Adsorption/Retention of Petroleum Sulfonates in Berea Cores

1977 ◽  
Vol 17 (05) ◽  
pp. 353-357 ◽  
Author(s):  
J.H. Bae ◽  
C.B. Petrick
Keyword(s):  
Adsorption Isotherm ◽  
Aqueous Solutions ◽  
Flow Rate ◽  
Oil Recovery ◽  
Reservoir Rock ◽  
Equivalent Weight ◽  
Flow Rates ◽  
The Core ◽  
Petroleum Sulfonate ◽  
Pass Through

Abstract A series of petroleum sulfonate adsorption experiments was conducted in 2-in.-diameter, 2-ft-long Berea cores initially saturated with 1-percent NaCl brine. The sulfonates used had an average equivalent weight of 430 with a broad equivalent-weight distribution. The concentration ranged from 0.01 to 8 per cent. The flow rates investigated ranged from 2 to 36 ft/D. Adsorption was determined either from analysis of the effluent concentrations or by extraction of sulfonates from the core. The physical properties of the solutions were also measured. In several tests, Na2CO3 was used as a sacrificial chemical, either in a preflood or added to the sulfonate solution. It was found that at certain concentrations, apparent adsorption is dependent on the flow rate. The sulfonate adsorption isotherm was found to pass through a maximum. The value of the pass through a maximum. The value of the adsorption maximum and the concentration at which it occurs are also dependent on the flow rate. The time required for adsorption equilibrium was found to increase with increasing sulfonate concentration. A sacrificial chemical reduced the sulfonate adsorption. However, sulfonate adsorption increased gradually with time. Adsorption tests should be conducted at realistic flow rates. Introduction One of the major problems in surfactant flooding is the adsorption of surfactants on the reservoir rock. If adsorption is excessive, surfactants are depleted rapidly from the slug as it moves through the reservoir; consequently, it loses the ability to lower the oil-water interfacial tension. Thus, the magnitude of adsorption is an important technical as well as economic parameter. It has been reported that the adsorption of petroleum sulfonates is selective. The high-equivalent-weight sulfonates are adsorbed preferentially whole low-equivalent-weight preferentially whole low-equivalent-weight sulfonates show almost no adsorption. Most of the adsorbed sulfonates had an equivalent weight of 500 or more. This type of fractionation was considered to be the main cause for poor oil recovery in a field pilot test. The literature data on the adsorption of petroleum sulfonates from aqueous solutions indicate petroleum sulfonates from aqueous solutions indicate that there is a maximum in the adsorption isotherm. Furthermore, the adsorption of sulfonate is reduced significantly when sacrificial chemicals are used. The experimental methods used in these measurements differ from one another and, on occasion, the adsorbed sulfonates are defined to be the amount extracted by a solvent after a brine flush. The term "adsorption" is used here rather loosely. Some people prefer the term retention to adsorption since there may be physical retention in a core. The physical retention may or may not exist in a given experiment and detection of it may be very difficult. The objective of this work is to investigate the adsorption phenomenon in dynamic core tests. Several questions are examined: How is the adsorption isotherm related to the general properties of the solution? Do the dynamic test conditions affect the adsorption measurement? Are sacrificial chemicals useful in reducing sulfonate adsorption? EXPERIMENTAL PROCEDURES The petroleum sulfonate used was a blend of sulfonates, TRS 18 and TRS 40 obtained from Witco Chemical Co., and has an average equivalent weight of 430. The equivalent weight ranged from 250 to 650, with about 80 percent ranging from 350 to 550, almost evenly distributed. Isopropyl alcohol was used as a cosolvent at 1/10 of the sulfonate concentration. A 1-percent NaCl brine was used as the aqueous medium. Weight percentage is used throughout this paper. All adsorption tests were conducted at room temperature of 72 degrees F in 2-in.-diameter, 2-ft-long Berea cores saturated with brine. The permeability to brine in all tests was 450 + 25 md. The sulfonate solution was injected continuously into the cores using a positive-displacement pump. The produced fluids were collected in a fraction collector. In most cases, at the end of sulfonate injection, the sulfonate in the core was extracted immediately with a methanol-chloroform mixture. SPEJ P. 353

