Petroleum Sulfonate Research Articles

Emulsion formation and stability of surfactant–polymer flooding

Emulsification plays a pivotal role in the process of enhanced oil recovery, especially in chemical flooding. Surfactant–polymer flooding is a promising technique with significant potential for improving oil recovery in medium and high permeability oilfields in China. Emulsification has emerged as one of the key mechanisms facilitating oil recovery in surfactant–polymer flooding. This study aimed to assess the effects of surfactant structure and concentration, polymer, oil–water ratio, clay content, and injection rate on the formation of different emulsion types and their stabilities. The assessment was conducted based on the actual conditions of surfactant–polymer flooding in the Qizhong area of the Xinjiang oilfield. The findings revealed that KPS-1 (petroleum sulfonate) demonstrated superior emulsifying and solubilizing abilities for crude oil compared to BS-18 (betaine), whereas BS-18 exhibited better emulsifying stability. KPS, which was a combination system of KPS-1 and BS-18, displayed favorable emulsifying ability. However, the emulsifying stability of the three surfactants decreased in the presence of HPAM (hydrolyzed polyacrylamide). The oil–water ratio primarily influenced the morphology of the emulsion. When the oil–water ratio exceeded 6:4, a water-in-oil emulsion was formed, and the viscosity of the emulsion reached its maximum at an oil–water ratio of 7:3. Moreover, clay demonstrated a significantly high ability to emulsify, resulting in the formation of emulsions with increased viscosity and robust stability. Regarding the injection rate, effective emulsification occurred when the injection rate reached 1 m/d, while emulsions with high viscosity were observed at an injection rate of 7 m/d.

Effect of adsorption of different types of surfactants on conglomerate reservoir minerals on chemical oil recovery efficiency

Using surfactants to extract oil, the anionic surfactant Karamay petroleum sulfonate (KPS), the zwitterionic surfactant octadecyl betaine (BS-18) and the nonionic surfactant coconut oil fatty acid diethanolamide (6501) were selected for adsorption experiments with minerals contained in the conglomerate reservoir with different mineral compositions to study the adsorption law of different types of surfactants. Zeolite and montmorillonite, which have the highest specific surface area and zeta potential among the minerals in the conglomerate reservoir, have the most obvious adsorption effect on surfactants, resulting in a large amount of adsorption of KPS and BS-18. The three types of surfactants were then used to conduct physical simulation oil recovery experiments with conglomerate core samples, and the results showed that 6501 had better overall performance, the best adsorption resistance, and a higher degree of recovery in oil recovery experiments, which provided a basis for the selection of surfactants in the process of chemical drive in conglomerate reservoirs.

Degradation of anti-rust oil film in a simulated coastal atmosphere: Inhibition mechanism and in-situ monitoring

Anti-rust oils (ARO) are widely used to inhibit atmospheric corrosion of metal structures, but their degradation mechanisms are unclear, particularly in coastal environments. In this work, we first prepared a kind of ARO made of sodium petroleum sulfonate (SPS) and white oil, then coated the ARO on a mild steel plate to investigate its deterioration process beneath saline water droplets by Quartz crystal microbalance (QCM) and electrochemical mapping techniques. It shows that the SPS concentration is crucial to the ARO inhibition property. When the SPS content is lower than its critical micelle concentration (CMC), saline droplets may intrude the barrier formed by the nonpolar paraffin groups of SPS and then adsorb on the steel surface, resulting in localised corrosion. However, once the SPS content exceeds its CMC, the saline droplets will be emulsified and captured in the oil phase by the reverse micelle effect, thus inhibiting the corrosion of steel substrates. Moreover, the atmospheric corrosion rate of mild steel obeys a power decaying under ARO film. Finally, a capacitive sensor was invented to evaluate the degree of degradation of ARO in situ by dielectric constant measurement.

Study on the Alkali-Free Three-Component Flooding System in the Daqing Oilfield.

