Neutron scattering measurements of carbon dioxide adsorption in pores within the Marcellus Shale: Implications for sequestration

Environmental Science & Technology
By: , and 

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Abstract

Shale is an increasingly viable source of natural gas and a potential candidate for geologic CO2sequestration. Understanding the gas adsorption behavior on shale is necessary for the design of optimal gas recovery and sequestration projects. In the present study neutron diffraction and small-angle neutron scattering measurements of adsorbed CO2 in Marcellus Shale samples were conducted on the Near and InterMediate Range Order Diffractometer (NIMROD) at the ISIS Pulsed Neutron and Muon Source, STFC Rutherford Appleton Laboratory along an adsorption isotherm of 22 °C and pressures of 25 and 40 bar. Additional measurements were conducted at approximately 22 and 60 °C at the same pressures on the General-Purpose Small-Angle Neutron Scattering (GP-SANS) instrument at Oak Ridge National Laboratory. The structures investigated (pores) for CO2 adsorption range in size from Å level to ∼50 nm. The results indicate that, using the conditions investigated densification or condensation effects occurred in all accessible pores. The data suggest that at 22 °C the CO2 has liquid-like properties when confined in pores of around 1 nm radius at pressures as low as 25 bar. Many of the 2.5 nm pores, 70% of 2 nm pores, most of the <1 nm pores, and all pores <0.25 nm, are inaccessible or closed to CO2, suggesting that despite the vast numbers of micropores in shale, the micropores will be unavailable for storage for geologic CO2 sequestration.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Neutron scattering measurements of carbon dioxide adsorption in pores within the Marcellus Shale: Implications for sequestration
Series title Environmental Science & Technology
DOI 10.1021/acs.est.6b05707
Volume 51
Issue 11
Year Published 2017
Language English
Publisher ACS
Contributing office(s) Eastern Energy Resources Science Center
Description 7 p.
First page 6515
Last page 6521