Pressurized and Fluid filled fracture propagation in porous media using phase field approach Sanghyun Lee University of Texas at Austin This work presents phase field modeling of pressurized and fluid-filled fracture propagation in a poroe-elastic medium. Here lower-dimensional fracture surface is approximated by using the phase field function. The two-field displacement-phase-field system solves fully-coupled constrained minimization problem due to the crack irreversibility. This constrained optimization problem is handled by using active set strategy. The pressure is obtained by using a diffraction equation where the phase-field variable serves as an indicator function that distinguishes between the fracture and the reservoir. Then the above system is coupled via a fixed-stress iteration. In addition, we couple with transport system for proppant filled fracture by using a power-law fluid system. The numerical discretization in space is based on Galerkin finite elements for displacements and phase-field, and an Enriched Galerkin method is applied for the pressure equation in order to obtain local mass conservation. Nonlinear equations are treated with Newton’s method. Predictor-corrector dynamic mesh refinement allows to capture more accurate interface of the fractures with reasonable number for degrees of freedom.