Decreasing Oil Viscosity Research Articles

Iso-Permeability Point Trail Method to Determine the Relative Permeability Curve for a New Amphiphilic Polymer Flooding

Amphiphilic-polymer flooding, which can increase water viscosity, decrease oil viscosity, and improve oil displacement efficiency, is a promising oil exploitation method for heavy oil. Due to oil–water emulsification, shear-thinning, and changes in oil viscosity when determining the relative permeability data of new amphiphilic polymers, the conventional J.B.N. method is not accurate. This paper presents a new method called the iso-permeability point trial method to determine the relative permeability curve by combining the J.B.N. method, the Corey model, and the relationship between water saturation and the relative permeability ratio. To avoid using polymer viscosity, a mathematical equation was derived based on the characteristics of the relative permeability curve. The results indicate that the new method is feasible and the obtained curve is more reasonable and smooth. The influence of concentration, permeability, and oil viscosity on amphiphilic-polymer displacement relative permeability was also analyzed, demonstrating that under the same water saturation, the water relative permeability is lower than that of water flooding but the oil relative permeability is bigger, which manifests as the iso-permeability point moves to the right and results in a lower residual oil saturation. In addition, the aforementioned trends are more obvious when the amphiphilic-polymer concentration is high, formation permeability is low, and oil viscosity is low.

Pore-scale investigation on the flow behavior and oil displacement of ultralow IFT surfactant flooding based on CFD simulation

In order to investigate the flow behavior and oil displacement of ultralow interfacial tension (IFT) surfactant flooding, the experimentally validated computational fluid dynamics simulation model is constructed by coupling the Navier-Stokes equations and the Cahn-Hilliard equation. The mixed surfactant solution is prepared using the ionic liquid surfactant and the nonionic surfactant, and the fluid parameters are measured experimentally. Due to the reduced oil-water IFT, the low pressure drop in porous medium and the decreased oil viscosity, ultralow IFT surfactant contributes to increasing the mobility ability of the fluid front in pores, and its optimal injection velocity is 0.01 m/s. In addition, the sweep area of surfactant flooding in oil-wet porous medium is significantly larger than that of brine flooding because of wettability alteration. Finally, for different porosity models, the residual oil content and the pressure drop of surfactant flooding show a 66.7% and 71.4% decrease than those of brine flooding, respectively, proving its better displacement performance.

High-efficiency and all-weather crude oil spill remediation by an eco-friendly self-heating MXene-coated poly(butylene adipate-co-terephthalate) porous monolith

Frequent oil spill incidents have resulted in serious environmental pollution posing a great threat to human health and ecological system, thus developing new absorbents to efficiently remove and recycle high-viscosity crude oil is attracting more attention. We herein report an eco-friendly flexible poly(butylene adipate-co-terephthalate) (PBAT)-based monolith with MXene (Ti3C2Tx) and polydimethylsiloxane (PDMS) coatings (P-MXene@PBAT monolith) by convenient and economical preparation method for self-heating driven fast crude oil cleanup. Due to unique three-dimensional interconnected pore structure and superior hydrophobicity, the P-MXene@PBAT showed high saturated absorption capacity and cyclic separation efficiency for multifarious low-viscosity oils. The P-MXene@PBAT was endowed with excellent photo/electro-thermal performance via wrapping MXene layer. The maximum surface temperature of monolith quickly reached up to 81 °C under 1.0 kW m−2 (1.0 sun) irradiation and 91 °C under 8 V voltage, respectively. Furthermore, the P-MXene@PBAT could self-heat crude oil to dramatically decrease oil viscosity and accelerate separation process. Specially, the P-MXene@PBAT was able to continuously separate crude oil from water with a simple pump-assisted absorption device (crude oil flux of 204 kg m−2 h−1), which adapted to varied working conditions by coupling solar heating and Joule heating. Such environmental-friendly all-weather absorbent design provides a sustainable strategy for efficient remediation of crude oil spill.