Cosurfactants in Micellar Systems Used for Tertiary Oil Recovery

1976 ◽  
Vol 16 (03) ◽  
pp. 161-167 ◽  
Author(s):  
S.C. Jones ◽  
K.D. Dreher
Keyword(s):  
Physicochemical Properties ◽  
Phase Behavior ◽  
Oil Recovery ◽  
Electrolyte Concentration ◽  
Weight Percent ◽  
Reservoir Rock ◽  
Equivalent Weight ◽  
Petroleum Sulfonate ◽  
Micellar Systems

Abstract The influence of alcohols used as cosurfactants on several micellar systems was investigated. These alcohols modify phase behavior and control the amount of brine or hydrocarbon that a microemulsion can "solubilize." Also, viscosity can be adjusted using the right cosurfactant for mobility control. Relationships between cosurfactant concentration and electrolyte concentration, hydrocarbon type, or temperature are presented. Introduction Micellar slugs used as oil-displacing agents in extra-oil recovery projects are usually composed of surfactant(s), hydrocarbon, water, electrolyte, and one or more alcohols that serve as cosurfactants. Physicochemical properties of these systems have Physicochemical properties of these systems have been presented by several authors; phase behavior has received special attention. Such emphasis is justified because of displacement-mechanism considerations and micellar-slug deterioration by reservoir rock and fluids. Other work has been concerned with defining the role of particular sulfonates in oil displacement and loss of surfactant to reservoir rock. Healy et al. presented detailed analyses of a single surfactant/cosurfactant combination in micellar systems and laboratory oil recovery experiments. Papers have presented qualitative information on the role of cosurfactants. Gogarty and Tosch found that the amount of 2-propanol (IPA) required to produce phase-stable systems depended on produce phase-stable systems depended on hydrocarbon type. They and others reported that IPA makes a micellar slug more compatible with reservoir brines, whereas oil-soluble alcohols enhance compatibility with crude oils. Cosurfactants have various effects on viscosity; IPA usually causes a reduction. Healy and Reed noted a decrease in viscosity upon addition of tertiary amyl alcohol (TAA). For the system examined, TAA increases the size of the water-external region in the ternary phase diagram. Others have reported that cosurfactants increase water solubility of sulfonates and reduce adsorption on reservoir rock. Although cosurfactants have been shown to perform a variety of functions, no systematic quantitative study of their effect on physicochemical properties of micellar systems has appeared in the petroleum literature. This paper will show how cosurfactants affect phase behavior, control hydrocarbon and brine solubility, interact with electrolyte concentration, and change viscosity and electrical conductivity. Systems examined include a low-water-concentration, oil-external microemulsion; a water-external microemulsion; and "intermediate" systems for which the continuous phase is not clearly defined. Each type of micellar system has been tested in field applications of the Maraflood oil recovery process. process. MATERIALS AND METHODS Compositions of the six micellar systems studied are shown in Table 1, which also indicates the source and equivalent weight of the petroleum sulfonate surfactants used. Table 2 lists information about the alcohols used as cosurfactants. Viscosities were measured at 72 deg. F and at 3 or 6 rpm with a Brookfield Model LVT viscometer equipped with a UL adaptor. Shear rates at this speed are about 5 to 10 sec-1. All phase-behavior experiments were performed at 72 deg. F, with the exception of the relationships shown in Fig. 11. Systems were observed for a minimum of 24 hours. PHASE BEHAVIOR WITH ALCOHOL PHASE BEHAVIOR WITH ALCOHOL Alcohols as cosurfactants modify the phase behavior of a brine-hydrocarbon-surfactant micellar system. For example, Composition A in Table 1, composed of an oleophilic surfactant (470-equivalent-weight petroleum sulfonate), 28-weight-percent water, petroleum sulfonate), 28-weight-percent water, and hydrocarbon (light, straight run gasoline), separates into an aqueous phase in equilibrium with a microemulsion phase. SPEJ P. 161

scholarly journals Facile fabrication and characterization on alginate microfibres with grooved structure via microfluidic spinning

