Alternating N2 gas injection as a potential technique for enhanced gas recovery and CO2 storage in consolidated rocks : an experimental study

Mohammed, NUHU; Abbas, AJ; Enyi, GC; Suleiman, SM; Edem, DE; Abba, MK

Abstract

The promotion of enhanced gas recovery (EGR) and CO2 storage is still shrouded in contention, and is not well
accepted, due to the excessive in-situ CO2 mixing with the nascent natural gas. This adulterates the recovered
CH4 and thus, results in a high sweetening process cost thereby making the technique impractical. This has not
only limited the field application of EGR in actual projects to a few trails but renders it uneconomical. This study
aims to present, experimentally, alternating N2 injection as a potential technique for EGR and CO2 storage in
sandstone rock cores. A laboratory core flooding experiment was carried out to simulate a detailed process of
unsteady-state methane (CH4) displacement using Bandera gray core plug. This was carried out at 40 0C, 1500
psig, and 0.4 ml/min injection rate by alternative injection of N2 and CO2 in succession designed to suit the
application based on optimum operating conditions. The results show that both CO2 storage capacity and CH4
recovery improved significantly when gas alternating gas (GAG) injection was considered. The best results were
observed at lower N2 cushion volumes (1 and 2 PV). Therefore, the GAG injection method with N2 as cushion gas
can potentially increase both CO2 storage and CH4 recovery of the gas reservoir. This technique if employed will
assert the current position and provide vital information for further researches aimed at promoting environmental
sustainability and economic viability of the EGR and CO2 sequestration processes.

Citation

Mohammed, N., Abbas, A., Enyi, G., Suleiman, S., Edem, D., & Abba, M. (2020). Alternating N2 gas injection as a potential technique for enhanced gas recovery and CO2 storage in consolidated rocks : an experimental study. Journal of Petroleum Exploration and Production Technologies, 10(8), 3883-3903. https://doi.org/10.1007/s13202-020-00935-z

• Journal Article Type: Article
• Acceptance Date: Jun 11, 2020
• Online Publication Date: Jun 20, 2020
• Publication Date: Dec 1, 2020
• Deposit Date: Jun 10, 2020
• Publicly Available Date: Jul 1, 2020
• Journal: Journal of Petroleum Exploration and Production Technology
• Print ISSN: 2190-0558
• Electronic ISSN: 2190-0566
• Publisher: Springer Verlag
• Volume: 10
• Issue: 8
• Pages: 3883-3903
• DOI: https://doi.org/10.1007/s13202-020-00935-z
• Publisher URL: https://doi.org/10.1007/s13202-020-00935-z
• Related Public URLs: https://link.springer.com/journal/13202