Investigating the potential of microbial enhanced oil recovery in carbonate reservoirs using Bacillus persicus

In this study, several laboratory experiments were conducted to evaluate the performance of Bacillus persicus as a microbial enhanced oil recovery (MEOR) agent in conventional and fractured carbonate reservoirs. In these experiments, it was observed that using the microbial solution as an imbibing fluid can produce 12.5% of the original oil in place. Complementary imbibition experiments demonstrated that lower recoveries are achievable using Sodium Dodecyl Sulfate (SDS) surfactant and supernatant solutions. In order to investigate effective mechanisms, various experiments, including wettability alteration measurements, biosurfactant production tests, viscosity, and pH measurements, were performed. The contact angle tests exhibited that the selected microorganism can alter the wettability of carbonate surfaces by reducing the water/oil contact angle from 132° to 54°, representing a change from an oil-wet to water-wet state. Bacillus persicus also showed favorable results in biosurfactant production tests, including interfacial tension, emulsion index E24%, and oil displacement experiments. The viscosity measurements showed that the bacterial solution could decrease oil viscosity by about 27%. Moreover, no significant changes were found in the pH of the microbial solution during incubation and after treatment. Finally, core flooding experiments exhibited that microbial solution injection as a tertiary oil recovery method could recover 37.52% of the original oil in place. The results obtained in this study demonstrated the potential of MEOR plans targeting oil-wet/mixed-wet fractured and non-fractured carbonate reservoirs.

Stimulating relative permeability changes by low-frequency elastic waves: Theory and lab experiments

A model is presented to describe how low-frequency vibrations can induce changes to relative permeabilities in dual-porosity dual-permeability rocks. We show that a combination of two physical processes may cause this effect: 1) the wave-induced two-phase fluid flow between soft pores (fractures or cracks) and stiff pores (matrix); and 2) the contact angle hysteresis effect. These two effects lead to redistribution of fluid saturation between fractures and matrix, which may explain alteration of relative permeabilities by small transient strains (∼10−6) in rocks where the fluid flow occurs primarily through the fracture network, and fluid storage occurs predominantly in the porous matrix. We assume that the frequency is low enough that viscous and inertial effects are negligible and that any stress-induced increments of pore pressure are uniform within wetting and nonwetting fluid phases. We demonstrate that pulse-like vibrations are much more efficient in changing relative permeabilities than sinusoidal-shaped vibrations. Furthermore, we show that two waveforms with the same amplitude and frequency but with different polarities could have opposite effects on the alteration of relative permeabilities. Specifically, extensional pulses increase oil relative permeability and decrease water relative permeability in the water-wet rock. Contrary, compressional pulses decrease oil relative permeability and increase water relative permeability in the water-wet rock. To validate theoretical results, we developed a unique low-frequency laboratory setup and experimental methods. We performed drainage and imbibition cycles on a sandstone sample using oil and water as pore fluids. During flooding, the sample was excited by small-strain seismic pulses of a specific shape, with varying polarization direction, frequency, and amplitude. The preliminary laboratory results validate the theoretical model qualitatively. The proposed model may contribute to environmentally friendly and low-cost methods for stimulating hydrocarbon production in conventional reservoirs without invasive chemicals or fracking. In unconventional reservoirs, however, this technology can be envisioned as supplementary to standard EOR/IOR techniques. Normally, the seismic wave energy is too low to increase absolute permeability or decrease oil viscosity; only relative permeabilities can be affected.

