Application of Hydrodynamic Flow Modeling Integrated with Geomechanics for Partially Depleted Sandstone Reservoir: Fwu CO2-EOR Project

This work utilizes a full-field, history-matched, compositional hydrodynamic coupled geomechanical model for assessing the Farnsworth Field Unit’s (FWU) active CO₂-WAG project. Depletion impacts the volumetric strain which intern affects the permeability of the formation. These geomechanical impacts are accounted for by using the Kozeny–Carman relationship, applied at varying coupled frequencies and compared to uncoupled simulations. These permeability updates can affect the volume of CO₂ sequestered and the safety and security of the stored CO₂.

A static mechanical earth model (MEM) which incorporated the existing Southwest Regional Partnership (SWP) geological model, available geophysical logs, 3-dimensional seismic elastic inversion properties and lab derived strength and failure criteria was constructed for use in transient coupled geomechanical model. Appropriate overburden, under-burden, and side-burden formations required to impose mechanical boundary conditions are also included. The Kozeny–Carman relationship coupled at various frequencies, are utilized to perform hydrodynamic geomechanical simulations of primary, secondary (water-flooding) and tertiary (CO₂ WAG) recovery periods. These results are used to investigate the range of geomechanical outcomes. Volumetric strains and effective stress perturbations are assessed along with diagnostic tools such as p-q stress paths and Mohr circles with associated failure envelopes. Fault parameters such as slip tendency and distance to failure are also presented. These form the basis for a discussion of appropriate geomechanical modeling criterion for the Morrow B.

The Kozeny–Carman relationship has been applied to the Morrow B coupled compositional hydrodynamic geomechanical simulation. Traditional geomechanical diagnostic procedures: Mohr Coulomb circles and p-q stress paths with associated failure lines, fault closeness to failure and slip tendency have been used to illustrate our findings.

This is the first study of coupled hydrodynamic-geomechanical simulation of Morrow B CO₂-WAG project and provide an assessment of caprock integrity and mechanical fault stability.