Geomechanical Modeling of High-Pressure Water Injection in Unconsolidated Formations

ABSTRACT: Subsurface water injection is an essential technology for many industrial applications, such as secondary oil and gas recovery, wastewater management and new energies. In renewable energy production, subsurface water injection plays an important role in geothermal applications and CO2 storage. The wastewater for reinjection from oil and gas production or other industrial processes contains impurities that can cause porous media blockage at the subsurface near the injection well wall, potentially leading to injection under fracturing conditions. Through numerical modeling, this article examines the high-pressure injection in an offshore unconsolidated formation at nearly 1000 meters of burial depth, considering the tension fracturing phenomenon, the viscoplastic behavior of the rock and the permeability damage induced by solids in the injected water. The results indicate the relevance of filter cake in fracture propagation due to a smaller leak-off of injected fluid to the porous formation. The stimulated reservoir volume around the injection point obtained in the simulations comprises a tension fracture and a shear plastic zone with enhanced permeability.