| Abstract |
The geometry and size of reservoirs stimulated by proppant-free hydraulic are controlled by presence of natural fractures and in situ stresses. This is due to the two requirements of proppant-free hydraulic stimulation: presence of natural fiactures and sufficiently large shear stress required to extend natural fractures. Results from numerical modeling study show that proppant-free stimulation is not simply controlled by either natural fractures or in situ stresses, but rather it is the interaction of both factors. In a normal or strike-slip stress regime, vertical to sub-vertical fractures can be stimulated with less effort when the horizontal in situ stress is parallel to the average direction of natural fractures, with the resulting reservoirbeing strongly elongated in the common direction. In a reverse fault stress regime, on the other hand, sub-horizontal fractures can be stimulated with low stimulation pressure which result in a horizontally dominant reservoir. When multiple sets of natural fractures exist, it is likely that stimulated reservoirs will preferentially develop in the direction of maximum horizontal stress. It is also found that a high deviatoric stress helps develop a large volume of stimulatedreservoir. |