Search

Worm gearbox has the relative sliding motion between a tooth of worm and worm wheel which causes friction energy loss. The loss in friction energy is transfer into an equivalent amount of heat and that heat dissipate into lubricant oil. The frictional heat dissipation into lubricant oil causes an increment in the temperature of the lubricant oil and a decrement in the overall performance of the gearbox. To observe the effect of different operating parameters on increment in temperature of lubricant oil, one response parameter was defined i.e. Lubricant Heating Time (time required to raise the temperature of lubricant from 350 to 500. Oil volume, oil type, load on worm wheel and process time were taken as operating parameters. Every operating parameter was varied at three different levels. From the experimental results, it is observed that for all the oils if the load on the worm wheel increases keeping the oil volume constant then Lubricant Heating Time decreases and it follows the linear decrement relationship with the load on worm wheel. Also, for all the oils if the oil volume increases keeping the load on the worm wheel constant then Lubricant Heating Time increases and it follows a linear increment relationship with oil volume. It is observed that the rate of increase of temperature of lubricant oil initially was very high, latter on it decreases. The viscosity of oil affects the rate of increases in the temperature of lubricant oil. There exists an inverse relationship between Lubricant Heating Time and oil viscosity.

In this paper, the effects of clearance between piston and cylinder and oil viscosity index on the friction of area between the piston and cylinder of an internal combustion (IC) engine were investigated experimentally and theoretically. To this end, two values of 33 and 66 µm for the piston clearance, and two types of engine oil namely SAE10W40 and SAE20W50 were considered. To carry out the experiments, the engine was run under motored condition. The experiments were implemented at different oil temperatures and engine speeds. Based on the experimental results, although reduction in the piston clearance and the use of 20W50 oil caused an increase in the friction, but the effects of these two parameters became less with an increase in oil temperature and engine speed. The experimental results showed that the effect of clearance on the friction was more noticeable for low speeds. The maximum influence of the piston clearance decrease on the friction was 16% with the use of 20W50 oil at 1000 r/min when the oil temperature was 35 °C. The minimum influence of the piston clearance on the friction was 0.5% when the oil temperature was 90 °C and the engine speed was set on 6000 r/min. The theoretical results showed that the most contribution of the friction of piston/ring/cylinder assembly belonged to the piston skirt. Moreover, the effect of the piston skirt on the friction at high speeds was more than that of the piston rings. The friction value of the piston rings was not significantly altered by changing the engine speed, but it was considerably changed by the oil temperature variation. Whereas the piston skirt friction had an increasing trend with the speed rise, the change in the engine oil temperature, especially for low temperatures, had no significant effect on the piston skirt friction.

To explore the synergistic mechanism of polymer and surfactant in the binary combination flooding of low-permeability reservoirs, the adaptability experiment of polymer salt-resistant partially hydrolyzed polyacrylamide and nonionic surfactant was carried out in the indoor system. Experiments at different ratios are also performed. The results show that the selected poly/surface binary flooding system increases with the concentration of polymer or surfactant, the viscosity of the poly/surface binary system also increases and, at the same time, has better temperature and salt resistance. The viscosity of the binary system will decrease when the salinity increases. When the surfactant concentration CS = 0.2% and the polymer concentration CP = 0.2%, the viscosity of the system is the highest. The viscosity of the poly/table binary system at different concentrations decreases when the temperature rises: pure polymer (CP = 0.2%), poly/table binary system displacement fluid CP = 0.1% + CS = 0.2% and CP = 0.2% + CS = 0.2%; and the injection pressure first rises and then drops. The final recovery rate is 51.8%, which meets the development of most oil reservoirs.

In the present research, the rheological behavior of MWCNT (50%)-ZnO (50%)/5W50 nanofluid is investigated in the temperature range of 5–55 °C, different solid volume fractions (SVFs) between 0 and 1%, and shear rates (SRs) of 666.5–10,664 s−1. With the aim of preventing unwanted viscosity increase in nano-engine oil and according to test results, the SVF of 0.05% and 0.1% was selected as best choices for having an enriched engine oil containing nanoparticles with improved thermal conductivity and controlled viscosity behavior. Also, to check the sensitivity of nano-engine oil viscosity against unwanted changes in temperature and SVF, a sensitivity analysis was carried out on the produced nano-engine oil. Focusing on the results shows that the lowest sensitivity of viscosity occurs at lower temperatures and SVFs that are about 0.1% and 0.5% at a temperature of 5 °C and SVF of 0.05%, respectively. On the other hand, at higher temperatures and SVFs, the sensitivity of viscosity against temperature and SVF reaches its highest values that are about 1.2% at 55 °C and 6% at SVF of 1%. Based on results SVF of 0.05% is the most suitable enriched nano-engine oil with lowest viscosity influens level against dispersed nanoparticles and also with low level of sensitivity. Proposing a mathematical-based correlation is another achievement of the present study to predict the rheological behavior of nano-engine oil.

2,3,3,3-tetrafluoroprop-1-ene (R1234yf) and trans-1,3,3,3-tetrafluoropropene (R1234ze(E)) as the promising refrigerants have attracted wide attention. To understand better of the refrigeration-cycle performance working with new refrigerants, the thermodynamic properties of refrigerant/oil mixtures should be well known, especially the viscosity of the refrigerant/oil mixture. Using a dual-capillary method, the viscosities were measured for POE75 saturated with R1234yf and R1234ze(E) from 303.15 to 348.15 K. The viscosity trends of R1234yf/POE75 and R1234ze(E)/POE75 mixtures are similar. As rising solubility, a sharp decrease of viscosity appeared firstly, and then it goes to be flat. Results show that the dissolved refrigerant in oil largely reduces the oil viscosity. Comparing to viscosity models including an empirical model (modified Setchenow-type equation) and Eyring's absolute rate theory coupled with three excess Gibbs energy models (Eyring-MTSM model, Eyring-NRTL model, and Eyring-wilson model), the Eyring-MTSM model give better results than the other studied models.

