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Due to their large surface-area-to-volume ratio and enhanced chemical reactivity, nanoparticles have attracted increasing interest among researchers in the upstream petroleum industry for enhanced oil recovery (EOR) applications which target the recovery of oil left behind by primary and secondary recoveries, by pressure depletion and waterflooding, respectively. In EOR applications, fluids not originally present in the reservoir, such as polymer, surfactant, carbon dioxide or steam, are injected into the reservoir to either increase the sweep efficiency or to mobilize remaining oil so as to reduce the residual oil saturation. In these applications, EOR agents are used to either reduce the mobility of the injected fluid relative to that of oil or to increase the ratio of viscous to interfacial forces, that is, capillary number. In this chapter, we begin with a discussion of the potential use of nanoparticles in the upstream oil industry. This will be followed by a discussion of the unique physics and chemistry of nanoparticles. Then a detailed discussion on how nanoparticles can be used to improve the mobility control and capillary number will be given. It is shown that nanoparticles hold promise in either augmenting existing EOR agents (e.g., surfactant and polymer) or may even replace them to become EOR agents in their own right, although many technical challenges still exist and research is in its early stage. Next the HSE aspects of nanoparticles both in laboratory investigation and field applications will be discussed. We will then conclude with suggestions for future research. With ever increasing advances of nanoparticle technology in many fields of science and engineering, we believe translation of this knowledge to EOR will yield tangible fruits in the not too distant future. However, concerted multidisciplinary efforts will be needed to realize this goal.

Summary This paper presents rapid techniques of reservoir connectivity evaluation in a mature oilfield with multi-stacked sandstone reservoir and recovery process involving waterflooding, through production and injection data analyses. The issue in waterflooding here is to understand the influence of water injection to oil production in complex reservoir geology. Hence, accurate interpretation of reservoir connectivity is critical to have high flow efficiency. Prudent reservoir management often requires fast solution to evaluate and subsequently improve the efficiency of the on-going waterflooding performance and also for tertiary recovery purposes. Therefore, dynamic data analytics workflow applying Pearson’s Correlation Coefficient (PCC) interwell connectivity technique verified with Streamline is proposed. The PCC and Streamline techniques are able to provide rapid framing analysis of reservoir network incorporating production and injection data. Both techniques can identify areas with good or poor connectivity, injection efficiency and barrier/sealing fault in relatively short timeframe (weeks). Identification of these areas can provide important information for reservoir characterization, reservoir dynamic behaviour and reservoir management plans. It can be utilized as an efficient tool for management to decide strategic business decision to improve oil recovery through waterflood optimization and enhanced oil recovery processes.

Summary Government of the Republic of Indonesia urgently requires accelerating oil and gas production through EOR methods because oil and gas sector still plays an important role in Indonesian economy. This paper presented the observation of opportunities and challenges in developing first nanotechnology in enhanced oil recovery (Nano-EOR) in Indonesia. This study introduced a developed screening criterion and a methodology for evaluation Nano-EOR candidates in Indonesia. Prior to introducing Nano-EOR in Indonesia in the middle of 2017, the government have done with previous studies of top 34 EOR potential fields and concluded into: CO2 (18%), steam flooding (3%) and chemical flooding (79%). We presented the difficulties those techniques to be implemented currently in Indonesia. Hence, it is required a breakthrough solution of fast-tracking and cost-efficient method. As an emerging EOR technology, we investigated Nano-EOR as new fast-tracking and cost-efficient techniques. We observed several recognized benefits and challenges during developing Nano-EOR for fast-tracking implementation at low oil price situation. Based on our study, Nano-EOR is favourable for the most listed potential oilfield for EOR, proven technique and can tackle current constraints of traditional EOR techniques. The discussion about challenges from technical, fiscal, and regulation aspects are also included in this paper.

Chemical enhanced oil recovery is another strong growing technology with the potential of a step change innovation, which will help to secure future oil supply by turning resources into reserves. While Substantial amount of crude oil remains in the reservoir after primary and secondary production, conventional production methods give access to on average only one-third of original oil in place, the use of surfactants and polymers allows for recovery of up to another third of this oil. Chemical flooding is of increasing interest and importance due to high oil prices and the need to increase oil production. Research in nanotechnology in the petroleum industry is advancing rapidly and an enormous progress in the application of nanotechnology in this area is to be expected. Nanotechnology has the potential to profoundly change enhanced oil recovery and to improve mechanism of recovery. This paper, therefore, focuses on the reviews of the application of nano technology in chemical flooding process in oil recovery and reviews the application nano in the polymer and surfactant flooding on the interfacial tension process.

