Current developments and future outlook in nanofluid flooding: A comprehensive review of various parameters influencing oil recovery mechanisms

Preparation of Janus Polymer Nanosheets and Corresponding Oil Displacement Properties at Ultralow Concentration

Conventional methods for preparing Janus nanosheets, including graphene oxide-based nanosheets, molybdenum disulfide-based nanosheets, and silicon dioxide-based nanosheets, as well as polymer-based nanosheets, involve complicated procedures, poor repeatability, and difficulty in imparting Janus properties, which hinder further application. Here, the present authors develop a facile modified suspension polymerization method for preparing Janus polymer nanosheets, in which deep eutectic solvents completely replace water as the continuous phase. Janus polymer nanosheets can be fabricated using common hydrophobic and hydrophilic monomers, such as styrene (St), butyl acrylate (BA), acrylamide (AM), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), acryloyloxyethyl trimethylammonium chloride (DAC), and maleic anhydride (MAH). Additionally, the thickness of the Janus polymer nanosheets can be precisely controlled in a range from 40 to 100 nm by adjusting the volume ratio of higher alkanes to the hydrophobic monomer. Subsequently, the emulsification properties of polystyrene-based nanosheets were evaluated, showing better performance at concentrations ranging from 1 to 50 mg/L compared with higher concentrations. This observation aligns with the corresponding reduction in interfacial tension and changes in the moduli of the interfacial film. Moreover, the adsorption of the nanosheets onto the core alters its wettability, changing it from a water-wettable state to an oil-wettable state. Consequently, a series of core flooding tests reveal that the poly(St-co-AM), poly(St-co-MAH), and poly(St-co-AMPS) nanosheets enhance oil recovery and reduce injection pressure at ultralow concentrations (50 mg/L).

Surface modification of nanoparticles for enhanced applicability of nanofluids in harsh reservoir conditions: A comprehensive review for improved oil recovery

Nanoparticles improve traditional Enhanced Oil Recovery (EOR) methods but face instability issues. Surface modification resolves these, making it vital to understand its impact on EOR effectiveness. This paper examines how surface-modified nanoparticles can increase oil recovery rates. We discuss post-synthesis modifications like chemical functionalization, surfactant and polymer coatings, surface etching, and oxidation, and during-synthesis modifications like core-shell formation, in-situ ligand exchange, and surface passivation. Oil displacement studies show surface-engineered nanoparticles outperform conventional EOR methods. Coatings or functionalizations alter nanoparticle size by 1-5 nm, ensuring colloidal stability for 7 to 30 days at 25 to 65 °C and 30,000 to 150,000 ppm NaCl. This stability ensures uniform distribution and enhanced penetration through low-permeability (1-10 md) rocks, improving oil recovery by 5 to 50 %. Enhanced recovery is achieved through 1-25 μm oil-in-water emulsions, increased viscosity by ≥30 %, wettability changes from 170° to <10°, and interfacial tension reductions of up to 95 %. Surface oxidation is suitable for carbon-based nanoparticles in high-permeability (≥500 md) reservoirs, leading to 80 % oil recovery in micromodel studies. Surface etching is efficient for all nanoparticle types, and combining it with chemical functionalization enhances resistance to harsh conditions (≥40,000 ppm salinity and ≥ 50 °C). Modifying nanoparticle surfaces with a silane coupling agent before using polymers and surfactants improves EOR parameters and reduces polymer thermal degradation (e.g., only 10 % viscosity decrease after 90 days). Economically, 500 ppm of nanoparticles requires 56.25 kg in a 112,500 m3 reservoir, averaging $200/kg, and 2000 ppm of surface modifiers require 4 kg at $3.39/kg. This results in 188,694.30 barrels, or $16,039,015.50 at $85 per barrel for a 20 % increase in oil recovery. The economic benefits justify the initial costs, highlighting the importance of cost-effective nanoparticles for EOR applications.

