Extrapolating fracture orientations from horizontal wells using stress trajectory models

Abstract

This paper presents a recently developed approach for extrapolating fracture orientations from horizontal wells. It is commonly accepted that tension fractures propagate perpendicular to the minimum principal stress. The hypothesis has been tested that in some cases, by modelling the stress trajectories within a faulted compartment, it is possible to reproduce the orientations of the tension fractures. The stress trajectory models we present are based on photo-elastic techniques. The models are first calibrated against outcrop fracture patterns and are subsequently applied to a reservoir database consisting of a 3D seismic block and a horizontal well with almost complete FMS image coverage. The results show that tension fractures may show perturbed orientations in the vicinity of faults. It is shown that by appropriate characterization of the seismic and well fracture data, it may be possible to use stress trajectory models to predict fracture orientation in a reservoir.