This study investigates the effect of a stabilizer on nanofluid stability and incremental oil during the enhanced oil recovery process. Untreated nanoparticles tend to form aggregates that are larger than the primary particle size when dispersed in liquid. This phenomenon affects the flooding process because the particles will be retained at the inlet injection point rather than be transported through a porous medium. A non-toxic (environmentally friendly) stabilizer, polyvinylpyrrolidone, is studied that successfully improves the stability of silica-based nanofluids at a particular time and temperature. In addition, it alters nanofluids properties such as the surface conductivity, pH, viscosity, and the particle size distribution that takes into account the nanofluids stability. During coreflooding as a tertiary process, improving the stability of nanofluids significantly affects the increase in oil recovery. These investigations will go beyond the nanofluids restriction at higher concentrations (e.g., 0.1 wt% or higher). Stability is observed as an important parameter in accomplishing successful nanofluids for enhanced oil recovery process.

This paper presents the investigation of using nanoscale polyacrylamide-based spheres (nanospheres) as a displacement fluid in enhanced oil recovery (EOR). Coreflood experiments were conducted to evaluate the impact of nanospheres and its concentration dispersed in model formation water on oil recovery during a tertiary oil recovery process. The coreflood results showed that nanospheres can enhance residual oil recovery in the sandstone rock samples and its concentration showed a significant impact into incremental oil. By evaluating the contact angle, it was observed that wettability alteration also might be involved in the possible oil displacement mechanism in this process together with fluid behavior and permeability to water that might divert injected fluid into unswept oil areas and enhance the residual oil recovery. These investigations promote nanospheres aqueous disperse solution as a potential displacement fluid in EOR.

Coreflood experiments were conducted to evaluate the impact of the initial rock wettability on oil recovery during a tertiary oil recovery process using hydrophilic silica-based nanofluids at reservoir temperatures. An adopted scale of reservoir wettabilities (water-, intermediate-, and oil-wet systems) is used for the core plugs, which were prepared by aging processes. The relationships among temperature, initial wettability, and an additional oil recovery nanofluid flooding process were investigated. The results showed that the initial wettability affects oil recovery performance and showed a greater effect at higher temperatures, as represented by the reservoir temperature. An extended postflush nanoflooding was performed to evaluate incremental oil recovery, and this cycle shows great potential for field applications. By evaluating the contact angle and interfacial tension, it was found that wettability alteration plays a more dominant role in the oil displacement mechanism via nano-EOR. These results...

Chemistry of the injected water has been investigated as an important parameter to improve/enhance oil recovery (IOR/EOR). Numerous extensive experiments have observed that water chemistry, such as ionic composition and salinity, can be modified for IOR/EOR purposes. However, the possible oil displacement mechanism remains debatable. Nanoparticle recently becomes more popular that have shown a great potential for IOR/EOR purposes in lab-scale, where in most experiments, water-based fluid were used as dispersed fluid. As yet, there has been no discussion in the literature on the study of water chemistry on enhanced oil recovery using silica-based nanoparticles. A broad range of laboratory studies involving rock, nanoparticles and fluid characterization; fluid–fluid and fluid-rock interactions; surface conductivity measurement; coreflood experiment; injection strategy formulation; filtration mechanism and contact angle measurement are conducted to investigate the impact of water chemistry, such as water salinity and ionic composition including hardness cations, on the performance of silica-based nanoparticles in IOR/EOR process and reveal possible displacement mechanism. The experimental results demonstrated that water salinity and ionic composition significantly impacted oil recovery using hydrophilic silica-based nanoparticles and that the oil recovery increased with the salinity. The primary findings from this study are that the water salinity, the ionic composition and the injection strategy are important parameters to be considered in Nano-EOR. © The Author(s) 2015 Open Access This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.

