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Optimized formulation of thermoresponsive nanoemulsion-based gel for enhanced oil recovery (EOR) application

Optimized formulation of thermoresponsive nanoemulsion-based gel for enhanced oil recovery (EOR)... A thermoresponsive system of a nanoemulsion-based gel with favorable characteristics to enhanced oil recovery (EOR) application is presented. A full factorial design study with different formulations of thermosensitive nanoemulsion-based gels was performed to assess the influence of the oil chain length, concentration of polyethylene glycol (PEG 400) and con- centration of oil on the rheological behavior of the system. A formulation with low viscosity at room temperature and high viscosity at the temperature of the oil extraction well was presented. Hexane (6-carbon chain), capric acid (10-carbon chain) and isopropyl myristate (17-carbon chain) were used in concentrations of 5%, 10%, 15% and 20% wt%, also varying the concentration of PEG 400 in 0%, 3%, 6% and 9% wt%. The thermosensitive polymer used was a mixture of Plur onic F-127 and Pluronic F-68 6:1 wt% at 4.7% concentration. The surfactants used were Tween 80 and Span 80 (HLB = 13) at 20%. The formulation containing 20% isopropyl myristate (IPM) without the addition of PEG 400 showed a better response, with an increase in viscosity of more than 38 times in relation to its viscosity at 25 °C, and the maximum viscosity was reached at 53 °C. This is a promising formulation for EOR technology. Keywords Thermoresponsive gel · Nanoemulsion · Enhanced oil recovery · Design of experiment Introduction Enhanced oil recovery (EOR) is a technique that consists in the application of methods that improve the recovery process and increases the amount of crude oil extracted from an oil field. Among the existing methods are chemical, thermal, * Natália Cristina Dalibera nataliacd@ipt.br injection of miscible gas/solvent, ultrasonic vibration, and flooding with microorganisms. The flooding of oil extrac- Maria Helena Ambrosio Zanin mhzanin@ipt.br tion wells with polymers represents one of the chemical processes of EOR. In this process, water-soluble polymers Kleber Lanigra Guimaraes kleberlg@ipt.br are used to modify rheological properties of displacement fluid, improving the rate of oil mobility and, therefore, the Leonardo Alencar de Oliveira leonardo.alencar@petrobras.com.br efficiency of the process [5 ]. Thermosensitive polymers are interesting for EOR appli- Adriano Marim de Oliveira amarim@ipt.br cation due to the characteristics of their structure. They consist of a hydrophilic main chain with hydrophobic side Institute for Technological Research (IPT)-Laboratory chains and are considered alternative viscosifying agents of Chemical Processes and Particle Technology, Group for high temperature and high salinity conditions [11, 12]. for Bionanomanufacturing (BIONANO), Av. Prof. Almeida Prado 532-Butantã, São Paulo 05508-901, Brazil In these polymers, thermosensitive monomers with low critical solubility temperature (LCST) are incorporated into Leopoldo Américo Miguez de Mello Research Center (CENPES), Universitária da Universidade Federal Do the main polymer chain. Above the LCST, the formation Rio de Janeiro, DE, Av. Horácio Macedo, 651-Cidade, of physical networks occurs as these monomers rearrange Rio de Janeiro 21941-915, Brazil Vol.:(0123456789) 1 3 156 Applied Petrochemical Research (2021) 11:155–163 themselves in hydrophobic micro domains, increasing the segments become more hydrophobic. They observed that viscosity of the polymeric solution [12]. The combination there is no transition from liquid to gel in the absence of oil, of thermosensitive polymers with surfactants in micro and which suggests that the adsorption of Pluronic copolymers nanoemulsions has been explored mainly in pharmaceuti- at the droplets interface is a fundamental step for the ther- cal applications [8, 22, 27, 28], but has great potential for mosresponsive behavior of the system [8]. application in EOR, especially due to the ability to achieve Previous experiments demonstrated that the displacement ultra-low values of water–oil surface tension [18]. of micro and nanoemulsions in the porous medium improve Triblock copolymers of poly(oxyethylene) and oil recovery [4, 6, 9, 16, 17, 29]. There has been numerous poly(oxypropylene) units (PEO–PPO–PEO), commercially studies that investigate the use of polymers in EOR [3, 5, available as Plur onics , are non-ionic, water-soluble mate- 10, 15, 21, 25, 26], however, a formulation of a flooding rials that undergo thermal gelation in aqueous solution at fluid with physical–chemical and rheological characteris- appropriate concentrations [13, 24]. These polymers exhibit tics that are optimal for EOR application (a fluid with low surface active properties, amphiphilic character and are surface tension able to deliver high increase in viscosity at known to form gels in response to temperature increase [13]. temperatures around 60 °C with liquid-like behavior at room Variations in the number of PEO and PPO units provide temperature) is yet to be presented. a wide range of polyols with different physical and chemi- The aim of the present work is to develop an optimized cal properties [24]. Pluronic F-127 has a PEO–PPO ratio formulation of a thermoresponsive nanoemulsion-based gel of 7:3 with a molecular weight of 12,500 and is more read- suitable for EOR application. The studies were carried out ily soluble in cold than in hot water [14]. The aggregation by tuning the concentrations of cossurfactant polyethylene behavior of block copolymers is complex in comparison to glycol 400 (PEG 400) and oil, and the chain length of the low-molecular-weight non-ionic surfactants, which occurs oil in the presence of a mixture of known thermoresponsive over a range of concentrations rather than at a unique criti- triblock copolymers. This study was based on a formulation cal micelle concentration (CMC). As a result, CMC values proposed by Hashemnejad et al. which was developed aim- reported can be substantially different depending on the ing to achieve properties suited for cosmetics and pharma- experimental conditions and technique used [2]. ceutical applications [8]. Schmolka et al. studied a system composed of the non- ionic polymeric surfactant Plur onic F-127 with the addition of salts and drugs to form a thermosensitive gel suitable for Experimental application in burns [22]. Zhao et al. prepared microemul- sion-based thermosensitive gels (MBGs) also using the poly- Materials mer Pluronic F-127, in combination with a microemulsion system composed of isopropyl myristate (IPM), water and Cosurfactant polyethylene glycol 400 (PEG 400), oils n-hex- surfactants Span 20 and Tween 20 [28]. They observed that ane and isopropyl myristate (IPM) and surfactant Tween 80 the viscosity of the gels increased, and the gelation tempera- were all analytical grade and were purchased from Synth ture decreased with increasing in polymer concentration. In (Brazil). Capric acid 99.5%, Span 80 (analytical grade) and another study conducted by Zhao et al. MBGs were prepared ® ® block polymers Plur onic F-127 and Plur onic F-68 were using Pluronic F-123 in the presence of IPM, Span 20, purchased from Sigma-Aldrich (Germany). Tween 20 and water [27]. The results show that the micro- structures of the microemulsion drops are maintained in the MBGs. Methods Hashemnejad et  al. synthesized a nanoemulsion-base thermoresponsive gel through a low-energy cost process, Sample preparation with application in cosmetics and pharmaceuticals [8]. The oil used was isopropyl myristate (IPM), along with sur- The thermoresponsive nanoemulsion-based gels were made factants Tween 80 and Span 80 (HLB = 13), a mixture of Pluronic F-127 and F-68 in low concentrations (4.7%) and through a low-energy process described elsewhere [8]. Con- cisely, the preparation of the samples consists in mixing a cosurfactant polyethylene glycol (PEG 400). They stated that the rearrangement of Plur onic molecules as the temperature determined amount of oil and a determined amount of PEG 400 with surfactants Tween 80 and Span 80 (HLB = 13) at rises can be affected by hydrophobic regions, including oil droplets in the nanoemulsion and the central hydrophobic 20% wt% at room temperature, then adding ultrapure water dropwise into the mixture under stirring. Last, a mixture of structure of the micelles of surfactants Tween 80 and Span ® ® ® 80 [8]. As the temperature rises, Pluronic ’s PPO segments