NETL working with partners on technology to seal off leaks in orphaned wells
The National Energy Technology Laboratory (NETL) has been working with several partners to develop a technology to help seal problematic defects in wellbore casing cement, including those in orphaned oil and gas wells.
The technology could be used to prevent leakages of methane, a potent greenhouse gas (GHG), into the atmosphere and underground water supplies. Orphaned wells are significant emitters of methane – and there are an estimated 1 to 3 million of them in the U.S.
The project, which began in 2014, is being done by NETL in collaboration with the Montana State University Energy Research Institute and Center for Biofilm Engineering, Montana Emergent Technologies (MET), and others. The technology, which has undergone multiple laboratory and field tests, has been licensed as a commercial product. So far, it has been used by BioSqueeze Inc., formerly MET, to plug more than 40 wells across the United States.
Oil and natural gas wells are typically constructed by drilling through layers of rock. Steel pipe is inserted into the rock, and specialty cements are used between the casing and the rock interior of the wellbore. Cement defects can form during the initial cement placement. Mechanical stresses such as pressure cycling and thermal expansion or contraction, as well as physical aging, can also produce cement defects, creating potential hydrocarbon leakage pathways.
Cement and resins have been widely used to remediate damaged wellbore cement and stop leaks. But sealing small fissures is difficult because of the high viscosity and/or large particle size of the sealants. Some fissures are so small that cement particles from remedial operations cannot enter the pathway.
The solution developed under NETL oversight is a process called microbially induced calcite precipitation (MICP). It has a viscosity like water, allowing it to flow readily into the narrow leakage channels.
“The process promotes calcite precipitation in the channels, essentially growing new rock to plug the leak,” NETL’s Robert Vagnetti, project manager, Natural Gas & Oil, said.
This MICP technology, which contains no harsh chemicals, could be a game-changer to help meet provisions within the Infrastructure Investment and Jobs Act that President Joe Biden signed into law. The bill set aside nearly $5 billion to plug and clean up documented orphaned wells. It also directs the U.S. Secretary of Interior to offer states grants as large as $5 million to fund plugging, remediation, and reclamation of orphaned wells.
“In my career, the development of MICP stands out as an excellent example of how the U.S. Department of Energy and NETL can work with university, industry, and small business partners to spearhead the commercialization of a technology to solve not just an industry problem but to also address a critical climate change issue,” Vagnetti said.
The team that advanced this technology included Al Cunningham, Adrienne Phillips, Robin Gerlach, Lee Spangler and Catherine Kirkland (Montana State); Randy Hiebert, Jay McCloskey and Robert Hyatt (BioSqueeze); Jim Kirksey (Loudon Technical Services); Mike Gallagher (Gallagher Drilling); Wayne Rowe (Schlumberger); and Richard Esposito (Southern Company).