The results of a study of the phase behavior of six narrow oil fractions in the 150-350 K temperature range at atmospheric pressure using scanning calorimetry are presented. It is shown that there is a correlation between glass transition of the studied oil fractions and their mean boiloff temperature, molecular mass, and initial oil viscosity.

Heavy crude oil is one of the most potential fossil fuels at present and in the future. However, its high viscosity severely hinders its recovery from reservoir conditions. Heavy oil viscosity redu...

One of the elements that affect the reliability and service life of a hydraulic pump is the stability level of oil viscosity as a power successor. The stability level of oil viscosity is affected by changes in temperature. The compression and friction process that the oil receives to move the hydraulic pump will increase the oil temperature so that its viscosity level will decrease. To maintain the performance of the hydraulic pump, the oil temperature must be maintained at room temperature. In the case study at PLTA Ir. H. Djuanda, Lurah Kawi Street No.1 Jatiluhur-West Java, to cool the oil, a shell and tube heat exchanger type JPK 13699068 (single tube) is used. This research was conducted to test whether the heat exchanger is still working properly, the parameter is that the cooled oil exit temperature must be close to room temperature. The effectiveness of the heat exchanger will be tested by comparing the test results with the condition of the heat exchanger without impurity factors. The test was carried out by measuring the temperature of the HX intake oil at 44 0 C with a discharge of 0.437 kg/s, and the temperature of the HX inlet water at 28 0 C with a discharge of 0.498 kg/s. The results showed that, for the coefficient of U between 110 to 350 W/m 2 o C with a water impurity factor of 0.0001 m 2 o C/W and an oil impurity factor of 0.0002 m 2 o C/W, there was a decrease in effectiveness from an average of 74.5% to 73.7%, and there was an increase in oil temperature out of the heat exchanger from an average of 32.07 o C to an average of 32.21 o C.

Objective: The objective of the article is research into the effect of liquid crystal additive concentration and electric field on the viscosity of industrial oil, and study into influence of concentration on low-temperature properties of oil. Methods: The research and calculations were made by the methods presented in State Standards DSTU GOST 33-2003, GOST 25371-201 and GOST 20287-91. Findings: The authors obtained dependencies of change in viscosity and chilling temperature of industrial oil on liquid crystal additive concentration. Besides, they obtained dependencies of change in industrial oil viscosity treated by electric field at various concentrations of a liquid crystal additive. The study deals with the viscosity index for industrial oil with various concentrations of an additive. A range of the concentrations chosen was also substantiated. The results of the research were processed in Statistica software; regression equations which described dependencies of oil viscosity on additive concentration were obtained.

We experimentally investigate the rheology and stress fluctuations of granules densely suspended in silicone oil. We find that both thickening strength and stress fluctuations significantly weaken with oil viscosity $\eta_0$. Comparison of our rheological results to the Wyart-Cates model for describing different dynamic jamming states suggests a transition from frictional contacts to lubrication interactions as $\eta_0$ increases. To clarify the contribution from viscous interactions to the rheology, we systematically measure stress fluctuations in various flow states. Reduction of stress fluctuations with $\eta_0$ indicates that a strong lubrication layer greatly inhibits force correlations among particles. Measuring stress fluctuations in the strong shear thickening regime, we observe a crossover from asymmetric Gamma to symmetric Gaussian distributions and associated with it a decrease of lateral (radial) correlation length $\xi$ with increasing shear rate., Comment: 18 pages, 5 figures

This study aims to determine the effect of temperature on oil viscosity or viscosity using the falling ball method. The approach in this study uses a quantitative approach to the type of laboratory experimental research. The population of this research is cooking oil, by taking three types of oil samples. The three types consisted of palm oil, coconut, and olive which were then observed for their effects on temperature using the fall ball method. Data were collected through laboratory experiments with measurements three times using the falling ball viscosity method. The data analysis technique used is regression analysis. Based on tests that have been done, it can be observed that palm oil before it is heated has a viscosity value of 0.885 Ns / m2, when palm oil is heated to temperatures of 40˚C, 60˚C, 80˚C, and 100˚C the viscosity value changes to 0.854 Ns / m2, 0.754 Ns / m2, 0.828 Ns / m2 and 0.616 Ns / m2. Coconut oil before heating has a viscosity value of 0.828 Ns / m2, when heated with the same temperature the viscosity value changes to 0.666 Ns / m2, 0.588 Ns / m2, 0.572 Ns / m2, and 0.524 Ns / m2. Olive oil before heating has a value of 0.919 Ns / m2, when it is heated the value decreases to 0.869 Ns / m2, 0.774 Ns / m2, 0.746 Ns / m2, and 0.680 Ns / m2. Correlation value obtained based on data calculations is -0.616 meaning that temperature and viscosity have a strong relationship, a negative sign indicates that the relationship is inversely proportional. It can be seen that there is an effect of viscosity value on cooking oil temperature.

The effect of heavy stock oil heating by ultra-high frequency (microwave) electromagnetic field on oil viscosity changes is investigated in the present work. The influence of the phase state of supramolecular formations on the rheological properties of heavy oil after the application of various dielectric heating schemes is studied. The energy of the intermolecular interaction of asphaltene nanoaggregates of various sizes is estimated based on rheometric studies of heavy oil treated with microwave energy. It has been established that for a stable asphaltene oil, the hybrid microwave processing scheme is most effective.

