Effect of fluid properties on contact angles in the eagle ford shale measured with spontaneous imbibition

November 02, 2021

Joanna McFarlane (1), Victoria H. DiStefano (1,2,3), Philip R. Bingham (1), Hassina Z. Bilheux (1), Michael C. Cheshire (1,4), Richard E. Hale (1), Daniel S. Hussey (5), David L. Jacobson (5), Lindsay Kolbus (1,6), Jacob M. LaManna (5), Edmund Perfect (7), Mark Rivers (8), Louis J. Santodonato (1,9), Lawrence M. Anovitz (1)
ACS Omega, 6, Issue 48, November 2021: 32618–32630. DOI: 10.1021/acsomega.1c04177


Models of fluid flow are used to improve the efficiency of oil and gas extraction and to estimate the storage and leakage of carbon dioxide in geologic reservoirs. Therefore, a quantitative understanding of key parameters of rock–fluid interactions, such as contact angles, wetting, and the rate of spontaneous imbibition, is necessary if these models are to predict reservoir behavior accurately. In this study, aqueous fluid imbibition rates were measured in fractures in samples of the Eagle Ford Shale using neutron imaging. Several liquids, including pure water and aqueous solutions containing sodium bicarbonate and sodium chloride, were used to determine the impact of solution chemistry on uptake rates. Uptake rate analysis provided dynamic contact angles for the Eagle Ford Shale that ranged from 51 to 90° using the Schwiebert–Leong equation, suggesting moderately hydrophilic mineralogy. When corrected for hydrostatic pressure, the average contact angle was calculated as 76 ± 7°, with higher values at the fracture inlet. Differences in imbibition arising from differing fracture widths, physical liquid properties, and wetting front height were investigated. For example, bicarbonate-contacted samples had average contact angles that varied between 62 ± 10° and ∼84 ± 6° as the fluid rose in the column, likely reflecting a convergence–divergence structure within the fracture. Secondary imbibitions into the same samples showed a much more rapid uptake for water and sodium chloride solutions that suggested alteration of the clay in contact with the solution producing a water-wet environment. The same effect was not observed for sodium bicarbonate, which suggested that the bicarbonate ion prevented shale hydration. This study demonstrates how the imbibition rate measured by neutron imaging can be used to determine contact angles for solutions in contact with shale or other materials and that wetting properties can vary on a relatively fine scale during imbibition, requiring detailed descriptions of wetting for accurate reservoir modeling.

How Our Software Was Used

Dragonfly was used to determine the fracture thickness in CT images by calculating the diameter of a hypothetical sphere that could fit within the fracture boundary.

Author Affiliation

(1) Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831, United States.
(2) Bredesen Center, University of Tennessee, Knoxville, Tennessee 37996-3394, United States.
(3) U.S. Department of Energy, 19901 Germantown Road, Germantown, Maryland 20874, United States.
(4) Chevron, The Woodlands, Texas 77830, United States.
(5) Physical Measurements Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States.
(6) Indianapolis Metropolitan High School, 1635 West Michigan Street, Indianapolis, Indiana 46222, United States.
(7) Department of Earth and Planetary Science, University of Tennessee, Knoxville, Tennessee 37996-1526, United States.
(8) University of Chicago, Geophysical Sciences, 9700 South Cass Avenue, Building 434-A, Argonne, Illinois 60439, United States.
(9) Advanced Research Systems, 7476 Industrial Park Way, Macungie, Pennsylvania 18062, United States.