Numerical Simulation of Proppant Transportation and Distribution in the Nonplanar Fracture

Hydraulic fracturing of highly deviated wells is an effective means to develop ultra-deep oil and gas reservoirs. The transportation law of proppant becomes more complicated due to the complex nonplanar morphology formed by the distortion and extension of fractures in three-dimensional space. To investigate the transportation of proppant in nonplanar fracture, a fluid-solid coupling model of proppant transportation in the 3D nonplanar fracture was established and solved based on computational fluid dynamics (CFD) and discrete element method (DEM). The effects of displacement, proppant density, proppant size and fluid viscosity on proppant transportation and distribution were studied. The results show that: The shape of nonplanar fractures has a significant influence on proppant transportation. Compared with the flow form in planar fracture, the flow in nonplanar fracture appears eddy current. The collision frequency between proppant and fracture wall and other proppants increases, which increases the energy loss during sand-carrying fluid flow. By increasing the displacement, sand plugging in the near-wellbore area can be avoided and the length of sand bank in the fracture is increased. As proppant density and proppant size decrease, the length of the sand bank increases and the height decreases. High-viscosity fracturing fluid can effectively carry proppant for transportation and avoid proppant settlement near the wellbore to occur sand plugging. This study clarifies the laws of proppant transportation and distribution in the nonplanar fracture, and helps guide the design of proppant pumping construction parameters for ultra-deep highly deviated well fracturing.