Some numerical results obtained by modeling the thermogas displacement of oil from a porous reservoir are discussed. The displacement is performed by a heated water-gas mixture. The injected two-component gas consists of nitrogen and oxygen. Heat, carbon dioxide, and water vapors are released during the reaction process. The heat release decreases the oil viscosity and accelerates the displacement process.

The properties of petroleum and synthetic oils used as bases for anti-corrosion materials are determined. The viscosity-temperature characteristics determine the feasibility of applying oil coatings. Regression equations allowing the thickness of the resulting protective film to be calculated as a function of the oil viscosity are obtained. Results from wettability assessments indicate that the oil surface is hydrophilic. The oil films are permeable to water; stimulants, and corrosion inhibitors. Films of the studied oils inhibit anodic dissolution of steel and accelerate slightly cathodic reduction of oxygen. The nature of the oil base has little effect on the protection effectiveness if anti-corrosion additives Emulgin or Mobiin-3 are added at concentrations wt. %.

Rheological investigation and correlation development for the flow of heavy oil (HO) were done in a temperature range of 30–50 °C in the presence of natural surfactant extracted from Madhuca longif...

Purpose The purpose of this paper is to study the effects of single parameters for temperature characteristics of oil film in port plate pair and the relationship of calculated results and experimental results under different viscosity. Design/methodology/approach The paper established the mathematical model of oil film of port plate pair, calculated the energy equation of port plate pair, simulated for the oil film and temperature distribution and selected different kinds of lubricants to analyze the calculated value and the experimental value. Findings The results show: temperature rise of port plate pair is reduced with the increase of oil viscosity; temperature rise of port plate pair is decreased with rise of initial oil film thickness; temperature rise of port plate pair is increased with the rise of cylinder body speed, inclination angle and sealing belt width; and through the comparison of calculated value and experimental value, under the same viscosity and cylinder speed, experimental results are bigger. Originality/value This paper used the methods that the temperature of port plate pair was calculated numerically, and the results were consistent with experimental results, so it can get high precision.

This paper presents the research work on using a machine learning algorithm to predict the viscosity of Niger Delta oil reservoirs using formation volume factor and fluid density at bubble point pressure as correlating parameters. Oil Viscosity stands out when considering the amount of oil recoverable from the reservoir hence it is an important input into the recovery factor computation, material balance analysis, reservoir simulation/history match, EOR evaluations and many other applications. Laboratory techniques of obtaining oil viscosity are quite expensive and time consuming, hence the need for various mathematical correlations developed for its estimation. Majority of the correlations make use of empirical and experimental relationships developed from analyzing oil samples to obtain a trend to predict viscosity mostly for a basin. None of these has been developed for oil viscosity for Niger Delta fluids. Viscosity has been globally defined as the resistance to shear stresses within the fluid or the resistance of the fluid molecules to deformation. For a typical reservoir fluid system, where the liquid and gas exist in dynamic equilibrium, reservoir fluid composition along with temperature and pressure has been established to determine reservoir fluid viscosity1. Hence for an isothermal system and at a defined pressure in the reservoir the viscosity will be dependent on largely the composition. The reservoir fluid composition is also represented by the reservoir fluid density and the formation volume factor; therefore it is possible to deduce the viscosity of reservoir fluids from the oil density and formation volume factor even though a direct relationship has not been established between these parameters. Therefore, a correlation that can establish a relationship between the specific gravity (density) and FVF with viscosity will have significant value in the oil and industry. The data used for this analysis includes viscosity, formation volume factor, oil density at 2800 sample bubble point pressure. The data was obtained by analyzing over 3500 PVT Analysis reports, extracting the data points using a python work program, cleaning up the data and removing erroneous data, performing preliminary analysis to establish baseline relationships between the data. Supervised learning using a classification tree model was used as the machine learning approach. Seven different machine learning algorithms were reviewed, and the Random Forest Regressor was selected as the most suitable algorithm for the prediction. The model prediction results were quiet encouraging as the model was able to predict viscosity within 10% deviation from the experimental viscosity for over 80% of the cases resulting in about 90% prediction accuracy. The analysis of the results further revealed that the model could better predict viscosity of Medium to Light oil with an R2 value of between 0.90-0.96 without adjusting some obvious erroneous data points. Future of this research work will involve further in-depth analysis which will merge the preliminary QC plots with the results to evaluate the effect of the outlier sample points on the final predictability of the model. Also explore other machine learning models to further improve predictability and be able to predict viscosity across other pressure values other than the bubble point pressure to capture viscosity along the producing life of the reservoir.

The present work aims to study the effect of disk material and disk surface roughness on the oil recovery rate and oil recovery efficiency. Materials used in this study were steel, plastic, and woven fabric; two types of oil were used, namely, SAE50 and used car engine oil. The oil recovery rate was found to increase with increasing disk rotational speed. The rate of oil recovery ranged from 88.19 to 337.14 (mL/min) for SAE50 oil and ranged from 89.03 to 355.4 (mL/ min) for used oil depending on disk rotational speed and the type of disk. The rough steel disk performance is inferior to other disks except at high rotational speeds. Oil recovery efficiency was found to decrease with increasing disk rotational speed. The oil recovery efficiency ranged from 77 to 95.2 for SAE50 oil and ranged from 72 to 95.2 for used oil depending on disk rotational speed and the type of disk. Specific energy consumption ranged from 3.08×10−4 to 4.7×10−4 kW·h/kg of recovered SAE50 oil and ranged from 3.04×10−4 to 2.589×10−4 kW·h/kg of recovered used oil depending on disk rotational speed.

