Numerical simulation on the effect of particle shape on mechanical response of proppants in horizontal fractures

Particle geometry significantly influences the mechanical characteristics of sand. Hence, understanding the mechanical response of different shaped granular particle pack under compressive stress is important for estimating their influence on fracture conductivity as reported by Mollanouri Shamsi et al. (in: SPE paper SPE-190024-MS presented at the SPE Western Regional Meeting held in Garden Grove, California, 2018). Consequently, when modeling the behavior of granular assemblies, it is crucial that they are appropriately simulated as accurate as possible. In this study, a clumped particle logic which combines two or more spherical particles and allows for overlap is adopted to model proppant particle shapes. Three groups of particles: Particle A, Particle B and Particle C with different sphericity and aspect ratio are generated randomly and assembled between two rough parallel fracture plates. The rough surfaces which adhere to normal distribution were generated using Gaussian distribution model. A discrete element method approach using linear contact model is then implemented to replicate the real particle shapes and their assembly. Then, the fracture closure condition on each proppant pack is simulated by uniaxial compression. Results show that particle shape influences mechanical response (unconfined pack bed height, packing porosity, constrained modulus and coordination number) of proppant pack in fractures. The proposed work provides an effective insight for understanding mechanics of proppant of different shape and how it later influences fracture. It also avails an avenue for optimizing proppant shape based on expected combinations of field operations. [GRAPHICS] .

Automated summary

Particle geometry plays a significant role in the mechanical characteristics of sand under compressive stress. Understanding how different shaped granular particles respond mechanically is crucial for estimating their impact on fracture conductivity. The results of the study show that particle shape does influence the mechanical response of proppant pack in fractures.