity leaded by fracture closure were achieved. Besides, total time that fracture was entirely closed was also achieved after fracture being fully closed, flowback quantity consisted of two parts, fracture and formation. In addition, the model was solved through finite difference method and simulated by Matlab. In comparison with the target result, fracturing flowback rate, the modeling results, are almost identical with that of conventional methods. Therefore, this model can be taken as a reliable theoretical guidance to predict fracturing flowback rate in oil flied.