scholarly journals Microemulsion Rheological Analysis of Alkaline, Surfactant, and Polymer in Oil-Water Interface

Processes ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 762 ◽  
Author(s):  
Mohd Sofi Numin ◽  
Khairulazhar Jumbri ◽  
Anita Ramli ◽  
Noorazlenawati Borhan
Keyword(s):  
Crude Oil ◽  
Oil Recovery ◽  
Shear Thinning ◽  
Angular Frequency ◽  
Water Interface ◽  
Sweep Efficiency ◽  
Rheological Analysis ◽  
Fluid Behavior ◽  
Significant Difference ◽  
Oil Water

Injection of alkaline (A), polymer (P), and surfactant (S) chemicals in enhanced oil recovery (cEOR) processes increases output by changing the properties of the injected fluid. In this work, micellar fluid interactions were studied via microemulsion rheological analysis. Crude oil and stimulated brine with ASP or SP was used for bottle testing. The results revealed that no microemulsion was produced when ASP (Alkaline, Surfactant, and Polymer) or SP (Surfactant and Polymer) was left out during the bottle testing phase. The addition of ASP and SP led to the formation of microemulsions—up to 29% for 50% water cut (WC) ASP, and 36% for 40% WC SP. This shows that the addition of ASP and SP can be applied to flooding applications. The results of the rheological analysis show that the microemulsions behaved as a shear-thinning micellar fluid by decreasing viscosity with increase in shear rate. As per the power-law equation, the ASP micellar fluid viscoelastic behavior shows better shear-thinning compared to SP, suggesting more efficiency in fluid mobility and sweep efficiency. Most of the microemulsions exhibited viscoelastic fluid behavior (G’ = G”) at angular frequency of 10 to 60 rad s−1, and stable elastic fluid behavior (G’ > G’’) below 10 rad s−1 angular frequency. The viscosity of microemulsion fluids decreases as temperature increases; this indicates that the crude oil (i.e., alkanes) was solubilized in core micelles, leading to radial growth in the cylindrical part of the wormlike micelles, and resulting in a drop in end-cap energy and micelle length. No significant difference was found in the analysis of viscoelasticity evaluation and viscosity analysis for both ASP and SP microemulsions. The microemulsion tendency test and rheology test show that the addition of ASP and SP in the oil-water interface yields excellent viscoelastic properties.

Microscale Interactions of Surfactant and Polymer Chemicals at Crude Oil/Water Interface for Enhanced Oil Recovery

SPE Journal ◽  
2020 ◽  
Vol 25 (04) ◽  
pp. 1812-1826
Author(s):  
Subhash Ayirala ◽  
Zuoli Li ◽  
Rubia Mariath ◽  
Abdulkareem AlSofi ◽  
Zhenghe Xu ◽  
...  
Keyword(s):  
Crude Oil ◽  
Oil Recovery ◽  
High Salinity ◽  
Interfacial Shear ◽  
Experimental Techniques ◽  
Water Interface ◽  
Oil Droplets ◽  
Interfacial Film ◽  
Chemical Eor ◽  
Oil Water

Summary The conventional experimental techniques used for performance evaluation of enhanced oil recovery (EOR) chemicals, such as polymers and surfactants, have been mostly limited to bulk viscosity, phase behavior/interfacial tension (IFT), and thermal stability measurements. Furthermore, fundamental studies exploring the different microscale interactions instigated by the EOR chemicals at the crude oil/water interface are scanty. The objective of this experimental study is to fill this existing knowledge gap and deliver an important understanding on underlying interfacial sciences and their potential implications for oil recovery in chemical EOR. Different microscale interactions of EOR chemicals, at crude oil/water interface, were studied by using a suite of experimental techniques, including an interfacial shear rheometer, Langmuir trough, and coalescence time measurement apparatus at both ambient (23°C) and elevated (70°C) temperatures. The reservoir crude oil and high-salinity injection water (57,000 ppm total dissolved solids) were used. Two chemicals, an amphoteric surfactant (at 1,000 ppm) and a sulfonated polyacrylamide polymer (at 500 and 700 ppm) were chosen because they are tolerant to high-salinity and high-temperature conditions. Interfacial viscous and elastic moduli (viscoelasticity), interface pressures, interface compression energies, and coalescence time between crude oil droplets are the major experimental data measured. Interfacial shear rheology results showed that surfactant favorably reduced the viscoelasticity of crude oil/water interface by decreasing the elastic and viscous modulus and increasing the phase angle to soften the interfacial film. Polymers in brine either alone or together with surfactant increased the viscous and elastic modulus and decreased the phase angle at the oil/water interface, thereby contributing to interfacial film rigidity. Interfacial pressures with polymers remained almost in the same order of magnitude as the high-salinity brine. In contrast, a significant reduction in interfacial pressures with surfactant was observed. The interface compression energies indicated the same trend and were reduced by approximately two orders of magnitude when surfactant was added to the brine. The surfactant was also able to retain similar interface behavior under compression even in the presence of polymers. The coalescence times between crude oil droplets were increased by polymers, while they were substantially decreased by the surfactant. These consistent findings from different experimental techniques demonstrated the adverse interactions of polymers at the crude oil/water interface to result in more rigid films, while confirming the high efficiency of the surfactant to soften the interfacial film, promote the oil droplets coalescence, and mobilize substantial amounts of residual oil in chemical EOR. This experimental study, for the first time, characterized the microscale interactions of surfactant-polymer chemicals at the crude oil/water interface. The applicability of several interfacial experimental techniques has been demonstrated to successfully understand underlying interfacial sciences and oil mobilization mechanisms in chemical EOR. These techniques and methods can provide potential means to efficiently screen and optimize EOR chemical formulations for better oil recovery in both sandstone and carbonate reservoirs.