The load capacity of oil-immersed transformers affects the safety of power system operation. In order to fully exploit and utilize the load capacity of transformer, a novel improved model is proposed based on the principle of thermal- electric analogy. Firstly, solar radiation is introduced as a new heat source, and the thermal conductance is modified by considering the effect of temperature on oil viscosity. Then, a transformer load capacity evaluation model based on the thermal-electric analogy principle is proposed under the constraint conditions of top-oil temperature, hot-spot temperature, relative life loss, and auxiliary equipment capacity level. Finally, a 50 MVA transformer is carried out for oil temperature and load capacity. The results demonstrate that compared with Tang-model and the transformer guidelines, the error of the top-oil temperature and the hot-spot temperature of the new model is smaller. In addition, for periodic loads, transformer load capacity also represents different characteristics, which provides a guide for exploiting the load potential of power transformers.

This study investigates surface fatigue damages by keeping fixed the material of test gear teeth, rotation speed, lubricating oil, and the applied load, and changing the operating temperatures of oil. In experimental studies, pre- and post-test weights of gear teeth samples were established, surface roughnesses were measured, and micrograph examinations were carried out on teeth surface. As a result, surface roughness and wear were established to increase in proportion to the rise in temperature of oil.

Injection conformance reversion commonly observed during polymer flooding in offshore heterogeneous heavy-oil reservoirs weakens the volumetric sweep of polymer solution and compromises its EOR results. To investigate its mechanisms and impact factors, one mathematical model to predicate injection conformance behavior is constructed for heterogeneous reservoirs based on the Buckley-Leverett function. The different suction capability of each layer to polymer solution results in distinct change law of the flow resistance force, which in turn reacts upon the suction capability and creates dynamic redistribution of injection between layers. Conformance reversion takes place when the variation ratio of flow resistance force of different layers tends to be the same. The peak value and scope of conformance reversion decrease and reversion timing is advanced as oil viscosity or permeability contrast increases, or polymer concentration or relative thickness of low permeable layer decreases, which compromises the ability of polymer flooding to improve the volumetric sweep and lower suction of the low permeable layer. The features of offshore polymer flooding tend to make the injection conformance V-type and create low-efficiency circulation of polymer in a high permeable layer more easily. These results can provide guidance to improve the production performance of polymer flooding in offshore heterogeneous heavy-oil reservoirs.

This chapter addresses the phase behavior of heavy crude oil and multicomponent and multiphase fluid mixtures. First, for a hybrid thermal–noncondensable gas (NCG) process, the pressure–volume–temperature (PVT) behavior of a heavy oil-NCG mixture is experimentally studied. Correlations for the PVT behavior of the heavy oil-NCG mixture are discussed. Second, for a hybrid thermo-solvent process, the behavior and mechanisms of solvent extraction and asphaltene precipitation are discussed. A mathematical modeling method for the phase behavior of a heavy oil–solvent mixture is investigated. Third, for a hybrid thermochemical process, the mixture viscosity and interfacial tension between heavy oil and a chemical additive are studied and a systematic method is proposed to evaluate oil viscosity reduction. Moreover, emulsification between crude oil and chemical additives is discussed.

An algorithm utilizing four basic processes was described for chemical oil spill dispersion. Initial dispersion was calculated using a modified Delvigne equation adjusted to chemical dispersion, then the dispersion was distributed over the mixing depth, as predicted by the wave height. Then the droplets rise to the surface according to Stokes’ law. Oil on the surface, from the rising oil and that undispersed, is re-dispersed. The droplets in the water column are subject to coalescence as governed by the Smoluchowski equation. A loss is invoked to account for the production of small droplets that rise slowly and are not re-integrated with the main surface slick. The droplets become less dispersible as time proceeds because of increased viscosity through weathering, and by increased droplet size by coalescence. These droplets rise faster as time progresses because of the increased size. Closed form solutions were provided to allow practical limits of dispersibility given inputs of oil viscosity and wind speed. Discrete solutions were given to calculate the amount of oil in the water column at specified points of time. Regression equations were provided to estimate oil in the water column at a given time with the wind speed and oil viscosity. The models indicated that the most important factor related to the amount of dispersion, was the mixing depth of the sea as predicted from wind speed. The second most important factor was the viscosity of the starting oil. The algorithm predicted the maximum viscosity that would be dispersed given wind conditions. Simplified prediction equations were created using regression.

Oil-water emulsion effects on a seven-stage electrical submersible pump (ESP) performance are studied experimentally and numerically with computational fluid dynamics (CFD) simulation. At different oil-water fractions, temperatures, and ESP rotational speeds, the performance of the third stage was measured. The intention of this work is to validate and compare experimental data with CFD simulation results. In addition, flow structures can be visualized through the CFD simulation for oil-water emulsion flows. Density and mass flow rate are measured using the mass flowmeter while the emulsion effective viscosity is derived from the pipe viscometer installed downstream of the ESP. CFD simulations are carried out with estimated droplet sizes of the dispersed phase for oil-water flows, and the results are compared with the experiments. For the wall roughness, a higher value is used due to the extended use of the ESP. The three-dimensional, steady-state Reynolds-Averaged Navier–Stokes (RANS) equations with standard shear stress transport (SST) turbulence model are solved in ANSYS CFX solver by employing the frozen-rotor technique. With high-quality structured hexahedral mesh grids, the simulated pressure increment is compared with corresponding experimental results. For single-phase cases, results show considerable differences compared to experiments, which may be partially due to neglecting leakage losses in CFD simulations. When the two-phase simulation is conducted, it is confirmed that the solver takes oil and water as dispersion instead of emulsion, for which rheological behavior is not reflected. This is because the solver is based on two sets of Navier-Stokes equations for each phase. Consequently, the better approach for simulating the emulsion flow in ESPs by CFD methodology is to assume a single-phase, pseudo-homogeneous fluid with the rheology depending on the oil and water fractions and properties.

