Numerical Modeling of 3D Hydraulic Fractures Interaction in Complex Naturally Fractured Formations

The unconventional fracture model can simulate complex fracture network propagation in a formation with pre-existing natural fractures. The interaction between hydraulic fracture branches, or stress shadowing effect, could be modeled by 2D or 3D displacement discontinuity method (DDM). In this paper, we concentrate on a hydraulic fracture model that integrates 3D DDM for computing the induced 3D stress field around the propagating hydraulic fractures and incorporates the changes in induced stress into the fracture height calculations and propagation criterion. Examples show that for parallel fractures, the height growth may be promoted or suppressed depending on the relative fracture height. For fractures initiated from different formation layers, the fracture growth into the layer occupied by the other fractures is reduced due to the vertical stress shadowing effect.