Research Projects

The world needs to quickly shift its energy sources from fossil fuels to renewable sources to reduce global warming. The energy supply from renewable sources such as solar and wind is highly intermittent due to its dependence on atmospheric conditions, the time of the day, and seasons. Hydrogen is a promising zero-carbon option that can store surplus produced energy (during windy/sunny periods) at a large scale and lessen the intermittency problem of renewable sources. Further, the raw material for hydrogen production is abundant water, and hydrogen's energy content per mass is three times that of gasoline, making it the future fuel. However, because of hydrogen's low density, enormous storage space is required to store gigawatt hours of energy. Underground porous formations such as depleted hydrocarbon reservoirs and saline aquifers can provide sufficient space to store such large quantities of hydrogen. Storing in an underground porous formation brings in some technical challenges because of the high reactivity of hydrogen with the solid matrix of the porous formation. The injected hydrogen can undergo geochemical reactions with the solid matrix and microbial reactions with the bacteria in the matrix. The reactions can change the permeability of the porous formation via precipitation/dissolution and pore-clogging. Further, these reactions can induce instabilities at the interface between the hydrogen and the reservoir fluid present in the porous formation before hydrogen injection. The instabilities can result in residual hydrogen trapping within the reservoir fluid, making it unrecoverable during its withdrawal from the porous formation. Therefore it is necessary to quantify the change in permeability and the instabilities resulting from the reactions at an underground porous formation site before selecting the site as a storage location. The proposed research will use numerical simulations to quantify the permeability change induced by the reactions as hydrogen flows into a porous media saturated with reservoir fluid. Some methods developed in the literature for analysing the geological sequestration of carbon-di-oxide and underground natural gas storage will form the simulation's basis. The quantification will provide a relationship between the porous medium's permeability and porosity depending on the reaction type, the medium's ambient conditions, and the reservoir fluid. We will use the relationship to conduct a hydrodynamic stability analysis at the hydrogen-reservoir fluid interface to identify parameters that reduce residual hydrogen trapping in reservoir fluid. Such a relationship will be beneficial while carrying out a large-scale reservoir simulation to assess the feasibility of underground hydrogen storage locations.