Insights into stability of silica nanofluids in brine solution coupled with rock wettability alteration: An enhanced oil recovery study in oil-wet carbonates

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.

Copper Quantum Dot/Polyacrylamide Composite Nanospheres: Spreading on Quartz Flake Surfaces and Displacing Crude Oil in Microchannel Chips

Polyacrylamide, silica, and other nanoparticles have all been realized in the field of enhanced oil recovery. Researchers often explore the mechanisms of spreading behavior and simulated displacement to develop more efficient types of nanoparticles. In this study, copper quantum dots were introduced into a acrylamide copolymerization system to obtain composite nanospheres and its structure, topographic, and application performance were characterized. The results show that the composite nanospheres have a particle size of around 25 nm, are uniformly loaded with copper particles, and have good temperature resistance. The spreading ability on the quartz flake surfaces and displacement effect in microchannels of composite nanospheres, acrylamide copolymer nanospheres, and copper quantum dots were compared by nanofluid spreading experiments and microchannel chip oil displacement experiments. The results indicate that the composite nanospheres can effectively reduce the water contact angle, promote the spreading of aqueous phase, and accelerate the oil droplet removal process; the accelerating effect is stronger than other samples. Its oil displacement effect is also the strongest, and it is minimized by the influence of channel size, temperature, and dispersing medium, with better stratigraphic adaptability. This work supports the practical application of copper quantum dot/polyacrylamide composite nanospheres in the oilfield.

Transport and retention of silica nanoparticles in glass-bead columns: effects of particle size, type, and concentration of ionic species

Silica nanoparticles (SiO2 NPs) have garnered substantial attention as versatile additives in saline fluids, finding application in areas like environmental remediation, wastewater treatment, enhanced oil recovery, and carbon geo-sequestration. Despite their potential, the intricate interaction between electrolyzed nanoparticles and porous media remains inadequately researched in these contexts. This study delves into the pivotal yet underexplored aspect of silica nanoparticle absorption behavior within porous media, a key determinant of their practical effectiveness. The research focuses on silica particles with dimensions of 10 nm and 50 nm, synthesized via hydrolysis and condensation of tetraethyl orthosilicate (TEOS) in methanol. Employing packed glass bead columns as a surrogate for porous media, the study unravels the complex mechanisms governing nanoparticle transport and deposition. Comprehensive investigations encompass variations in particle sizes, ionic strength, and ionic species, resulting in the examination of 48 distinct flooding scenarios. UV/Vis spectrophotometry is used to quantify nanoparticle concentrations in effluents, elucidating their transport behavior within the porous media. Concurrently, pressure drop alterations across the media serve as indicators of particle plugging and changes in permeability. Intriguingly, specific conditions involving a nanofluid comprising 50 nm silica nanoparticles and 10,000 ppm of magnesium chloride exhibit pronounced permeability reduction, offering potential insights for optimizing applications. Particularly noteworthy is the unique reduction in silica particle retention on glass bead surfaces as salinity increases, especially in the presence of magnesium sulfate. A concentration of 5000 ppm magnesium sulfate induces a log-jamming mechanism, resulting in an amplified final-to-intermediate permeability ratio. Experimental outcomes align with observations from scanning electron microscopy, improving understanding of porous media retention mechanisms. This study contributes to a deeper understanding of interactions between nanoparticles and porous media, paving the way for enhanced application strategies.

A review on application of nanoparticles for EOR purposes: history and current challenges

Applications of nanotechnology in several fields of petroleum industry, e.g., refinery, drilling and enhanced oil recovery (EOR), have attracted a lot of attention, recently. This research investigates the applications of nanoparticles in EOR process. The potential of various nanoparticles, in hybrid and bare forms for altering the state of wettability, reducing the interfacial tension (IFT), changing the viscosity and activation of other EOR mechanisms are studied based on recent findings. Focusing on EOR, hybrid applications of nanoparticles with surfactants, polymers, low-salinity phases and foams are discussed and their synergistic effects are evaluated. Also, activated EOR mechanisms are defined and specified. Since the stabilization of nanofluids in harsh conditions of reservoir is vital for EOR applications, different methods for stabilizing nanofluids through EOR procedures are reviewed. Besides, a discussion on different functional groups of NPs is represented. Later, an economic model for evaluation of EOR process is examined and "Hotelling" method as an appropriate model for investigation of economic aspects of EOR process is introduced in detail. The findings of this study can lead to better understanding of fundamental basis about efficiency of nanoparticles in EOR process, activated EOR mechanisms during application of nanoparticles, selection of appropriate nanoparticles, the methods of stabilizing and economic evaluation for EOR process with respect to costs and outcomes.

