Review articleA comprehensive review on interaction of nanoparticles with low salinity water and surfactant for enhanced oil recovery in sandstone and carbonate reservoirs
Introduction
Due to the size of Nanoparticles (NPs), they exhibit special physical and chemical properties [1]. The NPs size varies in the range of 1–100 nm, which enhances their application in numerous professional fields. They have gained wide acceptance in different fields of science and engineering like pharmacy, medicines, ceramics, and metallurgy. The application of NPs to hydrocarbon reservoir formations has increased because of their mechanical and thermal stability properties [2], [3].
The advancement in technology has made the manufacturing of NPs to be easy and cost-effective [4]. This increases the application of NPs to the oil reservoirs for enhanced oil recovery (EOR) [5]. Several studies have shown that a dispersed solution of NPs is efficient to alter the wettability of the rocks towards water-wet [6], [7], [8], [9] and reduce the interfacial tension (IFT) [2], [10]. However, NPs become more popular in the petroleum field as a result of their capacity to prevent fines migration in the reservoir during low salinity water (LSW) injection [11], [12], [13], [14], [15], [16], [17], [18]. Currently, NPs are being combined with LSW or chemicals used in EOR such as surfactant and alkaline to alter the rheological properties of the fluid system like viscosity, control and reduce the surfactant adsorption on the pore walls of the reservoir and the fines migration, and enhance oil recovery.
During the past three decades, surfactant flooding has been implemented for tertiary recovery of oil in the depleted reservoirs. Surfactants reduce the IFT between brine and oil; thus, enhance recovery and lower the residual oil saturation [19], [20]. However, the surfactants are significantly absorbed by the porous media, which affects their capability to reduce the IFT [21]. Several studies have also revealed that there are optimum water salinity and optimum temperature for effective performance of surfactants. The optimum water salinity for effective performance of surfactants is lower than the reservoir brine salinity [22], [23], [24]. This impacts the effectiveness of surfactants for EOR at the field scale.
In order to improve the effectiveness of surfactants for tertiary oil recovery, various studies were conducted to show that the adsorption of surfactants on the walls of the pores is reduced by addition of NPs to surfactants [25], [26], [27], [28]. Zargartalebi et al. [10] observed that the adsorption of surfactants and the IFT between brine and oil can be drastically reduced with addition of NPs at a concentration below the critical micelle concentration (CMC) of the surfactants.
LSW injection into the reservoir formations has been a subject of discussion within the past two decades. The laboratory and the field implementations of the LSW injection into sandstone and carbonate reservoirs have been reported to be successful [29], [30], [31], [32], [33]. Also, different theories and hypotheses have been proposed as the drive mechanisms for tertiary recovery of oil during LSW injection. Some of the popular proposed hypotheses are the reduction of the IFT, the multi-ion exchange, the electrical double layer (EDL) effect, the salt-in effect, and the osmotic pressure [34], [35]. Fines migration has been argued to be vital in the recovery of oil especially in sandstone formations [32]. However, the results of some conducted experiments are in contradiction with the theory that fines migration contributes to more oil recovery during LSW injection [36], [37], [38], [39], [40]. Fines migration occurs due to a decrease in the brine salinity and an increase in the pH. Despite the arguments on the mechanisms used by LSW to improve oil recovery, there is still a consensus that LSW flooding alters the wettability of the rocks towards water-wet [38], [41], [42], [43].
NPs are currently being used in the treatment of fines migration during LSW injection [12], [15], [18], [44], [45]. However, the selection of the appropriate NPs to reduce fines migration in the reservoir is essential to the success of LSW injection. The desired NPs prevent the fines from damaging the formation by plugging the pore throats. Several approaches for the treatment of fines migration by NPs during LSW injection were proposed in order to assess the efficiency of the NPs [38], [41], [42], [43], [44].
Also, combination of LSW with surfactant injection has been applied to both carbonate [46], [47] and sandstone [48] formations. The injection of surfactant improves the oil recovery from the reservoirs by reducing the IFT between oil and water. The combination of LSW with surfactant injection improves oil recovery by altering the wettability of the rock and reducing the IFT of the fluid system [46], [47], [48].
Although the injection of NPs in combination with LSW or chemicals (such as surfactant) has been reported to be successful for oil recovery from different reservoir formations, there is no consensus on the most suitable NPs for a particular reservoir and the best scenario to apply NPs injection. Fig. 1 explains the different combinations of LSW, surfactant, and NPs that enhance the oil recovery from different reservoir formations. The combination of two or three solutions of LSW, surfactant, and NPs improves the performance of the fluid system. However, the best combination and the most effective injection pattern for the combination of LSW, surfactant, and NPs for EOR are still vague. Understanding the mechanisms behind the interactions at the fluid-fluid and the fluid-solid interfaces is a guide for proper designing of an EOR method.