ASP flooding is an important method to further improve oil recovery by a large margin. At present, it has entered the stage of industrial application, but there are still problems of scaling in the injection production system and high production maintenance costs. Based on the industrialized mature technology of weak alkali ASP flooding, sodium chloride is used to replace sodium carbonate, and the alkali-free three-component flooding (TC) system in the Daqing Oilfield is developed by mixing with petroleum sulfonate and partially hydrolyzed polyacrylamide. Based on the experiments of viscosity increasing, interface performance, stability, adsorption, and oil displacement effect, the differences between the alkali-free TC system and the weak alkali ASP system are compared and analyzed. The laboratory research results show that both systems are basically the same in terms of viscosity, viscoelasticity, shear resistance, interfacial activity, stability, and flowability. Due to the lack of alkaline water, the adsorption, emulsification, and oil displacement performance of the alkali-free TC system is slightly lower than that of the weak alkali ASP system. The recovery factor of core flooding can be increased by 27.31% over water flooding, which is 2.56 percentage points lower than that of the weak alkali ASP system. On the premise of the same 1% EOR effect, the agent cost of the alkali-free system is 17.02% lower than that of the alkali ASP system. This article innovatively verifies the feasibility of using NaCl instead of Na2CO3 and explains the mechanism of significantly improving oil recovery in composite systems under alkali-free conditions from the ion level. However, the emulsification effect of the alkali-free TC system is relatively weak. The next step of research would be to consider adding an E-surfactant to enhance the emulsification performance of the composite system. By improving the system composition, technical references are provided for the efficient development of other terrestrial sandstone oilfields.

Application of dodecyl amine/dodium petroleum sulfonate mixed collector in quartz-feldspar flotation separation

It’s highly challenging to separate feldspar from quartz by flotation owing to their similar crystal structure and physicochemical properties. Using mixed collectors has become a promising method to improve the quartz-feldspar separation. In this study, mixed dodecyl amine (DDA) and sodium petroleum sulfonate (SPS) surfactants were used in the flotation separation of feldspar and quartz, and the adsorption mechanism of mixed collectors and depression mechanisms of two depressants were investigated through zeta potential, contact angle and Fourier transform infrared (FT-IR) spectra. When the pH reached 4.5, the separation of feldspar from quartz was more obvious. In the presence of DDA/SPS collector, the contact angle of feldspar was increased more obviously leading to enhance hydrophobicity. The infrared spectra revealed the interaction of collectors on feldspar surface involved physical and chemical adsorption, whereas the adsorption of collector on quartz was only physical interactions. The use of sodium hexametaphosphate resulted in a significantly enhanced separation performance. The weaker physical adsorption of mixed collector on quartz can be destroyed by sodium hexametaphosphate. This study is beneficial for understanding the collect mechanisms of mixed cationic-anionic surfactants on quartz and feldspar minerals, and promotes the development of advanced feldspar separation techniques.

Research on the ratio of multicomponent emulsion flooding system

In recent years, field test and industrialized application of ASP (alkaline/surfactant/polymer) flooding has been carried out in oilfields, which has obtained an obvious effect on increasing oil and decreasing water and good economic efficiency. However, due to the large proportion of alkali in the ASP flooding system, there are problems such as severe scaling and high cost during field tests, which restrict the promotion of ASP flooding. In order to reduce the amount of alkali used, achieve the goal of reducing scaling and costs, and meanwhile improve emulsification performance while maintaining interfacial activity, a multicomponent emulsion flooding system was developed by combining emulsifier HEFR2 with petroleum sulfonate and sacrificial agent LSCP1 with NaOH.Through laboratory experiments, the water extraction rate, particle diameter, Tsi value, and interfacial activity of the multicomponent emulsion flooding system were tested under different conditions. The results show that when the mass ratio of petroleum sulfonate to emulsifier HEFR2 is between 3:1 and 5:1, and the mass ratio of sacrificial agent LSCP1 to NaOH is between 3:1 and 7:1, the multicomponent emulsion flooding system can maintain good emulsification stability and interfacial activity. The multicomponent emulsion flooding system significantly reduces the amount of alkali used, and the cost of chemical agents is 11% lower than that of the ASP flooding system. At the same time, it achieves the goal of improving the stability of emulsifiers, maintains interfacial activity and reduces costs. This technology has broad application prospects.