Bacterial community dynamics during MEOR biostimulation of an oil reservoir in sumatera Indonesia

Biostimulation is a method of microbial enhanced oil recovery (MEOR) by injecting nutrients into an oil well to stimulate the growth of indigenous bacteria and their activities dealing with the increasing of oil recovery. This study aimed to obtain an optimum nutrient formulation at laboratory scale to be applied for MEOR field biostimulation pilot project. Field monitoring of chemical and bacterial composition in oil well was also carried out up to twelve weeks after biostimulation. The oil composition was analyzed by GC-MS and column chromatography. Bacterial community analysis was performed using 16S rRNA gene as the biomarker, which was sequenced by Illumina Miseq Sequencing. Based on Response Surface Methodology (RSM), the optimum nutrient concentrations that increase bacterial growth and decrease oil viscosity were molasses 5% (w/v), NPK 0.5% (w/v), and DAP 0.5% (w/v). The relative abundance of the bacteria and the community composition constantly changed during the monitoring process. Injection of molasses stimulated the growth of the hydrocarbonoclastic bacteria until the end of monitoring period. • Higher nutrient concentrations does not always stimulate the indigenous bacteria. • During the MEOR monitoring process, saturated and resinic fractions increased. • SRB growth was successfully suppressed by biostimulation treatment. • Biostimulation rise the bacterial community to a significantly different and more diverse species.

Enhanced Oil Recovery by Cyclic Injection of Wettability Alteration Agent for Tight Reservoirs

Low primary recovery factor and rapid production decline necessitates the proposal of enhanced oil recovery methods to mobilize the remaining oil resource of tight reservoirs, especially for oil-wet ones, and wettability alteration by injecting a chemical agent such as a surfactant is a promising option. A discrete-fracture-network-based mathematical model is developed with consideration of the displacement mechanisms and complicated physical-chemical phenomena during EOR by wettability alteration, and this model numerically solved by the fully implicit method. Simulation cases are conducted to investigate the production performance and key factors of cyclic injection of a surfactant. Cyclic injection can significantly improve the production of oil-wet tight reservoirs, and the ultimate recovery factor can be increased by 10 percent. The reason is that a surfactant can alter the wettability of a reservoir from oil wet to medium or even water wet, which triggers spontaneous imbibition and favors oil movement from a matrix into a fracture. Better EOR results can be achieved with decreasing oil viscosity, increasing matrix permeability, or decreasing fracture spacing. Cyclic surfactant injection is applicable to reservoirs with an oil viscosity of less than 7 mPa·s, a matrix permeability bigger than 0.01 mD, or a fracture spacing smaller than 150 m. It is favorable for the wettability alteration method by maintaining capillary pressure and reducing residual oil saturation as much as possible.

Probir i karakterizacija emulgirajućih bakterija koje razgrađuju ugljikovodike iz obalnih voda Kaspijskog mora

As a result of 400 cultures screening isolated from the contaminated coastal zones of the Caspian Sea, 4 new strains were selected that had a stable growth and utilized oil with NaCl concentration close to that of seawater. Stenotrophomonas chelatiphaga wkal49, Stenotrophomonas chelatiphaga wkal51, Sphingobacterium kitahiroshimense wkar54, and Achromobacter sp. wkar55 were identified based on an analysis of the direct nucleotide sequence of the 16S rRNA gene fragment. The degree of oil degradation by these strains was above 50%. The hydrophobicity of the cell surface, emulsifying activity, the degree of influence on the viscosity of crude oil, and also the ability to produce surfactants were the four key factors that made up the studied parameters for the selected strains. The studied strains formed an emulsion layer on the surface of the culture medium. The most active producers of extracellular bioemulsifiers were the Stenotrophomonas chelatiphaga wkal49 and Stenotrophomonas chelatiphaga wkal51 strains. Both demonstrated the highest hydrophobicity, emulsification index, and the highest value for decreasing oil viscosity.