Experimental Analysis of Alkali-Brine-Alcohol Phase Behavior with High Acid Number Crude Oil

2021 ◽  
pp. 1-19
Author(s):  
D. Magzymov ◽  
T. Clemens ◽  
B. Schumi ◽  
R. T. Johns
Keyword(s):  
Crude Oil ◽  
Phase Behavior ◽  
Oil Recovery ◽  
Complex Mixture ◽  
Acid Number ◽  
Field Application ◽  
Water Interface ◽  
Total Acid ◽  
Oil Water

Summary A potential enhanced oil recovery technique is to inject alkali into a reservoir with a high-total acid number (TAN) crude to generate soap in situ and reduce interfacial tension (IFT) without the need to inject surfactant. The method may be cost-effective if the IFT can be lowered enough to cause significant mobilization of trapped oil while also avoiding formation of gels and viscous phases. This paper investigates the potential field application of injecting alkali to generate in-situ soap and favorable phase behavior for a high-TAN oil. Oil analyses show that the acids in the crude are a complex mixture of various polar acids and not mainly carboxylic acids. The results from phase behavior experiments do not undergo typical Winsor microemulsion behavior transition and subsequent ultralow IFTs below 1×10−3 mN/m that are conventionally observed. Instead, mixing of alkali and crude/brine generate water-in-oil macroemulsions that can be highly viscous. For a specific range of alkali concentrations, however, phases are not too viscous, and IFTs are reduced by several orders of magnitude. Incremental coreflood recoveries in this alkali range are excellent, even though not all trapped oil is mobilized. The viscous phase behavior at high alkali concentrations is explained by the formation of salt-crude complexes, created by acids from the crude oil under the alkali environment. These hydrophobic molecules tend to agglomerate at the oil-water interface. Together with polar components from the crude oil, they can organize into a highly viscous network and stabilize water droplets in the oleic phase. Oil-soluble alcohol was added to counter those two phenomena at large concentrations, but typical Winsor phase behavior was still not observed. A physicochemical model is proposed to explain the salt-crude complex formation at the oil-water interface that inhibits classical Winsor behavior.

Microscale Interactions of Surfactant and Polymer Chemicals at Crude Oil-Water Interface for Enhanced Oil Recovery

2019 ◽  
Author(s):  
Subhash Ayirala ◽  
Zuoli Li ◽  
Rubia Mariath Mariath ◽  
Abdulkareem AlSofi ◽  
Zhenghe Xu ◽  
...  
Keyword(s):  
Crude Oil ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Water Interface ◽  
Oil Water

Water Ion Interactions at Crude-Oil/Water Interface and Their Implications for Smart Waterflooding in Carbonates

SPE Journal ◽  
2018 ◽  
Vol 23 (05) ◽  
pp. 1817-1832 ◽  
Author(s):  
Subhash C. Ayirala ◽  
Ali A. Al-Yousef ◽  
Zuoli Li ◽  
Zhenghe Xu
Keyword(s):  
Crude Oil ◽  
Oil Recovery ◽  
Measurement Techniques ◽  
Fluid Interfaces ◽  
Water Interface ◽  
Oil Droplets ◽  
Coalescence Time ◽  
Ion Interactions ◽  
Phase Connectivity ◽  
Oil Water

