Shapes of Hydraulic Fractures in the Vicinity of Borehole-and-Branch Hole Junction
A. V. Azarov, A. V. Patutin, S. V. Serdyukov
Chinakal Institute of Mining, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630091 Russia
Keywords: Borehole with branch hole, intersecting boreholes, rock mass, stress state, directional hydraulic fracturing, fracture, fracture trajectory and shape, mathematical modeling, numerical investigations
Abstract
The authors describe numerical investigations of hydraulic fractures in boreholes with branches (intersecting boreholes). The directions of growing fractures were determined in the static problem solution by the criterion of maximum tangential stresses and in the quasi-static three-dimensional formulation with the analysis of fracture of an elastic uniform medium using the cohesive failure mode and the extended finite element method. It is found that some geometrical parameters of the starter fracture and the stress state nonuniformity have influence on the growth direction and shape of the created fractures. The X-shaped starter fracture, which simulates branching and intersections of boreholes, is preferable over the disc-shaped starter fracture in local control of hydraulic fracture orientation in rock mass under nonuniform compression.
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