Development of (γ-Al2O3-Zeolite Y)/α-Al2O3-HPCM Catalyst based on Highly Porous α-Al2O3-HPCM Support for Decreasing Oil Viscosity

Highly porous cellular material (α-Al2O3-HPCM) support was synthesized by the template method. Highly porous support was used for the synthesis of the catalyst. A thin secondary layer with 25–30 μ thick γ-Al2O3 and zeolite Y was applied on the α-Al2O3-HPCM surface ((γ-Al2O3 (85%)-zeolite Y (15%))/α-Al2O3-HPCM). The catalyst based on the highly porous support was tested in a process of decreasing oil viscosity. The catalyst in the form of cylindrical granules and a thermal process of decreasing oil viscosity without the catalyst were used as the basis for comparison. α-Al2O3-HPCM in the catalyst provides low-quantity pores (d < 10 nm) and a quantity of general acid centers compared with the granular catalyst. On the other hand, it shows a more significant oil viscosity decrease (from 2500 to 41 cPs) and a low rate of gas generation (137 mL/h) for the catalyst with highly porous support. A high oil fraction was observed in the presence of the (γ-Al2O3-zeolite Y)/α-Al2O3-HPCM compared to the granular catalyst. The presence of large transport cells (pores) 1500–2000 μ for the catalyst based on highly porous support allowed a work period four times longer than that of experiment only with temperature without catalysts.

Analysis of models for porosity evolution in reservoir during steam injection

Depletion of traditional hydrocarbon reserves leads to the development of extracting methods for heavy crude oil and bitumen characterized by extremely high viscosity. The most effective technology is the steam-assisted gravity drainage. The aim of this method is to decrease oil viscosity by injection of hot steam into the reservoir. Increase of temperature, pore pressure and change of stress-strain state during this process significantly affect porosity which is the key storage parameter of the reservoir. This work is devoted to the analysis of models for porosity evolution during the steam-assisted gravity drainage process. The authors have developed an original model to describe steam-assisted gravity drainage which includes the mass balance equation for a three-phase flow, the energy balance equation involving latent heat due to vaporization/condensation of water/steam and Darcy’s law for fluid filtration. Numerical implementation of the proposed equations was based on the pressure-saturation algorithm. The results have shown a substantial qualitative and quantitative disagreement between the considered models. Coupling of porosity with volumetric strain leads to the rise of its magnitude. Models relating porosity to pore pressure show simultaneous existence of high-porous (near the injection well) and low-porous (near the production well) areas. In case when porosity is dependent on effective stress a circular area of a compacted soil is formed. Therefore, to obtain a correct estimation of the oil production rate in an arbitrary reservoir it is necessary to define the prevailing mechanism of porosity evolution (volumetric strain, pore pressure or effective stress).

Development of a Model Test System for a Piston Ring/Cylinder Liner-Contact with Focus on Near-to-Application Seizure Behaviour

Physical simulations of tribo contacts in internal combustion engines can act as a supporting tool to match upcoming guidelines and emission restrictions. In particular, the scuffing resistance of the contact between the piston ring and cylinder liner suffers under decreasing oil viscosity and limitation of antiwear additives. This paper aims to provide an experimental method to simulate the scuffing of the piston ring/cylinder liner-contact and to validate this method with real engine parts and the literature from engine tests. The experimental methodology uses a linear tribometer TE77 to test specimens from original piston rings and liners under reciprocating motion. Additionally, the ring specimen is given the opportunity to perform secondary movements (ring twisting, ring turning) and to run under deficient lubrication conditions similar to the engine. A specially designed test strategy enables the reproducible creation of seizure of the tribosystem. The seizure resistance of two engine oils, tested for validation, correlates with the known engine performance. Therefore, the model test system can be seen as a reproducible tool for simulating seizure of a ring/liner-system, showing similar trends and wear mechanisms as in an engine. Surface analysis depicts similarities between the scuffed surfaces of an engine and the model and discusses the origin of seizure based on the model specimens together with the relevant literature.

