3D Modeling of Hydraulic Fracturing in Tight Gas Reservoirs by Using of FLAC3D and Validation through Comparison with FracPro

In this paper, the FDM-Program FLAC3D is used for the 3D simulation of fracture propagation on a field scale model, based on field data of a Rotliegend tight gas reservoir in North Germany. This reservoir was treated hydraulically by a massive fracturing. The results regarding the fracture propagation were compared with those in the semi-analytical P3D simulator FracPro. It was noticed that the original code FLAC3D was unsuitable for the applications of hydraulic fracture. In further investigations, our own developed algorithm with a moving boundary condition based on discontinuum mechanics was implemented in FLAC3D. The results showed a relatively good agreement with those of FracPro. The advantage of the new algorithm is above all that irregular fracture front can be realistically simulated, which in turn reflects the stress states in multi-layers and their different rock mechanical properties.