Examining fluid behavior in the presence of nanoparticles is essential to understand the displacement mechanism when a nanoparticle is used as novel enhanced oil recovery (EOR) method. Recent investigations showed that nanoparticles have great potential for EOR in the lab-scale. Since its displacement mechanism is not yet clearly understood, studies about fluid-fluid and fluid-rock interactions will be essential as a way to unlock how its mechanism. Saline water is studied in the presence of hydrophilic silica nanoparticles at different conditions such as temperature, concentration, various salt ions and nanoparticle size and initial rock wettability. The fluid properties measurement involves density, viscosity, pH and surface conductivity. Crude oil from a field in the North Sea is employed to measure interfacial tension between oil-phase and aqueous phase (saline water and nanofluids) at different temperatures. Contact angle is also measured among quartz rock as solid phase and those fluid phases at different initial rock wettability. These compatibility tests is useful to have better understanding about displacement mechanism and boundary of using nanoparticles as EOR method (Nano EOR) before applying in the field-scale. The processes and observations are outlined and also further detailed in the paper as a part to unlock nanoparticles flooding as a future promising EOR method. Introduction Nanofluid is a new class of fluid engineered and a new interdisciplinary area of great importance where nanoscience, nanotechnology, and thermal engineering come across (Yu and Xie, 2011). It is defined as nanoparticle that has average size less than 100 nm, suspended in traditional heat transfer fluid such as water, oil or ethylene glycol (Das et al., 2008). Nanofluid consists of two-phase systems, solid and liquid (Yu and Xie, 2011) since nanoparticles (NPs), as solid phase, is commonly dispersed in liquid. Nanofluids have greatly attracted in wide range fields application in recent years. Yu and Xie (2011) highlighted the current application of nanofluids such as heat and mass transfer enhancement (Kim et al., 2006, 2007a, and 2007b; Ma et al., 2007, and 2009), friction reduction and magnetic sealing in mechanical application (Kim et al., 1999; Shen et al., 2008; Yu et al., 2008; Mitamura et al., 2008; Chen and Mao, 2010; Peng et al., 2010; and Vekas et al., 2010), and biomedical application (Zhang et al., 2007; Jalal et al., 2010; Jones et al., 2008; Liu et al., 2009; Mahapatra et al., 2008; Nakano, 2008; Singh and Liliard, 2009; and Gajjar et al., 2009). The potential of nanofluids for oil and gas industries application has been summarized by Kong and Ohadi (2010), as presented in Table 1. It can be also used for geochemical exploration (Wang et al., 1997). Another benefit of nanofluids in drilling and sand problem has been investigated by Chaaudhury (2003), Zitha (2005), and Evdokimov et al. (2006). In heavy oil application, it can upgrade the viscosity of heavy oil and bitumen as a catalyst (Ying and Sun, 1997; Scott et al., 2003; and Hendraningrat et al., 2014a). The NPs easily aggregated once they hydrated. It is because they have a large surface-to-volume ratio due to the small particle size. For instance, Fig. 1 shows hydrated silica when dispersed in base fluid such as water (has hydrogen element). The materials with high surface-to-volume ratios react at much faster rates because additional surfaces are available to react. Therefore they possess high surface energies. The NPs consequently create an aggregate form to minimize this surface energy.

The development of current technology has enabled manufacturer to create various types of nanoparticles for multi-purposes in various sectors including the oil and gas industry. The use of nanoparticles for enhanced oil recovery (EOR) has been studied in the past decade both in the lab- and pilot-scale projects. Most of the research observed that nanoparticles are very attractive for EOR purposes. However, most of those studies use ??of silica-based nanoparticles. The use of other types of nanoparticles should be investigated as alternative solution. In this study, two water-based metal-oxides nanoparticles: Al2O3 and TiO2, were employed. The primary size of both nanoparticles ranged of 40-60 nm. Nanofluids was prepared by dispersing 0.05 wt.% metal-oxides nanoparticles with synthetic saline water. Berea sandstones cores are used as porous media with average porosity and permeability of 15% and 60 mD respectively. Coreflood experiment was conducted by injecting metal-oxides nanofluids as tertiary process (Nano-EOR). Degassed crude oil with viscosity ranged 5–50 cP was also used. To investigate the effect of temperature and rock wettability to oil recovery, coreflood experiment has been performed on various temperature condition and initial cores wettability: water-wet, intermediate-wet and oil-wet. The detailed process and results are outlined in the paper to reveal the possible application of metal-oxides nanoparticles as alternative EOR method.