SULFONATE ADDITIVES TO LUBRICATING OILS

To expand the resource base and increase the efficiency of sulfonate additives, the possibility of obtaining them based on mixed raw materials - petroleum oil M-8 and alkylbenzene synthesized using propylene fraction C18-С30 oligomers was studied. It is shown that during sulfonation of mixed raw materials, the yield of sulfonic acids is 89-93%, the content of hard-to-recycle waste - acid tar is lower than during sulfonation of petroleum oil by 30-35%. The influence of the ratio of ingredients in the initial mixture on the indicators of neutral sulfonate was studied and the conditions for obtaining additives of the required quality were found. The properties of the developed additives in M-11 oil at a concentration of 5% were studied by standard methods. The composition and structure of sulfonates were studied by elemental analysis and IR spectroscopy. The resulting additives have a micellar structure. The results of laboratory tests have shown that neutral, medium - and highly alkaline semi-synthetic calcium sulfonates have high physico-chemical and functional properties. The neutral sulfonate is superior in yield, active substance content, and dispersing properties to NСК petroleum sulfonate and OLOA 246B additive. Medium- and high-alkaline additives in terms of physicochemical and detergent properties are at the level of commercial petroleum sulfonates C-150, C-300 and Hightech 6060M additives, and surpass them in dispersing, anti-corrosion properties and stability against oxidation. Alkaline semi-synthetic calcium sulfonates have a high stability of the colloidal dispersion to the action of water and have better performance compared to analogues. With an increase in the alkalinity of the obtained additives, the physicochemical properties improve, which is associated with the features of their colloidal structure. Using the developed neutral and high-alkaline additives as detergent-dispersant components, experimental motor oils М-10DM and М-10G2, were prepared, which meet the requirements in terms of quality. The high efficiency of semi-synthetic sulfonates allows them to be used in modern motor oils

Degradation of polyacrylamide (PAM) in aqueous solution by electron beam technology: Efficiency, viscosity reduction and correlation with microstructure of polymer molecules

In this paper, we present a systematic evaluation about degradation of partially hydrolyzed polyacrylamide (HPAM) in aqueous solution by ionizing radiation to find relationship between HPAM decomposition, viscosity reduction and microstructure of polymer molecules. The viscosity of the two HPAM solution declined rapidly from 5.2 to 3.0 mPa s to 1.4–1.2 mPa s with the adsorbed dose of 0.1 kGy, and then reached the level of pure water at 0.5 kGy. The molecular weight declined remarkably from 1.6 × 107 Da to 1.4 × 105 Da (HPAM1) and from 1.2 × 107 Da to 1.1 × 106 Da (HPAM2) at 0.1 kGy. The HPAM solution changed from pseudoplastic fluid behavior to Newtonian fluid after irradiation. Following ionizing radiation, the presence of anion Na+, Ca2+, Mg2+, anions HCO3- and SO42-(1000–5000 mg/L) and surfactant sodium dodecyl sulfate (SDS) (50–100 mg/L) respectively has slight effect on the rate and extent of viscosity reduction, while CO32- and surfactant petroleum sulfonate exhibit a great negative effect on reducing HPAM viscosity. Ionizing radiation is able to destroy the molecular structure and spatial structure of HPAM. Both the C-C backbones and pendant are attacked. It is proposed that the degradation products include ammonium, aliphatic hydrocarbon, small molecular acids and compounds with double-bond. With the absorbed dose of 0.1 kGy, the micelles-like aggregates are broken into small particles by direct microscope observation, while the stretched and coiled molecular strands shrink and curl to form an irregular network from AFM and SEM observation. The chains break into fragment scattered randomly as increasing dose to 1.0 kGy. Both the diameter size and dispersity of HPAM molecules decreased remarkably after irradiation.·OH is the major active species responsible for HPAM degradation and viscosity reduction. This study contributes to a multiscale understanding the mechanism of ionizing radiation-induced degradation of HPAM in aqueous solution.