Pluronic F-127 and Pluronic F-68 (6:1 wt%), previously are adsorbed at the interface of the oil droplets, as these 1 3 Applied Petrochemical Research (2021) 11:155–163 157 solubilized in cold ultrapure water at 23.3% wt%, is added occurs at room temperature, however all samples showed an into the mixture under stirring at 4.7% wt%. increase in viscosity somewhere between 5 °C and 70 °C. The peak temperature should ideally be close to that of Experimental factorial design the oil wells (approximately 60 °C) to guarantee that the fluid would be at its maximum viscosity during extraction A full factorial experiment was designed and analyzed using work, increasing the oil displacement in the porous medium the software MiniTab 19.1.1. To verify the influence of the [7]. Samples that showed peak temperature between 50 °C factors on the rheological behavior of the system, the con- and 70 °C (samples 3, 4, 6, 7, 11, 13, 14, 15, 27, 28, 31, centration of PEG 400 (%PEG), the concentration oil (%Oil) 33, 34, 43, 44 and 47) have broadly different compositions. and oil chain length (CL) were evaluated. The concentration The difference in composition indicates that there is no clear of PEG 400 added to the formulation varied in 0%, 3%, 6% correlation between one factor studied and the peak tempera- and 9% (wt%) and the concentration of oil varied in 5%, ture response. It is likely that two or more factors and their 10%, 15% and 20% (wt%). The oils studied were n-hexane interactions are responsible for tuning the peak temperature (6-carbon chain), capric acid (10-carbon chain) and isopro- property of the system. pyl miristate (IPM) (17-carbon chain). The responses moni- The injection of chemical fluids to the oil wells seeks tored were viscosity of the system at 25 °C, temperature to increase miscibility between the injected fluid and the at which there was a peak in viscosity (peak temperature), oil, decrease the interfacial tension to increase wettability of increase in viscosity from room temperature and particle rock surface and increase viscosity of the injected fluid [7 ]. size. The experiments were carried out in randomized run The highest increase in viscosity of 3836.5% was obtained order to avoid bias. with sample 15, which has 20% IPM in its composition with no addition of PEG 400. IPM has low toxicity [28] and could Rheology and particle size be used as a component of a flooding fluid without signifi- cant environmental impact. The presence of IPM in concen- The rheology of the samples was analyzed using a Brook- trations above 15% in sample 15 and other samples which field R/S plus rotational rheometer equipped with a Searle- had high increase in viscosity (samples 4, 6 and 14) shows −1 type concentric cylinder geometry CC25, shear rate of 20  s that the presence and characteristics of the oil phase are criti- and temperature ramp from 5 °C to 70 °C. Particle size was cal in obtaining a thermoresponsive behavior of the system. analyzed by dynamic light scattering (DLS) on a Particulate The hypothesis is that there is synergistic effect occurring Systems NanoPlus equipment, after diluting the samples to between Pluronic copolymers and the nanoemulsion drop- 3.5% wt% with ultrapure water. lets [8]. The viscosity diagram of sample 15 is displayed in Online Resource 1. Surface tensiometry The viscosity at room temperature should be as low as possible to facilitate the pumping of the fluid into the wells. Surface tension of the optimized formulation was measured The lowest viscosities at 25 °C were obtained in samples at 25 °C using a DCAT 11 Dataphysics tensiometer. The with concentrations of oil lower than 10% (samples 1, method used was Wilhelmy plate with plate dimensions of 17, 33, 35, 42 and 43), however they did not show a high 10 mm × 19.9 mm × 0.2 mm (length × width × thickness). increase in viscosity nor did they have an adequate peak The surface tension measurements were done in triplicate. temperature. The low viscosity at room temperature with lower concentration of oil shows that the oil phase not only is linked to the gelling behavior of the system, but also has Results and discussion a direct influence on the viscosity at 25 °C, increasing the viscosity of the nanoemulsion before any temperature or A total of 48 experiments were performed in randomized shear trigger. order to determine the effect of the factors [concentration of Usually, a clear and stable nanoemulsion has its structures PEG 400 (%PEG), concentration of oil (%Oil) and oil chain (droplets of oil in water or water in oil interacting with the length (CL)] on four characteristic responses: viscosity of surfactants) in sizes up to 100 nm [7]. All samples formu- the system (η) at 25 °C, temperature at which the maxi- lated with capric acid (CL = 10) had a particle size bigger mum viscosity was reached (peak temperature), maximum than 100 nm, indicating that the chain length has a clear increase in viscosity and droplet size (particle size). Table 1 influence on particle size property. It also indicates that shows the experimental design matrix with factors and the capric acid could be considered a less suitable oil among results of the response variables studied. The increase in the oils studied to produce clear and stable nanoemulsions. viscosity of samples with peak temperature below 25 °C is Samples formulated with different CL, PEG concentration marked as 0% because in EOR the pumping process usually and oil concentration were able to produce nanoemulsions 1 3 158 Applied Petrochemical Research (2021) 11:155–163 Table 1 Experimental design matrix with factors and the results of the response variables studied Sample PEG concentra- Oil concentra- Chain length η at 25 °C (mPa.s) Peak tempera- Particle size (nm) Increase in η tion (%wt) tion (%wt) (carbons) ture (°C) from 25 °C 1 3 5 6 60.01 12.1 122.6 0.00% 2 0% 15% 10 6500.54 23.0 275.9 0.00% 3 6% 15% 17 2500.69 52.8 39.6 620.00% 4 3% 10% 17 560.04 57.5 40.4 1685.71% 5 9% 5% 10 1800.15 37.9 243.5 10.00% 6 3% 15% 17 750.72 56.3 38.5 2018.67% 7 9% 10% 6 340.88 63.0 121.7 76.47% 8 0% 10% 10 9940.40 22.4 283.8 0.00% 9 6% 15% 6 3390.62 43.4 119.2 112.39% 10 0% 20% 10 6760.86 10.7 275.8 0.00% 11 6% 20% 17 8230.40 55.1 47.4 234.14% 12 3% 10% 10 6100.72 20.9 308.0 4.92% 13 3% 20% 17 2340.10 52.2 62.3 988.89% 14 0% 15% 17 560.53 50.1 75.3 2917.86% 15 0% 20% 17 520.77 53.6 120.9 3836.54% 16 6% 5% 10 980.92 43.2 196.1 63.27% 17 0% 10% 6 85.09 15.7 148.3 0.00% 18 0% 5% 10 290.12 45.7 170.6 344.83% 19 6% 10% 10 10,300.89 23.8 177.6 0.00% 20 6% 15% 10 6170.55 22.2 233.0 0.00% 21 9% 15% 17 4590.65 47.4 38.9 226.80% 22 9% 20% 10 1460.38 15.4 335.9 0.00% 23 9% 5% 17 110.51 10.7 154.1 0.00% 24 3% 20% 6 9180.00 45.1 164.9 106.97% 25 9% 20% 6 12,250.32 40.2 149.4 31.43% 26 9% 20% 17 11,800.85 47.1 47.5 94.92% 27 0% 15% 6 300.01 68.0 138.8 250.00% 28 9% 10% 17 315.11 58.5 33.8 350.79% 29 3% 15% 10 7500.72 23.8 323.7 0.00% 30 6% 20% 10 5740.19 16.2 303.7 0.00% 31 3% 10% 6 590.03 55.4 139.1 806.78% 32 3% 5% 10 690.60 48.8 223.5 160.87% 33 0% 5% 6 80.61 70.6 114.5 275.00% 34 0% 10% 17 110.24 60.9 92.5 327.27% 35 0% 5% 17 60.81 20.0 123.7 0.00% 36 9% 15% 6 9900.42 44.3 44.9 66.67% 37 3% 15% 6 7190.30 48.1 133.7 171.21% 38 6% 5% 6 220.69 14.3 127.6 0.00% 39 0% 20% 6 620.62 40.6 182.8 448.39% 40 6% 20% 6 15,810.40 40.7 130.5 35.99% 41 9% 15% 10 5300.57 23.4 307.5 0.00% 42 6% 5% 17 60.00 15.0 136.6 0.00% 43 3% 5% 17 70.02 53.0 117.0 11.43% 44 6% 10% 6 640.99 55.1 97.0 681.25% 45 3% 20% 10 7950.33 13.8 354.2 0.00% 46 9% 10% 10 4800.01 30.6 303.0 6.25% 47 6% 10% 17 230.65 60.2 29.8 415.22% 48 9% 5% 6 140.62 6.5 124.3 0.00% 1 3 Applied Petrochemical Research (2021) 11:155–163 159 with particle size up to 100 nm, indicating that other factors the responses are significantly influenced by at least two fac- and their interactions are also influencing the response. tors or interaction of factors. The complexity of the system Analysis of variance (ANOVA) was performed to verify makes it hard to predict its behavior without a mathematical whether the influence of each component of the formulation model associated to each response. Statistical analysis also and their interactions are significant on the responses stud- makes it possible to propose an optimized formulation con- ied. The results of p-value and F value obtained for all the sidering how all the variables and their interactions influence factors and their interactions are shown in Table 2. the rheology of the system. P-value is the probability used to determine if the effect Table 3 