This work comprehensively reviews the mechanisms underlying the application of NPs in combination with LSW or chemicals like surfactant to the oil reservoirs. The review is divided into different parts in order to explain the mechanisms behind all the possible combinations of LSW, surfactant, and NPs used in the EOR techniques.
First, the stability of NPs in low and high salinity water is discussed to understand the behavior of the interaction between NPs and salt particles. Several techniques have been devised to determine the stability of NPs in solution. However, this work tries to relate the effects of the concentration of ions in solution and the concentration of NPs on the stability of NPs in solution. The significance of the zeta potential for determination of the NPs efficiency in reduction of fines migration is discussed. The variations in the contact angle and the oil recovery factor when a solution of NPs is injected into the reservoir is also reviewed using the results of the experiments reported by several studies in literature.
Then, the interaction forces that play critical roles in the recovery of oil when NPs is injected along with surfactant into the reservoir is discussed. Several results from existing experimental studies have shown that both the surface charge of selected NPs and the type of surfactant affect the IFT. The mechanisms responsible for the variation in the IFT are discussed.
Finally, the contributing mechanisms when LSW is injected along with surfactant to modify the wettability of the rock and reduce the oil-water IFT are reviewed. The basic screening criteria for the injection of NPs with LSW or surfactant into the reservoirs is thoroughly discussed and highlighted in this study.
This article is organized as follows. First, the interactions of NPs with deionized water and low and high salinity water are reviewed. Later, the interaction of NPs with surfactant is studied. Then, the interaction of LSW with surfactant is discussed. Finally, the summary and conclusions are presented.
Section snippets
NPs dispersed in deionized water and low and high salinity water
The Derjaguin-Landau-Verwey-Overbeek (DLVO) and the non-DLVO theories play important roles in the stability of NPs [49]. The DLVO theory states that the balance between the attractive forces (dispersion forces) and the electrostatic repulsive forces enhances the colloidal stability. An energy barrier created by the repulsive forces, which prevent the approaching of two particles to each other, results in a stable colloidal solution. Meanwhile, the attractive forces bring the particles together
NPs and surfactants
Surfactants are combined with NPs when an experiment is conducted in the laboratory for EOR [84]. However, the main objective of adding surfactants to NPs is to ensure the stability of NPs, which are unstable at a high concentration of salt solutions [87]. Recently, several studies have investigated the behavior of the adsorption of surfactant-NPs solutions in the porous media and the variation in IFT [76]. The mechanisms involved in the stability of NPs dispersed in a solution of high salinity
Low salinity water and surfactant
It has been shown that salinity is an important factor in the phase behavior of surfactant-oil-water micro-emulsion [35], [112], [113]. An optimum salinity of the solution is important for effective oil recovery. Teklu et al. [114] explained that several mechanisms account for the effective oil recovery during the injection of LSW in combination with the surfactant. Also, the minerals in the reservoir rock and the type of reservoir formation play important roles in the recovery mechanisms [115]
Summary and conclusions
The mechanisms involved during oil recovery from sandstone and carbonate reservoirs using combination of LSW, surfactant, and NPs are more complicated for EOR. Some of these mechanisms are the multi-ion exchange, the disjoining pressure, the electrophoresis, the adsorption, the diffusion, the fines migration, the osmotic pressure, and the EDL effects. Several factors which contribute to the mechanisms are listed as follows:
- •
The effective charges of the dispersed solution of NPs,
- •
The effective
Acknowledgment
The financial support from the Department of Petroleum Engineering in the College of Engineering and Applied Science at the University of Wyoming is gratefully appreciated.
References (118)
- et al.
A review on the application of nanofluids in vehicle engine cooling system
Int Commun Heat Mass Transfer
(2015) - et al.
Experimental study and mathematical model of nanoparticle transport in porous media
Powder Technol
(2009) - et al.
Stability and flooding analysis of nanosilica/NaCl/HPAM/SDS solution for enhanced heavy oil recovery
J Petrol Sci Eng
(2018) - et al.
Rate enhancement in unconventional gas reservoirs by wettability alteration
J Nat Gas Sci Eng
(2015) - et al.
Enhancement of surfactant flooding performance by the use of silica nanoparticles
Fuel
(2015) - et al.
Nanoparticles-assisted surface charge modification of the porous medium to treat colloidal particles migration induced by low salinity water flooding
Colloids Surf, A
(2013) - et al.
Application of nanofluid to control fines migration to improve the performance of low salinity water flooding and alkaline flooding
J Petrol Sci Eng
(2014) - et al.
Using nanofluids to control fines migration for oil recovery: nanofluids co-injection or nanofluids pre-flush?-A comprehensive answer
Fuel
(2018) - et al.
Adsorption of nonionic surfactants in sandstones
Colloids Surf, A
(2007) - et al.
Prediction of optimum salinity and solubilization ratio for microemulsion phase behavior with live crude at reservoir pressure
Fluid Phase Equilib
(2011)