This paper presents the investigation of aluminium oxides (Al2O3) nanoparticles for enhanced oil recovery (EOR) purposes. As comparison, a silica dioxides (SiO2) nanoparticle is also included in this study. The single primary size of both nanoparticles is 16-17 nm. Untreated nanoparticles tend to aggregate from primary particle size and cause bigger size when dispersed such as in formation water. In this paper, a dispersant is used and studied to avoid early nanoparticle aggregation. It is observed that dispersant will alter fluid behavior and successfully provide better stability at particular concentration. Based on coreflood experiment, Al2O3 nanofluid was successfully increased oil recovery with higher displacement efficiency 13% than SiO2 (5%) as tertiary process. Contact angle measurement was conducted to understand the oil displacement mechanism nanoparticles. Once Al2O3 nanofluid with dispersant introduced to the brine, it reduces contact angle from 54o to 21o which means the quartz plate has altered to be more strongly water-wet. However, SiO2 nanofluid altered only to be 31o. This measurement is consistent with additional oil recovery result where Al2O3 nanofluid has higher additional oil recovery than SiO2 as tertiary recovery. These investigations are essential to unlock the possibility of using aluminium oxides for EOR process.

Nanoparticles have become an attractive agent for improved and enhanced oil recovery (IOR & EOR) at laboratory scale recently. Most researchers have observed promising result and increased ultimate oil recovery by injecting nanofluids in laboratory experiments. In previous study, we observed that interfacial tensions (IFT) decreased when hydrophilic nanoparticles were introduced to brine. The IFT decreases as nanofluids concentration increase and this indicates a potential for EOR. We have also investigated nanofluid flow in glass micromodel and high permeability Berea sandstone (ss) cores, and we observed that the higher concentration of nanofluids; the more impairment of porosity and permeability. Since low permeability oil reservoirs have still huge volume of oil reserves, this study aims to reveal nanofluids possibility for EOR in low-medium permeability reservoir rocks and investigate its suitable concentration. In this paper, laboratory coreflood experiments were performed in water-wet Berea ss core plugs with permeability in range 9- 35 mD using different concentrations of nanofluids. Three nanofluids concentrations were synthesized with synthetic brine; 0.01, 0.05 and 0.1 wt.%. To investigate disjoining pressure as displacement mechanism due to nanoparticles, contact angle between crude oil from a field in the North Sea and brine/nanofluids have been measured. Increasing hydrophilic nanoparticles will decrease contact angle of aqueous phase and increase water-wetness. Despite increasing nanofluid concentration shows decreasing IFT and altering wettability, our results indicate that additional recovery is not guaranteed. The processes and results are outlined and also further detailed in the paper to reveal the possible application of nanofluid EOR in lower-medium permeability oil reservoir.

Abstract In last decade, a number of papers about nanoparticles studies have been published related to its benefit for oil and gas industries. Some of them discussed about the potential of nanoparticles for enhanced oil recovery (EOR) in the laboratory scale. One of possible EOR mechanisms of nanofluids has been described as disjoining pressure gradient (Chengara, 2004, and Wasan, 2011). The benefit of using silica nanoparticles was explained by Miranda (2012). Hence, the present study objective is to investigate the potential of hydrophilic silica nanoparticles suspension as enhanced oil recovery agent and find out the main mechanisms of nanofluids for EOR. In this study, hydrophilic nanoparticles with average particle size of 7 nm were used in both visualization glass micromodel flooding experiments and core flooding experiments. A water-wet transparent glass micromodel and Berea sandstone cores with 300–400 mD permeability were used as porous medium. Synthetic brine was used as disperse fluid for nanoparticles. In order to investigate the recovery mechanisms of nanofluids, interfacial tension (IFT) and contact angle between different concentration nanofluids and crude oil have been measured by using spinning drop and pendent drop methods. The experimental results indicate that the nanofluids can reduce the IFT between water phase and oil phase and make the solid surface more water wet. In the visualization glass micromodel flooding experiments, it was observed that nanofluids can release oil drops trapped by capillary pressure, while the high concentration nanofluids stabilized oil-water emulsion. For the core flooding experiments, nanofluids can increase recovery about 4–5% compared to brine flooding. These results indicate that these nanoparticles are potential EOR agents. The future expectation is that nanoparticles could mobilize more oil in the pore network at field scale to improve oil recovery.