2019 ◽  
Vol 6 (5) ◽  
pp. 181928 ◽  
Author(s):  
Xiaolin Zhang ◽  
Lin Weng ◽  
Qingsheng Liu ◽  
Dawei Li ◽  
Bingyao Deng
Keyword(s):  
Flow Rate ◽  
Loss Modulus ◽  
Fibre Diameter ◽  
Morphological Structure ◽  
Flow Rates ◽  
Alginate Solution ◽  
The Core ◽  
Facile Fabrication ◽  
Fabrication And Characterization ◽  
Alginate Fibres

Alginate microfibres were fabricated by a simple microfluidic spinning device consisting of a coaxial flow. The inner profile and spinnability of polymer were analysed by rheology study, including the analysis of viscosity, storage modulus and loss modulus. The effect of spinning parameters on the morphological structure of fibres was studied by SEM, while the crystal structure and chemical group were characterized by FTIR and XRD, respectively. Furthermore, the width and depth of grooves on the fibres was investigated by AFM image analysis and the formation mechanism of grooves was finally analysed. It was illustrated that the fibre diameter increased with an increase in the core flow rate, whereas on the contrary of sheath flow rate. Fibre diameter exhibited an increasing tendency as the concentration of alginate solution increased, and the minimum spinning concentration of alginate solution was 1% with the finest diameter being around 25 µm. Importantly, the grooved structure was obtained by adjusting the concentration of solutions and flow rates, the depth of groove increased from 278.37 ± 2.23 µm to 727.52 ± 3.52 µm as the concentration varied from 1 to 2%. Alginate fibres, with topological structure, are candidates for wound dressing or the engineering tissue scaffolds.

Microfluidic Fabrication of Helical Ca-Alginate Hydrogel Fibers

2021 ◽  
Vol 1035 ◽  
pp. 843-850
Author(s):  
Sha Chen ◽  
Jing Hua Gong ◽  
Jing Hong Ma
Keyword(s):  
Flow Rate ◽  
Helical Structure ◽  
Outer Flow ◽  
Flow Rates ◽  
Conductive Materials ◽  
Responsive Polymers ◽  
The Core ◽  
The Past ◽  
Sheath Fluid ◽  
Collection Tube

Helix is a sophisticated structure in nature and has many unique functions which makes it possible to store more information and energy, even receive more sensitive signals. Besides, as an effective method for preparing hydrogel fibers, microfluidic spinning has achieved unprecedented development in the past decade. However, hydrogel fiber with helical structure has began to be studied only in recent years. In this paper, the helical hydrogel fibers were prepared by the microfluidic spinning method. The microfluidic chip was assembled by PDMS connector, collection tube, inner and outer channels. Sodium alginate (SA) and calcium chloride were used as the core fluid and sheath fluid, respectively. By designing and adjusting the length of the chip, changing the concentration of SA and the ratio of two flow rates (inner flow rate/outer flow rate), a continuous and uniform helical hydrogel fiber was prepared. The relationships between the diameter of the fiber, the pitch of the helix and the concentration of SA, the ratio of two flow rates were discussed. The results showed that the diameter of the fiber was mainly affected by the core fluid. Within a certain range, as the concentration of SA increased, the diameter of the fiber increased. Besides, the pitch of the helix was greatly affected by the flow rate of sheath fluid. As the velocity of the sheath fluid increased, the pitch of the fiber increased. Such helical fiber could be used in micro sensors when added some conductive materials or crosslinked with some temperature responsive polymers such as N-isopropylacrylamide.

scholarly journals Experimental study of in-situ W/O emulsification during the injection of MgSO4 and Na2CO3 solutions in a glass micromodel

2020 ◽  
Vol 75 ◽  
pp. 87
Author(s):  
Sepideh Palizdan ◽  
Hossein Doryani ◽  
Masoud Riazi ◽  
Mohammad Reza Malayeri
Keyword(s):  
Experimental Study ◽  
Flow Rate ◽  
Oil Recovery ◽  
Deionized Water ◽  
Water Flooding ◽  
Flow Rates ◽  
Glass Micromodel ◽  
The Impact ◽  
Emulsification Process

