Influence of geologic discontinuities on hydraulic fracture propagation

Geologic discontinuities, such as joints, faults, and bedding planes, in conjunction with the deviatoric in situ stress state, material properties, and permeability can significantly affect the overall geometry of hydraulic fractures. This can occur by (1) arresting lateral or vertical propagation of a fracture, (2) reducing total fracture length via fluid leakoff, (3) limiting proppant transport and placement, and (4) enhancing the creation of multiple or secondary fractures rather than a single planar hydraulic fracture. Results from mineback experiments (fracture experiments conducted in a tunnel so they can be excavated for observation of the results), laboratory tests and analyses of these data are integrated to describe the complex fracture behavior found and to provide guidelines for predicting when this complex fracturing will occur. 33 references, 14 figures, 1 table.