Geo-barriers: Inducing mineral precipitation to engineer large-scale subsurface fluid containment structures

ABSTRACT: This study explores Geo-barrier formation through the in-situ precipitation of barite (BaSO4) by mixing Ba2+ and SO42- ions, offering a promising approach for enhancing subsurface gas storage security. The shape of the Geo-barrier is determined by horizontal advection, vertical advection, and buoyancy. Using numerical simulations on a 2D vertical homogeneous model, we examine the effects of several control (e.g., injection conditions) and state (e.g., Kv/Kh) parameters on Geo-barrier development under vertical injection configurations. The Geo-barrier shape is quantified using πS, defined as the ratio of vertical to horizontal length. Sensitivity analysis reveals that injection rate and injection rate ratio play a dominant role in controlling πS variations. Moreover, even when the Geo-barrier attains the same geometry, the time required for its formation varies depending on the reaction rate, which is primarily controlled by fluid molality. Lower molality slows down the reaction rate, resulting in a longer formation time despite achieving the same Geo-barrier geometry. This work highlights the interplay between flow dynamics and reaction kinetics, demonstrating the feasibility of controlled mineral precipitation for enhancing reservoir integrity in subsurface gas storage applications.