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Study on Proppant Transport among the Perforations within a Cluster and Accumulation in Inclined Wellbores Considering Turbulence Effect
Abstract
During hydraulic fracturing, the uniform distribution of proppant among perforations is crucial for enhancing reservoir permeability. However, problems such as uneven proppant distribution between perforations and accumulation-induced blockage often occur. Current research focuses on proppant distribution among perforation clusters in horizontal wellbores. Additionally, there is a lack of systematic studies, particularly regarding proppant distribution among perforations within a cluster, turbulence within the wellbore, and sand blockage issues. Moreover, in engineering practice, wellbores are often not horizontally oriented. These issues limit the reservoir permeability. This study employs CFD methods and the Euler-Euler model to systematically simulate the transport and accumulation of proppants among perforations within a cluster in inclined wellbores. The focus is on analyzing the effects of key variables considering turbulence, including injection velocity, fluid viscosity, sand ratio, proppant particle size, proppant density, number of perforations, and wellbore inclination angle, on proppant distribution and accumulation. This simulation required significant computational resources and was successfully completed at China’s National Supercomputing Center. Results show that rapid proppant accumulation initially reduces sand content in the fluid, decreasing the sand volume fraction in perforations. Additionally, turbulence at the toe of the wellbore significantly reduces accumulation at the toe and promotes uniform distribution through sweeping, increased turbulent viscosity, and backflow. Furthermore, adjusting the discharge angle and position of the perforation closest to the toe can further optimize proppant distribution and reduce the risk of sand blockage by leveraging turbulence. These findings provide valuable insights for optimizing fracturing designs in inclined reservoirs and proppant pumping strategies.
