Study on Activation Behavior of Complex Fracture Network in Weak-Planar Rock

Aiming at the problem of quantifying composition complex fracture network and activation after fracturing, a model weak plane with prefabricated structure is established based on finite element method, global embedded cohesive zone (CZM), real shale outcrop. Considering influence fully coupled stress/fluid, effects azimuth, horizontal stress difference, fracturing fluid viscosity, injection rate composition, geometry, stimulated reservoir volume (SRV) are studied. The concept relative rate, which can quantitatively analyze activation, proposed. results show that geometry two kinds conjugated controlled by most mechanical plane, is, respectively, axisymmetric centrosymmetric. composed fractures dominant free gas transport matrix microfractures adsorbed transport. viscosity SRV length not monotonous, while increase reduction appropriate will lead to width. effect difference does change monotonically, microfractures, total activated fractures, decrease fractures.