Factors Influencing Proppant Transportation and Hydraulic Fracture Conductivity in Deep Coal Methane Reservoirs

The gas production of deep coalbed methane wells in Linxing-Shenfu block decreases rapidly, the water output is high, the supporting effect is poor, the effective supporting fracture size is limited, and the migration mechanism of proppant in deep coal reservoir is not clear at present. To investigate the migration behavior of proppants in complex fractures during the volume reconstruction of deep coal and rock reservoirs, an optimization test on the conductivity of low-density proppants and simulations of proppant migration in complex fractures of deep coal reservoirs were conducted. The study systematically analyzed the impact of various fracture geometries, proppant types and fracturing fluid viscosities on proppant distribution. Furthermore, the study compared the outcomes of dynamic proppant transport experiments with simulation results. The results show that the numerical simulation is consistent with the results of the proppant dynamic sand-carrying experiment. Under the conditions of low viscosity and large pumping-rate, a high ratio of 40/70 mesh proppant can facilitate the movement of the proppant to the depths of fractures at all levels. The technical goal is to create comprehensive fracture support within intricate trapezoidal fractures in deep coal and rock reservoirs without inducing sand plugging. The sand ratio is controlled at 15%–20%, with a proppant combination ratio of 40/70:30/50:20/40 = 6:3:1. Proppant pumping operations can effectively address the issue of poor support in complex fractures in deep coal formations. The research results have been successfully applied to the development of deep coalbed methane in the Linxing-Shenfu block, Ordos Basin. © 2024 The Authors. Published by Tech Science Press. This work is licensed under a Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.