Staggered Solution of the Diseretized Fully-Coupled Biot's Equations

Coupling effects between deformation and fluid-flow in porous media as elucidated in Biot's theory are important in many problems. The monolithic solution technique is the most commonly used approach to solve the system of Biot's coupled equations. However, monolithic solution requires large computational efforts because of the large system of equations involved, and precludes the use of existing stand-alone geomechanics and fluid flow computer codes. To overcome these limitations, the paper presents a staggered and modular solution of Biot's theory. Fully-coupled effects are achieved by updating the compressibility matrix and by using an additional source term in the conventional discretized fluid flow equation. The proposed method is implemented using single fluid phase FE and FD fluid-flow codes coupled with a FE geomechanical code, and validated against available analytical solutions.