Engineered Precipitation Geobarriers Via Transverse Mixing for Subsurface Storage

ABSTRACT: In this study, we investigated the formation of precipitation-induced geobarriers via transverse mixing in a core-scale experimental setup. Using a specialized core flooding apparatus, we continuously injected two separate brines - one containing Ba2+ and the other SO42- - through a parallel dual-injection system at the inlet. This induced in-situ barite (BaSO4) precipitation, forming a mineral barrier. X-ray computed tomography (CT) imaging revealed the spatial distribution of the precipitate, confirming the development of a geobarrier along the central axis of the core. Subsequently, we extracted small cylindrical specimens perpendicular to the precipitation layer and directly measured their permeability. The results demonstrated a substantial permeability reduction from 10-14 m2 to 10-19 m2 at the precipitation layer, achieving caprock sealing capacity. These findings suggest that engineered precipitation-induced barriers offer a cost-effective and scalable approach to enhance subsurface storage integrity.