In-situ emulsification of injected brines of various types is gaining increased attention for the purpose of enhanced oil recovery. The present experimental study aims at evaluating the impact of injecting various solutions of Na2CO3 and MgSO4 at different flow rates resembling those in the reservoir and near wellbore using a glass micromodel with different permeability regions. Emulsification process was visualized through the injection of deionized water and different brines at different flow rates. The experimental results showed that the extent of emulsions produced in the vicinity of the micromodel exit was profoundly higher than those at the entrance of the micromodel. The injection of Na2CO3 brine after deionized water caused the impact of emulsification process more efficiently for attaining higher oil recovery than that for the MgSO4 brine. For instance, the injection of MgSO4 solution after water flooding increased oil recovery only up to 1%, while the equivalent figure for Na2CO3 was 28%. It was also found that lower flow rate of injection would cause the displacement front to be broadened since the injected fluid had more time to interact with the oil phase. Finally, lower injection flow rate reduced the viscous force of the displacing fluid which led to lesser occurrence of viscous fingering phenomenon.

Tertiary Surfactant Flooding: Petroleum Sulfonate Composition-Efficacy Studies

1973 ◽  
Vol 13 (04) ◽  
pp. 191-199 ◽  
Author(s):  
Walter W. Gale ◽  
Erik I. Sandvik
Keyword(s):  
Interfacial Tension ◽  
Oil Recovery ◽  
Weight Distribution ◽  
Capillary Rise ◽  
Equivalent Weight ◽  
Residual Oil ◽  
Surfactant Flooding ◽  
Petroleum Sulfonate ◽  
Low Interfacial Tension ◽  
Oil Water

Abstract This paper discusses results of a laboratory program undertaken to define optimum petroleum program undertaken to define optimum petroleum sulfonates for use in surfactant flooding. Many refinery feedstocks, varying in molecular weight and aromatic content, were sulfonated using different processes, Resulting sulfonates were evaluated by measuring interracial tensions, adsorption-fractionation behavior, brine compatability, and oil recovery characteristics, as well as by estimating potential manufacturing costs. The best combination o[ these properties is achieved when highly aromatic feedstocks are sulfonated to yield surfactants having very broad equivalent weight distributions. Components of the high end of the equivalent weight distribution make an essential contribution to interfacial tension depression. This portion is also strongly adsorbed on mineral surfaces and has low water solubility. Middle Portions of the equivalent weight distribution serve as sacrificial adsorbates while lower equivalent weight components Junction as micellar solubilizers for heavy constituents. Results from linear laboratory oil-recovery tests demonstrate interactions of various portions of the equivalent weight distribution. portions of the equivalent weight distribution Introduction Four major criteria used in selecting a surfactant for a tertiary oil-recovery process are:low oil-water interfacial tension,low adsorption,compatibility with reservoir fluids andlow cost. Low interfacial tension reduces capillary forces trapping residual oil in porous media allowing the oil to be recovered. Attraction of surfactant to oil-water interfaces permits reduction of interfacial tension; however, attraction to rock-water interfaces can result in loss of surfactant to rock surfaces by adsorption. Surfactant losses can also arise from precipitation due to incompatibility with reservoir fluids. Low adsorption and low cost are primarily economic considerations, whereas low interfacial tension and compatibility are necessary for workability of the process itself. Petroleum sulfonates useful in surfactant flooding have been disclosed in several patents; however, virtually no detailed information is available in the nonpatent technical literature. Laboratory evaluation of surfactants consisted of determining their adsorption, interfacial tension, and oil recovery properties. Adsorption measurements were made by static equilibration of surfactant solutions with crushed rock and clays and by flowing surfactant solutions through various types of cores. Interfacial tensions were measured using pendant drop and capillary rise techniques. Berea, pendant drop and capillary rise techniques. Berea, Bartlesville, and in some cases, field cores containing brine and residual oil were flooded with sulfonate solutions in order to determine oil recovery. Fluids used in these displacement tests are described in Table 1. Unless otherwise specified, displacements of Borregos crude oil were carried out with Catahoula water as the resident aqueous phase after waterflooding and displacements of phase after waterflooding and displacements of Loudon crude oil with 1.5 percent NaCl as the resident aqueous phase. In those examples where banks of surfactants were injected, drive water following the surfactant had the same composition as the resident water. Concentrations of sulfonates are reported on a 100-percent activity basis. PETROLEUM SULFONATE CHEMISTRY PETROLEUM SULFONATE CHEMISTRY A substantial portion of the total research effort TABLE 1 - PROPERTIES OF FLUIDS USEDIN FLOODING TESTS

scholarly journals Cellular Nutrition in Complex Three-Dimensional Scaffolds: A Comparison between Experiments and Computer Simulations

