An experimental study of acid matrix treatment performance on shale core samples

Rayan E. Khalil, Ahmed Mansour, Talal Gamadi

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Scopus citations

Abstract

Experimental and numerical studies have demonstrated that there is great potential of enhancing the oil recovery from tight formations. This study investigated the effect of acid matrix treatment by applying gas flooding on the core samples before and after the treatment. The aim of the acid stimulation treatment was to improve the low-permeability of the cores. Four core samples (0.5 in, 1.0 in, 1.5 in, and 2.0 in) from an outcrop of the Eagle Ford formation were used in this study. Permeability was measured before and after the acid treatment. The cores were CT-scanned to identify natural fractures. Different gas injection pressures were used to study the oil recovery and the time needed to penetrate through core samples. Furthermore, a solubility test was applied to identify the optimal acid concentration. The cores were re-scanned after the acid flooding treatments to detect any change. Gas flooding was applied to acidized core samples to detect changes in penetration time and recovery factor. A solubility test demonstrated that 15% of HCL was the optimal acid concentration for the Eagle Ford formation. The study showed the porosity, permeability, recovery factor, and penetration time before and after the acidizing treatment. Permeability was enhanced from 1.04 nanodarcies to 2.10 microdarcies. Furthermore, the study showed the effect of core length on penetration rate (in/min) of gas flooding and the recovery factor at each injecting pressure. The penetration time in this study varied from 207 to 112 minutes/inch when the injecting pressure increased from 1500 to 2500 psi. After acidizing, however, the penetration rate decreased to 8.4 minutes/inch using flooding of 300 psi. The CT scan showed improvement of the micro fracture width.

Original languageEnglish
Title of host publicationSociety of Petroleum Engineers - SPE Liquids - Rich Basins Conference - North America 2017
PublisherSociety of Petroleum Engineers
ISBN (Electronic)9781510847989
StatePublished - 2017
EventSPE Liquids - Rich Basins Conference - North America 2017 - Midland, United States
Duration: Sep 13 2017Sep 14 2017

Publication series

NameSociety of Petroleum Engineers - SPE Liquids - Rich Basins Conference - North America 2017

Conference

ConferenceSPE Liquids - Rich Basins Conference - North America 2017
CountryUnited States
CityMidland
Period09/13/1709/14/17

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  • Cite this

    Khalil, R. E., Mansour, A., & Gamadi, T. (2017). An experimental study of acid matrix treatment performance on shale core samples. In Society of Petroleum Engineers - SPE Liquids - Rich Basins Conference - North America 2017 (Society of Petroleum Engineers - SPE Liquids - Rich Basins Conference - North America 2017). Society of Petroleum Engineers.