Research Status and Challenges of Mechanism, Characterization, Performance Evaluation, and Type of Nano-Pour Point Depressants in Waxy Crude Oil

Nano-Pour point depressants have great potential to improve the low-temperature fluidity of waxy crude oil. This Review reviews the recent research progress of nano-pour point depressants in the field of crude oil pour point reduction. The effect and mechanism of nanocomposite pour point depressants are analyzed; the preparation, modification, and microstructure characterization of nanocomposite pour point depressants are introduced; the three main types of nano-pour point depressants, namely, silicon-based, carbon-based, and magnetic metal-based, are introduced; the results of the current research are outlined; and the challenges of the current research and possible directions of future research are also pointed out. The in-depth analysis of nano-pour point depressants and their potential to improve the low-temperature fluidity of waxy crude oil are reviewed in order to thoroughly analyze the mechanism of nano-pour point depressants and to prepare nano-pour point depressants that are more suitable for reducing crude oil coagulation.

Unveiling the revolutionary role of nanoparticles in the oil and gas field: Unleashing new avenues for enhanced efficiency and productivity

Prominent oil corporations are currently engaged in a thorough examination of the potential implementation of nanoparticles within the oil and gas sector. This is evidenced by the substantial financial investments made towards research and development, which serves as a testament to the significant consideration given to nanoparticles. Indeed, nanoparticles has garnered increasing attention and innovative applications across various industries, including but not limited to food, biomedicine, electronics, and materials. In recent years, the oil and gas industry has conducted extensive research on the utilization of nanoparticles for diverse purposes, such as well stimulation, cementing, wettability, drilling fluids, and enhanced oil recovery. To explore the manifold uses of nanoparticles in the oil and gas sector, a comprehensive literature review was conducted. Reviewing several published study data leads to the conclusion that nanoparticles can effectively increase oil recovery by 10 %-15 % of the initial oil in place while tertiary oil recovery gives 20-30 % extra initial oil in place. Besides, it has been noted that the properties of the reservoir rock influence the choice of the right nanoparticle for oil recovery. The present work examines the utilization of nanoparticles in the oil and gas sector, providing a comprehensive analysis of their applications, advantages, and challenges. The article explores various applications of nanoparticles in the industry, including enhanced oil recovery, drilling fluids, wellbore strengthening, and reservoir characterization. By delving into these applications, the article offers a thorough understanding of how nanoparticles are employed in different processes within the sector. This analysis may prove highly advantageous for future studies and applications in the oil and gas sector.

A numerical investigation of mathematical modelling in 3D hexagonal porous prism on oil recovery using nanoflooding

The use of nanomaterials as a means of recovering heavy and light oil from petroleum reservoirs has increased over the preceding twenty years. Most researchers have found that injecting a nanoparticle dispersion (nanofluids) has led to good results and increased the amount of oil that can be recovered. In this research, we aim to imitate the three-dimensional hexagonal prism in the existence of SiO2 and Al2O3 nanoparticles for better oil recovery. Porosity (0.1 ≤ φ ≤ 0.4 ), mass flow rate (0.05 m L / min ≤ Q ≤ 0.05 m l / min ), nanoparticle concentration (0.01 ≤ ψ ≤ 0.04 ), and the effect of relative permeability (kr) on oil and water saturation in the presence of gravity under different time durations are all investigated. The result obtained for the model is verified with existing experimental data. The results indicated that the infulence of nanoparticle volume fraction (VF) is significant in enhancing the oil recovery rate. It is also observed that at low porosity values the oil recovery is maximum. The maximum oil recovery is attained at low values of mass flow rate in the 3D hexagonal prism in the presence of silicon and aluminium nanoparticles It is also observed that the use of SiO2 gives a better oil recovery rate than Al2O3. It is also observed that maximum oil recovery is obtained at 99% at a flow rate of 0.05 mL/min in the presence of silicon injection.

