Development of Nanofluids for Perdurability in Viscosity Reduction of Extra-Heavy Oils

Abstract

The primary objective of this study is the development of nanofluids based on different diluent/dispersant ratios (DDR) for extra-heavy oil (EHO) viscosity reduction and its perdurability over time. Different diluents such as xylene, diesel, n-pentane, and n-heptane were evaluated for the formulation of the carrier fluid. Instability of asphaltenes was assessed for all diluents through colloidal instability index (CII) and Oliensis tests. Rheology measurements and hysteresis loop tests were performed using a rotational rheometer at 30 °C. The CII values for the alkanes type diluents were around 0.57, results that were corroborated with the Oliensis tests as asphaltenes precipitation was observed with the use of these diluents. This data was related to the viscosity reduction degree (VRD) reported for the different diluents. With the use of the alkanes, the VRD does not surpass the 60%, while with the use of xylene a VRD of approximately 85% was achieved. Dimethylformamide was used as a dispersant of the nanoparticles and had a similar VRD than that for xylene (87%). Subsequent experiments were performed varying the DDR (xylene/dimethylformamide) for different dosages up to 7 vol % determining that a DDR = 0.2 and a dosage of 5 vol % was appropriated for enhancing EHO VRD, obtaining a final value of 89%. Different SiO2 nanoparticles were evaluated in the viscosity reduction tests reporting the best results using 9 nm nanoparticles that were then included at 1000 mg·L−1 in the carrier fluid, increasing the VRD up to 4% and enhancing the perdurability based on the rheological hysteresis and the viscosity measurements for 30 days. Results showed a viscosity increase of 20 and 80% for the crude oil with the nanofluid and the carrier fluid after 30 days, respectively. The nanoparticles have a synergistic effect in the viscosity reduction and the inhibition of the viscoelastic network re-organization (perdurability) after treatment application which was also observed in the rheological modeling carried out with Cross and Carreau models as the reported characteristic relaxation time was increased almost a 20%. Moreover, the Vipulanandan rheological model denotes a higher maximum stress value reached by the EHO with the addition of nanofluids which is derived from the EHO internal structure rearrangement caused by the asphaltenes adsorption phenomenon.

Nanotechnology Applied to Thermal Enhanced Oil Recovery Processes: A Review

“…However, from the beginning of the adsorption of asphaltenes, the three-dimensional network is disorganized. With the increase in the shear rate, a decrease in viscosity occurs again, until it reaches a point where the magnitude of this value is independent of the shear rate [113].…”

“…However, from the beginning of the adsorption of asphaltenes, the three-dimensional network is disorganized. With the increase in the shear rate, a decrease in viscosity occurs again, until it reaches a point where the magnitude of this value is independent of the shear rate [113]. In a complement to the experimental studies, mathematically and computationally, studies have also been developed to understand the interactions between asphaltenes and nanoparticles, such as the solid-liquid equilibrium model (SLE) [109].…”

Design and Tuning of Nanofluids Applied to Chemical Enhanced Oil Recovery Based on the Surfactant–Nanoparticle–Brine Interaction: From Laboratory Experiments to Oil Field Application

“…The FTIR spectra of the nanoparticles are presented in Figure 5. As mentioned above, the wide band between 3650 and 3100 cm −1 correlated with O-H bonding, which in this case represented the Silanol Si-OH groups [61,76]. Moreover, the peak centered at 1600 cm −1 corresponded to the O-H scissoring [77], while the pronounced peak between 1000 and 1300 cm −1 denoted the asymmetric stretching of the O-Si-O bonds [49,78].…”

Improvement of Steam Injection Processes Through Nanotechnology: An Approach through in Situ Upgrading and Foam Injection

“…The viscosity measurements were made using a Kinexus Pro rheometer (Malvern Instruments, Worcestershire, UK). A parallel plate-plate geometry [61] (optimal for highly viscous fluids) was employed with a GAP of 0.3 mm, for different shear rates between 0 s −1 to 100 s −1 at 25 • C. The viscosity reduction degree (VRD) was calculated following the Equation (2) [61]:…”

“…This is the first measurement, the steam injection generates a %VRD of approximately 7.2%, due to the latent heat transferred by the steam towards the formation fluids, increasing the crude oil mobility, without generating a significant increase in the quality of the same. On the other hand, the The typical oil behavior is non-Newtonian, where the viscosity changes with the shear rate and becomes more noticeable at the lower values; notwithstanding, the nanocatalyst injection modifies the rheological properties making that the EHO behaves more as a Newtonian fluid and reducing its viscosity in all the shear rate range [61]. In this sense, the effluent obtained after the CeNi0.89Pd1.1 base-nanofluid injection, presents the best performance in terms of viscosity reduction, and rheological behavior; due to when the shear rate increases, the behavior of the fluid analyzed begins to be like a Newtonian liquid, since the internal structure of the fluid does not change drastically, independently of the shear rate.…”