Summary Smart waterflooding (SWF) through tailoring of injection-water salinity and ionic composition is receiving favorable attention in the industry for both improved and enhanced oil recovery (EOR) in carbonate reservoirs. Surface/intermolecular forces, thin-film dynamics, and capillary/adhesion forces at rock/fluid interfaces govern crude-oil liberation from pores. On the other hand, stability and rigidity of oil/water interfaces control the destabilization of interfacial film to promote coalescence between released oil droplets and to improve the oil-phase connectivity. As a result, the dynamics of oil recovery in smart waterflood is caused by the combined effect of favorable interactions occurring at both oil/brine and oil/brine/rock interfaces across the thin film. Most of the laboratory studies reported so far have been focused on only studying the interactions at rock/fluid interfaces. However, the other important aspect of characterizing water ion interactions at the crude oil/water interface and their impact on film stability and oil-droplet coalescence remains largely unexplored. A detailed experimental investigation was conducted to understand the effects of different water ions at the crude-oil/water interface by using several instruments such as Langmuir trough, interfacial shear rheometer, Attension tensiometer, and coalescence time-measurement apparatus. The reservoir crude oil and four different water recipes with varying salinities and individual ion concentrations were used. Interfacial tension (IFT), interface pressures, compression energy, interfacial viscous and elastic moduli, oil-droplet crumpling ratio, and coalescence time between crude-oil droplets are the major experimental data measured. The IFTs are found to be the largest for deionized (DI) water, followed by the 10-times-reduced-salinity seawater and 10-times-reduced-salinity seawater enriched with sulfates. Interfacial pressures gradually increased with compressing surface area for all the brines and DI water. The compression energy (integration of interfacial pressure over the surface-area change) is the highest for DI water, followed by the lower-salinity brine containing sulfate ions, indicating rigid interfaces. The transition times of interfacial layer to become elastic-dominant from viscous-dominant structures are found to be much shorter for brines enriched with sulfates, once again confirming the rigidity of interface. The crumpling ratios (oil drop wrinkles when contracted) are also higher with the two recipes of DI water and sulfates-only brine to indicate the same trend and to confirm elastic rigid skin at the interface. The coalescence time between oil droplets was the least in brines containing sufficient amounts of magnesium and calcium ions, while the highest in DI water and sulfate-rich brine, respectively. These results, therefore, showed a good correlation of coalescence times with the rigidity of oil/water interface, as interpreted from different measurement techniques. This study, thereby, integrates consistent results obtained from different measurement techniques at the crude-oil/water interface to demonstrate the importance of both salinity and certain ions, such as magnesium and calcium, on crude-oil-droplets coalescence, and to improve oil-phase connectivity in smart waterflood.

Application of Molecular Simulations to CO2-Enhanced Oil Recovery: Phase Equilibria and Interfacial Phenomena

SPE Journal ◽  
2013 ◽  
Vol 18 (02) ◽  
pp. 319-330 ◽  
Author(s):  
Dai Makimura ◽  
Makoto Kunieda ◽  
Yunfeng Liang ◽  
Toshifumi Matsuoka ◽  
Satoru Takahashi ◽  
...  
Keyword(s):  
Phase Equilibria ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
High Pressures ◽  
Co2 Enrichment ◽  
Interfacial Phenomena ◽  
Interfacial Region ◽  
Water Interface ◽  
Oil Water ◽  
Co2 Eor

Summary Molecular simulation is a powerful technique for obtaining thermodynamic properties of a system of given composition at a specific temperature and pressure, and it enables us to visualize microscopic phenomena. In this work, we used simulations to study interfacial phenomena and phase equilibria, which are important to CO2-enhanced oil recovery (EOR). We conducted molecular dynamics (MD) simulation of an oil/water interface in the presence of CO2. It was found that CO2 was enriched at the interfacial region under all thermal conditions. Whereas the oil/water interfacial tension (IFT) increases with pressure, CO2 reduces the IFT by approximately one-third at low pressure and one-half at higher pressure. Further analysis on the basis of our MD trajectories shows that the O=C=O bonds to the water with a “T-shaped” structure, which provides the mechanism for CO2 enrichment at the oil/water interface. The residual nonnegligible IFT at high pressures implies that the connate or injected water in a reservoir strongly influences the transport of CO2/oil solutes in that reservoir. We used Gibbs ensemble Monte Carlo (GEMC) simulation to compute phase equilibria and obtain ternary phase diagrams of such systems as CO2/n-butane/N2 and CO2/n-butane/n-decane. Simulating hydrocarbon fluids with a mixture of CO2 and N2 enables us to evaluate the effects of N2 impurity on CO2-EOR. It also enables us to study the phase behavior, which is routinely used to evaluate the minimum miscibility pressure (MMP). We chose these two systems because experimental data are available for them. Our calculated phase equilibria are in fair agreement with experiments. We also discuss possible ways to improve the predictive capability for CO2/hydrocarbon systems. GEMC and MD simulations of systems with heavier hydrocarbons are straightforward and enable us to combine molecular-level thinking with process considerations in CO2-EOR.