Water flooding has been applied for more than seventy years in both conventional and unconventional heavy oil reservoirs. Although it is generally accepted that the mechanisms of water flooding in heavy oil systems are totally different than that of light oil reservoirs, there is not a systematic study to specifically investigate water flooding in heavy oil systems. This article presents the findings of core flooding experiments in water-wet systems and gives some insights on the interplay between capillary and viscous forces in imbibition displacement processes. Seven different oils of various viscosities, ranging from 1 to 15,000 mPa.s at 25 °C, were used in nineteen core flooding experiments where injection velocity was changed from 0.7 to 24.3 ft/D (2.5 × 10−6 m/s to 86.0 × 10−6 m/s). An in-line densitometer was used to precisely determine breakthrough time. Capillary forces and instability analysis were used to quantify the balance between viscous and capillary forces. On physical grounds, the capillary number, which is the relative magnitude of viscous and capillary forces during a displacement, should be the first-order influence on residual oil saturation. However, Abrams (Abrams, 1975) showed that accounting for the viscosity ratio improves the correlation to residual oil saturation for oil viscosity below 37 mPa.s. Our observations extend the range of oil viscosity to 15,000 mPa.s and when combined with 178 datasets from the literature indicate that viscosity ratio has much more influence than capillary number on residual oil saturation. Standard models such as Buckley-Leverett theory predict that oil recovery at water breakthrough depends only on phase mobilities. However, our observations indicate that flow velocity also influences breakthrough oil recovery. At oil to water viscosity ratios smaller than 20, breakthrough oil recovery monotonically increases with increasing injection velocity. For intermediate viscosity ratios (20 < μo < 160), breakthrough oil recovery increases with decreasing injection velocity. At higher values of viscosity ratios, breakthrough oil recovery is almost independent of injection velocity. In these cases, late time oil recovery remarkably increases with decreasing injection velocity. This effect is more pronounced in more viscous oil systems suggesting the importance of imbibition in these systems. Our observations prove that water flooding, if applied at the most optimized mode that is a strong function of oil viscosity, can still be a very efficient EOR technique.

Summary The dynamics of a process in which a solvent in the form of a vapor or gas is introduced in a heavy-oil reservoir is considered. The process is called the solvent vapor-extraction process (VAPEX). When the vapor dissolves in the oil, it reduces its viscosity, allowing oil to flow under gravity and be collected at the bottom producer well. The conservation-of-species equation is analyzed to obtain a more-appropriate equation that differentiates between the velocity within the oil and the velocity at the interface, which can be solved to obtain a concentration profile of the solvent in oil. We diverge from an earlier model in which the concentration profile is assumed. However, the final result provides the rate at which oil is collected, which agrees with the previous model in that it is proportional to h, where h is the pay-zone height; in contrast, some of the later data show a dependence on h. Improved velocity profiles can capture this dependence. A dramatic increase in output is seen if the oil viscosity decreases in the presence of the solvent, although the penetration of the solvent into the oil is reduced because under such conditions the diffusivity decreases with decreased solvent. One other important feature we observe is that when the viscosity-reducing effect is very large, the recovered fluid is mainly solvent. Apparently, some optimum might exist in the solubility φo, where the ratio of oil recovered to solvent lost is the largest. Finally, the present approach also allows us to show how the oil/vapor interface evolves with time.

The influence of misalignment on a dynamically-loaded engine bearing is investigated using a mass-conserving cavitation algorithm. Whereas in statically loaded bearings misalignment can be conveniently characterized using two parameters known as the degree of misalignment DM and the misalignment angle α, an alternative approach is needed when the load changes direction. In this paper, the complication is treated by representing the severity of misalignment using two deflection angles θx and θy since these deflection angles remain constant in an engine bearing during operation. Effects of the variation of load, rotating speed, oil viscosity, supply pressure, journal mass and deflection angles are presented.

The air oxidation of super-heavy oil at low temperature was studied in laboratory and its influences on oil viscosity, component and steam sweep efficiency before and after air-injection were analyzed. The feasibility, operation mode and air flooding effect at the late stage of steam assisted gravity drainage (SAGD) were investigated by numerical simulation. The experimental results show for vertical-horizontal well pair SAGD test area of Xing VI Formation in Block Du 84 of Liaohe Oilfield, the low temperature oxidation occurred between 150–250 °C (steam chamber temperature), the oil viscosity increased greatly after low temperature oxidation, consequently, the oil displacement efficiency dropped sharply. Three development methods in the late stage of SAGD were simulated, i.e., steam + air low temperature oxidation, only air low temperature oxidation and only air high temperature oxidation. By comparing production dynamic curves and residual oil distribution etc., high temperature oxidation reduced the heat loss in late stage of SAGD, recovered the residual oil effectively, and prolonged reservoir development time. Key words: super heavy oil, SAGD, air injection, low temperature oxidation, high temperature oxidation

We present an experimental work in which the magnetoelastic resonance is used to determine the viscosity of lubricant oils in a wide range of values. Two different amorphous ribbons, clamped by one end, are immersed in oils with viscosities ranging from 32 to 320 cSt. The magnetoelastic resonance curve corresponding to the first longitudinal oscillation mode is measured inductively. An analysis method based in a least-squares fitting to a simple phenomenological expression, derived from the linear response formalism, allows determining the main parameters characterizing the resonance as a function of the oil viscosity. Both the frequency and the amplitude of the resonance show a strong dependence on the viscosity, but importantly, our analysis method additionally determines the dependence of the damping parameter, which is intrinsically dependent on the viscosity of the surrounding medium. We demonstrate that the analysis procedure is capable of analyzing a complex case in which two oscillation modes are excited simultaneously. We show that, in this case, the oils with larger viscosity produce a preferential damping of the higher frequency mode.

