Welcome to the Singer NMR Lab directed by Prof. Philip Singer at the Department of Chemical & Biomolecular Engineering at Rice University. The mission, objectives, motivation, and challenges are as follows:
Mission
Engage in research and development of hydrogen geostorage and recovery & carbon dioxide utilization and geostorage in unconventional organic-rich shale reservoirs, such as partially depleted gas shale reservoirs, by leveraging our:
– Advanced NMR facilities for measuring 1H relaxation & diffusion of hydrogen, methane, and carbon dioxide at reservoir pressures in unconventional shale cores
– Expertise in petrophysics, geology, geochemistry, reservoir engineering, and computational chemistry
Objectives
Investigate the physical, chemical, and transport processes for hydrogen geostorage and recovery & carbon dioxide utilization and geostorage in unconventional shale, from the molecular scale (nm), to the core scale (cm), and to the reservoir scale (km), using:
Advanced NMR (nuclear magnetic resonance) measurements of 1H relaxation at both 20 MHz & 2 MHz (plus diffusion at 2 MHz) on core samples saturated with hydrogen, methane, and carbon dioxide at pressures up to 5000 psi
Molecular simulations to help interpret the NMR results on the molecular (nm) scale
Reservoir simulations to upscale the NMR results to the reservoir (km) scale
Motivation
As the transition towards renewable energy sources intensifies, hydrogen is emerging as a promising energy carrier. One crucial yet challenging component of a hydrogen economy is the long-term storage of hydrogen, whether it is green hydrogen (i.e., hydrogen produced renewable energy sources) or blue hydrogen (i.e., hydrogen produced from steam methane reforming and carbon dioxide geostorage). To this end, partially depleted unconventional gas shale reservoirs show great promise for their vast existing geostorage capacity, their access to pipelines & other infrastructure, and their proximity to renewable energy sources, all in one centralized location.
The cumulative US dry shale gas production is ≈ 250 TCF (eia.gov), which is primarily composed of methane (≈ 5 Gt). This gives an estimate of the vast existing capacity for hydrogen (≈ 600 Mt) geostorage or carbon dioxide (≈ 13 Gt) geostorage in partially depleted gas shale reservoirs.
Furthermore, natural gas dissolves in kerogen by creating gas-filled nanopores in the kerogen matrix, thereby causing the kerogen to swell. The dissolved gas in kerogen is typically neglected in reserve estimates of gas shales. Recovery of dissolved gas could increase ultimate recovery by ≈ 20% (Etminan et al. 2014), and is promising for utilization of carbon dioxide, and subsequent geostorage.
Challenges
- When to stop producing methane and start injecting hydrogen for storage?
- How to predict the geostorage efficiency of hydrogen in the various pore systems?
- How to avoid hydrogen gas leakage from unintended fracture extensions?
- How to predict the evolution of the hydrogen/methane ratio during hydrogen recovery?
- How to optimize the energy yield from hydrogen to predict the return on investment?
- Will injection of carbon dioxide displace & produce the dissolved gas in kerogen?
- Will the increased recovery factor justify the cost of carbon dioxide injection?
- Can the injected carbon dioxide be simultaneously stored in the kerogen?
- Can unintended fracture extensions be avoided to minimize carbon dioxide leakage?