Use of Cosolvents To Improve Alkaline/Polymer Flooding

Fortenberry, Robert; Kim, Do Hoon; Nizamidin, Nabijan; Adkins, Stephanie; Arachchilage, Gayani W.P. Pinnawala; Koh, Heesong; Weerasooriya, Upali; Pope, Gary A.

doi:10.2118/166478-pa

Cited by 67 publications

(23 citation statements)

References 25 publications

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“…It has been found that the addition of low concentrations of certain inexpensive light cosolvents to AP solutions dramatically improves the performance of AP corefloods in two important ways [86]:…”

Section: Use Of Cosolventsmentioning

confidence: 99%

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Enhanced oil recovery

2015

Petroleum Engineer's Guide to Oil Field Chemicals and Fluids

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Section: Use Of Cosolventsmentioning

confidence: 99%

“…Twelve successful ACP corefloods using four different crude oils ranging from 12 • to 24 • API have been reported in detail [86]. The ACP process shows special promise for heavy oils, which tend to have large fractions of soap-forming acidic components, but is applicable across a wide range of oil gravity.…”

Section: Use Of Cosolventsmentioning

confidence: 99%

Enhanced oil recovery

2015

Petroleum Engineer's Guide to Oil Field Chemicals and Fluids

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“…Even though co-solvents improve aqueous stability, facilitate faster equilibration of the microemulsion phase, lower the microemulsion viscosity, mitigate the formation of ordered/condensed structures and broaden the low IFT salinity window, among other benefits (Salter, 1977;Abe et al, 1986;Sanz and Pope, 1995;Levitt et al, 2009;Frank et al, 2007;Sahni et al, 2010;Fortenberry et al, 2015), they also tend to increase the IFT. Developing chemistries with dual characteristics of a surfactant and a co-solvent could avoid or minimize this disadvantage.…”

Section: Introductionmentioning

confidence: 99%

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

Upamali

Liyanage

Cai

et al. 2016

SPE Improved Oil Recovery Conference

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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.

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“…This is especially beneficial for EOR when the macroemulsions, gels, or liquid crystals have a high viscosity. Co-solvents play a pivotal role in providing favorable microemulsion rheology (Walker et al, 2012;Fortenberry et al, 2015;Tagavifar, 2014). Co-solvents reduce the bending modulus (increasing the fluidity) of the interface which facilitates low microemulsion viscosity and Newtonian behavior (de Gennes and Taupin, 1982; Safinya…”

Section: Introductionmentioning

confidence: 99%

“…et al, 1989; Strey and Jonströmer, 1992;Wennerström and Olsson, 2014). Co-solvents widen the type III window and reduce both the shear viscosity and the interfacial viscosity, which is the basis for the process called alkaline-co-solvent-polymer (ACP) flooding (Fortenberry et al, 2015). Co-solvents are one tool used to optimize formulations.…”

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confidence: 99%

Co-solvent Partitioning and Retention

Chang¹,

Lansakara-P²,

Jang³

et al. 2016

All Days

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Favorable microemulsion rheology is required for achieving low surfactant retention and economic viability of chemical EOR. Co-solvents play a pivotal role in obtaining favorable microemulsion rheology as well as many other aspects of chemical EOR. We measured the partitioning of co-solvents between phases to better understand their behavior and how to select the best co-solvent for chemical EOR. There is an optimal co-solvent partition coefficient for microemulsion systems. Commercial co-solvents used for chemical EOR are actually mixtures of different components. We used HPLC to measure the partitioning of the constitutive components of phenol ethoxylate co-solvents between oil and water phases and between microemulsion and excess oil and water phases. These measurements show that the components partition independently and the partitioning of individual components is often different from the average. The co-solvent partition coefficients between oil and water were systematically evaluated as functions of the number of ethylene oxide groups, number of propylene oxide groups, temperature, salinity, and the equivalent alkane carbon number (EACN) of the oil. Novel alkoxylate co-solvents were also evaluated for chemical EOR. The novel alkoxylate co-solvents can be more effectively tailored to match the characteristics of different crude oils. Coreflood experiments were conducted to investigate co-solvent transport and retention. Co-solvents were identified that showed excellent performance and low retention. et al., 1989; Strey and Jonströmer, 1992;Wennerström and Olsson, 2014). Co-solvents widen the type III window and reduce both the shear viscosity and the interfacial viscosity, which is the basis for the process called alkaline-co-solvent-polymer (ACP) flooding (Fortenberry et al., 2015). Co-solvents are one tool used to optimize formulations. Solairaj et al. (2012) performed multivariable regression analysis on a dataset of multiple corefloods with optimized formulations, good mobility control, and favorable salinity gradients and showed a weak correlation between co-solvent concentration and surfactant retention. Co-solvents partition between oil, water and the surfactant micellar interface. Studying the partitioning of co-solvents aids their selection. The best co-solvent is determined by taking into account factors such as cost, impact on IFT, microemulsion viscosity, aqueous stability, and partition coefficients and often requires numerous laboratory experiments.The oil-water co-solvent partition coefficient is defined as the ratio of the co-solvent concentration in the oil divided by that in the water. Co-solvents that partition equally between the oil and water phases have a partition coefficient of 1. Based on previous studies, the ideal value for the oil-water partition coefficient is 1 taking into account considerations such as minimizing the chromatographic separation of the co-solvent and surfactant when a chemical slug is injected into an oil reservoir (Sahni et al., 2010).In biochemistry and organi...

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Use of Cosolvents To Improve Alkaline/Polymer Flooding

Cited by 67 publications

References 25 publications

Enhanced oil recovery

Enhanced oil recovery

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

Co-solvent Partitioning and Retention

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