The objective of this paper was to investigate the impact of wettability of porous media on pore-scale characteristics of residual nonaqueous phase liquids (NAPLs). Synchrotron X-ray microtomography was used to obtain high-resolution three-dimensional images of fractionally wet sand systems with mean grain size of 250 microm. Pore-scale characteristics of NAPL blobs such as volume, lengths, interfacial areas, and sphericity index were computed using three-dimensional image processing algorithms. Four systems comprised of 100, 50, 25, and 0% NAPL-wet mass fractions containing the residual NAPL were imaged and analyzed. Findings indicate that spatial variation in wettability of porous media surfaces has a significant impact on pore-scale characteristics of residual NAPL blobs in saturated porous media systems. As the porous media comprises more water-wet surfaces, residual NAPL blobs increase in size and length due to the entrapment at large pore bodies. NAPL-water interfacial areas tend to increase as the NAPL-wet surface fractions increase in the systems. Overall residual NAPL saturations are less in fractionally wet systems and increase as the systems become more NAPL-wet or water-wet.
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ACS Omega
December 2024
School of Engineering Science, University of Chinese Academy of Science, Beijing 100049, China.
Understanding the dynamic characterization of the CO miscible flooding process in low permeability reservoirs and its mechanism for oil recovery enhancement is crucial for controlling CO miscible flooding sweep efficiency and further enhancing oil recovery. This study was conducted in a low permeability reservoir in Jilin, China, using both online nuclear magnetic resonance CO miscible flooding and long-core CO miscible flooding experiments. A refined dynamic characterization of the CO miscible flooding process from the macroscopic core scale to the microscopic pore scale was achieved through multiple spatial online nuclear magnetic resonance testing methods.
View Article and Find Full Text PDFACS Appl Mater Interfaces
December 2024
Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955, Saudi Arabia.
Understanding rock wettability is crucial across various fields including hydrology, subsurface fluid storage and extraction, and environmental sciences. In natural subsurface formations like carbonate and shale, mixed wettability is frequently observed, characterized by heterogeneous regions at the pore scale that exhibit both hydrophilic (water-wet) and hydrophobic (oil-wet) characteristics. Despite its common occurrence, the impact of mixed wettability on immiscible fluid displacement at the pore scale remains poorly understood, creating a gap in effective modeling and prediction of fluid behavior in porous media.
View Article and Find Full Text PDFNanoscale
January 2025
University of Chinese Academy of Sciences, Beijing 100049, China.
ACS Omega
November 2024
Research Institute of Petroleum Exploration and Development, China National Petroleum Corporation, Beijing 100086, China.
In order to explore the microscopic storage mechanism of shale gas in water-bearing pores and its influencing factors, this article first establishes a molecular dynamics model for methane in different types of adsorbents using molecular dynamics simulation and the grand canonical ensemble Monte Carlo methods. These adsorbents include graphene, organic matter (kerogen), brittle minerals (quartz and albite), carbonate minerals (calcite), and clay minerals (illite, kaolinite, and montmorillonite). Then, by analyzing the molecular storage model and density distribution curves of methane in pores, the storage mechanisms of shale gas are analyzed and elucidated.
View Article and Find Full Text PDFLangmuir
October 2024
State Key Laboratory of Deep Oil and Gas, China University of Petroleum (East China), Qingdao 266580, P.R. China.
As a key resource in the oil and gas sector, shale gas development profoundly influences the advancement of the global energy industry. Deep shale gas reservoirs, typically found at depths exceeding 3500 m, represent a significant portion of total shale gas reserves. Currently, pore network models primarily simulate middle and shallow shale gas, insufficiently addressing the unique challenges posed by high-temperature and high-pressure conditions in deep shale gas formations.
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