Researchers at Missouri University of Science and Technology are studying methods for extracting natural gas from tight sands and shale formations using a single-molecule imaging system.
"The problem is that the pore size [in tight formations] is so small, only a few nanometers," said Baojun Bai, assistant professor of petroleum engineering and leader of the research.
In conventional reservoirs gas flows through pores that are a few micrometers in width. A single nanometer is one billionth of a meter. A micrometer is one millionth of a meter. In other words, a micrometer is 1,000 times larger than a nanometer.
"At the nanometer scale, materials behave differently. No one really knows how natural gas flows at that level," Bai said. "We want an improved understanding of how the gas flows through the pore space -- specifically, how natural gas in a nanoscale pore behaves. The flow behavior will be different than the conventional behavior, but we don't know how exactly."
Shale samples for the research will come from industry partners on the project: Baker Hughes Inc. and Hess Corp., as well as other shale gas operators.
"I expect that we can create a new mathematical model to predict the gas flow through the nano-level pores," Bai said. In addition, Bai and professor of chemistry Yinfa Ma hope to "comprehensively characterize the pore distribution in the shale because not all of the rock is homogeneous."
The researchers will also study how hydraulic fracturing fluids and proppants affect gas flow.
"With the novel single-molecule imaging system I designed, we can directly monitor the flowing behavior of natural gas, polymer solutions and surfactants in nano-pores, individually or simultaneously," Ma said. "This can be used for new flow model developments and correlated with mathematical models developed by our project partners."
The project is funded through a three-year, $1.2 million grant from the Research Partnership to Secure Energy for America under a U.S. Department of Energy contract as well as support from Baker Hughes, Hess, the university and the Colorado School of Mines.