The Influence of Surface Heterogeneity of Fluorite on the Adsorption of Alkyl Sulfonates

Surface heterogeneity of minerals can significantly affect the adsorption of collectors. Petroleum sulfonate is widely used as a fluorite collector, but how the surface heterogeneity of fluorite influences the adsorption of alkyl sulfonates remains unknown. Herein, two kinds of surface heterogeneity situations, i.e., edge and (1 1 1) _vacancy, were modeled, and the adsorption of sodium dodecyl sulfonate on them was simulated. The results show that the stable adsorption configuration of sodium dodecyl sulfonate on the edge was in a bridged mode, and the stable interaction configuration with vacancy was in a tridentate mode. The 2p orbit of fluorine on the surface of the edge and the vacancy could hinder collector adsorption. After adsorption, the 3d orbit of calcium interacted with the collector orbit above Fermi level, and moved towards the lower energy level, benefiting the adsorption process. It was also found that the adsorption intensity/strength of alkyl sulfonate on fluorite was directly proportional to the interaction intensity of the collector with the 3d orbits of calcium ions on the surface and vacancy. Therefore, the rough fluorite surface had a stronger adsorption effect on the collector, and the existence of vacancy could improve the surface adsorption energy, and thus enhance the adsorption of the collector on the fluorite surface. The rough fluorite surface requires high collector concentration to achieve saturated monolayer adsorption, so increasing vacancy was the better choice to improve the adsorption capacity of alkyl sulfonate on the fluorite surface. This study provides novel insights into the flotation mechanism, in the context of surface heterogeneity, and could guide the design of high-performance collectors for fluorite ore flotation.

The Interfacial Dilational Rheology Properties of Betaine Solutions: Effect of Anionic Surfactant and Polymer.

Interfacial dilational rheology is one of the important means to explore the interfacial properties of adsorption films. In this paper, the interfacial rheological properties of the mixed system of sulfobetaine ASB with a linear alkyl group and two anionic surfactants, petroleum sulfonate (PS) and alkyl polyoxyethylene carboxylate (AEC), were investigated by interfacial dilational rheology. The effect of the introduction of polymer hydrophobically modified polyacrylamide (HMPAM) on the interfacial properties of the mixed system was analyzed. In this experiment, the surfactant solution was used as the external phase and n-decane was used as the internal phase. A periodic sinusoidal disturbance of 0.1 Hz was applied to the n-decane droplets, and the changes of parameters such as droplet interfacial tension and interfacial area were monitored in real time with the help of a computer. The results show that the betaine ASB molecule responds to the dilation and compression of the interface through the change of ion head orientation, while the feedback behavior of petroleum sulfonate PS and AEC molecules embedded with oxygen vinyl groups in the molecule is diffusion and exchange between the interface and the bulk phase. Therefore, the interface film formed by ASB alone is higher, and the film formed by PS and AEC molecules alone is relatively lower. After adding two kinds of anionic surfactants to the betaine system, the ionic head of PS or AEC molecules will be attached to the positive center of the hydrophilic group of ASB molecules by electrostatic attraction and no longer adsorb and desorb with the interface deformation. The interfacial rheological properties of the compound system are still dominated by betaine, with higher dilational modulus and lower phase angle. When a small amount of HMPAM is added, or the content of hydrophobic monomer AMPS in the bulk phase is low, the intermolecular interaction at the interface is enhanced, the slow relaxation process is intensified, and the interfacial film strength is increased. As the content of AMPS further increases, hydrophobic blocks and surfactant molecules will form interfacial aggregates similar to mixed micelles at the oil-water interface, which will regulate the properties of the film by affecting the adsorption of surfactants at the interface. As long as the interfacial tension is the same, the properties of the interfacial film are the same. Based on the colloid interface science and the background of enhanced oil recovery, this study provides a reference for the field application of chemical flooding formulations.

Corrosion Behavior on 20# Pipeline Steel by Sulfate-Reducing Bacteria in Simulated NaCl Alkali/Surfactant/Polymer Produced Solution.

