New England Research AutoLab 2000 Laboratory System
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The AutoLab 2000 is a versatile triaxial apparatus for petrophysical and mechanical rock properties measurements at in situ conditions on specimens from 0.75 to 2.0 inches in diameter. Based on experimental requirements, the apparatus can be designed to operate at confining pressures to 30,000 psi (200 MPa) and pore pressures to 15,000 psi (100 MPa) with a pressure vessel bore diameter as large as 7.5 inches.
AutoLab 2000 is a complete laboratory system which performs standard rock mechanics tests and facilitates the measurement of coupled processes. Velocity, permeability, and resistivity transducers are designed to accommodate strain instrumentation. Measure strain, and compressional and shear wave velocities to compare static and dynamic elastic moduli; relate changes in permeability to stress induced anisotropy; or correlate electrical resistivity with pore volume compression. AutoLab software acquires these data while simultaneously controlling the loading paths. Rapid data reduction and informative reports speed up analysis.
Key features include:
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Deformation experiments for conventional and specialized loading paths |
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Pore volume compressibility |
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Servo-hydraulic control of strain rate, force, confining pressure, pore pressure, and flow rate |
| Two pore pressure intensifiers to facilitate fluid exchange |
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Strain measurement with either LVDTs or strain gages |
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Temperatures to 250 degrees F (121 degrees C) |
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Integrated electronics console for servo-amplifiers and signal conditioning |
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AutoLab software for system control and data acquisition. |
Optional Coreholders:
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PS2 ultrasonic transducers for compressional and shear wave velocities |
| Permeability (with water or brine) assemblies spanning a range of 10 nanoDarcys to 500 milliDarcys |
| Electrical resistivity (formation factor). |
The versatility of the AutoLab 2000 supports a comprehensive suite of experimental conditions. The following applications have been incorporated into previous systems:
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Velocities parallel and normal to the core axis |
| Location and number of acoustic emissions associated with specimen damage |
| Permeability parallel and normal to the core axis |
| Two-phase fluid flow at high flow rates to evaluate sanding potential |
| True triaxial loading on prismatic specimens |
| Effect of fluid substitution on the strength of shales. |
The apparatus is compact and convenient. Many systems generate force parallel to the core axis with large hydraulic cylinders operating at 3,000 psi. This necessitates a large load frame. NER adopted a different approach. A piston divides the pressure vessel into two chambers. The overburden pressure on the rock is developed in the lower chamber. When the pressure in the top chamber is greater, a differential stress is exerted on the specimen. The pressure in each chamber is controlled with high-pressure, servo hydraulic intensifiers. The axial loading operates in force or displacement control. High-pressure translates to reduced size for a high-capacity unit.
The pressure vessel is a tube with no threaded closures for greater safety at high pressures. The vessel is lowered onto the base pedestal and secured by moving a yoke between the top plate of the loading frame and the top of the pressure vessel. The differential stress, confining pressure, and pore pressure are generated with three servo-controlled hydraulic intensifiers housed in a separate safety enclosure.
