A quantitative assessment of hydraulic-fracturing jobs relies on accurate predictions of fracture growth during slickwater injection for single and multistage fracturing scenarios. This requires consistent modeling of underlying physical processes, from hydraulic fracturing to long-term production. In this work, we use a recently introduced phase-field approach to model fracture propagation in a porous medium. This approach is thermodynamically consistent and captures several characteristic features of crack propagation such as joining, branching, and nonplanar propagation as a result of heterogeneous material properties. We describe two different phase-field fracture-propagation models and then present a technique for coupling these to a fractured-poroelastic-reservoir simulator. The proposed coupling approach can be adapted to existing reservoir simulators. We present 2D and 3D numerical tests to benchmark, compare, and demonstrate the predictive capabilities of the fracture-propagation model as well as the proposed coupling scheme.