SUMMARYResults are presented for three-dimensional planar fracture propagation in the presence of variations in confining stress, reservoir properties and frac-fluid viscosity when the well-bore pressure is constant throughout the frac-job. Solid rock deformation during the frac-job is described by the dislocation method with singular integral equations, and the fluid flow in the fracture is represented by the finite element method. A convergence study is undertaken on the three-dimensional numerical model, and good agreement is obtained with results from laboratory tests and from the simpler circular model.