shows the order of importance of statistically sig- or the interaction of effects in the model is statistically sig- nificant factors for each response based on the results from nificant. For a 95% confidence level, the p-value should be ANOVA in Table 2. less or equal to 0.05 for a factor to be considered statistically The oil chain length (CL) is the main influence factor on significant [23]. The degree of significance can be ranked three out of four responses studied and its interaction with based on F values. The greater the F value, the more signifi - %Oil also shows important effect on all four responses. The cant the factor is, if its p-value is less than 0.05. The results interaction between CL and %Oil and %Oil alone also have of p-values from ANOVA reported in Table 2 show that all significant influence on all responses studied. That again conr fi ms that the presence and properties of the oil phase are critical in defining the rheological behavior of the system. Table 2 Results of F values and p-values from ANOVA for each The concentration of cosurfactant PEG 400 and its inter- response, considering all factors and their binary interactions actions have the least significant influence on the responses in general. Hashemnejad et al. found that an increase in the Response Factor F value p-value concentration of PEG 400 lowers the gelation temperature %PEG 4.33 0.022 of their nanoemulsion-based system [8]. Prior studies of %Oil 18.51 0 Pluronic aqueous solutions also showed that the presence η at 25 °C CL 5.31 0.018 of short PEG chains lowers the critical micellization tem- %PEG*%Oil 3.28 0.021 perature [19, 20]. We were able to obtain a formulation with %PEG*CL 1.73 0.183 desired rheological behavior without addition of PEG 400 %Oil*CL 5.43 0.004 (sample 15). However, Table 2 and Table 3 show that %PEG %PEG 1.87 0.177 and %PEG interactions do have statistically signic fi ant inu fl - %Oil 14.03 0 ence on the responses, even if they are less significant than Peak temperature CL 30.22 0 the influence of other factors and interactions. The %PEG %PEG*%Oil 1.84 0.143 should, therefore, be considered when doing optimization %PEG*CL 3.25 0.03 calculations. The direction and magnitude of the influence %Oil*CL 21.45 0 of each factor can be verified through the coefficients in the %PEG 3.95 0.026 equations of each model adjusted, found in Online Resource %Oil 37.13 0 Increase in η from 25 °C CL 76.89 0 The results of the tests used to assess the adequacy of %PEG*%Oil 1.08 0.423 the models are summarized in Table 4. The coefficient of %PEG*CL 2.23 0.091 determination (R ) measures the total variability of the %Oil*CL 21.69 0 model, however a potential problem with this statistic is that %PEG 29.5 0 it always increases as factors are added, whether they are %Oil 15.92 0 2 2 significant or not [23]. The adjusted-R (R aj) is a statistic Particle size CL 1055.64 0 adjusted to the number of factors in the model in a way that %PEG*%Oil 8.2 0 it decreases if insignificant factors are added, thus it is pre- %PEG*CL 14.44 0 ferred to use the adjusted-R to evaluate the model adequacy %Oil*CL 52.09 0 2 2 [23]. The predicted-R (R pred) assess if the model is good Table 3 Order of importance of Response Order of importance of statistically significant factors statistically significant factors for each response η at 25 °C %Oil > %Oil*CL > CL > %PEG > %PEG*%Oil Peak temperature CL > %Oil*CL > %Oil > %PEG*CL Increase in η from 25 °C CL > %Oil > %Oil*CL > %PEG Particle size CL > %Oil*CL > %PEG > %Oil > %PEG*CL > %PEG*%Oil 1 3 160 Applied Petrochemical Research (2021) 11:155–163 Table 4 Statistics used to test the adequacy of the models proposed this response that we are unaware of and were not consid- 2 2 2 2 2 ered. For the other responses, the values of R and R aj Response R R aj R pred show that the models are well fitted for the data presented η at 25 °C 92.42% 77.76% 22.46% (R values above 95%) and are reasonably adjusted to the Peak temperature 95.72% 87.44% 42.32% number of significant factors of each model (R aj values Increase in η from 25 °C 95.22% 87.51% 65.99% above 87%), indicating that the regression explained the Particle size 99.52% 98.58% 95.89% process adequately. The low values of R pred for peak temperature and increase in η show that the models are unable to explain the variability in new data well due to at making predictions, namely, it determines whether there overfitting. However, the model proposed for particle size is an overfitting of the model. can explain variability of new data effectively, with R The statistics of adequacy show that the model pro- pred of 95,89%. posed for η at 25 °C is neither well adjusted for the num- Figures  1, 2, 3 and 4 depict the three-dimensional ber of significant factors nor it is a good predictor. This surface plots of the main interaction effects between might indicate that there are external factors influencing factors on the responses increase in η, η at 25 °C, peak Fig. 1 Response surface plot of increase in viscosity as function of: a concentration of PEG 400 and concentration of oil at CL = 11.5; b concentration of PEG 400 and chain length at %Oil = 12.5%; c concentra- tion of oil and chain length at %PEG = 4.5% Fig. 2 Response surface plot of viscosity at 25 °C as function of: a concentration of PEG 400 and concentration of oil at CL = 11.5; b concentration of PEG 400 and chain length at %Oil = 12.5%; c concentra- tion of oil and chain length at %PEG = 4.5% 1 3 Applied Petrochemical Research (2021) 11:155–163 161 Fig. 3 Response surface plot of temperature in which there is a peak in viscosity as function of: a concentration of PEG 400 and concentration of oil at CL = 11.5; b concentration of PEG 400 and chain length at %Oil = 12.5%; c concentra- tion of oil and chain length at %PEG = 4.5% Fig. 4 Response surface plot of particle size as function of: a concentration of PEG 400 and concentration of oil at CL = 11.5; b concentration of PEG 400 and chain length at %Oil = 12.5%; c concentra- tion of oil and chain length at %PEG = 4.5% temperature and particle size, respectively, at a fixed value tension of the water at the same temperature. This feature of of the third parameter. low surface tension is desirable for EOR application because The surface plots in Figs.  1, 2, 3 and 4 show that the it improves the wettability of the rocks in the reservoir [18]. samples prepared with capric acid (CL = 10) resulted in sys- The wettability is related to capillarity effects and is critical tems with larger particles, lower peak temperature, higher in determining the affinity of the oil with the reservoir rock viscosity at 25 °C and lower increase in viscosity, which is and how easily it will be displaced [7]. the opposite of ideal for EOR application. Higher concen- The emulsion phase inversion technique used to prepare trations of oil result in higher increase in viscosity, however the nanoemulsion is a low-energy easy-to-scale method that it also results in higher viscosity at 25 °C. All four three- makes the use of the technology cost-effective. In contrast to dimensional plots showed non-linear surfaces, which justi- traditional emulsification processes, such as ultrasonication fies the need of adding center points to a two-level full facto- and high-pressure homogenization, this synthesis method rial design. Optimization was designed to achieve maximum offers the feasibility of large scale production [8 ]. increase in viscosity, minimum viscosity at 25 °C and maxi- mum peak temperature with α = 0.05, and sample 15 was pointed out with composite desirability of 0.73. The equa- tions of each model adjusted are found in Online Resource 1. The surface tension of sample 15 at 25  °C was 33.363 ± 0.028 mN/m, being 54% lower than the surface 1 3 162 Applied Petrochemical Research (2021) 11:155–163 included in the article’s Creative Commons licence, unless indicated Conclusions otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not In current work, full factorial design technology was used to permitted by statutory regulation or exceeds the permitted use, you will determine the significant parameters, investigate the inter - need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativ ecommons .or g/licenses/b y/4.0/. action among them and optimize conditions to formulate a thermoresponsive nanoemulsion-based gel suitable for EOR application. Despite the complexity of the system, it was possible to adjust mathematical models that fitted the pre - References sented data well for three out of four