Study on the Law and Influencing Factors of Proppant Settling in Fracturing Fluid

The law of proppant settling in fracturing fluid affects the distribution of proppant in the fracture, which is one of the important factors affecting the fracturing effect. In order to study the proppant settling law in fracturing fluid, an experimental device that simulate the proppant settle was developed. Through the physical simulation experiment, the influence of the factors such as fracturing fluid viscosity, proppant particle size, sand fluid ratio on proppant settling law in fracturing fluid was studied. The experimental results showed that the main factors affecting the proppant settling characteristics in the fracturing fluid were the viscosity of the fracturing fluid, the proppant size, and the sand ratio in the descending order. The higher the viscosity of the fracturing fluid was, the less the proppant settled, the lower the settlement ratio was, the slower the sand settled, and the stronger the sand suspension performance was. And with the increasing of the viscosity, the more obvious the trend was. The larger the proppant particle size was, the settlement ratio remained almost the same, but the settling time decreased sharply, the sand settled faster, the sand suspension performance was worse. The higher the sand ratio was, the more the proppant settled, which was almost linear relationship with the increasing of sand ratio, but the settlement ratio decreased slightly, the settling time increased slightly, which showed that the sand suspension performance increased slightly. Considering factors such as sand carrying capacity, formation damage and economic cost performance, there was an optimal matching relationship among viscosity of fracturing fluid, particle size of proppant and sand fluid ratio. The research results enriched the evaluation method of proppant settlement law in fracturing fluid, and provided the basis for the optimization of fracturing fluid and proppant in the design of fracturing scheme.