Cavity Expansion and Fracture Propagation in Dunnville Sandstone

Abstract

Fracture initiation of a pressurized circular cavity in Dunnville Sandstone was observed using a cavity expansion apparatus and particle tracking technique called digital image correlation. Different far-field stress configurations were used to determine its effect on the fracture initiation and propagation. The results of the tests show fracture initiation as a percent of the borehole breakdown (peak) pressure was determined to decrease as the far-field stress increased. In addition, the crack opening displacement at the borehole wall measured at peak pressure increased as the far-field stress increased.