High-viscosity Oil Research Articles

The evaluation of the efficiency of horizontal wells

The number of fields that have reached stage IV of development is increasing every year. Due to the high level of water cut, it becomes difficult to develop residual recoverable reserves. Also, due to the increase in the share of high-viscosity oils in Kazakhstan, the task of their effective development becomes more complicated. The development of terrigenous reservoirs, which have a complex structure and contain high-viscosity oil, is usually characterized by low production rates and oil recovery factors. Currently, technologies that ensure high efficiency in the development of such deposits are very expensive.
 In this regard, the development of oil fields through the commissioning of horizontal wells is becoming more in demand, capable of increasing the efficiency of developing oil reserves. Drilling of horizontal wells is considered for:
 
 floating reservoirs with low reservoir production coverage due to high water cut. High levels of water cut are due to breakthroughs of bottom water and degraded technical condition of wells (annular flows, wear and leakage of the string, depressurization of previously isolated intervals and poor quality of cement adhesion);
 thin layers, not involved in the production. Basically, thin layers are not involved in the production due to the low performance of vertical wells;
 on horizons with high-viscosity oil. In highly viscous horizons, the injected water breaks through to the bottom of production wells along the base of the reservoir when the horizon is not developed.
 
 Also in the Atyrau region, fields with hard-to-recover reserves (fields with high oil viscosity and low permeability of the productive horizon) are being developed. It is in such fields that horizontal wells have already been drilled and will be drilled in the future.
 The presented article discusses the results of the analysis of the drilled horizontal wells in the North Volga and Aknur oil fields.

Increased oil recovery through the use of combined technology

There is a growing number of fields in the world that are at the last stage of development. These fields are characterized by high residual oil saturation and water saturation. In addition, newly discovered fields are characterized by the content of high-viscosity oil. The development of such reservoirs is associated with great difficulties. This paper considers a combined technology that allows to intensify oil production from oil reservoirs. The studies were carried out on a homogeneous reservoir model in the following sequence. First, we carry out the displacement of oil by injecting electrochemically modified water (catholyte). Then we pump in a gas-liquid emulsion slug, which we push through with water or catholyte. The combined action of the emulsion and catholyte leads to an increase in the pressure drop and a change in the filtration rate. As a result, this leads to an increase in the oil recovery factor.

Mucilage-inspired robust antifouling coatings under liquid mediums

Recently, antifouling coatings with unique superwetting that resist the aggressive organic liquids, small- molecule dyes or high-viscosity liquids has attracted widespread researchers’ attentions. However, the instability of these coatings under different liquid mediums tremendously constrains its practical applications. In nature, various mucilaginous organisms such as Loach, Earthworm and Chinese yam live in different environments (muddy water, sludge or soils) without being corrupted. Inspired by their mucilaginous antifouling property, here aluminum phosphate (AP) inorganic binder was introduced to combine inorganic nanoparticles (TiO2) and polytetrafluoroethylene (PTFE) organic nanoparticles together, forming stable organic–inorganic composite AP-TiO2@PTFE coatings. The wettability, surface energy, and mechanical property of the composite coatings could be adjusted by regulating the mass ratios of organic–inorganic components. Furthermore, the perfluoropolyether (PFPE) lubricant acted as the mucilage was infused into the porous coatings to construct lubricant-infused surface of AP-TiO2@PTFE@PFPE. Importantly, the prepared AP-TiO2@PTFE@PFPE coatings exhibited excellent anti-contamination property to various organic liquids (surface tensions: 18.43–72.8 mN/m), dye molecules and high-viscosity crude oil even after multiple abrasion or bending cycles under different environmental medium, which exhibits great application potentials in advanced functional composite coatings for materials protections.

Characteristic Forced and Spontaneous Imbibition Behavior in Strongly Water-Wet Sandstones Based on Experiments and Simulation