responses studied. A proposed model was also able to explain variability of new 1. Abidin AZ, Puspasari T, Nugroho WA (2016) (2012) Polymers for enhanced oil recovery technology. Procedia Chem 4:11–16. https data effectively for particle size, with R pred of 95,89%. ://doi.org/10.1016/j.proch e.2012.06.002 A formulation containing 20% IPM was able to reach an 2. Bohorquez M et al (1999) A study of the temperature-dependent increase in viscosity of 3836.54% at 53 °C compared to its micellization of pluronic F127. J Colloid Interface Sci 216(1):34– viscosity at 25 °C of 520 mPa.s. It also presented surface 40. https ://doi.org/10.1006/jcis.1999.6273 3. Cao PF, Mangadlao JD, Advincula RC (2015) Stimuli-respon- tension of 33.363 ± 0.028 mN/m at 25 °C, 54% lower than sive polymers and their potential applications in oil-gas indus- the surface tension of water at the same temperature. try. Polym Rev 55(4):706–733. https ://doi.or g/10.1080/15583 The core-flooding experiments and stability in the pres- 724.2015.10405 53 ence of salts are yet to be evaluated, still the formulation 4. Castro Dantas TN et al (2014) Implementing new microemul- sion systems in wettability inversion and oil recovery from car- proposed shows great potential for EOR application. We bonate reservoirs. Energy Fuels 28(11):6749–6759. https://doi. presented a clear and stable nanoemulsion-based gel with org/10.1021/ef501 697x liquid-like behavior at room temperature, high increase in 5. Chen Q et  al (2013) Thermoviscosifying polymer used for viscosity with increase in temperature, low surface tension enhanced oil recovery: rheological behaviors and core flooding test. Polym Bull 70(2):391–401. https ://doi.org/10.1007/s0028 and environmentally friendly formulation. The system pre- 9-012-0798-7 sented could be used as a flooding fluid in oil recovery since 6. Daghlian Sofla SJ, Sharifi M, Hemmati Sarapardeh A (2016) its physical–chemical properties favor room temperature Toward mechanistic understanding of natural surfactant flood- pumping, wettability of the rocks, miscibility with oil and ing in enhanced oil recovery processes: the role of salinity, sur- factant concentration and rock type. J Mol Liq 222:632–639. with displacement fluid and enhanced fluid displacement. https ://doi.org/10.1016/j.molli q.2016.07.086 The rheological characteristics of the optimal formulation 7. Dantas TNC et al (2019) Microemulsions and nanoemulsions presented can also be tuned using the statistical models pro- applied to well stimulation and enhanced oil recovery (Eor). posed in this study without the need of numerous time and BJPG 12(4):251–265. https ://doi.org/10.5419/bjpg2 018-0023 8. Hashemnejad SM et al (2019) ‘Thermoresponsive nanoemul- resource consuming bench experiments. sion-based gel synthesized through a low-energy process. Nat Commun 10(1):1–10. https ://doi.or g/10.1038/s4146 7-019- Supplementary Information The online version contains supplemen- 10749 -1 tary material available at https:// doi.org/10.1007/s13203-02 1-00269-9 . 9. Hosseini-Nasab SM et  al (2016) ‘A new chemical-enhanced oil recovery method? Colloids Surf 507:89–95. https ://doi. Author contribution NCD: formal analysis, investigation, writing— org/10.1016/j.colsu rfa.2016.07.087 original draft preparation. MHAZ: project administration, investiga- 10. Iglauer, S. et  al. (2004) Alkyl polyglycoside surfactants for tion, writing—reviewing and editing. KLG: conceptualization, supervi- improved oil recovery’, Proceedings—SPE Symposium on sion. LAO: funding acquisition. AMO: conceptualization, supervision, improved oil recovery, 2004-April (December 2018). https ://doi. funding acquisition. org/10.2523/89472 -ms 11. Kamal MS et al (2015) Review on polymer flooding: rheology, Funding The authors would like to thank Petrobras (Brazil) for finan- adsorption, stability, and field applications of various polymer sys- cial support. tems. Polym Rev 55(3):491–530. https ://doi.org/10.1080/15583 724.2014.98282 1 12. Kamal MS, Sultan A (2017) Thermosensitive water soluble poly- Declarations mers: a solution to high temperature and high salinity reservoirs. Soc Petrol Eng 2017:2115–2130 Conflict of interest We know of no conflicts of interest associated with 13. Al Khateb K et al (2016) In situ gelling systems based on Plu- this publication, and there has been no significant financial support ronic F127/Pluronic F68 formulations for ocular drug deliv- that could have impacted its results. ery. Int J Pharm 502(2):70–79. https ://doi.or g/10.1016/j.ijpha rm.2016.02.027 Open Access This article is licensed under a Creative Commons Attri- 14. Lenaerts V et  al (1987) Temperature-dependent rheological bution 4.0 International License, which permits use, sharing, adapta- behavior of Pluronic F-127 aqueous solutions. Int J Pharm 39(1– tion, distribution and reproduction in any medium or format, as long 2):121–127. https ://doi.org/10.1016/0378-5173(87)90206 -7 as you give appropriate credit to the original author(s) and the source, 15. Li X et al (2017) Comparative studies on enhanced oil recovery: provide a link to the Creative Commons licence, and indicate if changes thermoviscosifying polymer versus polyacrylamide. Energy Fuels were made. The images or other third party material in this article are 1 3 Applied Petrochemical Research (2021) 11:155–163 163 31(3):2479–2487. https://doi.or g/10.1021/acs.energyfuel s.6b026 treatment via the full factorial design methodology. Sep Purif 53 Technol 132:50–61. https://doi.or g/10.1016/j.seppur .2014.04.051 16. Liu D et al (2010) A new fracturing fluid with combination of sin- 24. Vadnere M et al (1984) Thermodynamic studies on the gel-sol gle phase microemulsion and gelable polymer system. J Petrol Sci transition of some pluronic polyols. Int J Pharm 22(2–3):207–218. Eng 73(4):267–271. https://doi.or g/10.1016/j.petrol.2010.07.008 https ://doi.org/10.1016/0378-5173(84)90022 -X 17. Nandwani SK et  al (2017) Study on interfacial properties of 25. Wever DAZ et al (2013) Comb-like thermoresponsive polymeric Imidazolium ionic liquids as surfactant and their application in materials: synthesis and effect of macromolecular structure on enhanced oil recovery. Colloids Surf 516:383–393. https ://doi. solution properties. Polymer 54(21):5456–5466. https ://doi. org/10.1016/j.colsu rfa.2016.12.037org/10.1016/j.polym er.2013.07.039 18. Pal N et al (2019) Gemini surfactant/polymer/silica stabilized 26. Wever DAZ et al (2013) Polymer molecular architecture as a tool oil-in-water nanoemulsions: design and physicochemical charac- for controlling the rheological properties of aqueous polyacryla- terization for enhanced oil recovery. J Petrol Sci Eng 183:106464. mide solutions for enhanced oil recovery. Ind Eng Chem Res https ://doi.org/10.1016/j.petro l.2019.10646 4 52(47):16993–17005. https ://doi.org/10.1021/ie403 045y 19. Pandit NK, McGowan R (1998) Gelation of pluronic F127-pol- 27. Zhao X et al (2012) Rheological properties and microstructures yethylene glycol mixtures: relationship to PEG molecular of thermo-sensitive microemulsion-based gels. Advanc Mater Res weight. Drug Dev Ind Pharm 24(2):183–186. https ://doi. 557–559:1009–1012 org/10.3109/03639 04980 90856 05 28. Zhao XY et  al (2007) Preparation of temperature-sensitive 20. Pragatheeswaran AM, Chen SB (2013) Effect of chain length microemulsion-based gels formed from a triblock copolymer. of PEO on the gelation and micellization of the pluronic F127 Colloids Surf 307(1–3):100–107. https ://doi.org/10.1016/j.colsu copolymer aqueous system. Langmuir 29(31):9694–9701. https rfa.2007.05.006 ://doi.org/10.1021/la401 639g 29. Zhao Z, Lü G (2010) Visco-elastic properties of VES diverting 21. Sarsenbekuly B et  al (2017) Study of salt tolerance and tem- acid for carbonate reservoirs. Chin J Chem Eng 18(3):511–514. perature resistance of a hydrophobically modified polyacryla-https ://doi.org/10.1016/S1004 -9541(10)60251 -0 mide based novel functional polymer for EOR. Colloids Surf 514(66):91–97. https ://doi.org/10.1016/j.colsu rfa.2016.10.051 Publisher’s Note Springer Nature remains neutral with regard to 22. Schmolka IR (1972) Artificial skin I. Preparation and properties jurisdictional claims in published maps and institutional affiliations. treatment of burns. J Biomed Mater Res 6:571–582 23. Seyed Shahabadi SM, Reyhani A (2014) ‘Optimization of oper- ating conditions in ultrafiltration process for produced water 1 3 http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Applied Petrochemical Research Springer Journals

