Roles of stress wave and gas pressure in presplitting

Conference · Mon Jan 01 04:00:00 EST 1968 · Proc. Symp. Rock Mech.; (United States)

OSTI ID:6816812

Kutter, H K; Fairhurst, C

This discussion is concerned with the physical phenomena in the fracture process of presplitting and only indirectly with the establishment of the optimum presplitting parameters. Its nature is qualitative, rather than quantitative. The phenomena which occur when an explosive charge is detonated in the borehole are examined. The main role of the stress wave is to generate a densely radially fractured zone around the borehole. The subsequent gas pressure, exerted against the walls of a highly (radially) fractured cavity, generates a quasi-static stress field. This stress field was found to be the same as that of a pressurized cylindrical ''equivalent cavity'' with a radius equal to that of the crack tips. Under these conditions, the quasi-static stresses become appreciable and cause further extension of the radial cracks. It was found that under gas pressure, the longest of the radial cracks would extend first, and extension of 2 diametrically opposed radial cracks requires the least pressure. From these observations concerning the single shot, the transition to a whole series of more or less simultaneous shots, as in presplitting, can readily be made.

• Research Organization: Imperial College of Science and Technology
• OSTI ID: 6816812
• Report Number(s): CONF-670470-
• Conference Information: Journal Name: Proc. Symp. Rock Mech.; (United States) Journal Volume: 9
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
020300* -- Petroleum-- Drilling & Production
BOREHOLES
CAVITIES
COMMINUTION
CRACK PROPAGATION
ELASTICITY
FAILURES
FRACTURED RESERVOIRS
FRACTURING
MECHANICAL PROPERTIES
SHOCK WAVES
STRESSES
TENSILE PROPERTIES