Laboratory Testing and Numeric Simulation on Laws of Proppant Transport in Complex Fracture Systems

Abstract Stimulated reservoir volume fracturing, in unconventional gas and tight oil development, is a key technology. Injecting low viscosity sand-laden fluid of high flow rate, it can form complex fracture networks. Therefore, placement of proppant deep into the complex fracture networks brings a conductive path for production enhancement and reduces flowing resistance when fluid flowing form rock matrix to wellbore. At current, it is still unclear that sand features of low viscosity sand-laden fluid of high flow rate, and especially for proppant transport in subsidiary fractures are also not clearly understand. In this study, we fully think about the practical condition of engineering. Thus, in terms of similarity criterion of geometry and Reynolds number, we build a large scale of proppant placement in visualization complex fracture networks device which can changes angles of fractures, width of fractures and numbers of fractures. Due to the single factors experiment, this paper will discuss a series tests to evaluate proppants transport in complex fracture networks. Different slick water treatment tests are simulated by pumping sand slurry through the visualization complex fracture networks device while varying parameters of perforation, angles of fractures, proppant size, pump rate and proppant concentration. From the experiment, treatment tests which are used in variable factors can obtain different laws about traction carpet feature, traction carpet areas, balance hight and balance time in complex fracture networks. This paper also describes a 3-D physical model. This model is designed by SolidWorks software and using grid software to make complex fracture grids. Afterwards, using fluent software to simulate proppant concentration distribution field in the model of complex fracture networks. In addition, comparing the results between physical model and numerical model, the results can reveal, during the process of SRV, the law of proppant placement in complex fracture networks and serve as guidelines for engineering design.