Investigation of Hydraulic Fracture Re-Orientation Effects in Tight Gas Reservoirs
B. Hagemann1 J. Wegner1 L. Ganzer1
1Clausthal University of Technology, Clausthal-Zellerfeld, Germany
In tight gas formations where the low matrix permeability prevents successful and economic production rates, hydraulic fracturing is required to produce a well at economic rates. As production from the well and its initial fracture declines, re-fracturing treatments are required to accelerate recovery. The orientation of the following hydraulic fracture depends on the actual stress-state of the formation. The stress alters during depletion and a stress reversal region appears. This behavior causes a different fracture orientation of the re-fracture. COMSOL Multiphysics is used to investigate the re-fracture orientation in a two-dimensional reservoir model. The model represents a fractured vertical well in a reservoir of infinite thickness. Different cases with anisotropic and heterogeneous permeability are set up to determine its significance.