Surfactants And Interfacial Phenomena

Adsorption of surfactants on sand surface in enhanced oil recovery: Isotherms, kinetics and thermodynamic studies

Microbial enhanced oil recovery (MEOR) is a type of enhanced oil recovery (EOR) technology, generally employed as a tertiary stage where oil recovery using primary and secondary traditional methods is not feasible anymore. Amongst several potential biological agents useful for MEOR, biosurfactants (biologically produced amphiphilic surfactants) play key roles. They are mostly equivalent to or better than their chemical counterparts in several aspects including; better environmental compatibility, production from renewable waste substrates, maintaining activity at harsh environmental conditions, lower or no environmental toxicity. Biosurfactants are still not cost-competitive when compared to chemical surfactants. Different strategies like the use of cheaper raw materials, optimization of media components, fermentation processes and downstream processes, use of hyperproducers are currently explored to improve biosurfactant production economics. Biosurfactant mediated MEOR (BS-MEOR) could be applied by either in-situ or ex-situ techniques. In-situ BS-MEOR could be applied by injecting biosurfactant producing microorganisms in the oil well with or without additional nutrients. Generally followed by shut-in phase and subsequently monitoring microbial activities, metabolites production and oil recovery from the producer wells. Whereas for ex-situ BS-MEOR applications, the biosurfactant is produced outside the oil well and injected directly for enhancing oil recovery. This review highlights the biosurfactant production and economics, general protocols for applications from lab-to-field scale, different successful trials along with pros and cons of both in-situ and ex-situ BS-MEOR applications.

Biosurfactants: Production and potential applications in microbial enhanced oil recovery (MEOR)

The use of surfactants in enhanced oil recovery: A review of recent advances

Adsorption analysis of natural anionic surfactant for enhanced oil recovery: The role of mineralogy, salinity, alkalinity and nanoparticles

Surfactant loss due to adsorption on the porous medium of an oil reservoir is a major concern in enhanced oil recovery. Surfactant loss due to adsorption on the reservoir rock weakens the effectiveness of the injected surfactant in reducing oil–water interfacial tension (IFT) and making the process uneconomical. In this study, surfactant concentrations in the effluent of the corefloods and oil–water IFT were determined under different injection strategies. It was found that in an extended waterflood following a surfactant slug injection, surfactant desorbed in the water phase. This desorbed surfactant lasted for a long period of the waterflood. The concentration of the desorbed surfactant in the extended waterflood was very low but still an ultralow IFT was obtained by using a suitable alkali. Coreflood results show an additional recovery of 13.3% of the initial oil in place was obtained by the desorbed surfactant and alkali. Results indicate that by utilizing the desorbed surfactant during the extended waterflood operation the efficiency and economics of the surfactant flood can be improved significantly.

Adsorption–Desorption of Surfactant for Enhanced Oil Recovery

All the time the flow of fluids happens below the surface of the earth. These flow processes can only be imagined, but not be fully visualised on how fluid flow behaviour occurs though the porous medium of the rocks. Hence comes the play of microfluidic micromodels. These are a transparent version of slices (2 dimensional) porous structure of rocks such as sandstone duplicated onto materials such as glass, polymers and silicon wafers. Fluids such as crude oil, surfactant and polymer solutions and gases such as carbon dioxide (CO2) are injected through special pumps into these transparent micromodels. The flow patterns and behaviours hence developed inside the micromodels are studied and analysed. Micromodels have helped in different branches of science such as medicine, genetics, liquid channelling and enhanced oil recovery (EOR). The concern of this paper is to study the flow behaviour and EOR in micromodels. Micromodels can be made to represent a micro version of a partially saturated rock with crude oil. The various chemical EOR processes such as surfactant flooding, polymer flooding, gas flooding injected into crude oil filled micromodels with water saturation is studied. The advancement of front developed between displacing and displaced fluids, the fingering effect, the presence of high permeability streaks is observed. Also the breakthrough of the flood front is analysed from the various experiments reviewed. This review paper is undertaken so as to help researchers find a consolidated and concise literature of the trends and developments in microfluidics especially in EOR.

https://link.springer.com/content/pdf/10.1007/s13202-019-0610-4.pdf

Review on microfluidic studies for EOR application

Effects of CO2-foam stability, interfacial tension and surfactant adsorption on oil recovery by alkaline-surfactant-alternated-gas/CO2 flooding

The volumetric sweep efficiencies of CO2 flooding for enhanced oil recovery (EOR) are generally low due to problems of viscous fingering and gravity override. This paper attempts to study a relatively new and promising method to reduce the mobility of CO2 flooding and increase oil recovery under reservoir conditions. Referred to as alkaline-surfactant-alternated-gas/CO2 (ASAG) flooding, this method is essentially the synergic combination of chemical and immiscible CO2 flooding. In this work, chemical formulations were identified through foam stability tests based on their foaming ability coefficients. The selected formulations were further tested for their capabilities to reduce oil–water interfacial tensions (IFT) to ultra-low value. With the best performing formulations, the laboratory-scale core flooding experiments were conducted to evaluate their EOR potential. The core flooding experiments were performed with sandstone reservoir core samples from two different depths of a major depleted oil field of Upper Assam Basin, India. This study reports the successful application of a natural anionic surfactant (black liquor) as a co-surfactant and foaming agent during ASAG flooding. It was observed that higher oil recovery of 14.26% original oil in place (OOIP) was obtained by surfactant-alternated-gas (SAG) flooding compared to 12.03% OOIP by immiscible CO2 alternated with brine (WAG) flooding. The highest residual oil recovery of 20% OOIP was obtained for ASAG flooding with the alkali, surfactant and black liquor in the chemical slug. Oil recovery performances during SAG and ASAG flooding were found to be better for core samples with lower porosity–permeability due to stronger foam formation in lower permeability cores.

/pdf/enhanced-oil-recovery-by-alkaline-surfactant-alternated-gas-q97omgzmdf.pdf

Enhanced oil recovery by alkaline-surfactant-alternated-gas/CO2 flooding

Surfactant loss due to adsorption on the reservoir rock is one of the major concerns in enhanced oil recovery (EOR) processes. It weakens the effectiveness of the injected slug in reducing oil-water interfacial tension (IFT) and makes the process uneconomical. In this study, an attempt is made to investigate the adsorption of Na-lignosulphonate onto the porous media of Oil India Limited (OIL) petroleum reservoir rocks. The data were interpreted from the well-known models and it was found that the Langmuir model is a good fit for the pH and brine data over the entire range of variables. Adsorption increases with NaCl concentration and decreases with increase in pH.

Subrata Borgohain Gogoi

Papers

Adsorption–Desorption of Surfactant for Enhanced Oil Recovery

Review on microfluidic studies for EOR application

Effects of CO2-foam stability, interfacial tension and surfactant adsorption on oil recovery by alkaline-surfactant-alternated-gas/CO2 flooding

Enhanced oil recovery by alkaline-surfactant-alternated-gas/CO2 flooding

Adsorption of non-petroleum base surfactant on reservoir rock