New Surfactants and Co-Solvents Increase Oil Recovery and Reduce Cost

Abstract

The ability to develop high performance, low cost chemical formulations for chemical EOR involves the use of not only highly efficient surfactants tailored to specific crude oil and reservoir conditions, but also the technical know-how for combining the surfactants and other chemicals to create the best formulation as a complete package. Scientific understanding of how the molecular structures of surfactants and co-solvents affect microemulsion properties greatly speeds up the process of arriving at optimal formulations for enhanced recovery of a specific crude oil in a specific oil reservoir. With the main emphasis on reducing the chemical cost of the formulations, a new slate of novel chemicals, both surfactants and co-solvents, has been developed and shown to have superior performance. We have synthesized and tested new classes of surfactants with different hydrophobe sizes and structures varying from large-mediumshort-ultrashort in order to meet the needs of a variety of crude oil requirements. We have also developed ultra-short hydrophobe surfactants (with 2-ethylhexanol hydrophobe) possessing dual surfactant / cosolvent properties. Such duality in performance helps, in some cases, to minimize or altogether offset the use of co-solvents while maintaining low microemulsion viscosities, faster equilibration, and other desirable behavior. Thus, 2-ethylhexanol-propoxy-sulfate was developed as a surfactant that also encompasses co-solvent properties. The novel Gemini surfactants have also been incorporated in formulations and core flood experiments with excellent results. The new co-solvents offer advantages such as short equilibration time for the microemulsion formation and lower microemulsion viscosity. Systematic studies using these new surfactants and co-solvents clearly show that we now have the capability of developing highly robust formulations to meet the needs of a variety of reservoirs, resulting in high oil recoveries with low surfactant retention, which is the key to lowering the chemical costs and improving the economics of chemical enhanced oil recovery. Experiment Materials and Procedure MaterialsAnionic Surfactants Oleyl, tridecyl alcohol and 2-ethylhexanol alkoxylates were supplied by Harcros Chemicals and subsequent sulfation and carboxymethylation steps were done in the laboratories of the University of Texas at Austin. Alcohol alkoxylates used to synthesize the Gemini surfactants were also supplied by Harcros Chemicals. The C 13 -13PO-sulfate, C 15-18 IOS, C 19-23 IOS, C 20-24 IOS, and C 19-28 IOS surfactants were obtained from Stepan Chemicals and Shell Chemicals. Structures of the new surfactants and co-solvents used in this study are listed in Figs. 1.

Low-tension gas process in high-salinity and low-permeability reservoirs

“…Lu et al (2014) successfully tested Guerbet carboxylates at high-temperature, high-salinity conditions using phase behavior, aqueous stability and coreflooding tests. Upamali et al (2016) reported up to 90% oil recovery post-waterflood at 68 °C using a blend of ethoxylated propoxylated carboxylates and IOS. Abalkhali et al (2019) reported tertiary oil recovery up to 90% in ASP corefloods using a blend of ethoxylated propoxylated carboxylates and IOS for carbonate rock at 100 °C and 60,000 ppm salinity.…”

Exploring the Potential Application of Palm Methyl Ester Sulfonate as an Interfacial Tension Reducing Surfactant for Chemical Enhanced Oil Recovery

“…Through this interaction, the surfactant molecule decreases the interfacial tension of the crude oil thereby increasing crude oil mobility and oil recovery [7][8][9][10][11][12][13][14][15]. Though various conventional surfactants are proven to provide effective results with respect to their interaction with the crude oil in reservoirs for incremental oil recovery [16][17][18][19][20][21][22], the primary problem associated with this method is the environmental issue encountered during post implementation stage. As most of the conventional surfactants used in this method are anionic and derived from petrochemicals, these chemicals possess a molecular structure that can harm the aquatic organisms.…”

Synthesis and evaluation of Jatropha oil-based emulsified acids for matrix acidizing of carbonate rocks

“…Triglyceride oils such as from palm, coconut, sunflower, and Jatropha curcas have been utilized in various oil and gas exploration and production phases, such as in drilling (Adesina et al 2012;Fadairo et al 2013) and enhanced oil recovery operations as surfactants (Majidaie et al 2012;Mumtaz et al 2015;Soffian et al 2015;Karasinghe et al 2016;Nordiyana et al 2016) oil phases for drilling and completion fluids (Amanullah 2005;Okeke et al 2013;Yegin et al 2017) and corrosion inhibitors (Anand and Meenakshi 2011;Malarvizhi et al 2015;Rostron et al 2017) due to being non-toxic, biodegradable and possessing high viscosity, thermal stability, corrosion inhibition and effective interfacial tension alteration capabilities; these properties enable greater cutting carrying capability in drilling fluids (Fadairo et al 2013), better miscibility of fluids in flooding operations (Jeirani et al 2006) and prevention against deterioration of subsurface metal equipment (Mohadyaldinn et al 2017).…”