Complex fracture shapes in hydraulic fracturing with orientated perforations

Based on rock mechanical tests and practical data interpretation, a three dimensional finite element model is established to study factors influencing fracture shape in orientated hydraulic fracturing. The stress interference around neighboring perforations causes fracture initiation, and the main factors influencing fracture shapes are horizontal principal stress difference and the angle between the perforation orientation and the maximum horizontal stress. The computations also reveal that hydraulic fractures will not always initiate along perforation orientation, and usually the initial hydraulic fracture is in a zigzag shape. When the horizontal stress difference and the perforation angle are great, dual fractures will happen along perforation and the maximum stress directions. So improving the accuracy of stress measurement and orientated perforation can avoid the generation of complex-shape hydraulic fractures.