Application of flue‐gas foam in thermal‐chemical flooding for medium‐depth heavy oil reservoirs

AbstractHeat loss in wellbore during steam injection is considerable due to the deep burial of medium‐depth heavy oil reservoirs, leading to a low steam quality in the bottom of well. As for hot water flooding, the mobility ratio between oil and water is small, which decreases oil recovery. Flue‐gas foam assisted thermal‐chemical flooding is a new method for heavy oil reservoir. Compared to hot water flooding, flue‐gas foam assisted thermal‐chemical flooding can decrease oil viscosity, achieving higher sweep efficiency. However, the combined mechanisms of all the injected components have not been studied systematically. In this work, the role of CO2, viscosity reducer and hot water for oil viscosity reduction and distribution characteristics of residual oil were studied using the numerical simulation methods. Results show that although the percentage of viscosity reduction contribution of viscosity reducer can be as high as 60%, only wider range of this effect can help recover more remaining oil effectively. In the presence of flue‐gas foam, CO2 and viscosity reducer can decrease oil viscosity in the upper and bottom layers of the reservoir, respectively. Two parameters of the area proportion of removed‐oil (ARRO) and the average removed‐oil saturation (SDRO) are defined. It is believed that both ARRO and SDRO are quite small for the hot water flooding, which is assisted by viscosity reducer. The flue‐gas foam can obviously expand the area of removed‐oil, but the average removed‐oil saturation is slightly lower. The combination of flue‐gas foam and viscosity reducer is a promising displacement method.

Improving Water-oil Relative Permeability Parameters Using New Synthesized Calcium Oxide and Commercial Silica Nanofluids

This paper addressed the application of new hydrophobic synthesized calcium oxide (CaO) and silicon dioxide (SiO2) nanofluids to low permeability carbonate porous media. Crude oil and plugs were selected from one of oil reservoirs in the west of Iran. The main goal of this paper is comparing the results of improving water-oil relative permeability parameters in low permeability plugs of carbonate cores in the presence of new synthesized CaO and SiO2 nanofluids. All the experiments were performed at a temperature of 40 °C and at a nanoparticle concentration of 45 ppm. The experimental approaches were designed into two main steps: 1) the effects of both nanoparticles on the changes in interfacial tension (between oil and brine) and oil viscosity 2) the effects of both nanoparticles on wettability (qualitatively) and relative permeability parameters. SiO2 and CaO decreased interfacial tension from 46.414 mN/m to 41.772 mN/m and 32.860 mN/m respectively. Moreover, SiO2 and CaO decreased oil viscosity from 9.90 cP to 8.61 cP and 8.01 cP respectively. Based on the obtained results in the core flood experiments, although CaO and SiO2 nanofluids decreased effective water permeability, effective oil permeability and ultimate oil recovery increased. Moreover, it was seen that the CaO nanofluid improved oil flow in carbonate cores more than the commercial SiO2 flooding. Finally, it was seen that both nanoparticles change the wettability from oil-wet to water-wet (qualitatively).

Technical and economic feasibility of a novel heavy oil recovery method: Geothermal energy assisted heavy oil recovery

Conventional hot water flooding generally has disadvantages of high energy consumption and large capital expenses. To improve the economy of hot water flooding, a novel geothermal energy assisted heavy oil recovery method is presented. To validate this idea, a numerical simulation study is conducted to analyze the performance of the heat exchange well and heavy oil recovery process. Furthermore, the new method and conventional hot water flooding are compared to examine the economic feasibility of this new method based on the financial net present value. Finally, factors that may affect the feasibility of this new method are discussed. The simulation results show that compared with cold water flooding, the new method can increase heavy oil recovery by more than 7%. Moreover, the financial net present values of the new method at different oil prices all surpass those of the conventional water flooding, and thus the new method proposed is feasible both technically and economically. The analysis on the factors affecting the feasibility reveals that the critical oil price (the oil price when the financial net present value equals 0) of the new method decreases with increasing heavy oil reservoir thickness, decreasing oil viscosity, permeability variation coefficient and initial reservoir pressure.

