Branch Fractures in Oriented Hydraulic Fracturing, Modeling, and Experiments.

A three-dimensional finite element model is established to study factors influencing factures in oriented hydraulic fracturing. The results indicate factors include horizontal principal stress difference and the angle between oriented perforation and the maximum horizontal stress. The computations reveal that hydraulic fracture will not always initiate along a perforation, and usually the hydraulic fracture is in a zigzagged shape. When the stress difference and the perforation angle are great, dual fractures will appear along both perforation and the maximum stress directions, verified by laboratory experiments. For improving the accuracy of stress measurement, oriented perforation can reduce the complexity of hydraulic fractures. [ABSTRACT FROM PUBLISHER]