The corrosion behavior of sulfate-reducing bacteria (SRB) on 20# carbon steel in the NaCl alkali-surfactant-polymer (ASP) flooding system was studied by scanning electron microscopy, electrochemical measurement, X-ray photoelectron spectroscopy, and laser confocal microscopy. The results showed that the presence of SRB results in a large viscosity loss of the system. SRB can use hydrolyzed polyacrylamide (HPAM) as a nutrient to grow, and the number of SRB remained at a high level after 15 days. Weight loss and electrochemical tests indicated that SRB promoted corrosion of pipeline steel. The corrosion of carbon steel in the early stage of immersion was inhibited by the biofilm formed on the surface, and the thick biofilm in the later stage of immersion caused serious pitting corrosion. The localized corrosion caused by SRB was not inhibited by HPAM and sodium petroleum sulfonate (surfactant) adsorbed on the surface.

Study on the Effect of Different Viscosity Reducers on Viscosity Reduction and Emulsification with Daqing Crude Oil.

The urgent problem to be solved in heavy oil exploitation is to reduce viscosity and improve fluidity. Emulsification and viscosity reduction technology has been paid more and more attention and its developments applied. This paper studied the viscosity reduction performance of three types of viscosity reducers and obtained good results. The viscosity reduction rate, interfacial tension, and emulsification performance of three types of viscosity reducers including anionic sulfonate, non-ionic (polyether and amine oxide), and amphoteric betaine were compared with Daqing crude oil. The results showed that the viscosity reduction rate of petroleum sulfonate and betaine was 75-85%. The viscosity reduction rate increased as viscosity reducer concentration increased. An increase in the oil-water ratio and polymer decreased viscosity reduction. When the concentration of erucamide oxide was 0.2%, the ultra-low interfacial tension was 4.41 × 10-3 mN/m. When the oil-water ratio was 1:1, the maximum water separation rates of five viscosity reducers were different. With an increase in the oil-water ratio, the emulsion changed from o/w emulsion to w/o emulsion, and the stability was better. Erucamide oxide and erucic betaine had good viscosity reduction and emulsification effects on Daqing crude oil. This work can enrich knowledge of the viscosity reduction of heavy oil systems with low relative viscosity and enrich the application of viscosity reducer varieties.

Dynamic Interfacial Tensions of Surfactant and Polymer Solutions Related to High-Temperature and High-Salinity Reservoir.

Betaine is a new surfactant with good application prospects in high-temperature and high-salinity reservoirs. The interfacial properties of two kinds of betaine mixtures with a good synergistic effect were evaluated in this paper. On this basis, the effects of temperature-resistant, salt-resistant polymers with different contents of 2-acrylamide-2-methylpropanesulfonic acid (AMPS) on dynamic interfacial tensions (IFTs) against n-alkanes and crude oil were studied. The experimental results show that the IFTs between betaine ASB and n-alkanes can be reduced to ultra-low values by compounding with anionic surfactant petroleum sulfonate (PS) and extended anionic surfactant alkoxyethylene carboxylate (AEC), respectively. ASB@AEC is very oil-soluble with nmin value ≥14, and ASB@PS is relatively water-soluble with nmin value of 10. The water solubility of both ASB@PS and ASB@AEC is enhanced by the addition of water-soluble polymers. The HLB of the ASB@AEC solution becomes better against crude oil after the addition of polymers, and the IFT decreases to an ultra-low value as a result. On the contrary, the antagonistic effect in reducing the IFT can be observed for ASB@PS in the same case. In a word, polymers affect the IFTs of surfactant solutions by regulating the HLB.