A critical review of the development and demulsification processes applied for oil recovery from oil in water emulsions

The formation of stable emulsions is a fundamental problem in oil industry that can result in a sequence of environmental and operational problems. Chemical demulsification is extensively applied for the recovery of oil from water as well as water from oil. This review introduces different chemical demulsifiers applied for the demulsification and recovery of oil from oil in water (O/W) emulsions. Main types of surfactants (anionic, cationic, nonionics and amphoteric) involved in the formation of emulsions and enhances their stability were discussed. Promising demulsifiers such as nanoparticle (NP), hyperbranched polymers, and ionic liquids (IL), which achieved high oil recovery rate, parameters influencing demulsification efficiency and demulsification mechanisms were explored. Lastly, improvements, challenges, and new changes being made to chemical demulsifiers were underlined. Functionalized magnetic nanoparticles and hyperbranched polymers were very effective in recovering oil from O/W emulsions with an efficiency >95%. Polymers with highly hydrophilic content and high molecular weight can achieve excellent oil recovery rates due to higher interfacial activity, higher dispersion, and presence of specific functional groups. Although ionic liquids could achieve oil recovery up to 90%, high cost limits their applications. NPs showed excellent oil recovery behavior at low concentrations and ambient temperature. Demulsification efficiency of NPs can be enhanced by functionalize with other components (e.g., polymers and surfactants), while service life can be extend by silica coating. Future challenges include scaling up the use of NPs in oil recovery process and highlighting contrasts between lab-scale and field-scale applications.

Investigation of SiO2 Nanoparticle Retention in Flow Channels, Its Remediation Using Surfactants and Relevance of Artificial Intelligence in the Future

In this study, the effect of these variables on commercial silica NP retention was presented in a fabricated flow model considering only the physical adsorption aspects of silica NP retention. From our observations, it was established that while silica NP concentration, flow rate and salt are key variables in influencing silica NP agglomeration and retention, the effect of temperature was highly subdued. The effect of salt-induced agglomeration was particularly severe at moderate salinity (≈4 wt% NaCl). To mitigate the effect of salt-induced agglomeration, a commonly used anionic surfactant, sodium dodecyl sulfate (SDS) was added to the solution and the silica NP retention was tabulated. An amount of 0.3 wt% SDS was found to negate salt-induced agglomeration significantly, paving the way for use of silica NP solutions, even in the presence of saline conditions. A section on the prospective use of artificial intelligence for this purpose has been included. This study is useful for understanding NP retention behaviour, especially in the presence of salinity and its mitigation using surfactants, in flow applications.

Formation Damage Induced by Water-Based Alumina Nanofluids during Enhanced Oil Recovery: Influence of Postflush Salinity

Injecting nanofluids (NFs) has been proven to be a potential method to enhance oil recovery. Stranded oil is produced by wettability alteration where nanoparticles form a wedge film on pore wall surfaces, which is thought to shrink the pore space of the reservoir. Furthermore, ensuring the stability of the injected NF during the application is a major challenge. A low permeability reservoir and salinity of water make the response of NF injection to the formation damage more difficult. This article, therefore, studied the formation damage induced by the injection of alumina nanofluids (Al-NFs) in a relatively low permeability (7.1 mD) sandstone core. The salinity of the postflush water was also considered to mitigate the destructive impact. Al-NF was formulated by dispersing alumina nanoparticles (Al-NPs) in an aqueous solution of sodium dodecylbenzene sulfonate (SDBS) at its critical micelle concentration (CMC, 0.1 wt %). The formation damage, inherent to Al-NF injection, was evaluated by core-flooding tests. The assays consisted of the injection of 1 PV Al-NF (0.05 wt %) at the trail of which postflush at different salinities was flooded. The study found that the salinity of the postflush has an effect on the formation damage and oil recovery factor (RF). A chase water with a salinity concentration of 3 wt % sodium chloride (NaCl) produced an RF of 8.7% compared to a base case of water-flooding with a pressure drop of up to 13 MPa across the core (70 mm in length). These results pertained to the deposition of Al-NPs at the injection end. However, lowering the postflush salinity to 1 wt % NaCl mitigated the formation damage as evidenced by the decrease in pressure (35%) and an increase in RF to 17.2%.

Investigation of the effect of particle stability on the transport properties and thermal behavior of ethylene glycol-water/[Formula: see text] binary nanofluids

Nanofluids (Nfs) are considered as an effective working media in different thermal processes. Over the years, much attention has been paid to the problem of nanoparticle stability in base fluids in an unconfined area of research, especially in the field of thermal applications. There is still concern about the stability of nanoparticles and their effects on the transport properties and thermal performance in thermal systems. In the present paper, the transport properties and thermal behavior of ethylene glycol-water/[Formula: see text] binary Nfs are investigated in two sections, considering the effect of particle stability and size growth. The first section covering the experimental work, which includes the preparation and characterization of the Nfs where different percentages of base fluids at different pH values are used for this purpose. The characterization of the Nfs explains the effect of the zeta potential on the particle size distribution and the hydrodynamic diameter of suspended particles. The second section involves the theoretical study, where the transport properties and thermal behavior of the Nfs are estimated taking into consideration the effect of the particle stability and size growth. It is found that the binary Nfs that contain different types of base fluids show different stability behavior at different pH values at the same particle concentration. Ethylene glycol-water/[Formula: see text] binary Nfs at pH = 9 contain a low hydrodynamic diameter of suspended particles, and Nfs have good stability behavior. On the other hand, the Nfs at pH = 2 contain the maximum size of the particle hydrodynamic diameter. The Nfs that include 25% water + 75% ethylene glycol show a better stability behavior in comparison with other types of Nfs that included 75% water + 25% ethylene glycol. Particle size growth shows a significant effect on the transport properties (thermal conductivity and viscosity) as well as the particle-fluid interaction Nusselt number, Biot number, and convection heat transfer coefficient.