Researchers at Virginia Tech’s mining and minerals engineering department and the Virginia Center for Coal and Energy Research have stepped up to the plate to take on a National Academy of Engineering grand challenge by developing methods, providing assessments, and conducting ongoing research into the injection of carbon dioxide (carbon sequestration) into unconventional storage reservoirs in the Central Appalachian Basin.
The growth of carbon dioxide emissions has been implicated as a prime contributor to global warming and is identified as one of the National Academy of Engineering’s “Grand Challenges,” a list of 14 critical issues ranging from health and security to sustainability and the environment, considered essential for humanity to flourish.
One promising solution is carbon sequestration, a process for capturing carbon dioxide and storing it safely away from the atmosphere. The work being carried out at Virginia Tech focuses specifically on Carbon Capture, Utilization and Storage (CCUS), whereby a process is developed which economically extracts natural gas from wells while creating pore space for storing carbon dioxide.
Dr. Nino Ripepi, assistant professor in the department of mining and minerals engineering, has served as lead project manager for a series of funded projects, spanning multiple phases. He is joined by co-principle investigators Michael Karmis, department Stonie Barker Professor and Director of VCCER, and Ellen Gilliland, department assistant professor.
The overarching project, CO2 Injection Projects in Unconventional (Coal/Organic Shale) Reservoirs, seeks to test the storage potential of unmineable coal seams and shale reservoirs while better understanding the adsorption and swelling behaviors between methane and CO2. The research is funded by the US Department of Energy and the National Energy Technology Laboratory (NETL), with funding and donation of wells cost-shared from industry partners.
The first phase of the research focused on the identification and characterization of potential on-shore geologic formations suitable for carbon storage. Results from this first phase indicated the potential for both enhanced gas recovery as well as significant storage capacity in the Central Appalachian Basin.
The second phase of the work consisted of “Huff and Puff ” tests in several vertical coal bed methane (CBM) wells and one horizontal shale gas well. Tests were carried out in Russell and Buchanan Counties, Virginia, for the vertical CBM wells, and in Morgan County, Tennessee, for the horizontal shale well. Huff and Puff testing is a cyclic process by which a well is injected with a fluid or gas to aid in the recovery of methane or test the reservoir’s capacity to store injected CO2.
Phase two, funded at $12.5 million, resulted in the successful injection of over 14,000 tons of CO2 in the three vertical coal bed methane and one horizontal shale gas wells, indicating high storage capacity and the potential for commercialization and economic development.
The promising results of the onshore projects allowed the Virginia Tech team to shift its sights off shore for the third phase of its research. The Southeast Off shore Storage Resource Assessment, or SOSRA, is a 3-year research initiative receiving over $1 Million in funding by the U.S. Department of Energy. This project aims to provide high-quality assessment of prospective carbon dioxide storage resources off the Eastern Gulf of Mexico as well as the Mid and South Atlantic Seaboards. Results of this work have provided an overview of the basic geological framework of the Mid-Atlantic region as well defined key planning areas. The team has identified three zones in the Mid-Atlantic region favorable to carbon dioxide sequestration: the Baltimore Canyon Trough, the Carolina Trough and the lower Potomac Aquifer that could be future test sites to verify the efficacy of carbon storage.