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Green Dream or Green Nightmare? CCS Could Boost Shale Gas Production

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Penn State University

Injecting carbon dioxide into shale gas wells would stimulate even more gas production.

study area map

Area map of the Marcellus Shale study – Image: Penn State

Marcellus Shale and other natural gas plays are considered valuable for what can be extracted from them, but what if they could also be valuable and environmentally helpful after they are been depleted?

That is a question Penn State faculty are looking at as part of a research project the National Energy Technology Lab’s Regional University Alliance is conducting. Seth Blumsack, John T. Ryan Jr. Faculty Fellow, and Turgay Ertekin, head, Department of Energy and Mineral Engineering, and holds the George E. Trimble Chair in Earth and Mineral Sciences, are part of the group studying whether it would be possible and make economic sense to capture carbon dioxide produced at large point sources and pump it into existing natural gas wells.

“It’s driven by the potential social problem of managing carbon dioxide emissions,” said Blumsack, who is also a faculty affiliate in Penn State’s Earth and Environmental Systems Institute.

“The big boys like power generating plants and transportation get a lot of press,” Blumsack said. “But, heavy industry is a substantial contributor to global carbon dioxide emissions. The annual emissions from a really big facility, like a steel mill or cement plant, can rival the annual carbon dioxide emissions from a moderately-sized coal-fired power plant.”

The study, the first of its kind, is also looking at what is known as enhanced gas production  — injecting carbon dioxide into the wells and stimulating more gas production. That scenario would mean separating the two gases, then pushing the carbon dioxide back into the formation, potentially reaping the economic benefit of the additional gas production — depending on its market price.

“What we are trying to do is develop and analyze the protocols to help us really understand the efficiency of sequestering carbon dioxide in shale reservoirs,” Ertekin said. “These reservoirs have been holding a different gas for millions of years in a secure way. They may turn out to be a dependable repository for us to sequester carbon dioxide in a secure way.”

While using old oil and gas wells to store waste fluids, including those from hydraulic fracturing, has a long history, using those wells for carbon dioxide storage is new territory. Similarly, U.S. Environmental Protection Agency regulations covering carbon dioxide sequestration were designed with underground saline aquifers, not former natural gas drilling sites, in mind.

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