Work in SUETRI-A on CCUS is aligned with the Stanford Center for Carbon Storage SCCS as well as the Carbon Utilization and Storage Partnership CUSP WEST. Our interests include basin-scale assessment of storage formations using rapid evaluation and ranking methods that are relatively simple to implement. The assessment methodology clarifies prospective carbon dioxide storage amounts taking into account formation specific properties as well as restrictions including sites that pose technical risk or are located in regions with surface restrictions including sensitive habitats and dense populations. In this way, we advance toward adding certainty to estimates of carbon dioxide storage potential and identification of potentially acceptable sites for injection.
Also at the scale of fields and basins, we are developing methods to model the heterogeneous distribution of stress in the subsurface. This knowledge is essential to robust geomechanical assessment to avoid mechanical damage to the storage formation and overlying strata.
With respect to monitoring the progress of carbon storage activities, we are extending our past work using Interferometric synthetic aperture radar (InSAR) in combination with in-depth understanding of formation deformation. As a formation undergoes injection, surface movement, in some cases, correlates with the progress of storage operations as well as the volume of pore space that is contacted. Monitoring using InSAR may provide an option for both long- and short-term assessment of the efficacy of storage operations.
Pivoting to carbon utilization, carbon dioxide enhanced recovery provides a means to decrease the climate impacts of oil and gas production. Hence, our continued interest in enhanced recovery as described in a subsequent area. Because of its low viscosity and availability, water is used as a hydraulic fracturing fluid in nearly all hydraulic fracturing operations. Carbon dioxide is a potential substitute for aqueous fracturing fluids and may have a number of advantages including reduction of stress on water resources, less water to be disposed, and/or less water recycled. The expense and lack of availability of carbon dioxide, however, makes water the fracturing fluid of choice. Our research contributes toward a shift toward reduced water consumption in upstream petroleum operations.
Hydrogen is expected to make significant contributions as an energy carrier for decarbonizing the energy system and meeting net-zero emission targets. Emissions free hydrogen may be produced via both steam methane reforming of natural gas with geological carbon storage or electrolysis using renewable electricity. Solar and wind energy are intermittent but hydrogen production and storage can help reduce or eliminate intermittency if storage is done economically and at large scale. Underground formations have the potential to store many multiple TWh of energy due to the large volumetric capacity of depleted oil and gas reservoirs as well as saline formations. Although hydrogen storage has been successfully implemented in salt caverns in the UK and the US Gulf Coast for over 30 years, the geographic availability of evaporitic formations with suitable thickness and extent offers limited storage capacities. Subsurface saline aquifers and depleted oil/gas fields offer storage capacity that is several orders of magnitude larger than that of salt caverns; thus, subsurface geologic formations have the potential for hydrogen storage at very large scales
The objective of our research is to understand the properties and conditions of subsurface reservoirs to enable temporal storage of high purity hydrogen. This understanding of optimal reservoir properties guides screening and identifying potential sites for underground hydrogen storage. Our research efforts are interdisciplinary, combining geospatial mapping, geology, geophysics, petrophysics and reservoir engineering, to identify and select sites for underground hydrogen storage. In addition, we carry out reservoir simulation to understand the long-term effects of injection and withdrawal of hydrogen. We are also identifying relevant experimental work to aid in our understanding of how hydrogen reacts with components of the subsurface during storage.
Aspects of our work in the area of seal durability also apply here as hydrogen storage formation seals will encounter a molecule (H2) that they have not encountered in large concentration as well as seals will be subjected to cyclic depletion and withdrawal as hydrogen is withdrawn and injected. Monitoring efforts described under CCUS also crossover into this area for studying injection/withdrawal operations at formation scale.