Forced and spontaneous imbibition of water is performed to displace oil from strongly water-wet Gray Berea (~130 mD) and Bentheimer (~1900 mD) sandstone core plugs. Two nonpolar oils (n-heptane and Marcol-82) were used as a non-wetting phase, with viscosities between 0.4 and 32 cP and brine (1 M NaCl) for the wetting phase with viscosity 1.1 cP. Recovery was measured for both imbibition modes, and pressure drop was measured during forced imbibition. Five forced imbibition tests were performed using low or high injection rates, using low or high oil viscosity. Seventeen spontaneous imbibition experiments were performed at four different oil viscosities. By varying the oil viscosity, the injection rate and imbibition modes, capillary and advective forces were allowed to dominate, giving trends that could be captured with modeling. Full numerical simulations matched the experimental observations consistently. The findings of this study provide better understanding of pressure and recovery behavior in strongly water-wet systems. A strong positive capillary pressure and a favorable mobility ratio resulting from low water relative permeability were main features explaining the observations. Complete oil recovery was achieved at water breakthrough during forced imbibition for low and high oil viscosity and the recovery curves were identical when plotted against the injected volume. Analytical solutions for forced imbibition indicate that the pressure drop changes linearly with time when capillary pressure is negligible. Positive capillary forces assist water imbibition, reducing the pressure drop needed to inject water, but yielding a jump in pressure drop when the front reaches the outlet. At a high injection rate, capillary forces are repressed and the linear trend between the end points was clearer than at a low rate for the experimental data. Increasing the oil viscosity by a factor of 80 only increased the spontaneous imbibition time scale by five, consistent with low water mobility constraining the imbibition rate. The time scale was predicted to be more sensitive to changes in water viscosity. At a higher oil-to-water mobility ratio, a higher part of the total recovery follows the square root of time. Our findings indicate that piston-like displacement of oil by water is a reasonable approximation for forced and spontaneous imbibition, unless the oil has a much higher viscosity than the water.

Evaluation on the Basis and Application Performance of a Modified Surface Active Oil-displacing Agent

The oil development has entered the water flooding stage in Changqing Oilfield. Due to the low reservoir permeability and the high oil viscosity, the water-flooding does not achieved the desired effect. A large amount of oil is retained in the reservoir due to the high water surface tension and oil-water interfacial tension. Currently, the performance of an oil-displacing agent is suitable for Changqing oilfield to mitigate this situation, but with high application cost due to its synthesis in an organic solution. In this study the oil-displacing agent is modified, and an amphiphilic oil-displacing agent is synthesized through aqueous polymerization. With addition of the oil-displacing agent, the surface/interface activity of water and oil changed significantly. The surface tension of water and oil reduces from 69mN/m to 25mN/m and from 21mN/m to 7.8mN/m respectively in the 1500mg/L oil-displacing agent at 60℃, and the oil-water interfacial tension reaches the ultra-low level. In addition, the oil-displacing agent has the good oil emulsification ability, and the emulsion shows stable performance. The core flooding experiment shows that the 2000mg/L oil-displacing agent can increase the oil recovery by 20% compared with the water flooding, and this meets the production needs in the oilfield. Since the oil-displacing agent contains a large number of chelating functional groups, so it can also chelate the heavy metal ions in the reservoir to prevent precipitation with incompatible anions in the injected water.

Synthesis and mechanism analysis of a new oil soluble viscosity reducer for flow improvement of Chenping heavy oil

Oil soluble viscosity reducers have gradually attracted the attention of petrochemical research due to their cleanliness and high efficiency. Considering the high viscosity and non-Newtonian fluid properties of Chenping heavy oil found in China, a series of new oil soluble viscosity reducers with different proportions and molecular weights were prepared by free radical polymerization using octadecyl acrylate, 2-allylphenol and N-methylolacrylamide as monomers. The viscosity reducer was applied to different types of heavy oil and found that it exhibited a better effect on heavy oils with high asphaltene content. The test of rheological behavior of heavy oil with additive was performed at wide range of shear rate (3–90 s−1) and temperature range (30–100 °C). The apparent viscosity reduction rate was up to 70.09%, which was better than the industrially relevant ethylene–vinyl acetate copolymer under the same test condition. In addition, the effect of viscosity reducers on the components of heavy oil and the energy change of the system simulated by molecular dynamics simultaneously was investigated. The consistency of the simulated and experimental results show that the effect of viscosity reduction closely related to the crystallization process of wax and the viscosity reducer can reconstruct the surface structure of asphaltene and diminish the connection of benzene ring.

Influence of working conditions on the function of external respiration in underground oil mine workers