EMULSION INVERSION OF CRUDE OIL BY SOLID PARTICLE AND SURFACTANT ADDITION

Crude oil produced as water-in-oil (W/O) emulsion can show high viscosity, causing difficulties during pipeline transportation. The production of O/W emulsion by adding an aqueous phase containing solid particles and surfactant is an alternative to decrease oil viscosity. Thus, the objective of this work is to study the synergistic effect of a surfactant (Triton X-100) and a solid particle (sodium bentonite) addition on emulsion inversion. Emulsions were characterized in conductivity, rheology, kinetic stability, and droplet size analyses. W/O to O/W emulsions inversion occurred when aqueous solutions were between 30 and 40% (m/m), according to conductivity and rheology analyses. The increment of water content from 30 to 50 % (w/w) increased mean droplet size from 2.6 to 10.6 µm, increased phase separation from 9.5 to 68.0 (v/v), and decreased emulsion viscosity from 183 to 1.07 mPa.s. Aqueous solution containing solid particle and surfactant affected emulsions’ properties, producing systems with lower viscosity than crude oil, making it easier for oil pumping and pipeline transportation.

Experimental and numerical investigation of mutual solvents for EOR applications

Abstract More than half of the oil discovered in existing oil reservoirs is left behind after primary and secondary recovery. It is essential to increase oil recovery from existing fields to meet future oil demand. The injection of solvents, an established enhanced oil recovery (EOR) technique, has shown significant improvement in oil recovery over conventional water floods. However, injection of pure solvent slugs is expensive for field operators. To mitigate this problem, recent literature has proposed the use of brines that are saturated with mutual solvents (which dissolve in both oil and water phases). In this paper, we investigate the behavior of two mutual solvents, carbon dioxide (CO2) and diethyl ether (DEE). We have performed several core-floods in sandstone and carbonate cores. Injecting CO2-rich brine (carbonated water) into sandstone cores did not improve oil recovery. However, there was an improvement in oil recovery as a result of carbonated water injection in carbonate cores, which also displayed significant plugging during the experiment. There was also a noticeable improvement in oil recovery in the case of DEE-rich brine, but without any plugging issues. Mutual solvents dissolved in oil, swelled oil, and decreased oil viscosity which mobilized the oil. The experimental work was corroborated with numerical modeling to reproduce the results of both the solvents. Although the simulator is capable of handling rock–fluid interactions, such as mineral dissolution, the exact nature of the grain mobilization and pore-throat plugging was not incorporated in the numerical model. As a result, the simulator was unable to fully mimic the experimental observations of carbonated water floods. In contrast, since there was no apparent nor significant rock-fluid interaction in the DEE-rich brine case, it was successfully matched by the simulator.

Water-in-oil emulsification in a bifurcated tree-like network: Flow distribution properties and their impact on the emulsion polydispersity

This paper presents a numerical study on the water-in-oil emulsification process through the parallelization of micro/mini-channels. Firstly, the single-phase fluid flow distribution uniformity in the bifurcated tree-like fluidic network is discussed. Secondly, the separate roles of the oil viscosity and the interfacial tension on the plug details are clarified. Finally, the impact of flow distribution non-uniformity among the parallel mini-channels on polydispersity of the produced emulsion is evaluated by modelling.The obtained results show that for bifurcated tree-like fluidic network, the single phase flow distribution is the flow distribution non-uniformity increases linearly with the increasing mean Rech once a transitional Re is reached. The water plug length and volume increase with the increasing interfacial tension and the decreasing oil viscosity under our tested conditions. Correcting factors relevant to the modified liquid properties have to be added in the predictive correlations for plug length and volume. For water-in-oil emulsification in parallel channels, its polydispersity Pw is affected by the single phase flow distribution uniformity, the total water/oil flow-rate ratio and most importantly by the flow-rate ratio distribution non-uniformity. An empirical correlation has been proposed to predict the emulsion Pw based on these influencing factors.