Optimized formulation of thermoresponsive nanoemulsion-based gel for enhanced oil recovery (EOR) application

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Abstract

A thermoresponsive system of a nanoemulsion-based gel with favorable characteristics to enhanced oil recovery (EOR) application is presented. A full factorial design study with different formulations of thermosensitive nanoemulsion-based gels was performed to assess the influence of the oil chain length, concentration of polyethylene glycol (PEG 400) and con- centration of oil on the rheological behavior of the system. A formulation with low viscosity at room temperature and high viscosity at the temperature of the oil extraction well was presented. Hexane (6-carbon chain), capric acid (10-carbon chain) and isopropyl myristate (17-carbon chain) were used in concentrations of 5%, 10%, 15% and 20% wt%, also varying the concentration of PEG 400 in 0%, 3%, 6% and 9% wt%. The thermosensitive polymer used was a mixture of Plur onic F-127 and Pluronic F-68 6:1 wt% at 4.7% concentration. The surfactants used were Tween 80 and Span 80 (HLB = 13) at 20%. The formulation containing 20% isopropyl myristate (IPM) without the addition of PEG 400 showed a better response, with an increase in viscosity of more than 38 times in relation to its viscosity at 25 °C, and the maximum viscosity was reached at 53 °C. This is a promising formulation for EOR technology. Keywords Thermoresponsive gel · Nanoemulsion · Enhanced oil recovery · Design of experiment Introduction Enhanced oil recovery (EOR) is a technique that consists in the application of methods that improve the recovery process and increases the amount of crude oil extracted from an oil field. Among the existing methods are chemical, thermal, * Natália Cristina Dalibera nataliacd@ipt.br injection of miscible gas/solvent, ultrasonic vibration, and flooding with microorganisms. The flooding of oil extrac- Maria Helena Ambrosio Zanin mhzanin@ipt.br tion wells with polymers represents one of the chemical processes of EOR. In this process, water-soluble polymers Kleber Lanigra Guimaraes kleberlg@ipt.br are used to modify rheological properties of displacement fluid, improving the rate of oil mobility and, therefore, the Leonardo Alencar de Oliveira leonardo.alencar@petrobras.com.br efficiency of the process [5 ]. Thermosensitive polymers are interesting for EOR appli- Adriano Marim de Oliveira amarim@ipt.br cation due to the characteristics of their structure. They consist of a hydrophilic main chain with hydrophobic side Institute for Technological Research (IPT)-Laboratory chains and are considered alternative viscosifying agents of Chemical Processes and Particle Technology, Group for high temperature and high salinity conditions [11, 12]. for Bionanomanufacturing (BIONANO), Av. Prof. Almeida Prado 532-Butantã, São Paulo 05508-901, Brazil In these polymers, thermosensitive monomers with low critical solubility temperature (LCST) are incorporated into Leopoldo Américo Miguez de Mello Research Center (CENPES), Universitária da Universidade Federal Do the main polymer chain. Above the LCST, the formation Rio de Janeiro, DE, Av. Horácio Macedo, 651-Cidade, of physical networks occurs as these monomers rearrange Rio de Janeiro 21941-915, Brazil Vol.:(0123456789) 1 3 156 Applied Petrochemical Research (2021) 11:155–163 themselves in hydrophobic micro domains, increasing the segments become more hydrophobic. They observed that viscosity of the polymeric solution [12]. The combination there is no transition from liquid to gel in the absence of oil, of thermosensitive polymers with surfactants in micro and which suggests that the adsorption of Pluronic copolymers nanoemulsions has been explored mainly in pharmaceuti- at the droplets interface is a fundamental step for the ther- cal applications [8, 22, 27, 28], but has great potential for mosresponsive behavior of the system [8]. application in EOR, especially due to the ability to achieve Previous experiments demonstrated that the displacement ultra-low values of water–oil surface tension [18]. of micro and nanoemulsions in the porous medium improve Triblock copolymers of poly(oxyethylene) and oil recovery [4, 6, 9, 16, 17, 29]. There has been numerous poly(oxypropylene) units (PEO–PPO–PEO), commercially studies that investigate the use of polymers in EOR [3, 5, available as Plur onics , are non-ionic, water-soluble mate- 10, 15, 21, 25, 26], however, a formulation of a flooding rials that undergo thermal gelation in aqueous solution at fluid with physical–chemical and rheological characteris- appropriate concentrations [13, 24]. These polymers exhibit tics that are optimal for EOR application (a fluid with low surface active properties, amphiphilic character and are surface tension able to deliver high increase in viscosity at known to form gels in response to temperature increase [13]. temperatures around 60 °C with liquid-like behavior at room Variations in the number of PEO and PPO units provide temperature) is yet to be presented. a wide range of polyols with different physical and chemi- The aim of the present work is to develop an optimized cal properties [24]. Pluronic F-127 has a PEO–PPO ratio formulation of a thermoresponsive nanoemulsion-based gel of 7:3 with a molecular weight of 12,500 and is more read- suitable for EOR application. The studies were carried out ily soluble in cold than in hot water [14]. The aggregation by tuning the concentrations of cossurfactant polyethylene behavior of block copolymers is complex in comparison to glycol 400 (PEG 400) and oil, and the chain length of the low-molecular-weight non-ionic surfactants, which occurs oil in the presence of a mixture of known thermoresponsive over a range of concentrations rather than at a unique criti- triblock copolymers. This study was based on a formulation cal micelle concentration (CMC). As a result, CMC values proposed by Hashemnejad et al. which was developed aim- reported can be substantially different depending on the ing to achieve properties suited for cosmetics and pharma- experimental conditions and technique used [2]. ceutical applications [8]. Schmolka et al. studied a system composed of the non- ionic polymeric surfactant Plur onic F-127 with the addition of salts and drugs to form a thermosensitive gel suitable for Experimental application in burns [22]. Zhao et al. prepared microemul- sion-based thermosensitive gels (MBGs) also using the poly- Materials mer Pluronic F-127, in combination with a microemulsion system composed of isopropyl myristate (IPM), water and Cosurfactant polyethylene glycol 400 (PEG 400), oils n-hex- surfactants Span 20 and Tween 20 [28]. They observed that ane and isopropyl myristate (IPM) and surfactant Tween 80 the viscosity of the gels increased, and the gelation tempera- were all analytical grade and were purchased from Synth ture decreased with increasing in polymer concentration. In (Brazil). Capric acid 99.5%, Span 80 (analytical grade) and another study conducted by Zhao et al. MBGs were prepared ® ® block polymers Plur onic F-127 and Plur onic F-68 were using Pluronic F-123 in the presence of IPM, Span 20, purchased from Sigma-Aldrich (Germany). Tween 20 and water [27]. The results show that the micro- structures of the microemulsion drops are maintained in the MBGs. Methods Hashemnejad et  al. synthesized a nanoemulsion-base thermoresponsive gel through a low-energy cost process, Sample preparation with application in cosmetics and pharmaceuticals [8]. The oil used was isopropyl myristate (IPM), along with sur- The thermoresponsive nanoemulsion-based gels were made factants Tween 80 and Span 80 (HLB = 13), a mixture of Pluronic F-127 and F-68 in low concentrations (4.7%) and through a low-energy process described elsewhere [8]. Con- cisely, the preparation of the samples consists in mixing a cosurfactant polyethylene glycol (PEG 400). They stated that the rearrangement of Plur onic molecules as the temperature determined amount of oil and a determined amount of PEG 400 with surfactants Tween 80 and Span 80 (HLB = 13) at rises can be affected by hydrophobic regions, including oil droplets in the nanoemulsion and the central hydrophobic 20% wt% at room temperature, then adding ultrapure water dropwise into the mixture under stirring. Last, a mixture of structure of the micelles of surfactants Tween 80 and Span ® ® ® 80 [8]. As the temperature rises, Pluronic ’s PPO segments Pluronic F-127 and Pluronic F-68 (6:1 wt%), previously are adsorbed at the interface of the oil droplets, as