eprintid: 14096 rev_number: 2 eprint_status: archive userid: 1 dir: disk0/00/01/40/96 datestamp: 2023-11-10 03:28:39 lastmod: 2023-11-10 03:28:39 status_changed: 2023-11-10 01:52:44 type: article metadata_visibility: show creators_name: Janssen, M.T.G. creators_name: Pilus, R.M. creators_name: Zitha, P.L.J. title: A Comparative Study of Gas Flooding and Foam-Assisted Chemical Flooding in Bentheimer Sandstones ispublished: pub keywords: Alkalinity; Computerized tomography; Enhanced recovery; Floods; Foams; Gases; Injection (oil wells); Sandstone; Secondary recovery; Surface active agents, Alkaline; Continuous gas injections; Core flood experiments; Displacement mechanisms; Enhance oil recoveries; Enhanced oil recovery; Immiscible gas injection; Water alternating gas, Oil well flooding, comparative study; displacement; enhanced oil recovery; fluid injection; foam; immiscible fluid; reservoir flooding; sandstone; surfactant note: cited By 22 abstract: A laboratory study of principal immiscible gas flooding schemes is reported. Very well-controlled experiments on continuous gas injection, water-alternating-gas (WAG) and alkaline�surfactant�foam (ASF) flooding were conducted. The merits of WAG and ASF compared to continuous gas injection were examined. The impact of ultra-low oil�water (o/w) interfacial tension (IFT), an essential feature of the ASF scheme along with foaming, on oil mobilisation and displacement of residual oil to waterflood was also assessed. Incremental oil recoveries and related displacement mechanisms by ASF and WAG compared to continuous gas injection were investigated by conducting CT-scanned core-flood experiments using n-hexadecane and Bentheimer sandstone cores. Ultimate oil recoveries for WAG and ASF at under-optimum salinity (o/w IFT of 10�1 mN/m) were found to be similar 60 ± 5% of the oil initially in place (OIIP). However, ultimate oil recovery for ASF at (near-)optimum salinity (o/w IFT of 10�2 mN/m) reached 74 ± 8% of the OIIP. Results support the idea that WAG increases oil recovery over continuous gas injection by drastically increasing the trapped gas saturation at the end of the first few WAG cycles. ASF flooding was able to enhance oil recovery over WAG by effectively lowering o/w IFT (< 10�1 mN/m) for oil mobilisation. ASF at (near-)optimum salinity increased clean oil fraction in the production stream over under-optimum salinity ASF. © 2019, Springer Nature B.V. date: 2020 publisher: Springer official_url: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85059583139&doi=10.1007%2fs11242-018-01225-3&partnerID=40&md5=2eb849c64235d598d6ad420120f77e73 id_number: 10.1007/s11242-018-01225-3 full_text_status: none publication: Transport in Porous Media volume: 131 number: 1 pagerange: 101-134 refereed: TRUE issn: 01693913 citation: Janssen, M.T.G. and Pilus, R.M. and Zitha, P.L.J. (2020) A Comparative Study of Gas Flooding and Foam-Assisted Chemical Flooding in Bentheimer Sandstones. Transport in Porous Media, 131 (1). pp. 101-134. ISSN 01693913