Dynamics and Mechanisms of Water Imbibition in Shale Oil Reservoir Through Integrated Nano-to-Centimeter-Scale Imaging

Published

February 8, 2023

Author(s)

Sheng Peng, Priyanka Periwal, Jacob LaManna, Pavel Shevchenko

Abstract

Water imbibition is an important process in shale oil reservoirs after hydraulic fracturing and in water-based enhanced oil recovery. However, understanding of the process, including dynamics and mechanisms, is still limited. In this paper, a multiscale imaging technique that covers nano- to cm-scale integrating neutron radiography, micro-CT, and SEM is developed. This integrated imaging technique was applied to investigate the water imbibition depth and rate, and the controlling factors in water-oil displacement in shale. The processes of vertical water imbibition in the matrix and horizontal imbibition from the microfractures in the 1-inch (25.4 mm) core sample were explicitly demonstrated and distinguished through neutron radiography image analysis. Imbibition depth and rate were calculated on the basis of image analysis as well. Estimation of oil recovery through water imbibition and water uptake in shale matrix was conducted for an example shale field. Specific mechanisms of water-oil displacement, including wettability and pore size effect, were revealed through the micro-CT and SEM image analysis. Heterogeneity/homogeneity of water-oil displacement in the 1-inch diameter sample was examined by analysis for 1.5-mm diameter miniplug samples from different laminas of the core. This integrated multiscale imaging technique provides an innovative method for systematic investigation of water-oil two-phase flow in fractured nanoporous rocks. The results for a specific shale oil reservoir provide more comprehensive information for optimal strategy of improved oil recovery. Heterogeneity/homogeneity of the pore system in shale at different length scales is also discussed.

Citation

Transport in Porous Media

Pub Type

Journals

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Keywords

water imbibition, oil recovery, shale, neutron imaging, micro-CT, multiscale imaging

Citation

Peng, S. , Periwal, P. , LaManna, J. and Shevchenko, P. (2023), Dynamics and Mechanisms of Water Imbibition in Shale Oil Reservoir Through Integrated Nano-to-Centimeter-Scale Imaging, Transport in Porous Media, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=932672 (Accessed March 18, 2025)