Chemical flooding is of increasing interest and importance due to high oil prices and the need to increase oil production. Research in nanotechnology in the petroleum industry is advancing rapidly, and an enormous progress in the application of nanotechnology in this area is to be expected. The nanotechnology has been widely used in several other industries, and the interest in the oil industry is increasing. Nanotechnology has the potential to profoundly change enhanced oil recovery and to improve mechanism of recovery, and it is chosen as an alternative method to unlock the remaining oil resources and applied as a new enhanced oil recovery method in last decade. This paper therefore focuses on the reviews of the application of nanotechnology in chemical flooding process in oil recovery and reviews the applications of nanomaterials for improving oil recovery that have been proposed to explain oil displacement by polymer flooding within oil reservoirs, and also this paper highlights the research advances of polymer in oil recovery. Nanochemical flooding is an immature method from an application point of view.

This paper presents systematic studies of hydrophilic metal oxide nanoparticles (NPs) dispersed in brine intended to reveal their potential to enhance oil recovery (EOR) in various rock wettability systems. The stability in suspension (nanofluid) of the NPs has been identified as a key factor related to their use as an EOR agent. Experimental techniques have been developed for nanofluid stability using three coupled methods: direct visual observation, surface conductivity and particle size measurements. The use of a dispersant has been investigated and has been shown to successfully improve metal oxide nanofluid stability as a function of its concentration. The dispersant alters the nanofluid properties, i.e. surface conductivity, pH and particle size distribution. A two-phase coreflood experiment was conducted by injecting the stable nanofluids as a tertiary process (nano-EOR) through core plugs with various wettabilities ranging from water-wet to oil-wet. The combination of metal oxide nanofluid and dispersant improved the oil recovery to a greater extent than either silica-based nanofluid or dispersant alone in all wettability systems. The contact angle, interfacial tension (IFT) and effluent were also measured. It was observed that metal oxide-based nanofluids altered the quartz plates to become more water-wet, and the results are consistent with those of the coreflood experiment. The particle adsorption during the transport process was identified from effluent analysis. The presence of NPs and dispersant reduced the IFT, but its reduction is sufficient to yield significant additional oil recovery. Hence, wettability alteration plays a dominant role in the oil displacement mechanism using nano-EOR. © The Author(s) 2014 Open Access This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.

Align with current dynamic technology development, waterflooding techniques have been improved and optimized to have better oil recovery performance. In addition the latest worldwide industries innovation trends are miniaturization and nanotechnology materials such as nanoparticles. Hence one of the ideas is using nanoparticles to assist waterflood performance. However it is crucial to have a clear depiction of some parameters that may influences displacement process. The focus of this study is to investigate the effects of some parameters influencing oil recovery process due to nanoparticles such as particle size, rock permeability, initial rock wettability, injection rate and temperature. This study is part of our ongoing research in developing nanofluids for future or alternative enhanced oil recovery (Nano-EOR) method. Three different sizes of hydrophilic silica nanoparticles with single particle diameter range from 7 to 40 nm were employed and have been characterized under scanning electron microscope (SEM). Nanofluids were synthesized using 0.05 wt.% nanoparticles that dispersed into synthetic brine (NaCl 3 wt.% ~ 30,000 ppm). The contact angle variation due to nanoparticles size was also measured at room condition. Coreflood experiment has been conducted using 26 Berea sandstone cores to evaluate the effect of those parameters above on oil recovery due to Nano-EOR. The cores permeability was in range from 5 to 450 mD. To study the effect of initial rock wettability on oil recovery due to Nano-EOR, original core wettability has been changed with aging process from water-wet to intermediate and oil-wet respectively. Temperature was also studied in range 25-80 °C to fulfill the possibility of applying Nano-EOR at reservoir temperature. The coreflood testing was repeated for each case to have consistency result. The processes and results are outlined and also further detailed in the paper to bring knowledge about nanoparticles flooding as a future promising EOR method.