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Claudia Bergemann ◽  
Patrick Elter ◽  
Regina Lange ◽  
Volker Weißmann ◽  
Harald Hansmann ◽  
...  
Keyword(s):  
Shear Stress ◽  
Cell Viability ◽  
Computer Simulations ◽  
Flow Rate ◽  
Oxygen Supply ◽  
Three Dimensional ◽  
Flow Rates ◽  
The Core ◽  
Local Oxygen

Studies on bone cell ingrowth into synthetic, porous three-dimensional (3D) implants showed difficulties arising from impaired cellular proliferation and differentiation in the core region of these scaffolds with increasing scaffold volumein vitro. Therefore, we developed anin vitroperfusion cell culture module, which allows the analysis of cells in the interior of scaffolds under different medium flow rates. For each flow rate the cell viability was measured and compared with results from computer simulations that predict the local oxygen supply and shear stress inside the scaffold based on the finite element method. We found that the local cell viability correlates with the local oxygen concentration and the local shear stress. On the one hand the oxygen supply of the cells in the core becomes optimal with a higher perfusion flow. On the other hand shear stress caused by high flow rates impedes cell vitality, especially at the surface of the scaffold. Our results demonstrate that both parameters must be considered to derive an optimal nutrient flow rate.

scholarly journals GROWTH RATE DISPERSION (GRD) OF THE (010) FACE OF BORAX CRYSTALS IN FLOWING SOLUTION

2010 ◽  
Vol 4 (3) ◽  
pp. 145-148
Author(s):  
Suharso Suharso ◽  
Gordon Parkinson ◽  
Mark Ogden
Keyword(s):  
Growth Rate ◽  
Aqueous Solutions ◽  
Normal Distribution ◽  
Flow Rate ◽  
Growth Rates ◽  
Experimental Conditions ◽  
Solution Flow ◽  
Flow Rates ◽  
Growth Rate Distribution ◽  
Flowing Solution

The growth rates of borax crystals from aqueous solutions in the (010) direction at various flow rates were measured. The observed variations of the growth rate can be represented by a normal distribution.  It was found that there is no correlation between growth rate distribution and solution flow under these experimental conditions.   Keywords: Growth rate dispersion (GRD), borax, flow rate

Characterization of Petroleum Sulfonates by a Nonaqueous Titration Method

1981 ◽  
Vol 21 (06) ◽  
pp. 771-778 ◽  
Author(s):  
Kim R. Voss ◽  
Clark E. Bricker ◽  
M.J. Michnick ◽  
G.P. Willhite
Keyword(s):  
Molecular Weight ◽  
Interfacial Tension ◽  
Oil Recovery ◽  
Perchloric Acid ◽  
Molecular Species ◽  
New Method ◽  
Equivalent Weight ◽  
Petroleum Sulfonate ◽  
Wet Ashing

