Reactivity of CO 2 with Utica, Marcellus, Barnett, and Eagle Ford Shales and Impact on Permeability

• Main Authors: Angela Goodman (1798087), Barbara Kutchko (9763313), Sean Sanguinito (7329557), Sittichai Natesakhawat (2058235), Patricia Cvetic (9763310), Igor Haljasmaa (11449671), Richard Spaulding (11449674), Dustin Crandall (1664671), Johnathan Moore (9525923), Lauren C. Burrows (11449677)
• Format: Other Non-Article Part of Journal/Newspaper
• Language: unknown
• Published: 2021
• Subjects: Biophysics; Biochemistry; Biotechnology; Inorganic Chemistry; Space Science; Environmental Sciences not elsewhere classified; Biological Sciences not elsewhere classified; Chemical Sciences not elsewhere classified; Physical Sciences not elsewhere classified; formed carbonic acid; enhance oil recovery; eds ); mercury; density functional theory; 40 ° c; xrd ); carbon; shale cores due; saturated fluid due; ray computed tomography; western gulf basin; storing carbon dioxide; unconventional shale formations; impact hydrocarbon production; dissolve carbonate pockets; could tie co; shale using x; shale matrix surfaces; core shale samples; promote significant reactivity; permeability increased appreciably; eagle ford shales; 2 </ sub; shale mechanical properties; carbon dioxide; shale formations; eagle ford; xenon x; ray diffraction; promote reactivity; fluid reactivity; addressed using; flow properties; chemical properties; worth basin; basin scale; appalachian basin; barnett shale; united states; swelling clays; surface area; sulfur analysis; seal integrity; results showed; recovering hydrocarbons; predicted based; make use; intrusion porosimetry; following questions; examine samples; dry co; dispersive spectroscopy; decreased nanoporosity; bend arch; 3 mpa; Carbonic acid
• Online Access: https://doi.org/10.1021/acs.energyfuels.1c01995.s001

In order to reduce greenhouse gas emissions while recovering hydrocarbons from unconventional shale formations, processes that make use of carbon dioxide to enhance oil recovery while storing carbon dioxide (CO 2 ) should be considered. Here, we examine samples from three shale basins across the United States (Utica and Marcellus Shales in the Appalachian Basin, Barnett Shale in the Bend Arch-Ft. Worth Basin, and Eagle Ford in the Western Gulf Basin) to address the following questions: (1) do changes from reaction with CO 2 and fluids at the micrometer and nanometer scale alter flow pathways and, in turn, impact hydrocarbon production, CO 2 storage, and seal integrity and (2) can CO 2 or fluid reactivity be predicted based on physical or chemical properties of shale formations? Experiments were conducted at 40 °C and 10.3 MPa to characterize the interaction between CO 2 and shale using X-ray diffraction (XRD), carbon and sulfur analysis, in situ Fourier transform infrared spectroscopy (FT-IR), feature relocation scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS), mercury (Hg) intrusion porosimetry, and Brunauer–Emmett–Teller (BET) surface area and pore size analysis coupled with density functional theory (DFT) methods. Changes in mechanical, physical, and flow properties of shale cores due to CO 2 exposure were addressed using a New England Research Autolab 1500 and Xenon X-ray computed tomography (CT) scanning. Results showed that CO 2 did not promote significant reactivity with the shale if water was not present; only shales with swelling clays or residual interstitial pore water reacted with dry CO 2 to promote reactivity in shale. When water was added as a reactant, CO 2 formed carbonic acid and reacted with the shale to dissolve carbonate pockets, etched and pitted the shale matrix surfaces, and increased the microporosity and decreased nanoporosity. Porosity and permeability increased appreciably in core shale samples after exposure to CO 2 saturated fluid due to dissolution of carbonate. Shale mechanical properties were not altered. Trends were not observed that could tie CO 2 or fluid reactivity to physical or chemical properties of the shale formations at the basin scale from the samples we examined. However, if the shale contained significant amounts of carbonate and water was available to react with the CO 2 , pore sizes were altered in the matrix and permeability and porosity increased.