these 1 3 Applied Petrochemical Research (2021) 11:155–163 157 solubilized in cold ultrapure water at 23.3% wt%, is added occurs at room temperature, however all samples showed an into the mixture under stirring at 4.7% wt%. increase in viscosity somewhere between 5 °C and 70 °C. The peak temperature should ideally be close to that of Experimental factorial design the oil wells (approximately 60 °C) to guarantee that the fluid would be at its maximum viscosity during extraction A full factorial experiment was designed and analyzed using work, increasing the oil displacement in the porous medium the software MiniTab 19.1.1. To verify the influence of the [7]. Samples that showed peak temperature between 50 °C factors on the rheological behavior of the system, the con- and 70 °C (samples 3, 4, 6, 7, 11, 13, 14, 15, 27, 28, 31, centration of PEG 400 (%PEG), the concentration oil (%Oil) 33, 34, 43, 44 and 47) have broadly different compositions. and oil chain length (CL) were evaluated. The concentration The difference in composition indicates that there is no clear of PEG 400 added to the formulation varied in 0%, 3%, 6% correlation between one factor studied and the peak tempera- and 9% (wt%) and the concentration of oil varied in 5%, ture response. It is likely that two or more factors and their 10%, 15% and 20% (wt%). The oils studied were n-hexane interactions are responsible for tuning the peak temperature (6-carbon chain), capric acid (10-carbon chain) and isopro- property of the system. pyl miristate (IPM) (17-carbon chain). The responses moni- The injection of chemical fluids to the oil wells seeks tored were viscosity of the system at 25 °C, temperature to increase miscibility between the injected fluid and the at which there was a peak in viscosity (peak temperature), oil, decrease the interfacial tension to increase wettability of increase in viscosity from room temperature and particle rock surface and increase viscosity of the injected fluid [7 ]. size. The experiments were carried out in randomized run The highest increase in viscosity of 3836.5% was obtained order to avoid bias. with sample 15, which has 20% IPM in its composition with no addition of PEG 400. IPM has low toxicity [28] and could Rheology and particle size be used as a component of a flooding fluid without signifi- cant environmental impact. The presence of IPM in concen- The rheology of the samples was analyzed using a Brook- trations above 15% in sample 15 and other samples which field R/S plus rotational rheometer equipped with a Searle- had high increase in viscosity (samples 4, 6 and 14) shows −1 type concentric cylinder geometry CC25, shear rate of 20  s that the presence and characteristics of the oil phase are criti- and temperature ramp from 5 °C to 70 °C. Particle size was cal in obtaining a thermoresponsive behavior of the system. analyzed by dynamic light scattering (DLS) on a Particulate The hypothesis is that there is synergistic effect occurring Systems NanoPlus equipment, after diluting the samples to between Pluronic copolymers and the nanoemulsion drop- 3.5% wt% with ultrapure water. lets [8]. The viscosity diagram of sample 15 is displayed in Online Resource 1. Surface tensiometry The viscosity at room temperature should be as low as possible to facilitate the pumping of the fluid into the wells. Surface tension of the optimized formulation was measured The lowest viscosities at 25 °C were obtained in samples at 25 °C using a DCAT 11 Dataphysics tensiometer. The with concentrations of oil lower than 10% (samples 1, method used was Wilhelmy plate with plate dimensions of 17, 33, 35, 42 and 43), however they did not show a high 10 mm × 19.9 mm × 0.2 mm (length × width × thickness). increase in viscosity nor did they have an adequate peak The surface tension measurements were done in triplicate. temperature. The low viscosity at room temperature with lower concentration of oil shows that the oil phase not only is linked to the gelling behavior of the system, but also has Results and discussion a direct influence on the viscosity at 25 °C, increasing the viscosity of the nanoemulsion before any temperature or A total of 48 experiments were performed in randomized shear trigger. order to determine the effect of the factors [concentration of Usually, a clear and stable nanoemulsion has its structures PEG 400 (%PEG), concentration of oil (%Oil) and oil chain (droplets of oil in water or water in oil interacting with the length (CL)] on four characteristic responses: viscosity of surfactants) in sizes up to 100 nm [7]. All samples formu- the system (η) at 25 °C, temperature at which the maxi- lated with capric acid (CL = 10) had a particle size bigger mum viscosity was reached (peak temperature), maximum than 100 nm, indicating that the chain length has a clear increase in viscosity and droplet size (particle size). Table 1 influence on particle size property. It also indicates that shows the experimental design matrix with factors and the capric acid could be considered a less suitable oil among results of the response variables studied. The increase in the oils studied to produce clear and stable nanoemulsions. viscosity of samples with peak temperature below 25 °C is Samples formulated with different CL, PEG concentration marked as 0% because in EOR the pumping process usually and oil concentration were able to produce nanoemulsions 1 3 158 Applied Petrochemical Research (2021) 11:155–163 Table 1 Experimental design matrix with factors and the results of the response variables studied Sample PEG concentra- Oil concentra- Chain length η at 25 °C (mPa.s) Peak tempera- Particle size (nm) Increase in η tion (%wt) tion (%wt) (carbons) ture (°C) from 25 °C 1 3 5 6 60.01 12.1 122.6 0.00% 2 0% 15% 10 6500.54 23.0 275.9 0.00% 3 6% 15% 17 2500.69 52.8 39.6 620.00% 4 3% 10% 17 560.04 57.5 40.4 1685.71% 5 9% 5% 10 1800.15 37.9 243.5 10.00% 6 3% 15% 17 750.72 56.3 38.5 2018.67% 7 9% 10% 6 340.88 63.0 121.7 76.47% 8 0% 10% 10 9940.40 22.4 283.8 0.00% 9 6% 15% 6 3390.62 43.4 119.2 112.39% 10 0% 20% 10 6760.86 10.7 275.8 0.00% 11 6% 20% 17 8230.40 55.1 47.4 234.14% 12 3% 10% 10 6100.72 20.9 308.0 4.92% 13 3% 20% 17 2340.10 52.2 62.3 988.89% 14 0% 15% 17 560.53 50.1 75.3 2917.86% 15 0% 20% 17 520.77 53.6 120.9 3836.54% 16 6% 5% 10 980.92 43.2 196.1 63.27% 17 0% 10% 6 85.09 15.7 148.3 0.00% 18 0% 5% 10 290.12 45.7 170.6 344.83% 19 6% 10% 10 10,300.89 23.8 177.6 0.00% 20 6% 15% 10 6170.55 22.2 233.0 0.00% 21 9% 15% 17 4590.65 47.4 38.9 226.80% 22 9% 20% 10 1460.38 15.4 335.9 0.00% 23 9% 5% 17 110.51 10.7 154.1 0.00% 24 3% 20% 6 9180.00 45.1 164.9 106.97% 25 9% 20% 6 12,250.32 40.2 149.4 31.43% 26 9% 20% 17 11,800.85 47.1 47.5 94.92% 27 0% 15% 6 300.01 68.0 138.8 250.00% 28 9% 10% 17 315.11 58.5 33.8 350.79% 29 3% 15% 10 7500.72 23.8 323.7 0.00% 30 6% 20% 10 5740.19 16.2 303.7 0.00% 31 3% 10% 6 590.03 55.4 139.1 806.78% 32 3% 5% 10 690.60 48.8 223.5 160.87% 33 0% 5% 6 80.61 70.6 114.5 275.00% 34 0% 10% 17 110.24 60.9 92.5 327.27% 35 0% 5% 17 60.81 20.0 123.7 0.00% 36 9% 15% 6 9900.42 44.3 44.9 66.67% 37 3% 15% 6 7190.30 48.1 133.7 171.21% 38 6% 5% 6 220.69 14.3 127.6 0.00% 39 0% 20% 6 620.62 40.6 182.8 448.39% 40 6% 20% 6 15,810.40 40.7 130.5 35.99% 41 9% 15% 10 5300.57 23.4 307.5 0.00% 42 6% 5% 17 60.00 15.0 136.6 0.00% 43 3% 5% 17 70.02 53.0 117.0 11.43% 44 6% 10% 6 640.99 55.1 97.0 681.25% 45 3% 20% 10 7950.33 13.8 354.2 0.00% 46 9% 10% 10 4800.01 30.6 303.0 6.25% 47 6% 10% 17 230.65 60.2 29.8 415.22% 48 9% 5% 6 140.62 6.5 124.3 0.00% 1 3 Applied Petrochemical Research (2021) 11:155–163 159 with particle size up to 100 nm, indicating that other factors the responses are significantly influenced by at least two fac- and their interactions are also influencing the response. tors or interaction of factors. The complexity of the system Analysis of variance (ANOVA) was performed to verify makes it hard to predict its behavior without a mathematical whether the influence of each component of the formulation model associated to each response. Statistical analysis also and their interactions are significant on the responses stud- makes it possible to propose an optimized formulation con- ied. The results of p-value and F value obtained for all the sidering how all the variables and their interactions influence factors and their interactions are shown in Table 2. the rheology of the system. P-value is the probability used to determine if the effect Table 3 shows the order of importance of statistically sig- or the interaction of effects in the model is statistically