Interaction Of Growing Cracks In Hydraulic Fracturing

Abstract

Recently, hydraulic fracturing has been utilized to extract natural gas and oil from low-permeability shale rocks. This technique has been studied in hundreds of papers. A deep understanding of the fracture network formation in hydraulic fracturing is essential to advancing the technology, e.g., to enhance the quality of fracking, and to keep aquifers from being contaminated. In the present study, the Linear Elastic Fracture Mechanics (LEFM) is applied to approach the crack extension behaviors in brittle rocks under hydraulic loading. The boundary element method is used to carry out the simulation where numerical treatment is only needed upon the cracks and the boundaries. When cracks extend, only new elements are added, but no re-meshing is necessary. With an appropriate crack extension criterion, the problems of crack initiation, crack interaction, and crack arrest are studied. This effort provides the oil and gas industry with more knowledge and understanding of crack growth in fracking.