Three-dimensional propagation of hydraulic fractures extending from open holes

An experimental investigation is made on the shape of hydraulically induced fractures extending from a line source. The fracture characteristics utilized in this study were the facial features, hackle marks, rib marks, and steps. The results indicate that hydraulic fractures extending from a line source propagate on a hyperbolic path, with their edge having an elliptical shape. The major axis of the ellipses lies along the line source. The treatment fluid flow inside the hydraulic fracture also is hyperbolic. The equations presented for the fracture opening show that the hydraulic fracture starts as a Griffith crack and extends into a penny-shaped fracture. (11 refs.)