Summary A new method is described for the determination of the equivalent weight for petroleum sulfonates. The method is based on the direct acidimetric titration of the sulfonate in acetic acid/acetic anhydride solvent using a titrant of perchloric acid in dioxane. From the titration, the moles of perchloric acid required to react with the sulfonate is measured. The equivalent weight is calculated from the grams of sample titrated and the moles of acid used. The potentiometric titration can be carried out in less than 10 minutes and can be done with 10 to 100 mg of sample. The accuracy and precision of the procedure were examined by the titration of sodium salts of p-toleuene sulfonate, 2-naphthalene sulfonate, and petroleum sulfonates. In general, values for the equivalent weight were within 2% of those values determined by the Epton titration, by wet ashing methods, or from the theoretical value. The relative standard deviation (RSD) for the procedure is estimated to be 0.5%. For p-toluene sulfonate, an RSD of 0.15% was calculated. The new method was used to determine the equivalent weights for three fractions of a petroleum sulfonate obtained by the preferential elution from silica gel with alcohol. A series of samples with varying equivalent weight was prepared by proportional combination of the three fractions. Analysis by high-performance liquid chromatography (HPLC) gave a set of data points of peak areas for the series. A plot of equivalent weight as a function of disulfonate to total peak area ratio resulted in a straight line. The slope of this line is descriptive of the molecular weight range for the petroleum sulfonate. Introduction Petroleum sulfonates are used to liberate a residual oil from a porous medium in a tertiary oil-recovery process. One mechanism for the release of oil is the reduction of the interfacial tension between water and oil to values on the order of 10−3 dyne/cm.1–5 The performance of a sulfonate as a surfactant depends on its molecular size and structure. For a pure single-species sulfonate, these properties can be correlated with the alteration of the interfacial tension between water and oil. The same cannot be done for a petroleum sulfonate because the sulfonate is a mixture of molecular species with unknown structures. Previous studies6,7 have shown that the overall composition of a petroleum sulfonate is altered by the preferential partitioning of the molecular species to the oil, water, and rock phases. This causes the composition of the sulfonate to change constantly as it flows through the porous media contacting water and oil. To correlate oil-recovery efficiency with a property of the sulfonate, analytical methods are needed to characterize the effluent from core floods. One parameter for characterizing petroleum sulfonates is the average equivalent weight, which is the weight in grams containing 1 mol of sulfonate functional groups. Sufficient sample is often not available for the equivalent weight analysis by the ASTM wet ashing procedure, and the oil in the sample may often interfere with the Epton titrate method. Therefore, a study was initiated to develop a method for the determination of equivalent weight of petroleum sulfonates in the 10- to 100-mg range. Of equal importance is a method to count sulfonate groups and to differentiate mono- and disulfonate molecules. The latter can be achieved by HPLC using an anion exchange column.8 However, quantification of the effluent from the HPLC column remains a problem. No detector is available that responds specifically to the sulfonate functional group -SO3−. Specific ion-electrodes of the liquid- or solid-membrane type show varying response to sulfonates depending on the molecular weight of the sulfonate.9,10

Phase Behavior Studies of Two Model Surfactant Systems

1982 ◽  
Vol 22 (01) ◽  
pp. 53-60 ◽  
Author(s):  
William J. Benton ◽  
Natoli John ◽  
Syed Qutubuddin ◽  
Surajit Mukherjee ◽  
Clarence M. Miller
Keyword(s):  
Aqueous Solutions ◽  
Phase Boundary ◽  
Phase Behavior ◽  
Oil Recovery ◽  
Develop Model ◽  
Middle Phase ◽  
Lower Phase ◽  
Interfacial Tensions ◽  
Petroleum Sulfonate ◽  
Surfactant Systems