Steam flooding (SF) is an effective technology to exploit thin heavy-oil reservoirs. Long-term indoor experiments and field tests, however, show that SF has the problems of great heat loss and a limited steam-chamber affected area, which severely limits steam utility and the ultimate economic benefit of thin heavy-oil reservoirs. In this paper, based on a specific oil field in China, we designed a two-dimensional experimental model to investigate the effect of solvents on steam-chamber distribution and production dynamics, and the effect of heat-solvent coupling (molar ratio of steam and solvent) on steam-chamber front expansion. Then, based on the parameters of indoor experiments, we built a numerical model by CMG STARS to further study the influence of solvent migration in steam chambers under different injection molar ratios of steam and solvent. The results show that: i) According to experimental results, for SF, steam-chamber affected area is limited and oil recovery is low which is only 21.3%. After the solvent is added, steam-chamber affected area can be largely enlarged and displacement efficiency can be enhanced. Compared with SF, oil recovery of Solvent-Enhanced Steam Flooding (SESF) can be enhanced to 34.3%–58.3%; ii) According to the results of the numerical simulation, oil viscosity can be greatly reduced after the solvent is added. As a result, steam-chamber expansion can be improved, steam-chamber affected area can be enlarged, and displacement efficiency can be enhanced; iii) the optimal injection molar ratio of steam and solvent was around 8:1 for SESF.

To prevent the occurrence of the cavitation phenomenon in hydraulic shock absorber, the production process of the cavitation during the recovery process of shock absorber is studied, and the parameter model of cavitation production mechanism is built. Based on Computational Fluid Dynamics (CFD) numerical method, a high-precision mesh model of shock absorber is established and the simulation analysis is carried out by using FLUENT software. Therefore, the specific position and distribution of cavitation in the hydraulic shock absorber are obtained, and the measures to inhibit cavitation are put forward. Finally, the simulation results are verified by experimental study and the experimental results show that the cavitation is mainly distributed around the recovery valve of shock absorber, and the cavitation phenomenon becomes more obvious with increasing the piston speed; using low viscosity oil and increasing the diameter of piston rod can effectively inhibit cavitation phenomenon. This study provides a certain reference for preventing the cavitation phenomenon of hydraulic shock absorber.

In this study, radial basis function (RBF) and multilayer perceptron (MLP) neural networks were proposed for accurate prediction of under-saturated oil viscosity. To this end, more than 600...

An investigation was conducted for the improvement of the physical properties of Lubricating oil. The copolymer used is ethylene propylene diene monomer (EPDM). The oil viscosity index (VI) and viscosity/temperature characteristics were improved at different concentrations 2468 and 10% by weight solutions. The efficiency of the additive as viscosity index and flow improvers was investigated. FT-IR analysis determines the change in the carbonyl group. Thermo gravimetric analysis (TGA), is used to study the degradation and thermal stability of the studied base stock samples. Keywords: Lubricating oil, Copolymer (EPDM) viscosity index, FT-IR spectroscopy, Thermogravimetric analysis

The objective of this study is to reduce heavy oil viscosity through the catalytic decomposition of heavy fractions by ultrasound cavitation using metal oxide nanoparticles and water as a hydrogen donor, leading to the reduction of asphaltene content through its conversion into lighter components. NiO nanoparticles were synthesized over a 7 nm silica support using the incipient wetness technique. Emulsified heavy oil (HO) with 40%v/v of water and 13°API was used to evaluate the ultrasound cavitation process over different exposure times and nanoparticle dosages. The viscosity of the emulsified HO before and after ultrasound cavitation was measured with and without nanoparticles. Significant viscosity reduction was obtained, showing best results at 90 minutes of ultrasound exposure time with a nanoparticle dosage of 2000 mg/L, leading to a viscosity reduction at 10 s-1 and 25°C, and an asphaltene content reduction of 44 and 16%, respectively. Resumen El objetivo de este estudio es la reducción de viscosidad de crudos extra-pesados mediante la descomposición catalítica de las fracciones pesadas del crudo y su conversión en sub-compuestos más livianos utilizando cavitación por ultrasonido asistida por nanopartículas. Nanopartículas de NiO fueron sintetizadas sobre sílice nanoparticulada de 7 nm usando la técnica de impregnación incipiente. Un crudo emulsionado con un contenido aproximado de 40%v/v de agua y 13°API fue usado para evaluar el proceso de cavitación aplicando distintos tiempos de exposición y dosificaciones de nanopartículas. La viscosidad del crudo a 10 s-1 y 25°C fue medida antes y después del tratamiento en ausencia y presencia de nanopartículas. Los mejores resultados observados fueron a un tiempo de exposición de 90 minutos con una dosificación de nanopartículas de 2000 mg/L, generando reducciones de viscosidad y en el contenido de asfaltenos del 44 y 16%, respectivamente.