Effect of Salinity on Hydroxyapatite Nanoparticles Flooding in Enhanced Oil Recovery: A Mechanistic Study

Fluid-fluid interactions can affect any enhanced oil recovery (EOR) method, including nanofluid (NF) brine-water flooding. Flooding with NFs changes wettability and lowers oil-water interfacial tension (IFT). Preparation and modification affect the nanoparticle (NP) performance. Hydroxyapatite (HAP) NPs in EOR are yet to be properly verified. HAP was synthesized in this study using co-precipitation and in situ surface functionalization with sodium dodecyl sulfate in order to investigate its impact on EOR processes at high temperatures and different salinities. The following techniques were employed, in that sequence, to verify its synthesis: transmission electron microscopy, zeta potential, thermogravimetric analysis, Fourier transform infrared spectroscopy, X-ray diffraction, particle size analysis, and energy-dispersive X-ray spectra. The outcomes showed the production of HAP, with the particles being evenly dispersed and stable in aqueous solution. The particles' surface charge increased from -5 to -27 mV when the pH was changed from 1 to 13. The HAP NFs at 0.1 wt % altered the wettability of sandstone core plugs from oil-wet at 111.7 to water-wet at 9.0 contact angles at salinity ranges of 5000 ppm to 30,000 ppm. Additionally, the IFT was reduced to 3 mN/m HAP with an incremental oil recovery of 17.9% of the initial oil in place. The HAP NF thus demonstrated excellent effectiveness in EOR through IFT reduction, wettability change, and oil displacement in both low and high salinity conditions.

A Bibliometric Analysis of Research and Development of Nanofluids

Nanofluid concept was defined over 28 years ago. Since then, a veritable science has been developed around this concept. From 1993 until 2020, up to 18021 articles were published in high-quality journals worldwide. The high scientific interest in nanofluids lies in their exceptional thermophysical properties and their possibilities to design more efficient processes and systems. Although the numerous articles, there is a lack of information on the scope, its social and economic impact, or its future trends. This study provides an overview through bibliometric methods that allow better knowledge of the research field. The main goal is to offer a more generalized and strategic vision to help those researchers interested in this topic with accurate information on its impact. In addition, this study helps to maximize international collaborations and provide relevant information to decision-makers. The analysis reveals that research in nanofluids in the last decade has experienced a great specialization in a wide variety of new applications, reaching more new sectors. The main research communities, the most productive authors, or the most relevant journals are some of the analyzed metrics that provide key parameters for contextualization, allowing a clear vision of the current state of the nanofluids research field.

Effect of Nanoparticles on the Thermal Stability and Reaction Kinetics in Ionic Nanofluids

Nowadays, the incorporation of nanoparticles into thermal fluids has become one of the most suitable strategies for developing high-performance fluids. An unconventional improvement of thermo–physical properties was observed with the addition of 1% wt. of nanoparticles in different types of fluids, such as molten salts, allowing for the design of more thermally efficient systems using nanofluids. Despite this, there is a lack of knowledge about the effect that nanoparticles produce on the thermal stability and the decomposition kinetics of the base fluid. The present study performs IR- and UV-vis spectroscopy along with thermogravimetric analysis (TGA) of pure nitrate and nitrate based nanofluids with the presence of SiO₂ and Al₂O₃ nanoparticles (1% wt.). The results obtained support that nanoparticles accelerate the nitrate to nitrite decomposition at temperatures below 500 °C (up to 4%), thus confirming the catalytic role of nanoparticles in nanofluids.