William J. Benton, Carnegie-Mellon U. John Natoli, Carnegie-Mellon U. Qutubuddin, Syed SPE, Carnegie-Mellon U. Mukherjee, Surajit, Carnegie-Mellon U. Miller, Clarence M., SPE, Carnegie-Mellon U. Fort Jr., Tomlinson, Carnegie-Mellon U. Abstract Phase behavior studies were carried out for two systems containing pure surfactants but exhibiting behavior similar to that of commercial petroleum sulfonates. One system contained the isomerically pure surfactant sodium-8-phenyl-n-hexadecyl-n-sulfonate (Texas 1). The other contained sodium dodecyl sulfate (SDS). Additional components used in both systems were various pure short-chain alcohols, NaCl brine and n-decane. Aqueous solutions containing surfactant, cosurfactant, and NaCl were studied over a wide range of compositions with polarizing and modulation contrast microscopy, as well as the polarized light screening technique. Viscosity measurements were conducted on selected scans of the Texas 1 system. Maxima and minima of the scans were correlated with textural changes observed with microscopy. The aqueous solutions were contacted with equal volumes of n-decane, and phase behavior and interfacial tensions were determined. The middle microemulsion phase was found to be oil continuous close to the upper phase boundary and water continuous close to the lower phase boundary. Both the Texas 1 and SDS systems showed similar behavior in that the middle microemulsion phase was observed over the entire range of surfactant concentrations studied. Introduction Surfactant systems usually consisting of petroleum sulfonate, an alcohol, salt, and water have been used for enhanced oil recovery. Various parameters important to oil recovery by surfactant flooding, such as interfacial tension and viscosity, are related strongly to the phase behavior of the microemulsion systems. The relationship of ultralow interfacial tensions to phase separation has been treated in our laboratory. The recovery of petroleum from laboratory cores and field tests appears to be related directly to phase behavior. It is important to understand phase behavior to identify the mechanisms involved and improve the efficiency of the oil-recovery process. The physicochemical aspects of the phase behavior of microemulsion systems containing commercial petroleum sulfonates as surfactants have been well documented by Healy and Reed and others. However, the systems studied were not pure, and the commercial surfactants sometimes contained as much as 40% inactive ingredients. There is a need to develop model microemulsion systems using pure components. Such systems would provide an experimental platform for verifying or interpreting the implications of any model for the phase behavior of multicomponent microemulsion systems and also allow the behavior of commercial systems to be predicted and understood. The objective of our work has been to fulfill these needs. Microemulsions have been classified as lower phase (l), upper phase (u), or middle phase (m) in equilibrium with excess oil, excess brine, or both excess oil and brine, respectively. Transitions among these phases have been studied as functions of salinity, alcohol concentration, temperature, etc. The middle-phase microemulsion is particularly significant because microemulsion/excess brine and microemulsion/excess oil tensions can be ultra low simultaneously. The concept of an optimal parameter as proposed originally by Reed and Healy when equal amounts of oil and brine are solubilized in the middle phase has been followed in this paper. We have shown earlier that the structure of petroleum sulfonate solutions exhibits a general pattern of variation with salinity. SPEJ P. 53^

scholarly journals Adsorption of Surface Active Ionic Liquids on Different Rock Types under High Salinity Conditions

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Shilpa Kulbhushan Nandwani ◽  
Mousumi Chakraborty ◽  
Smita Gupta
Keyword(s):  
Ionic Liquids ◽  
Adsorption Isotherm ◽  
Oil Recovery ◽  
Carbonate Rock ◽  
Adsorption Mechanism ◽  
High Salinity ◽  
Reservoir Rock ◽  
Rock Surface ◽  
Rock Types ◽  
Surface Active

Abstract A new class of surface active ionic liquids (SAIL) have been reported to be a greener alternative to the conventional surfactants in enhanced oil recovery (EOR). These SAILs work efficiently under harsh salinity conditions encountered in the reservoir thereby recovering more additional oil during the tertiary oil recovery process. Adsorption mechanism of SAILs on different rock surface is however, not yet reported in the literature. This article highlights adsorption mechanism of three cationic SAILs having different headgroups, viz., imidazolium, pyridinium, pyrrolidinium, on different rock surfaces (crushed natural carbonate rock and crushed sandstone rock). All the SAILs studied here however had the same tail length and same anion (Br−) attached to it. XRD and XPS characterization techniques reveal that the crushed natural carbonate rock contains a substantial amount of silica, thus rendering it a slight negative charge. Static adsorption tests show that the retention efficiency on the natural carbonate type of rock for all the SAILs was lower than the conventional cationic surfactant, CTAB. The adsorption data obtained thereby was examined using four different adsorption isotherm models (Langmuir, Freundlich, Redlich-Peterson, and Sips). Results suggest that Sips adsorption isotherm model can satisfactorily estimate the adsorption of all the surface active agents on the natural carbonate rock. Factors like mineralogical composition of rock surface, presence of divalents, temperature, and structure of surfactants strongly affect the amount of surfactant adsorbed on reservoir rock. In order to evaluate the simultaneous effect all these factors as well as their interdependence on the retention capability of the three SAILs, a design of experiments approach has been employed further in this study. Statistical analysis of the data obtained after performing the full factorial experiments reveal that at high salinity, imidazoluim based SAIL show minimal adsorption on crushed natural carbonate rock at higher temperature. In general, at a given ionic strength, with increasing temperature as the amount of divalent in the aqueous solution increases, the amount of SAIL adsorbed on both the rock types decreases. Electrostatic attraction is the basic mechanism in governing adsorption of SAILs on the two types of rock surfaces. Results presented in this work can be used for EOR schemes.

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