Review of the Application of Natural Surfactants in Enhanced Oil Recovery: State-of-the-Art and Perspectives

Abstract

Injecting surfactant by means of chemical enhanced oil recovery (cEOR) has acquired predominant attention in improving oil recovery by changing either fluid/rock and/or fluid/fluid interaction due to ion-pair forming and/or surfactant adsorption on the rock surface. As the main surfactant role in EOR, IFT reduction refers to adsorbing of surfactant molecules on the residual oil/water interface, which causes an increase in capillary number; as a result, trapped oil drops in porous media get free and start to move through the pore space toward the production well. The toxic nature, excessive cost, and environmental issues are the obvious limitations in applying the chemical surfactants in EOR, hence, looking for a less-expensive and eco-friendly type of surfactant has become a significant task to researchers to study the natural surfactant as an alternative to chemical surfactants. A deep understanding about the classification of natural surfactants, fabrication methods, and the difference between each class is crucial to propose a new plant-derived natural surfactant. This study tried to review up-to-date published studies related to the natural surfactant types and prepare a comprehensive catalog respective to natural surfactant that helps researchers with regard to future work in natural surfactant application in EOR. In addition, comparisons of each class performance and the impact of nanoparticles and the salinity on them in reducing IFT, altering wettability, and improving the recovery factor have been investigated. It had been concluded that natural surfactant can be produced from different plant parts (leaf, root, steam, fruit, and seed) based on the fabrication method. Natural surfactants synthesized from seed oil are stronger, compared with those extracted from the plant part (i.e., IFT reduction by 98%). Generally, injecting natural surfactants expressed low to high performance in improving the ultimate oil recovery from 2% to 40% original oil in place (OOIP).

Performance Evaluation of the Green Surfactant-Treated Nanofluid in Enhanced Oil Recovery: Dill-Hop Extracts and SiO2/Bentonite Nanocomposites

“…This can happen due to the ability of the nonionic surfactant molecules in creating micelles which affected the organization and mobility of the charged particles and ions that exist inside the solution. In addition, the presence of the polar functional groups in the nonionic surfactants can interact with the hydrogen molecules easily and alter the conductivity of the ions through hydrogen bonding. − …”

“…The range at which the micelles can be developed is dependent on the chemical structure and other properties of the surfactant. Because both used natural surfactants are different, they have different characteristics, chemical, and molecular structures. − Thus, the dill extract might have a chemical structure that easily boots self-association of surfactant molecules into the micelles at lower concentrations compared with that of the hop extract. In addition, the CMC can be influenced by the molecular weight of the surfactant, and a smaller molecular weight of the dill might lead to the lower concentration of creating micelles.…”

“…Although some challenges can be observed, such as the cost of materials and process, availability of green sources, methodology used, and production of large scale. According to Hama et al (2023), there is still a doubt on the cost of producing these large-scale materials compared with the conventional materials due to the price for the need of chemical reagents involved in the extraction, purification, synthesis, and saponification processes . Meanwhile, the source of the plant might be a problem, but sometimes the aim is to use the waste of the fruits or unconsumable plants.…”

Investigation of the Passiflora Plant as a Promising Natural Surfactant for Enhanced Oil Recovery: Insights into Crude Oil–Water–Rock Interaction

“…The level of the supply and demand of the material source also affects the overall cost of the natural surfactant, especially for the plants that are useable in other industries, such as food supply or medicine. Overall, the expected cost for the natural surfactant might be a bit higher compared with the cost of the commercial surfactants but they can eliminate the negative impacts on the environment …”

Impact of the Naturally Driven Surfactant in EOR Application: Experimental, Microscopic, and Numerical Analyses

“…The different extraction methods include spray drying, maceration, Soxhlet extraction, ultrasonic extraction, and chemical conversion of herbal to produce natural surfactants. 19 Investigating the contrast between natural and conventional approaches is a cornerstone of scholarly pursuits within the EOR domain, signifying a fundamental paradigm shift in research objectives. 20 There is also a substantial amount of research on natural surfactants considering IFT and wettability results, as presented in Table 1.…”