We have 4 apparatus that allow the measurement of low permeability (<10-17 m2) rocks. Each can also measure other petrophysical and mechanical properties, which are detailed below.
PERMEABILITY / ACOUSTIC VELOCITY
Hydrostatic apparatus 1: this standard hydrostatic apparatus is provided with several sample assemblies adapted to measure both permeability and acoustic velocity (Vp and Vs). Argon gas is normally used as a pore fluid but other fluids may also be used. A synthetic ester is the confining pressure fluid. Confining pressures of up to 400 MPa are used (equivalent to 15 km depth of burial). The apparatus is operated at ambient temperature conditions. Porosity changes (elastic and inelastic compaction) can be monitored via a pore volumometer as total confining pressure is applied.
PERMEABILITY AT ELEVATED TEMPERATURES
Hydrostatic apparatus 2: this apparatus is dedicated to measuring permeability of tight rocks. Confining pressures of up to 60 MPa (equivalent to 2.6 km depth of burial) are generated by a water confining medium. Argon gas is presently used as a gas pore fluid. The apparatus is also equipped with a furnace that can reach temperatures of 200 oC.
PERMEABILITY / GEOMECHANICAL
Triaxial apparatus 1: this apparatus has been specifically designed for work on shale. Confining and pore pressure ranges are 0-200 MPa. The furnace is capable of reaching temperatures up to 150 oC. Pore pressure can be gas or liquid. Samples up to 3 cm in diameter can be accommodated. A range of loading paths are available including; axisymmetric compression, axisymmetric extension, controlled normal stress, controlled mean pressure, etc. Simultaneous permeability, acoustic emission (AE) and acoustic velocity measurements can be made. Electrical conductivity can also be measured. Porosity changes (elastic and inelastic compaction) can be monitored via a pore volumometer as total confining pressure and/or axial load is applied.
PERMEABILITY / GEOMECHANICAL
Triaxial apparatus 2: this apparatus is able to apply axial differential stress via a servo-controlled system at confining pressure up to 400 MPa (equivalent to 15 km depth of burial). Argon gas is normally used as a pore fluid but other fluids may also be used. A synthetic ester is the confining pressure fluid. Controlled pore pressure and pore volumometry are available using either gases or liquids as pore fluids.
Samples can be strained in both extension and compression at room temperature. Porosity changes can be monitored via a pore volumometer as total confining pressure and/or axial load is applied.
Paterson gas apparatus: this apparatus operates in compression, extension and torsion at confining pressures up to 300 MPa. It uses argon gas as the confining pressure fluid to enable high temperature operation. It has the capacity to operate at very high temperatures (up to 1200 oC). Argon gas is used as a pore fluid.
SHEAR / RESIDUAL STRENGTH TESTS
ELE direct shear apparatus: the specimen is subjected to a constant normal load while an increasing horizontal (shear) force is applied to one of the sections of the shear box. The loading cell has a normal load capacity up to 3 MPa.
- Reversible stepping motor for residual strength tests
- Infinitely variable speed drive from 0.00001 to 9.99999 mm min-1
- Maximum shear force - 500 N or 5000 N using a 10:1 lever ratio device
- Speed drive ratio - stepper motor 1/100000 resolution
UNCONFINED COMPRESSIVE STRENGTH / ELASTIC PROPERTIES
The loading frame can exert up to 230 kN of axial load. Strain gauges can measure both axial and lateral deformation of the sample. Acoustic emissions can be recorded through 8 channels and Vp/Vs can be recorded. Unconfined compressive strength and both static and dynamic elastic properties can be determined.
The sample preparation laboratory is fully equipped with:
- Core drill
- Horizontal wire saw
- Faceters trim saw
- Lapping machines
- Core end grinding machines
- Crushing and grinding machines for powder sample preparation