URTeC: 3723858 Effect of Hydrogen Exposure on Shale Reservoir Properties and Evaluation of Hydrogen Storage Possibility in Depleted Unconventional Formations Elie Bechara* 1 , Talal Gamadi 1 , Athar Hussain 1 , Hossein Emadibaladehi 1 , 1. Texas Tech University Copyright 2022, Unconventional Resources Technology Conference (URTeC) DOI 10.15530/urtec-2022-3723858 This paper was prepared for presentation at the Unconventional Resources Technology Conference held in Houston, Texas, USA, 20-22 June 2022. The URTeC Technical Program Committee accepted this presentation on the basis of information contained in an abstract submitted by the author(s). The contents of this paper have not been reviewed by URTeC and URTeC does not warrant the accuracy, reliability, or timeliness of any information herein. All information is the responsibility of, and, is subject to corrections by the author(s). Any person or entity that relies on any information obtained from this paper does so at their own risk. The information herein does not necessarily reflect any position of URTeC. Any reproduction, distribution, or storage of any part of this paper by anyone other than the author without the written consent of URTeC is prohibited. Abstract Hydrogen has been recently gaining global popularity for being a great potential low-carbon energy carrier, essentially considered for eco-friendly transportation, power, and heating. However, storage has been an issue due to the material’s low density which suggests greater volumetric capacity compared to other gases such as CH4, and lower temperatures to accommodate storage facilities. This has called for exploring alternatives such as underground hydrogen storage in porous media (UHSP), essentially considered in saline aquifers and depleted hydrocarbon reservoirs. Across the U.S., many depleted shale reservoirs hold large volumetric capacities possibly suitable for hydrogen storage. Studying the effect of reservoir rock and fluid exposure to hydrogen would help explore this possibility. Experimental work has been done on conventional rock, which begs the question of the effect on abundant unconventional shale. Exposure of shale samples to compressed hydrogen gas at in-situ conditions would help determine changes in wettability, permeability, and porosity. Sample properties are measured before and after exposure. Another interest is the effect of hydrogen exposure on fluid properties, such as interfacial tension between oil and water. Also, gas flooding techniques can be used to estimate the effect of hydrogen on oil recovery, to better understand the interaction with reservoir fluids. Moreover, exploring the interaction between hydrogen and CH4 would give an idea about the effect of natural gas presence. Any significant chemical reaction would be noted in the process. An increase in permeability and porosity would suggest better storage. Change in wettability would define what fluids could accompany hydrogen when extracted after storage, and could help estimate hydrogen extraction rates. A change from oil-wet to water-wet can lead to oil production. Primary experiments have not shown a significant effect on wettability, but changes in temperature and pressure could prove otherwise. If hydrogen flooding shows decent oil recovery, that could imply more space for hydrogen to be stored in. Hydrocarbon production during storage and extraction could attract operators to look more into UHSP. It should be noted that hydrogen can always react with fluid or rock to generate toxic acid gases. It is intriguing to see how those gases affect reservoir behavior. Downloaded from http://onepetro.org/URTECONF/proceedings-pdf/22URTC/2-22URTC/D021S035R004/2802362/urtec-3723858-ms.pdf/1 by Texas Tech University user on 22 February 2023