Effect of oil displacement agent on corrosion behavior of NaCl - Alkali/ Surfactant/ Polymer flooding pipeline steel

The research examined the effect of oil displacement agent (Hydrolyzed polyacrylamide, Sodium petroleum sulfonate, NaCl) on corrosion behavior of 20# steel in simulated NaCl ASP flooding solution. Scanning electron microscope (SEM), Transmission Electron Microscope (TEM), X-ray Photoelectron Spectroscopy (XPS), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization were performed to investigate the corrosion mechanism of oil displacement agent on carbon steel. The results demonstrated HPAM (hydrolyzed polyacrylamide) and SPS (sodium petroleum sulfonate) can be adsorbed on the surface of carbon steel to played a role in corrosion inhibition. For-HPAM, the corrosion inhibition rate decreases at high concentrations, which was ascribed to the saturation of adsorption amount and the thinning of corrosion product layer at higher concentrations. For-SPS, the formation of hemi-micellar aggregates caused desorption of the inhibitor from the metal/solution interface at higher concentrations. For -NaCl, NaCl promoted the occurrence of corrosion. Although the adsorption of oxygen on the surface of carbon steel was inhibited by a higher concentration of Cl−, a corrosion cell was formed under the action of the adsorption layer of HPAM and SPS, which promoted localized corrosion.

2-D pore-scale oil recovery mechanisms of the anionic and nonionic surfactants

Surfactants are widely used in enhanced oil recovery (EOR) processes due to their amphiphilic properties, specifically oil enhancement effects including reducing interfacial tension, changing wettability, and emulsification. As the industrial application of EOR is refined, it is necessary to reveal the dominant EOR mechanism of different surfactants in multiphase flow accurately. However, current research on surfactant is usually mixed with multiple agents in the displacement process, so the dominant mechanism is difficult to be clarified. Thus, three commonly used surfactants (amphoteric--alcohol ether sulfate (AES); biological--lipopeptide (ZT); anionic--petroleum sulfonate (PS)) were selected for the dominant EOR mechanism study. The result of conventional interfacial behavior experiments showed that the three surfactant types have similar ability to reduce oil-water interfacial tension, indicating that the difference of the three agents is not the interfacial tension. The contact angle experiments showed that the three agents reduced the solid-liquid contact angle by 36°, 37°, and 16°, respectively, showing that both AES and ZT have a stronger ability to change the wettability than PS. However, the difference between AES and ZT is still unclear. The microscopic oil displacement experiments showed that PS have no emulsification effect, while both AES and ZT can emulsify the remaining oil into oil droplets. However, it can be observed that the oil droplet size of AES and ZT are small (5–100 µm) and large (20–100 µm), respectively. Therefore, the two oil droplet types can cause the "bridging" effect and "Jamin" effect, respectively, and make the fluid flow perpendicular to the direction of the flow field. This is the main reason for the two surfactant types can improve the sweep volume. The overall recovery improved by the three surfactant types is 29.5% (AES), 28.1% (ZT), and 20.1% (PS), respectively. The dominant EOR mechanism of PS is to reduce the oil-water interfacial tension, while AES and ZT are emulsification.

Wettability-Based Retention of Encapsulated Petroleum Sulfonate in Carbonate Rocks at High-Temperature and High-Salinity Conditions

Understanding retention of chemicals onto the rock surface with varying wettabilities allows for better understanding of behavior and performance of the chemicals for applications in oil-bearing rocks. This work studied dynamic retention properties of the low-cost encapsulated petroleum sulfonate nanofluid–Nano-Surfactant (NS)–to the Indiana limestone outcrop surfaces at various wettabilities and surface chemistry while under high-temperature and high-salinity (HTHS) reservoir conditions. Different wettabilities and surface chemistry of the Indiana limestone outcrops were achieved through chemical functionalization utilizing silane coupling agents (4-phenylbutyltrimethoxysilane, n-decyltrimethoxysilane, and 9-phenanthrenyltriethoxysilane), and the NS transport in those core plugs was studied via dynamic core flooding. Incorporating 4-phenylbutyl and n-decyl functional groups onto mineral surfaces made the porous media less water-wet but did not change the transport performance of the NS when compared to the water-wet (untreated) core plugs. In comparison, the propagation of the NS was slightly delayed in the porous medium covered by 9-phenanthrenyl groups, and retention increased from 0.69 to 0.72 mg/g. Results suggested that transport of the NSs was not impacted by variation in surface wettability and that polyaromatic groups on the rock surface were the primary contributor to the increased interaction between the NS and the carbonate minerals.

