Modeling of multiphase fluids flow in anisotropic rock mass during CO2 sequestration in fractured reservoirs

Abstract

Understanding multiphase flow in fractured rock is essential for optimizing CO₂ storage in natural reservoirs. This study presents a model for CO₂ and water flow in fractured coal, examining the effects of injection pressure, reservoir conditions, and fracture characteristics on storage efficiency. Results indicate that connected fractures enhance fluid transfer, while isolated fractures retain less CO₂. The rock matrix exhibits higher pressure than single fractures, and CO₂ diffuses more efficiently than water due to its lower viscosity, although molecular size also influences transport. Coal's anisotropic permeability directs flow along high-permeability fractures, leading to uneven pressure distribution, preferential flow paths, and reduced sweep efficiency in lower-permeability zones. These results highlight the critical role of fracture connectivity and fluid properties in CO₂ migration and storage. By improving the understanding of fluid flow dynamics in fractured porous media, this paper provides valuable insights for enhancing CO₂ sequestration strategies, contributing to more effective carbon storage and greenhouse gas reduction efforts.