sig- nificant factors for each response based on the results from nificant. For a 95% confidence level, the p-value should be ANOVA in Table 2. less or equal to 0.05 for a factor to be considered statistically The oil chain length (CL) is the main influence factor on significant [23]. The degree of significance can be ranked three out of four responses studied and its interaction with based on F values. The greater the F value, the more signifi - %Oil also shows important effect on all four responses. The cant the factor is, if its p-value is less than 0.05. The results interaction between CL and %Oil and %Oil alone also have of p-values from ANOVA reported in Table 2 show that all significant influence on all responses studied. That again conr fi ms that the presence and properties of the oil phase are critical in defining the rheological behavior of the system. Table 2 Results of F values and p-values from ANOVA for each The concentration of cosurfactant PEG 400 and its inter- response, considering all factors and their binary interactions actions have the least significant influence on the responses in general. Hashemnejad et al. found that an increase in the Response Factor F value p-value concentration of PEG 400 lowers the gelation temperature %PEG 4.33 0.022 of their nanoemulsion-based system [8]. Prior studies of %Oil 18.51 0 Pluronic aqueous solutions also showed that the presence η at 25 °C CL 5.31 0.018 of short PEG chains lowers the critical micellization tem- %PEG*%Oil 3.28 0.021 perature [19, 20]. We were able to obtain a formulation with %PEG*CL 1.73 0.183 desired rheological behavior without addition of PEG 400 %Oil*CL 5.43 0.004 (sample 15). However, Table 2 and Table 3 show that %PEG %PEG 1.87 0.177 and %PEG interactions do have statistically signic fi ant inu fl - %Oil 14.03 0 ence on the responses, even if they are less significant than Peak temperature CL 30.22 0 the influence of other factors and interactions. The %PEG %PEG*%Oil 1.84 0.143 should, therefore, be considered when doing optimization %PEG*CL 3.25 0.03 calculations. The direction and magnitude of the influence %Oil*CL 21.45 0 of each factor can be verified through the coefficients in the %PEG 3.95 0.026 equations of each model adjusted, found in Online Resource %Oil 37.13 0 Increase in η from 25 °C CL 76.89 0 The results of the tests used to assess the adequacy of %PEG*%Oil 1.08 0.423 the models are summarized in Table 4. The coefficient of %PEG*CL 2.23 0.091 determination (R ) measures the total variability of the %Oil*CL 21.69 0 model, however a potential problem with this statistic is that %PEG 29.5 0 it always increases as factors are added, whether they are %Oil 15.92 0 2 2 significant or not [23]. The adjusted-R (R aj) is a statistic Particle size CL 1055.64 0 adjusted to the number of factors in the model in a way that %PEG*%Oil 8.2 0 it decreases if insignificant factors are added, thus it is pre- %PEG*CL 14.44 0 ferred to use the adjusted-R to evaluate the model adequacy %Oil*CL 52.09 0 2 2 [23]. The predicted-R (R pred) assess if the model is good Table 3 Order of importance of Response Order of importance of statistically significant factors statistically significant factors for each response η at 25 °C %Oil > %Oil*CL > CL > %PEG > %PEG*%Oil Peak temperature CL > %Oil*CL > %Oil > %PEG*CL Increase in η from 25 °C CL > %Oil > %Oil*CL > %PEG Particle size CL > %Oil*CL > %PEG > %Oil > %PEG*CL > %PEG*%Oil 1 3 160 Applied Petrochemical Research (2021) 11:155–163 Table 4 Statistics used to test the adequacy of the models proposed this response that we are unaware of and were not consid- 2 2 2 2 2 ered. For the other responses, the values of R and R aj Response R R aj R pred show that the models are well fitted for the data presented η at 25 °C 92.42% 77.76% 22.46% (R values above 95%) and are reasonably adjusted to the Peak temperature 95.72% 87.44% 42.32% number of significant factors of each model (R aj values Increase in η from 25 °C 95.22% 87.51% 65.99% above 87%), indicating that the regression explained the Particle size 99.52% 98.58% 95.89% process adequately. The low values of R pred for peak temperature and increase in η show that the models are unable to explain the variability in new data well due to at making predictions, namely, it determines whether there overfitting. However, the model proposed for particle size is an overfitting of the model. can explain variability of new data effectively, with R The statistics of adequacy show that the model pro- pred of 95,89%. posed for η at 25 °C is neither well adjusted for the num- Figures  1, 2, 3 and 4 depict the three-dimensional ber of significant factors nor it is a good predictor. This surface plots of the main interaction effects between might indicate that there are external factors influencing factors on the responses increase in η, η at 25 °C, peak Fig. 1 Response surface plot of increase in viscosity as function of: a concentration of PEG 400 and concentration of oil at CL = 11.5; b concentration of PEG 400 and chain length at %Oil = 12.5%; c concentra- tion of oil and chain length at %PEG = 4.5% Fig. 2 Response surface plot of viscosity at 25 °C as function of: a concentration of PEG 400 and concentration of oil at CL = 11.5; b concentration of PEG 400 and chain length at %Oil = 12.5%; c concentra- tion of oil and chain length at %PEG = 4.5% 1 3 Applied Petrochemical Research (2021) 11:155–163 161 Fig. 3 Response surface plot of temperature in which there is a peak in viscosity as function of: a concentration of PEG 400 and concentration of oil at CL = 11.5; b concentration of PEG 400 and chain length at %Oil = 12.5%; c concentra- tion of oil and chain length at %PEG = 4.5% Fig. 4 Response surface plot of particle size as function of: a concentration of PEG 400 and concentration of oil at CL = 11.5; b concentration of PEG 400 and chain length at %Oil = 12.5%; c concentra- tion of oil and chain length at %PEG = 4.5% temperature and particle size, respectively, at a fixed value tension of the water at the same temperature. This feature of of the third parameter. low surface tension is desirable for EOR application because The surface plots in Figs.  1, 2, 3 and 4 show that the it improves the wettability of the rocks in the reservoir [18]. samples prepared with capric acid (CL = 10) resulted in sys- The wettability is related to capillarity effects and is critical tems with larger particles, lower peak temperature, higher in determining the affinity of the oil with the reservoir rock viscosity at 25 °C and lower increase in viscosity, which is and how easily it will be displaced [7]. the opposite of ideal for EOR application. Higher concen- The emulsion phase inversion technique used to prepare trations of oil result in higher increase in viscosity, however the nanoemulsion is a low-energy easy-to-scale method that it also results in higher viscosity at 25 °C. All four three- makes the use of the technology cost-effective. In contrast to dimensional plots showed non-linear surfaces, which justi- traditional emulsification processes, such as ultrasonication fies the need of adding center points to a two-level full facto- and high-pressure homogenization, this synthesis method rial design. Optimization was designed to achieve maximum offers the feasibility of large scale production [8 ]. increase in viscosity, minimum viscosity at 25 °C and maxi- mum peak temperature with α = 0.05, and sample 15 was pointed out with composite desirability of 0.73. The equa- tions of each model adjusted are found in Online Resource 1. The surface tension of sample 15 at 25  °C was 33.363 ± 0.028 mN/m, being 54% lower than the surface 1 3 162 Applied Petrochemical Research (2021) 11:155–163 included in the article’s Creative Commons licence, unless indicated Conclusions otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not In current work, full factorial design technology was used to permitted by statutory regulation or exceeds the permitted use, you will determine the significant parameters, investigate the inter - need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativ ecommons .or g/licenses/b y/4.0/. action among them and optimize conditions to formulate a thermoresponsive nanoemulsion-based gel suitable for EOR application. Despite the complexity of the system, it was possible to adjust mathematical models that fitted the pre - References sented data well for three out of four responses studied. A proposed model was also able to explain variability of new 1. Abidin AZ, Puspasari