Introduction. The article presents a non-combined observational cross-sectional retrospective study, which studied the functions of respiration of 3 categories of workers (sinkers, woodworkers, underground miners) depending on working conditions. Materials and methods. Analyzed depersonalized data from outpatient records of periodic medical examinations of underground workers from 2013 to 2017. The article presents only the analysis of spirograms. The study of respiratory function was carried out using an expert class spirometer SpiroLab III (MIR, Italy). The results were assessed by a doctor of functional diagnostics. Production factors were studied according to the results of a special assessment of working conditions carried out in oil mines according to the methodology for conducting a special assessment of working conditions, approved by order of the Ministry of Labour of Russia No. 33n dated January 24, 2014. Statistical methods were used to analyze the material: methods of parametric statistics (mean (M), standard deviation, error of the mean (m), Student’s test), the data are presented in the format M ± m, the differences were considered significant at p < 0.05. Results. An analysis of occupational morbidity among oil miners has been carried out, risk groups have been identified by profession, length of service and age. It was revealed that after 4-5 years of work in the profession, there is a tendency to impairment of the function of external respiration according to the obstructive type (decrease in forced expiratory volume in the first second (FEV1), formed vital capacity of the lungs (FVC), peak expiratory flow rate (PEF) , Tiffno index). This is suggested to be due to a combination of factors of the production environment such as oil hydrocarbons and the severity of labour. The analysis of working conditions made it possible to determine the list of harmful production factors affecting the development and occurrence of occupational diseases by workers involved in thermal mining of high-viscosity oil. Limitations. The smoking factor in the work is considered as a qualitative one, it is probably more logical to consider it as a quantitative one - smoking experience (number of years), then a connection with changes in the functions of external respiration may be revealed. Conclusion. After 4-5 years of work, oil miners show a tendency to obstructive disorders of the respiration function. The genesis of the identified changes requires further clarification.

The Effect of Ethanol on Brake Torque, Brake Specific Fuel Consumption, Smoke Opacity, and Exhaust Gas Temperature of Diesel Engine 4JB1 Fueled by Diesel-Jatropha Oil

The growth of diesel vehicles has consequences for the consumption of diesel oil. Therefore, using Jatropha as an alternative fuel reduces dependence on diesel oil and it does not interfere with food availability. However, the high viscosity of jatropha oil makes the fuel pump work harder. In addition, the low calorific value reduces the quality of the fuel which creates unique problems. Ethanol, with its low viscosity and high oxygen content, is expected to be effective in reducing jatropha problems for diesel engines. Therefore, this study aims to evaluate the addition of ethanol to the brake torque, brake-specific fuel consumption, exhaust gas temperature, and smoke opacity. The 4JB1 diesel engine with an EGR was tested on a 10% (DJ10) and 20% (DJ20) diesel-jatropha mixture. The experimental results showed that brake torque increased by 1.51% in the DJ10 application, brake specific fuel consumption decreased by 7.05%, exhaust gas temperature decreased by 0.67%, and smoke opacity increased by 25.91%. While in the DJ20 application, brake torque increased by 3.19%, brake-specific fuel consumption decreased by 30.08%, exhaust gas temperature decreased by 0.67%, and smoke opacity increased by 69.03%.

Testing and Evaluation of the Oil Absorption Characteristics of Cotton Fibers

ABSTRACT The wetting property to different oil of cotton fibers which come from different regions of China was studied. The surface adsorption characteristics of cotton fibers were characterized. It is found that the oleophilic and hydrophobic properties of all the raw cotton fibers are fantastic and the average static contact angle of cotton fibers to water is 135.36°, but it is less than 51° to different oil such as engine oil, waste oil and salad oil. In the dynamic spreading process, the droplets of water formed on the surface of cotton fibers and the contact angles of all the cotton fibers to water is not changing with time while the oil liquids were quickly and completely spread out almost in 2000 ms. The speed of spreading is closely relevant with the viscosity of oil and the higher oil viscosity, the slower wetting velocity. The contact angles of cotton fibers come from different regions to the same oil liquid had little changes, thus the adsorption velocity difference of cotton fibers to engine oil, waste oil and salad oil was not significant, respectively.

Photothermal bio-based membrane via spectrum-tailoring and dual H-bonding networks strategies for seawater treatment and crude oil viscosity reduction