Microfluidic Study of the Effect of Nanosuspensions on Enhanced Oil Recovery

The essential advantages of microfluidic studies are the excellent visualization of the processes of oil displacement from the porous medium model, simple cleaning, and the possibility of the repeated use of the microfluidic chip. The present article deals with the process of oil displacement by suspension flooding using a microfluidic chip, simulating a porous medium, and the suspensions of silicon dioxide nanoparticles (22 nm). The mass concentration of nanoparticles in suspensions ranged from 0.1 to 2 wt%. Five mass concentrations (0.125 wt%, 0.25 wt%, 0.5 wt%, 1 wt% and 2 wt%) were considered. The article presents the experimental photographs of the oil displacement process by water and SiO2 suspension. It is shown that, with the increasing concentration of nanoparticles, the oil recovery factor increases. A significant effect is observed at 0.5 wt% concentration of nanoparticles. It is shown that the increase in oil recovery during flooding by SiO2 suspension with the maximum concentration was 16%.

Enhanced oil recovery from fractured carbonate reservoirs using nanoparticles with low salinity water and surfactant: A review on experimental and simulation studies

Nearly half of the world's oil reserves are found in carbonate reservoirs, which have heterogeneous formation characteristics and are naturally fractured. Because of the permeability contrast between the matrix and fracture network in these reservoirs, primary and secondary oil recovery processes are ineffective. Consequently, there has been a growing interest in enhanced oil recovery (EOR) from fractured carbonate reservoirs (FCRs) over the past years and many successful attempts have involved the use of different thermal or non-thermal EOR methods to improve oil recovery. Nonetheless, many researchers have recently directed their studies towards the use of low salinity water (LSW), nanoparticles (NPs), and surfactant (LNS) as EOR agents in carbonates because they are environmentally friendly and incur low costs. Several studies have reported the successful application of the solutions of LSW, NPs, and surfactants either as individual solutions or in combinations, to carbonate formations. The challenges associated with their implementations such as fines migration for LSW flooding, surfactant adsorption onto the pore walls, and instability of NPs under harsh conditions, have also been identified in literature and addressed. However, relatively few investigations have been conducted on FCRs to study the effectiveness of these LNS EOR applications in the presence of fractures. This review, therefore, presents the reports of EOR in FCRs using LNS and identifies the mechanisms that influence these results. It has been shown that fines migration could either promote EOR or reduce recovery based on the occurrence of formation damage. In addition, surfactants with the tendency to form micro-emulsions will be efficient for EOR applications in FCRs. Finally, LNS solutions show promising results with emerging techniques such as alternating injection, which could be applied in FCRs. The findings from this study set the stage for future investigations into EOR in FCRs.

Experimental Investigation of Polymer-Coated Silica Nanoparticles for EOR under Harsh Reservoir Conditions of High Temperature and Salinity

Laboratory experiments have shown higher oil recovery with nanoparticle (NPs) flooding. Accordingly, many studies have investigated the nanoparticle-aided sweep efficiency of the injection fluid. The change in wettability and the reduction of the interfacial tension (IFT) are the two most proposed enhanced oil recovery (EOR) mechanisms of nanoparticles. Nevertheless, gaps still exist in terms of understanding the interactions induced by NPs that pave way for the mobilization of oil. This work investigated four types of polymer-coated silica NPs for oil recovery under harsh reservoir conditions of high temperature (60 ∘C) and salinity (38,380 ppm). Flooding experiments were conducted on neutral-wet core plugs in tertiary recovery mode. Nanoparticles were diluted to 0.1 wt.% concentration with seawater. The nano-aided sweep efficiency was studied via IFT and imbibition tests, and by examining the displacement pressure behavior. Flooding tests indicated incremental oil recovery between 1.51 and 6.13% of the original oil in place (OOIP). The oil sweep efficiency was affected by the reduction in core's permeability induced by the aggregation/agglomeration of NPs in the pores. Different types of mechanisms, such as reduction in IFT, generation of in-situ emulsion, microscopic flow diversion and alteration of wettability, together, can explain the nano-EOR effect. However, it was found that the change in the rock wettability to more water-wet condition seemed to govern the sweeping efficiency. These experimental results are valuable addition to the data bank on the application of novel NPs injection in porous media and aid to understand the EOR mechanisms associated with the application of polymer-coated silica nanoparticles.