Rock Deformation and Fluid Transport
Our laboratory currently houses several mechanical and transport systems, dedicated to test natural rocks samples at in-situ conditions. We aim to identify the mechanisms that control bulk rock deformation and fluid flow, and how these processes relate to coarser-scale fault movement and fluid transport. Our scale of focus therefore varies from the crustal scale to the reservoir scale. Our current focus is mainly on unconventional reservoir rocks including shales.
The following people in the Stress and Crustal Mechanics Group regularly work in our lab: Arjun Kohli, Fatemeh Rassouli, and Shaochuan Xu. The work in our mechanical and transport lab is supplemented by high-resolution image analysis performed at the Stanford Nanocharacterization Lab, but also at other locations. Often, our lab results support reservoir geomechanics interpretations made by others in the Stress & Crustal Mechanics group.
Equipment
GCTS RTR-1000 | Triaxial system capable of rock deformation experiments up to confining and pore pressures up to 140 MPa (20000 psi), with a maximum axial load of 1000 kN. The cell accepts samples with a diameter of up to 75 mm (3 inch) with a length of two times the diameter, and can hold different types of sensors including internal load cells, LVDT’s, and ultrasonic transducers. Currently, we are using the machine to test the creep behavior of unconventional rocks (SX).
NER Autolab 2000 | Recently upgraded, triaxial system capable of testing under confining pressures up to 200 MPa (29000 psi). Since we test mainly using gases as pore fluids, we use a separate Quizix pump to generate He, CO2, CH4, and N2 pore pressures up to 10 MPa (1500 psi). The NER cell accepts either one- or two-inch core samples and holds an internal load cell, LVDT’s, and an ultrasonic transducer. All experiments in this system run under room temperature. We use this system to investigate mechanisms of time-dependent deformation of shales (FR).
Thermally-controlled permeability system | Set-up consisting of a Temco core holder, coupled to a Quizix pump and a manually operated confining pressure cylinder. All components are enclosed in a sealed polystyrene box, which is thermally controlled by two heaters and a powerful fan. We are capable of running experiments with the following maximum testing conditions: 41 MPa (6000 psi) confining pressure, 34 MPa (5000 psi) fluid pressure and a constant temperature of 40 °C. We use this system to conduct stress-dependent permeability measurements on gas shales (SX).
Manometric adsorption system | Various pressure cells submerged in a temperature bath and coupled with an Argilent MicroGC. This system is used to determine the chemical composition of gas mixtures.
Related Publications
- A viscoplastic model of creep in shale. (2020). Society of Exploration Geophysicists. https://doi.org/10.1190/geo2018-0700.1
- Zoback, M., Singh, A., & Xu, S. (2019). Integrated Analysis of the Coupling Between Geomechanics and Operational Parameters to Optimize Hydraulic Fracture Propagation and Proppant Distribution. Society of Petroleum Engineers.
- Variation of the least principal stress with depth and its effect on vertical hydraulic fracture propagation during multi-stage hydraulic fracturing. (2019). American Rock Mechanics Association.
- Comparison of short-term and long-term creep experiments in shales and carbonates from unconventional gas reservoirs. (2018). https://doi.org/10.1007/s00603-018-1444-y
- Static and dynamic response of Bakken cores to cyclic hydrostatic loading. (2018). https://doi.org/10.1007/s00603-018-1443-z
- Laboratory experiments simulating poroelastic stress changes associated with depletion and injection in low-porosity sedimentary rocks. (2017). https://doi.org/10.1002/2016JB013668
- The Effects of Gas Adsorption on Swelling, Visco-plastic Creep and Permeability of Sub-bituminous Coal. (2011). 45th US Rock Mechanics / Geomechanics Symposium held in San Francisco, CA.
- Visco-plastic Properties of Shale Gas Reservoir Rocks. (2011). 5th U.S. Rock Mechanics / Geomechanics Symposium, San Francisco, California.
- Hagin, P., & Zoback, M. (2007). A dual power law model for prediction and monitoring of long-term compaction in unconsolidated reservoir sands. Geophysics, 72(5), E165-E173. http://scitation.aip.org/journals/doc/GPYSA7-ft/vol_72/iss_5/E165_1.html
- Hagin, P., Sleep, N., & Zoback, M. (2007). Application of rate-and-state friction laws to creep compaction of unconsolidated sand under hydrostatic loading conditions. Jour. Geophys. Res., 112. https://doi.org/10.1029/2006JB004286