Novel Large-Hydrophobe Alkoxy Carboxylate Surfactants for Enhanced Oil Recovery

Abstract

A new class of surfactants has been developed and tested for chemical enhanced oil recovery (EOR) that shows excellent performance under harsh reservoir conditions. These novel Guerbet alkoxy carboxylate (GAC) surfactants fulfill this need by providing large, branched hydrophobes; flexibility in the number of alkoxylate groups; and stability in both alkaline and nonalkaline environments at temperatures up to at least 120 C. The new carboxylate surfactants were recently manufactured at a cost comparable to other commercial EOR surfactants by use of commercially available feedstocks. A formulation containing the combination of a carboxylate surfactant and a sulfonate cosurfactant resulted in a synergistic interaction that has the potential to reduce the total chemical cost further. One can obtain both ultralow interfacial tension (IFT) with the oils and a clear aqueous solution (even under harsh conditions such as high salinity, high hardness, and high temperature with or without alkali) with these new large-hydrophobe alkoxy carboxylate surfactants. Both sandstone and carbonate corefloods were conducted, with excellent results. Formulations were developed for both active oils (contains naturally occurring carboxylic acids) and inactive oils (oils that do not produce sufficient amounts of soap/ carboxylic acid), with excellent results. IntroductionThe recent development of new surfactants has greatly broadened the applications of chemical EOR (CEOR) to a much wider range of reservoir conditions with a relatively low chemical cost. A better understanding of the relationship between the surfactant structure and performance has improved the process of screening and identifying suitable high-performance surfactants for EOR (Solairaj 2011;Solairaj et al. 2012). The use of microemulsion phasebehavior observations used in this study is a very efficient way to screen surfactants (Jackson 2006;Zhao et al. 2008;Levitt et al. 2009;Flaaten et al. 2010;Solairaj et al. 2012). Adkins et al. (2010) demonstrated that Guerbet alkoxy sulfates made with large hydrophobes exhibited good performance under a wide range of conditions. Furthermore, Guerbet alkoxy sulfates can be made in various hydrophobicities by changing the number of propylene oxide (PO) and ethylene oxide (EO) groups to tailor them to different reservoir conditions including high salinity and high hardness. However, Guerbet alkoxy sulfates at neutral pH are not chemically stable above approximately 60 C. Their stability improves if the pH is increased to the range of 10 to 11. However, such high pH requires the use of alkali, and there are circumstances when that is not practical (e.g., when gypsum or anhydrite is present in the reservoir rock or when soft water is

Extended Surfactants Including an Alkoxylated Central Part Intermediate Producing a Gradual Polarity Transition—A Review of the Properties Used in Applications Such as Enhanced Oil Recovery and Polar Oil Solubilization in Microemulsions

“…Other university and industry groups carried out fundamental studies to make these surfactants (Cox and Weerasooriya, 1999;Weerasooriya, 1999) and to improve the solubilization of polar soils without alcohol cosurfactants, particularly in the Institute for Applied Surfactant Research in Norman, OK, USA (Arpornpong et al, 2013;Attaphong et al, 2012;Attaphong and Sabatini, 2017;Budhathoki et al, 2016a;Charoensaeng et al, 2009;Do et al, 2014;Naksuk et al, 2009;Phan et al, 2010aPhan et al, , 2010bPhaodee et al, 2019;Witthayapanyanon et al, 2006Witthayapanyanon et al, , 2008aWitthayapanyanon et al, , b, 2010, as well as other independent research and development groups (Abdel-Azim et al, 1998;Acosta et al, 2012;Adkins et al, 2010;Aoudia et al, 1995;Barnes et al, 2008;Dong et al, 2015;Flaaten et al, 2010;Hadji et al, 2015;Hammond and Acosta, 2012;He et al, 2014;Hirasaki et al, 2011;Hornof and Hombek, 1990;Huang et al, 2004;Jakobs et al, 1999Jakobs et al, , 2000Johannessen and Spildo, 2013;Khristov et al, 2011;Klaus et al, 2010Klaus et al, , 2011Klaus et al, , 2012Liyanage et al, 2015;Lu et al, 2014a;Lu et al, 2014b;…”

Experimentally investigation of the effects of nanoparticles‐enriched ASP formulations on the spontaneous imbibition in a fractured sandstone reservoir

“…Outcomes of their study unveiled that new carboxylate surfactants work better than previously available commercial surfactants not only because they can endure harsh reservoir conditions but also because they can be manufactured from widely available feedstocks. [13] By carrying out several core-flooding experiments on the natural outcrop sandstone cores, Zhu et al (2014) investigated the efficiency of the ASP formulations prepared using alkylbenzene sulfonate surfactants. They conducted experiments with both weak (Na 2 CO 3 or Na 2 CO 3 + NaHCO 3 ) and strong (NaOH) alkali solutions and reached the conclusion that weak alkali solution with surfactant heavy alkylbenzene sulfonate could increase the oil recovery by 22-23% after water-flooding process, which is a better achievement in comparison with strong caustic ASP system.…”

“…[4] Lu et al (2012) conducted a research study in the chemical-based EOR techniques' domain and introduced novel large-hydrophobe alkoxy carboxylate surfactants. The novel proposed Guerbet alkoxy carboxylate surfactants by Lu et al (2012) is able to cope with harsh reservoir conditions through providing large branched hydrophobes, flexibility in the number of alkoxylate groups, and stability in both alkaline and non-alkaline environments at temperatures up to at least 120°C. They prepared various formulations of the indicated surfactants for both active and inactive oils and investigated the…”

Offshore Chemical Enhanced Oil Recovery

“…Sulfate surfactants are suitable for temperatures below 60 o C. For higher temperatures, sulfonate surfactants are recommended (Barnes et al, 2008;Levitt et al, 2009). Surfactant formulations with large-hydrophobe EO-PO carboxylates have also been studied (Adkins et al, 2012;Solairaj, 2012;Lu et al, 2014). Examples of sulfate surfactants are alcohols EO-PO sulfate.…”