Isolation and Characterization of Oil-Degrading Bacteria from One of South Sumatera’s Oilfield

Microbial Enhanced Oil Recovery (MEOR) is a tertiary oil recovery method that utilizes microbes to enhance oil production. This research was focused on the isolation and characterization of indigenous bacteria from a South Sumatra’s oilfield which were able to degrade heavy crude oil and decrease oil viscosity. The total of 33 colonies were successfully isolated based on sequential isolation method and screened based on oil degradation activity and SARA analysis. Isolate G3, G7, and N6 were choosen as the best candidate as they were able to reduce oil viscosity up to 22,67%; 23,14%; and 24,36% respectively. Based on 16S rRNA analysis, isolate G3 which was able to degrade aromatic fraction (38,27%) and resin (29,26%) was identified as Pseudoxhantomonas taiwanensis. Isolate G7 which degraded aromatic fraction (61,14%) was identified as Brevibacillus agri while N6 which degraded asphaltene fraction (51.76%) was identified as Bacillus subtilis. In addition, the change in nalkana fraction (C11 – C28) abundance relative to phytan showed that all of the bacterial isolates were able to change those fractions of crude oil. This study showed that three bacterial species isolated from South Sumatran Oilfield were able to degrade heavier fraction of crude oil and reduce its viscosity. This result suggests that those bacteria are highly potential to be applied for MEOR technology.

Influence of silicon oxide and aluminum oxide nanoparticles on air and CO2 foams stability in presence and absence of oil

One of the major issues in foam application for enhanced oil recovery (EOR) is the foam stability in presence and absence of oil. In this study, a systematic experimental study of the bulk and bubble scale stability of air and CO2 foams stabilised by sodium dodecyl sulphate (SDS) and nanoparticles were conducted. Foam-oil interactions were further study in etched glass micromodel in order to investigate and compare the foam performance at static and dynamic conditions. Influence of nanoparticles hydrophobicity and oil types on foam behaviors were assessed. Static bulk and bubble-scale experiments were conducted with KRUSS dynamic foam analyser while the flow characteristics experiments were conducted in etched glass porous medium. Results show that the foam half-life increased while the size of generated bubbles decreased with the presence of nanoparticles in the surfactant solution. Successful propagation of nanoparticles-SDS foam through capillary snap-off and lamellae division was observed in presence of oil in the porous medium. Foam stability decreases with decreasing oil viscosity and density. Except for hydrophobic aluminum oxide nanoparticles with contact angle of 118.19°, the static and dynamic stability of the air and CO2 foams increased with increasing nanoparticles hydrophobicity. The addition of nanoparticles into the surfactant solution considerably improved foam stability due to the adsorption and aggregation of the nanoparticles at the thin lamellae and plateau border. This prevents liquid drainage and film thinning by increasing film elasticity and film strength from 23.2 µm to 136µm. It can be concluded from this study, that stable air and CO2 foams can be generated with nanoparticles- surfactant mixed systems in absence and presence of oil with favourable nanoparticles hydrophobicity.

Effect of Diluents on the Rheological Properties of Maya Crude Oil

Understanding the rheological properties of mixtures of heavy oil or bitumen and diluents, specifically at low temperatures, is key in designing different processes employed in the production or transportation of these resources reliably and efficiently. The effect of diluents (n-heptane, toluene, and toluene + butanone (50:50 vol %)) on the non-Newtonian behavior of Maya crude oil including shear thinning and thixotropy at temperatures from 258 to 333 K are discussed. Toluene + butanone (50:50 vol %) addition to Maya crude oil induces the greatest reduction in shear thinning behavior irrespective of temperature. Thixotropic properties of mixtures of Maya crude oil and diluent were studied through startup experiments. It was shown that toluene + butanone (50:50 vol %) is the best diluent in moderating the thixotropic effect, whereas n-heptane showed the most pronounced thixotropic effect. It was shown that toluene + butanone (50:50 vol %) is more promising in decreasing oil viscosity in comparison to two other diluents tested. Less of this diluent is required to decrease the viscosity to a certain value, which confirms its potential to be used in the industry as a diluent. The results presented also provide a reliable database for model development and evaluation.