SUBSTITUTION OF PETROLEUM BASE WITH MES BASE SURFACTANT FOR EOR: LABORATORY SCREENING

Most of Indonesian oil fi eld had been categorized as mature fi led in which production had been declinedfor some time. Therefore EOR (Enhanced Oil Recovery) technology is a must to be implemented to thesekinds of fi eld. There are several EOR technologies had been employed successfully in laboratory and alsofi eld scales, including gas, thermal, and chemical injection. Most Indonesian oil fi elds have productivelayers depths below 2200ft that will not suitable for gas injection. So that chemical injections become animportant alternative that can be implemented to more wide range of depths. These technologies coveralkaline, surfactant, and polymer injection. This paper will highlight the selection and formulation ofsurfactant formulated from MES (Methyl Ester Sulfonates) produced from Palm Oils. These palm oils areavailable very abundant in Indonesia due to plenty farm palm oil in Indonesia. Normally Surfactants areformulated from petroleum sulfonates which are generated from petroleum base. By Using Surfactant that willbe manufactured from palm oil, it will be expected that the price will be cheaper compare to the surfactantfrom petroleum. A series of researches have been done to select the sources of palm oils, producing MESby sulfonation processes, and fi nally surfactant screening for EOR. Several types of MES produced fromvaries of palm oil taken from market such as: CPO (crude palm oil), several packed palm oils of differenttrademarks have been generated. These MES, then, have been given codes to differentiate among these MESsuch as: 1. CCO-MES (A), 2. CCO ME-MES (B), 3. Oleic Acid- MES (C), 4. Natrium Bisulfi t- MES1 (D),5. ME+H2SO4-MES2 (E), 6. CPO-MES (F). These MES production, then, have been formulated to becomesurfactant formula by adding some chemicals and solvent. After that alkaline ((Na2CO3) with optimizedconcentrations were added to generate the best EOR properties. All those Surfactant-MES have been testedusing Lemigas standard laboratory EOR screening; those are compatibility tests, IFT measurements, thermalstability, adsorption, fi ltration, phase behavior, imbibitions and core fl ooding. The result of the screening ofthe MES-chemicals mixtures shows that mixture of CPO-MES (F) with chemical and solvent with the mixturecomposition denoted as FChS811 has the best performance. 1% of this mixture has the best properties forEOR after adding 0.1% of Alkaline (Na2CO3). Laboratory test results indicates that fulfi ll screening criteriasuh as good compatibility and no precipitation, low IFT, thermal stability, low adsorption, low fi ltrationratio, Winsor type-I phase behavior, high RF on imbibition and core fl ooding tests. This Surfactant-MESmixture has a potential to be implemented for a fi eld trial with Huff and Puff method.

Study on the Synergistic Effects between Petroleum Sulfonate and a Nonionic–Anionic Surfactant for Enhanced Oil Recovery

Nonionic–anionic surfactants are expected to be applied in chemical flooding due to their important properties such as ultralow IFT values, good salt tolerance, and no chromatographic separation in porous media. In this study, a new type of nonionic–anionic–hydrophobic group structure surfactant N, N-dihydroxyethylalkylamide carboxylate (EAMC) was synthesized. The synergistic effects between petroleum sulfonate (KPS) and EAMC in reducing interfacial tension (IFT) and emulsification properties were studied. The influences of salt, alkali and Ca2+ on the IFTs of surfactant solutions were also investigated. One-dimensional core flooding experiments were used to characterize the enhanced oil recovery capability of the KPS and EAMC mixed system. The experimental results show that both EAMC and KPS have high interfacial activity and can reduce IFTs to about 0.01 mN/m order of magnitude against decane at optimized concentrations. The area occupied by the hydrophilic group of EAMC on the interface is smaller than that of its own hydrophobic group. The interfacial film formed by EAMC alone is relatively loose. The IFTs of KPS containing different structure petroleum sulfonates is affected by the difference in the adsorption rate of petroleum sulfonates on the interface, which shows that both the dynamic and equilibrium interfacial tensions can have the lowest values. However, the IFTs of the EAMC solutions against crude oil can be reduced to ultralow values because the mixed tight adsorption film is formed by EAMC and crude oil fraction molecules with synergistic effect. On the other hand, the KPS molecule has a hydrophobic part with large size and no synergism with crude oil fractions can be observed in the solutions containing only KPS. The combination of EAMC and KPS shows synergistic effect, namely ultralow IFT values, good emulsification properties, high alkali tolerance, and good salt and Ca2+ tolerance during a wide percentage range of EAMC. The best formula of EAMC and KPS system can be applied for EOR after polymer flooding. The studies in this paper are helpful for the design and application of a chemical flooding formula with nonionic–anionic–hydrophobic group structure surfactants.