Pore-to-Core EOR Upscaling for CO2 Foam for CCUS

SPE Journal ◽  
2019 ◽  
Vol 24 (06) ◽  
pp. 2793-2803 ◽  
Author(s):  
Arthur Uno Rognmo ◽  
Sunniva Brudvik Fredriksen ◽  
Zachary Paul Alcorn ◽  
Mohan Sharma ◽  
Tore Føyen ◽  
...  
Keyword(s):  
Oil Recovery ◽  
Apparent Viscosity ◽  
Shear Thinning ◽  
Liquid Films ◽  
Carbonate Reservoir ◽  
Sweep Efficiency ◽  
Reference Case ◽  
Foam Generation ◽  
Co2 Foam ◽  
Gas Fractions

Summary This paper presents an ongoing CO2–foam upscaling research project that aims to advance CO2–foam technology for accelerating and increasing oil recovery, while reducing operational costs and lessening the carbon footprint left during CO2 enhanced oil recovery (EOR). Laboratory CO2–foam behavior was upscaled to pilot scale in an onshore carbonate reservoir in Texas, USA. Important CO2–foam properties, such as local foam generation, bubble texture, apparent viscosity, and shear–thinning behavior with a nonionic surfactant, were evaluated using pore–to–core upscaling to develop accurate numerical tools for a field–pilot prediction of increased sweep efficiency and CO2 utilization. At pore–scale, high–pressure silicon–wafer micromodels showed in–situ foam generation and stable liquid films over time during no–flow conditions. Intrapore foam bubbles corroborated high apparent foam viscosities measured at core scale. CO2–foam apparent viscosity was measured at different rates (foam–rate scans) and different gas fractions (foam–quality scans) at core scale. The highest mobility reduction (foam apparent viscosity) was observed between 0.60 and 0.70 gas fractions. The maximum foam apparent viscosity was 44.3 (±0.5) mPa·s, 600 times higher than that of pure CO2, compared with the baseline viscosity (reference case, without surfactant), which was 1.7 (±0.6) mPa·s, measured at identical conditions. The CO2–foam showed shear–thinning behavior with approximately 50% reduction in apparent viscosity when the superficial velocity was increased from 1 to 8 ft/D. Strong foam was generated in EOR corefloods at a gas fraction of 0.70, resulting in an apparent viscosity of 39.1 mPa·s. Foam parameters derived from core–scale foam floods were used for numerical upscaling and field–pilot performance assessment.

Study and Evaluation of Changqing Crude Oil Antiwaxing Agent

2019 ◽  
Vol 953 ◽  
pp. 166-171 ◽  
Author(s):  
Qing Mei Luo ◽  
Jian Yang ◽  
Li Jun She ◽  
Wen Jie Wan ◽  
Yun Ma ◽  
...  
Keyword(s):  
Crude Oil ◽  
Removal Rate ◽  
Salt Content ◽  
Water Interface ◽  
Wax Deposition ◽  
Wetting Ability ◽  
Deposit Surface ◽  
Low Salt ◽  
Oil Water ◽  
Wax Removal

In order to solve the problems of wax deposit, this study evaluated the effect of wax cleaning agent used in Changqing and adjusted its formulation. The results showed that the wax removal rate of oil based dewaxing agent was slightly higher than that of emulsion dewaxing agent for crude oil with low salt content. It is possible that the emulsion dewaxing agent contains a certain amount of mutual solvents, which improves its wetting ability at the oil-water interface and makes the oil and water dissolve each other. So that the wax deposit surface from hydrophilic hydrophobic to hydrophilic hydrophobic, forming anti-wax film to prevent wax deposition. Therefore, the wax removal ability of 1#, 3# oil wax is higher than that of oil base wax dewaxing agent.

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