Strategically Coupled Inertial Flow and Interface Evolution Model for Cavern Development by Dissolution Mining

Abstract

Shape control is important for large-scale underground caverns developed by dissolution mining; however, it is greatly complicated by turbulent brine flow and natural and forced convection. An improved model for simulating dissolution mining of large caverns over long injection periods is presented. The brine flow is modeled using the Reynolds-Averaged Navier-Stokes equations coupled with a mass conservation equation governing the evolution of the cavern walls. It is demonstrated that cavern wall irregularities previously assumed to be exclusively due to mineral heterogeneity are also readily attributable to the turbulent flow. Two competing dissolution mechanisms are identified, one enhancing dissolution unevenness and one that smooths out irregular dissolution features on the cavern walls. Two cavern construction methods were investigated: reverse and direct dissolution methods, which tend towards a “morning glory” and a “wide bottom decanter” shaped cavern, respectively. Results suggest that, because of the buoyancy effect, large roof spans are unavoidable without using an oil/air blanket; however, blanket usage leads to more jagged boundaries and can decrease the cavern construction rate. This study opens a path to the development of robust models of large-scale cavern development for energy storage and has implications for similar processes such as leach mining or ice melting.