T, Nugroho WA (2016) (2012) Polymers for enhanced oil recovery technology. Procedia Chem 4:11–16. https data effectively for particle size, with R pred of 95,89%. ://doi.org/10.1016/j.proch e.2012.06.002 A formulation containing 20% IPM was able to reach an 2. Bohorquez M et al (1999) A study of the temperature-dependent increase in viscosity of 3836.54% at 53 °C compared to its micellization of pluronic F127. J Colloid Interface Sci 216(1):34– viscosity at 25 °C of 520 mPa.s. It also presented surface 40. https ://doi.org/10.1006/jcis.1999.6273 3. Cao PF, Mangadlao JD, Advincula RC (2015) Stimuli-respon- tension of 33.363 ± 0.028 mN/m at 25 °C, 54% lower than sive polymers and their potential applications in oil-gas indus- the surface tension of water at the same temperature. try. Polym Rev 55(4):706–733. https ://doi.or g/10.1080/15583 The core-flooding experiments and stability in the pres- 724.2015.10405 53 ence of salts are yet to be evaluated, still the formulation 4. Castro Dantas TN et al (2014) Implementing new microemul- sion systems in wettability inversion and oil recovery from car- proposed shows great potential for EOR application. We bonate reservoirs. Energy Fuels 28(11):6749–6759. https://doi. presented a clear and stable nanoemulsion-based gel with org/10.1021/ef501 697x liquid-like behavior at room temperature, high increase in 5. Chen Q et  al (2013) Thermoviscosifying polymer used for viscosity with increase in temperature, low surface tension enhanced oil recovery: rheological behaviors and core flooding test. Polym Bull 70(2):391–401. https ://doi.org/10.1007/s0028 and environmentally friendly formulation. The system pre- 9-012-0798-7 sented could be used as a flooding fluid in oil recovery since 6. Daghlian Sofla SJ, Sharifi M, Hemmati Sarapardeh A (2016) its physical–chemical properties favor room temperature Toward mechanistic understanding of natural surfactant flood- pumping, wettability of the rocks, miscibility with oil and ing in enhanced oil recovery processes: the role of salinity, sur- factant concentration and rock type. J Mol Liq 222:632–639. with displacement fluid and enhanced fluid displacement. https ://doi.org/10.1016/j.molli q.2016.07.086 The rheological characteristics of the optimal formulation 7. Dantas TNC et al (2019) Microemulsions and nanoemulsions presented can also be tuned using the statistical models pro- applied to well stimulation and enhanced oil recovery (Eor). posed in this study without the need of numerous time and BJPG 12(4):251–265. https ://doi.org/10.5419/bjpg2 018-0023 8. Hashemnejad SM et al (2019) ‘Thermoresponsive nanoemul- resource consuming bench experiments. sion-based gel synthesized through a low-energy process. Nat Commun 10(1):1–10. https ://doi.or g/10.1038/s4146 7-019- Supplementary Information The online version contains supplemen- 10749 -1 tary material available at https:// doi.org/10.1007/s13203-02 1-00269-9 . 9. Hosseini-Nasab SM et  al (2016) ‘A new chemical-enhanced oil recovery method? Colloids Surf 507:89–95. https ://doi. Author contribution NCD: formal analysis, investigation, writing— org/10.1016/j.colsu rfa.2016.07.087 original draft preparation. MHAZ: project administration, investiga- 10. Iglauer, S. et  al. (2004) Alkyl polyglycoside surfactants for tion, writing—reviewing and editing. KLG: conceptualization, supervi- improved oil recovery’, Proceedings—SPE Symposium on sion. LAO: funding acquisition. AMO: conceptualization, supervision, improved oil recovery, 2004-April (December 2018). https ://doi. funding acquisition. org/10.2523/89472 -ms 11. Kamal MS et al (2015) Review on polymer flooding: rheology, Funding The authors would like to thank Petrobras (Brazil) for finan- adsorption, stability, and field applications of various polymer sys- cial support. tems. Polym Rev 55(3):491–530. https ://doi.org/10.1080/15583 724.2014.98282 1 12. Kamal MS, Sultan A (2017) Thermosensitive water soluble poly- Declarations mers: a solution to high temperature and high salinity reservoirs. Soc Petrol Eng 2017:2115–2130 Conflict of interest We know of no conflicts of interest associated with 13. Al Khateb K et al (2016) In situ gelling systems based on Plu- this publication, and there has been no significant financial support ronic F127/Pluronic F68 formulations for ocular drug deliv- that could have impacted its results. ery. Int J Pharm 502(2):70–79. https ://doi.or g/10.1016/j.ijpha rm.2016.02.027 Open Access This article is licensed under a Creative Commons Attri- 14. Lenaerts V et  al (1987) Temperature-dependent rheological bution 4.0 International License, which permits use, sharing, adapta- behavior of Pluronic F-127 aqueous solutions. Int J Pharm 39(1– tion, distribution and reproduction in any medium or format, as long 2):121–127. https ://doi.org/10.1016/0378-5173(87)90206 -7 as you give appropriate credit to the original author(s) and the source, 15. Li X et al (2017) Comparative studies on enhanced oil recovery: provide a link to the Creative Commons licence, and indicate if changes thermoviscosifying polymer versus polyacrylamide. Energy Fuels were made. The images or other third party material in this article are 1 3 Applied Petrochemical Research (2021) 11:155–163 163 31(3):2479–2487. https://doi.or g/10.1021/acs.energyfuel s.6b026 treatment via the full factorial design methodology. Sep Purif 53 Technol 132:50–61. https://doi.or g/10.1016/j.seppur .2014.04.051 16. Liu D et al (2010) A new fracturing fluid with combination of sin- 24. Vadnere M et al (1984) Thermodynamic studies on the gel-sol gle phase microemulsion and gelable polymer system. J Petrol Sci transition of some pluronic polyols. Int J Pharm 22(2–3):207–218. Eng 73(4):267–271. https://doi.or g/10.1016/j.petrol.2010.07.008 https ://doi.org/10.1016/0378-5173(84)90022 -X 17. Nandwani SK et  al (2017) Study on interfacial properties of 25. Wever DAZ et al (2013) Comb-like thermoresponsive polymeric Imidazolium ionic liquids as surfactant and their application in materials: synthesis and effect of macromolecular structure on enhanced oil recovery. Colloids Surf 516:383–393. https ://doi. solution properties. Polymer 54(21):5456–5466. https ://doi. org/10.1016/j.colsu rfa.2016.12.037org/10.1016/j.polym er.2013.07.039 18. Pal N et al (2019) Gemini surfactant/polymer/silica stabilized 26. Wever DAZ et al (2013) Polymer molecular architecture as a tool oil-in-water nanoemulsions: design and physicochemical charac- for controlling the rheological properties of aqueous polyacryla- terization for enhanced oil recovery. J Petrol Sci Eng 183:106464. mide solutions for enhanced oil recovery. Ind Eng Chem Res https ://doi.org/10.1016/j.petro l.2019.10646 4 52(47):16993–17005. https ://doi.org/10.1021/ie403 045y 19. Pandit NK, McGowan R (1998) Gelation of pluronic F127-pol- 27. Zhao X et al (2012) Rheological properties and microstructures yethylene glycol mixtures: relationship to PEG molecular of thermo-sensitive microemulsion-based gels. Advanc Mater Res weight. Drug Dev Ind Pharm 24(2):183–186. https ://doi. 557–559:1009–1012 org/10.3109/03639 04980 90856 05 28. Zhao XY et  al (2007) Preparation of temperature-sensitive 20. Pragatheeswaran AM, Chen SB (2013) Effect of chain length microemulsion-based gels formed from a triblock copolymer. of PEO on the gelation and micellization of the pluronic F127 Colloids Surf 307(1–3):100–107. https ://doi.org/10.1016/j.colsu copolymer aqueous system. Langmuir 29(31):9694–9701. https rfa.2007.05.006 ://doi.org/10.1021/la401 639g 29. Zhao Z, Lü G (2010) Visco-elastic properties of VES diverting 21. Sarsenbekuly B et  al (2017) Study of salt tolerance and tem- acid for carbonate reservoirs. Chin J Chem Eng 18(3):511–514. perature resistance of a hydrophobically modified polyacryla-https ://doi.org/10.1016/S1004 -9541(10)60251 -0 mide based novel functional polymer for EOR. Colloids Surf 514(66):91–97. https ://doi.org/10.1016/j.colsu rfa.2016.10.051 Publisher’s Note Springer Nature remains neutral with regard to 22. Schmolka IR (1972) Artificial skin I. Preparation and properties jurisdictional claims in published maps and institutional affiliations. treatment of burns. J Biomed Mater Res 6:571–582 23. Seyed Shahabadi SM, Reyhani A (2014) ‘Optimization of oper- ating conditions in ultrafiltration process for produced water 1 3

Journal

Applied Petrochemical Research – Springer Journals

Published: Mar 11, 2021

Keywords: Thermoresponsive gel; Nanoemulsion; Enhanced oil recovery; Design of experiment

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