Geothermal Exploitation

Mechanics of Fractures - Triaxial Testing

Triaxial Compressive Test

To characterize mechanical properties of the reservoir rocks, triaxial compressive tests are performed at a range of confining pressures. The triaxial compressive tests are commonly used to simulate in-situ stress conditions of the reservoirs and provide compressive strength and static values of elastic constants (e.g., Young's modulus and Poisson's ratio).

Triaxial Tests Capabilities

Core Lab's geomechanics lab is the most extensive facility of its kind. Triaxial rock testing measures rock strength and mechanical properties under various conditions:

  • Axial Load: up to 1M psi
  • Confining Pressure: up to 30K psi
  • Pore Pressure: up to 30K psi
  • Sample diameter up to 4 inches
  • Temperature: up to 350°F
Triaxial Testing

Triaxial Tests Press: TRI-XG 200/400

To continue the development of its range of triaxial press, Sanchez Technology (ST) has designed a press for solid deformation study working under high pressure and high temperature.

The press has been designed to inject corrosive fluids, to study thermo-hydro-chemo mechanical coupling mechanisms within the device operation pressure and temperature range. It can be controlled by stress/pressure range or deformation in ramp. Pore pressure is generated by an accurate double volumetric pump.

The capabilities of the ST Triaxial Cell are as follows:

  • Confinement Pressure up to 30K Psi
  • Maximal axial load up to 300K Psi
  • Operating Temperature up to 500°C
  • Axial deformation measurement
  • Speed of sound by P & S acoustic waves
Triaxial Cell

Triaxial Tests Data

Triaxial Test Data

Mohr-Coulomb analyses, determined from the triaxial compressive strength data, provide formation cohesion (initial shear strength) and angle of internal friction.

Triaxial Test Data

Compressive strengths from a series of triaxial compressive tests are plotted in order to determine the critical shear stress and predict conditions for hydraulic fracturing and borehole breakouts.