Repurposing Depleted Wells for Geomechanical Pumped Storage

Geomechanical Pumped Storage (GPS) is an innovative renewable energy storage method that utilizes the elastic deformation of subsurface formations to store and retrieve water for electricity generation during peak energy demand periods. By leveraging the elastic properties of underground formations and the lifting of overburden, GPS stores water within hydraulic fractures. This study aims to identify the most efficient GPS design to maximize energy storage in subsurface formations focusing on the hydraulic connection between the wellbore and the fractures. We developed a Mechanical Earth Model (MEM) to simulate different fracture closure modes including uniform and mouth closure modes. We modeled the interactions between fluid flow and rock deformation during water injection, storage, and recovery phases using poroelasticity principles. Results indicate that uniform fracture closure mode reduces fluid loss, thereby improving energy storage and recovery efficiency. Converting abandoned oil and gas wells into GPS sites could also reduce costs, which offers an adaptable and cost-effective energy storage solution.