Design and performance analysis of a formulation based on SDBS and ionic liquid for EOR in carbonate reservoirs

A large proportion of extant crude oil is found in carbonate reservoirs worldwide. Alkylbenzene sulfonates are inexpensive anionic surfactants but they cannot be used in these reservoirs due to their incompatibility with divalent ions and high adsorption on the rocks. This paper proposes the solution to that problem by blending this kind of surfactant with surface-active ionic liquids. Namely, a formulation containing sodium dodecylbenzenesulfonate (SDBS) and cocosalkylpentaethoximethylammonium methylsulfate ([C1EG][MeSO4]) was designed for the application. Two optimal blends, at 40/60 and 73.7/26.3 SDBS/[C1EG][MeSO4] ratios, were found in synthetic seawater via equilibria and interfacial tension (IFT) studies. Core-flooding tests were carried out to check the performance of both blends. The first blend ratio (40 wt% SDBS) was selected to define an optimal formulation (1 wt% blend in synthetic seawater at 298.15 K) due to its better injectability, higher reduction of the IFT, lower adsorption, and better oil recovery. Attained tertiary oil recovery (18% of the original oil in place), with low blend adsorption (0.37 mgblend/grock), shows the promising performance of the solution. The main mechanism associated with improved oil recovery is IFT reduction. This work offers a significant advance in the application of natural petroleum sulfonates in carbonate reservoirs.

Enhanced separation of emulsified oil from alkaline-surfactant-polymer flooding produced water by Gordonia sp. TD-4: From interactions to mitigation strategies and bio-demulsifying mechanisms

The complexity of emulsions from petroleum industries hinders the application of bio-demulsification. This study revealed the interactions between flooding agents in emulsified alkaline-surfactant-polymer (ASP) flooding produced water (PW) and carbon sources-mediated bio-demulsifiers (byproducts and bacterial cells of Gordonia sp. TD-4). The results demonstrated that synergistic and antagonistic effects existed between flooding agents (surfactant, alkali, and polymer) and bio-demulsifiers. Among these, petroleum sulfonate (PS) mediated emulsifying stability of ASP flooding PW was the dominant factor to affect bio-demulsifying performance. The solubilization of oil-soluble surface-active lipopeptide in micelles and the reduction of bacterial suspensibility constituted two dominant inhibitory mechanisms of PS. Based on the proposed inhibitory mechanisms, two enhanced bio-demulsifying methods toward PW stabilized by a high concentration of PS were established. Partly hydrolyzed polyacrylamide could hinder the solubilization of oil-soluble surface-active lipopeptides and enhance the competitive adsorption-derived bio-demulsification. The suspensibility of cells of TD-4 in the solution of PS could be improved by stimulating the stress response of TD-4, which in turn enhanced the bio-flocculation-derived bio-demulsification. The oil-soluble and membrane-like surface-active lipopeptides produced by TD-4 using oil-soluble carbon sources could sweep the suspended crude oil droplets and decrease the viscoelasticity of interfacial film. The bacterial cells grown in water-soluble carbon sources mainly served as hydrophobic adsorption sites to adsorb and flocculate the suspended nanometer-sized crude oil droplets. This study will innovate the application of biological-based technologies toward the emulsified PW from the petroleum industry.