The objective of this research is to investigate the efficacy of nanoparticles in reducing the viscosity of heavy oil. In this study, three types of metal oxide nanoparticles (CuO, Fe2O3, and NiO) are employed, and their effect on heavy oil viscosity is examined at three different concentrations (0.05, 0.1, and 0.5 wt.% of oil). For all test fluids, rheological measurements were obtained at four different temperatures ranging from 27 to 71 °C. The experimental work is conducted with two extremely viscous heavy oil samples having viscosity of approximately 77 and 350 Pas at ambient temperature. This study is unprecedented in terms of viscosity of heavy oil samples investigated. The heavy oil samples used in this study are 9–40 times more viscous than those used in previous similar studies. The addition of nanoparticles resulted in a notable reduction in viscosity of both heavy oil samples. For each type of nanoparticles, 50–70% viscosity reduction was observed. The level of viscosity reduction is sensitive to the types of nanoparticles, their concentration, and fluid temperature. Moreover, the results indicate existence of an optimum concentration of nanoparticles at which maximum viscosity reduction occurs. This optimum concentration is a function of the metal type and fluid temperature. To explain observed viscosity alteration behavior, the paper provides a theoretical overview of various molecular-level physical and chemical interactions between nanoparticles and heavy oil. Additionally, the study presents a new heavy oil viscosity data and delineates some of the challenges associated with viscosity measurement of heavy oil. This research provides valuable information for future rheological and core-flooding studies involving nanoparticle stabilized solvent-based emulsions. Besides, remarkable viscosity reduction obtained in this work reinforces the industry's interest in developing an economically feasible nanoparticle-based technique and helps to solve real problems in the field.

In a bottom-blown copper smelting furnace, the longitudinal wave formed on the bath surface plays an important role in slag tapping and settling of matte droplets entrapped in the slag layer. This study employs a laboratory-scale cold model of a bottom-blown copper smelting furnace to investigate the features of the longitudinal wave on the molten bath surface during smelting. Experimental variables, including the gas flow rate, water level, oil level, and oil viscosity, are adjusted in different combinations to simulate corresponding industrial conditions. The features of the longitudinal wave, including the amplitude and frequency, are recorded at several critical points, and the trends of these features along the length of the furnace are summarized to understand the transmission behavior of the longitudinal wave.

Cyclic Solvent Injection (CSI) has gained significant interest as a viable method among solvent injection processes to increase recovery factor of heavy oil reservoirs. The type of solvent, operating pressure, and oil viscosity markedly affect the performance of CSI. In this study, series of cyclic injection tests of pure CO2, CH4-CO2, and C3H8-CO2 were conducted at various operating pressures and mixture compositions to different (in term of viscosity) heavy oil samples. Sand pack models with absolute permeability of kabs = 6–10 D and porosity of o = 27–32% were used as representative of a typical heavy oil reservoir. In each cycle, the produced oil and pressured drop during soaking time were measured and CO2/solvent apparent solubility was calculated using the pressure decay method. Results showed that there is an optimum pressure in cyclic CO2 injection process in heavy oil systems; the pressure beyond which the ultimate oil recovery factor (RF) did not notably improve (near 4.82 MPa in this study). Higher concentration of C3H8 in the CO2 stream improved the oil recovery during cyclic injection. However, ultimate RF was not noticeably increased when C3H8 concentration in the mixture exceeded a certain value (near 50% in this study). Although C3H8 showed effective role on the performance of CSI, it was found that the recovery factor reduces with increased CH4 concentration in the CO2 stream. The highest recovery factor of RF = 73.8% was obtained by injecting mixture of 50% C3H8 - 50% CO2 under the operating pressure of Pinj = 1.72 MPa. The results of CSI tests on the heavy oil with viscosity of 6 430 mPa s were lower by almost 20% since the solvent solubility was noticeably lower. No oil production was observed after conducting the first cycle injection of optimum quantified solvents on oil with the viscosity of 22 000 mPa s. Small values of SUF, relatively high values of SOR, and low quality of the produced oil suggested that higher cycle numbers of CSI in heavy oil reservoirs is depending on the economic limits and might be conducted cautiously.

The main oil reservoirs in the Bohai area, with thick layer, high average permeability, high heterogeneity, loose rock cementation, and high oil viscosity, have entered the stage of medium and high water-cut development and faced serious problems of large channel development and injection profile reversal. For the actual demand, a comprehensive method of the combined operation of profile modification and water shutoff with in-depth displacement was proposed to enhance oil recovery in Bohai oilfield. The effects and mechanisms of both single operation and combined operation were compared quantitatively and clarified theoretically. The findings showed that the operation of profile modification and water shutoff using a composite gel system could effectively treat the channeling layer, and improve the macroscopic sweep efficiency of the oil displacement agents. For the in-depth displacement system using the surfactant/microsphere composites, the microspheres could realize the micro-fluid diversion by plugging the swept pores, and the carried surfactant solution could enter the unswept pores to displace the remaining oil, while the decrease of viscosity and interfacial tension could effectively reduce the seepage resistance and improve the oil displacement efficiency. Compared with the single operation, the combined operation could bring about the comprehensive treatment from three aspects of expanding the macro and micro sweep efficiency, as well as improving the oil displacement efficiency, which has achieved quite good performances in the field application. The proposed method can be an effective technology to treat similar oil reservoirs with high heterogeneity.

Summary An analysis of viscosity data for mixtures of different gases dissolved in three different heavy oils and bitumens revealed that, at the same molar concentrations and at the same pressure, each of these gases reduced the oil-phase viscosity by almost the same amount. Because the gases that were examined included both hydrocarbons and nonhydrocarbons, it was concluded that this behavior could be generalized to include most of the gases encountered in, or injected into, heavy-oil and bitumen reservoirs. This principle was discovered in the new results of a study on two heavy oils. These oils were mixed with methane or carbon dioxide or propane to achieve vapor/liquid equilibrium at various pressures. When the measured oil-phase viscosities were adjusted to the same pressure without further change to their compositions, and were subsequently plotted against gas concentration in mole percentage, all the values fell on approximately the same curve. The same behavior was subsequently observed in gas/bitumen data that had been published previously by other authors. Although it can be reasoned that the adjusted viscosities must begin to diverge at high concentrations when different gases are used, the differences were not experimentally discernable even at dissolved-gas concentrations as high as 60 mol%. The effect was the same when more than one dissolved gas was present. The application of this uniformity principle is expected to make it easier to compare the costs of using different solvent gases to reduce the viscosity of heavy oils and bitumens during enhanced-oil-recovery (EOR) operations.

