Center for Geomechanics and Mitigation of Geohazards (GMG)
The Center for Geomechanics and Mitigation of Geohazards (GMG) helps design strategies and technical solutions for safe and economic operations for carbon dioxide (CO2) storage, oil and gas extraction and production, and geothermal heat production. Its mission is to advance the understanding of geomaterials failure in the presence of fluids for industry applications and geohazard mitigation. It leverages cutting-edge modeling, computing, geophysical, and remote-sensing research to better understand how geomaterials fail when subjected to hydromechanical effects (for example, fluid pumping in or out of the subsurface, or slope instabilities induced by ground shaking or rainfall).
Natural hazards such as earthquakes and landslides threaten the safety and economic stability of urban centers as well as the structural integrity and smooth operation of their interconnected infrastructure systems. These events and the sustainability of fossil-fuel dependent economies depend on:
- Extracting oil and gas and geothermal resources safely, effectively and efficiently.
- Diminishing the impact that energy production and consumption have on the climate through CO2 sequestration, utilization and storage.
- Mitigating the risk posed by natural hazards such as earthquakes and landslides to the infrastructure systems that, in part, transmit and distribute energy resources to the public.
To carry out its research, GMG gathers industry and government stakeholders, and scientists and engineers with diverse expertise spanning geophysics, geology, remote sensing, computational mechanics, fracture mechanics, and applied mathematics.
- California Institute of Technology
Application of distributed acoustic sensing to monitor microseismicity and velocity changes in the subsurface
Distributed acoustic sensing (DAS) is a sensor technology that is gaining momentum in the oil and gas industry, especially in monitoring faint earth tremors and seismic velocity changes induced by stress and fluid during fluid injection or extraction. An objective of this project is to use the Pasadena, Calif., DAS array as a platform to research how to deal with the challenges of using DAS data for monitoring.
Experimental investigation of the interaction between fluids and failure of rock faults in shear
Fluids are known to trigger a range of slip events spanning from a slow, creeping motion to dynamic earthquake rupture growth. GMG studies the interaction of fluids and faulting in a highly instrumented experimental setup capable of injecting fluid at various rates onto a 3D polymethyl methacrylate specimenâ€™s interface, mimicking a fault in the Earthâ€™s crust.
Infrastructure system resiliency via ground deformation monitoring
Landslides pose a major hazard to local communities and infrastructure systems. Synthetic aperture radar (SAR) imagery, which is now acquired weekly from satellites with near-global coverage, can provide high-spatial resolution measurements of ground surface motion. GMGâ€™s goal is to assess how SAR images can be used in combination with conventional techniques to monitor ground deformation at millimeter-level precision and accuracy to help forecast landslides.
Microseismic monitoring with deep learning
This project is focused on developing an end-to-end microseismic monitoring workflow using deep neural networks. GMG develops and tests deep learning algorithms to detect and locate induced microearthquakes using, in particular, data from a deep geothermal well simulation. GMG also explores application to vertical component seismic surveys.
Modeling deformation and seismicity due to fluid injections
Pumping fluids in the subsurface produces deformation due to poroelastic and thermal effects. It can induce seismicity and affects transport properties of the medium. GMG aims to forecast and eventually control these effects for various applications, such as geothermal energy production and CO2 storage. GMG therefore develops new approaches to estimate fluids pressure, deformation, transport properties and forecast induced seismicity through a combination of data analysis, thermo-poroelastic stress modeling and reservoir modeling.
Understanding conditions for stable/unstable fault slip induced by fluid injections
When fluids enter an existing fault, they increase pore pressure and promote slip; however, to predict whether the resulting slip would be seismic or not, and how far induced earthquakes might reach, GMG needs detailed understanding of several mechanisms: the effect of pore pressure on fault stability; the effect of dilatancy and compaction on pore fluid; and changes in friction properties due to the presence of fluids. GMG develops numerical models to simulate and assess these effects.