GOHFER (Grid Oriented Hydraulic Fracture Exten-sion Replicator) is a planar 3-D geometry and fluid/solid transport simulator. The model relies heavily upon log-derived input data. Rock elastic properties, porosity and lithology can be input di-rectly from standard log ASCII (LAS) files. These data along with pore fluid gradients, regions of over-presure or depletion, and tectonic offsets are used to constrain in-situ stress profiles.