In this paper, the effect of asphaltene on the viscosity of Tahe heavy oil was studied. Firstly, the viscosity of the heavy oil with different asphaltene content was tested. Results showed that more asphaltene would lead to larger viscosity of the heavy oil. Secondly, it is observed that with the increased asphaltene content, there is a synchronous increasing tendency of storage modulus and viscosity. This indicates that asphaltene might form space netty aggregates in the heavy oil and result in the increased storage modulus and viscosity. Finally, causes of such asphaltene aggreggates and the influence mechanism of asphaltene on the heavy oil viscosity was analyzed in depth. It is found that through methylation modification experiments, the active hydrogen was removed from asphaltene molecules. In this way, the intermolecular forces including hydrogen bonding could be weakened. Then the molecular assembly variation of asphaltene aggregates was compared with the heavy oil viscosity. Results revealed that among all kinds of intermolecular forces, the ones related to active hydrogen are more beneficial to the space netty structure of alphaltenes and have more impact on the viscosity.

The significant reduction in heavy oil viscosity when mixed with $$\hbox {CO}_{2}$$ is well documented. However, for $$\hbox {CO}_{2}$$ injection to be an efficient method for improving heavy oil recovery, other mechanisms are required to improve the mobility ratio between the $$\hbox {CO}_{2}$$ front and the resident heavy oil. In situ generation of $$\hbox {CO}_{2}$$ -foam can improve $$\hbox {CO}_{2}$$ injection performance by (a) increasing the effective viscosity of $$\hbox {CO}_{2}$$ in the reservoir and (b) increasing the contact area between the heavy oil and injected $$\hbox {CO}_{2}$$ and hence improving $$\hbox {CO}_{2}$$ dissolution rate. However, in situ generation of stable $$\hbox {CO}_{2}$$ -foam capable of travelling from the injection well to the production well is hard to achieve. We have previously published the results of a series of foam stability experiments using alkali and in the presence of heavy crude oil (Farzaneh and Sohrabi 2015). The results showed that stability of $$\hbox {CO}_{2}$$ -foam decreased by addition of NaOH, while it increased by addition of $$\hbox {Na}_{2}\hbox {CO}_{3}$$ . However, the highest increase in $$\hbox {CO}_{2}$$ -foam stability was achieved by adding borate to the surfactant solution. Borate is a mild alkaline with an excellent pH buffering ability. The previous study was performed in a foam column in the absence of a porous medium. In this paper, we present the results of a new series of experiments carried out in a high-pressure glass micromodel to visually investigate the performance of borate–surfactant $$\hbox {CO}_{2}$$ -foam injection in an extra-heavy crude oil in a transparent porous medium. In the first part of the paper, the pore-scale interactions of $$\hbox {CO}_{2}$$ -foam and extra-heavy oil and the mechanisms of oil displacement and hence oil recovery are presented through image analysis of micromodel images. The results show that very high oil recovery was achieved by co-injection of the borate–surfactant solution with $$\hbox {CO}_{2}$$ , due to in-situ formation of stable foam. Dissolution of $$\hbox {CO}_{2}$$ in heavy oil resulted in significant reduction in its viscosity. $$\hbox {CO}_{2}$$ -foam significantly increased the contact area between the oil and $$\hbox {CO}_{2}$$ significantly and thus the efficiency of the process. The synergy effect between the borate and surfactant resulted in (1) alteration of the wettability of the porous medium towards water wet and (2) significant reduction of the oil–water IFT. As a result, a bank of oil-in-water (O/W) emulsion was formed in the porous medium and moved ahead of the $$\hbox {CO}_{2}$$ -foam front. The in-situ generated O/W emulsion has a much lower viscosity than the original oil and plays a major role in the observed additional oil recovery in the range of performed experiments. Borate also made $$\hbox {CO}_{2}$$ -foam more stable by changing the system to non-spreading oil and reducing coalescence of the foam bubbles. The results of these visual experiments suggest that borate can be a useful additive for improving heavy oil recovery in the range of the performed tests, by increasing $$\hbox {CO}_{2}$$ -foam stability and producing O/W emulsions.

The ability to control the properties of bio-inspired liquid-infused surfaces is of interest in a wide range of applications. Liquid layers created using oil-infused polydimethylsiloxane elastomers offer a potentially simple way of accomplishing this goal through the adjustment of parameters such as curing agent ratio and oil viscosity. In this work, the effect of tuning these compositional parameters on the properties of the infused polymer are investigated, including infusion dynamics, stiffness, longevity in the face of continuous liquid overlayer removal, and resistance to bacterial adhesion. It is found that that curing agent concentration appears to have the greatest impact on the functionality of the system, with a lower base-to-curing agent ratio resulting in both increased longevity and improved resistance to adhesion by Escherichia coli. A demonstration of how these findings may be implemented to introduce patterned wettability to the surface of the infused polymers is presented by controlling the spatial arrangement of bacteria. These results demonstrate a new degree of control over immobilized liquid layers and will facilitate their use in future applications.

The commonly used heavy oil viscosity models are just for low water cut stage, but they have some limitations when the viscosity of other oil samples is calculated in high water cut stage, this pap...