Dedicated to rock mechanics
Stress Measurement by Hydraulic Fracturing Technique
The in situ stress field components have been widely recognized as basic parameters in the engineering design of dams, tunnels, mines, buildings, highways and underground constructions. The horizontal in-situ stresses cannot be estimated. The horizontal stresses require to be measured direct in the field. The most common method of measuring in-situ stresses is hydraulic fracturing and Hydraulic Testing of Pre-Existing Fractures. Mesy India specializes in the field of Hydraulic Fracturing (Also know as Hydro Frac) and logging services which operates worldwide from India.
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Typically hydraulic fracturing is conducted in vertical boreholes. Therefore a short interval of the borehole is sealed off using a double packer system. Then the sealed off area is pressurized by water injection. The pressure is raised until the rock surrounding the bore hole fails in tension (breakdown pressure). Following breakdown, the injection of water is stopped (shut-in), the pressure within the test section drops until the fracture is closed fast (linear flow) and then slow (radial flow). The shut-in pressure equals the rock stress, at which the hydro fracture closes completely under the action of the stress acting normal to the hydro fracture plane. In a vertical test hole the new induced hydro fracture is expected to be vertical and perpendicular to the minimum horizontal stress. The hydraulic stress tests were conducted in close agreement with the ISRM - standard (Haimson, B.C. and Cornet, F.H., 2003).
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The in situ stress field components have been widely recognized as basic parameters in the engineering design of underground constructions. The horizontal in-situ stresses cannot be estimated. The horizontal stresses require to be measured direct in the field. The most common method of measuring in-situ stresses is hydraulic fracturing.
Sometimes in some of the rocks the fractures are already induced, in this case stress and other important parameters can be obtained by performing testing in pre-exsiting fractures. This is also known as Hydraulic Testing of Pre-Existing Fractures. The tools and equipment are same for both the methods.
The in situ stress field components have been widely recognized as basic parameters in the engineering design of dams, tunnels, mines, buildings, highways and underground constructions. The horizontal in-situ stresses cannot be estimated. The horizontal stresses require to be measured direct in the field. The most common method of measuring in-situ stresses is hydraulic fracturing and Hydraulic Testing of Pre-Existing Fractures. Mesy India specializes in the field of Hydraulic Fracturing (Also know as Hydro Frac) and logging services which operates worldwide from India.