To reach global carbon neutralization, the use of clean energy and biomaterials has become a trend to reduce CO2 emission. With the increasing concerns about freshwater shortage and crude oil pollution, water purification and sewage treatment have become particularly urgent. Solar energy is an environment-friendly energy to mitigate freshwater shortage stress and reduce crude oil pollution. However, how to make solar energy applied to effectively drive freshwater generation and crude oil pollution remedy is crucial. Herein, the electrospun membrane was explored as sustainable matrix with desirable solar-to-thermal performance. The strategy of spectrum-tailoring was proposed to tailor bandgap energy of vanadium disulfide (VS2) for photothermal conversion promotion and interfacial evaporation efficiency. Inspired by mussel, dopamine was polymerized on surface of VS2 (VS2@PDA) for spectrum tailoring (Solar absorptance, α, is 89.34 %). Bandgap energy of the complex favorably decreased from 2.06 to 1.41 eV. Combining the dual H-bonding networks, water evaporation enthalpy of the membranes dramatically decreased from 2370 to 1990.2 J/g and the resulted evaporators showed excellent salt resistance, with evaporation rate of 1.40 kg m-2h−1 (enhancement factor is 2.032) and extraordinary cyclic evaporation performance. Additionally, sunflower-inspired tilting model was architectured to eliminate disturbance of sun irradiation incident angles for effective solar-driven interfacial generation. The resulted membrane effectively treated the seawater and decreased high viscosity of the super-viscous crude oil under the sun irradiation, thus showing great potential in seawater treatment and crude oil pollution remedy. The designs maximized utilization of solar energy and evaporation rates by treating seawater and reducing crude oil pollution without consuming additional energy, thus contributing to carbon neutralization. Therefore, the integration of dual H-bonding networks and spectrum-tailoring strategies would facilitate the structure-functional unification and desirable photothermal capabilities, and bring about an application potential in the development of composite evaporators for carbon neutralization.

Small bubbles formation and contribution to the overall gas holdup in large diameter columns of very high viscosity oil

A limited number of studies are available in literature on the small bubbles which create from gas-very high viscosity oils interaction and its contribution to the gas holdup in the system. The rate of small bubble formation has an important impact on heat and mass transfer in many chemical and industrial processes. The work presented in the current paper provides unique information on the formation of bubbles of millimetre diameter in high viscosity oil. A column of 290 mm diameter and Silicon oil of 330 Pa.s viscosity, were employed besides Electrical Capacitance Tomography and a high-resolution camera to investigate the characteristics of the small bubbles. Mechanism of bubble generation, effect of gas injection time and flowrate were studied. The average void fraction, total gas-liquid height, overall Probability Density Function (PDF) profile, small bubbles volume fractions and diameter were measured. Small bubbles generate from the eruption of large bubbles, at gas injection nozzles, coalescence of large bubbles, and at liquid bridges at transition to churn flow regime. Properties and concentration of the small bubbles are controlled by the location of the bubble generation, gas flowrate, and gas injection time. Small bubbles contribute by 6.6- 30% to the total gas holdup. Bubble diameter increased from 0.68 mm to 0.75 mm and decreased from 1.1 mm to 0.75 mm at the top and the bottom sections of the column respectively after 60 minof gas injection.

Estimating Water Content in Water–Oil Mixtures and Porous MEDIA They Saturate: Joint Interpretation of NMR Relaxometry and Dielectric Spectroscopy

This article deals with the topical problem of estimating water content in water–oil mixtures within porous media they saturate, according to low-field NMR relaxometry and dielectric spectroscopy. The aim of the research is experimental validation of the capability of complex data interpretation to acquire information on the filtration-volumetric properties of drill cuttings, relaxation characteristics of oil-containing fluids, the water/oil ratio in water–oil mixtures, and their saturation of drill cuttings to control the composition of liquids produced from boreholes. The studies are carried out on samples of cuttings and oils taken from fields in the Northern regions of the West Siberian oil-and-gas province, where NMR studies have not been performed before. Based on the experimental data obtained, the possibility of water content assessment in water-in-oil mixtures and porous media they saturate were proved through NMR relaxometry. With the use of the proposed methodology, the amount of water in oil–water mixtures was established, and their main NMR characteristics were determined. The relative error in evaluating the proportion of water in mixtures based on high-viscosity oils is less than 10%, and about 20% for those based on light oils. When determining the oil–water ratio in the pore space of the drill cuttings, the error is about 15%. It was proven that joint use of these two techniques makes it possible to increase the reliability of the oil–water ratio assessment of all the samples studied. Furthermore, it was revealed that the NMR spectrum shifts to the right, and the spectrum of the complex permittivity shifts downwards during the transition from high-viscosity oils to light ones.

ТӨМЕН ӨНІМДІ ҰҢҒЫМАЛАРДЫ ПАЙДАЛАНУ ӘДІСТЕМЕЛЕРІН ЖЕТІЛДІРУ

The current stage of development of the oil industry of Kazakhstan is characterized by its entry into the stage of declining production. Many large deposits are characterized by a rapid increase in product wetting. An unfavorable geological and technological structure of oil reserves has been formed at the oilfield, where the share of traditional (technologically developed) reserves is only 35%. At the same time, the share of hard-to-extract oil reserves (low-permeable layers, residual reserves, deeply loaded horizons, high-viscosity oil, gas subsurface areas) is 2/3 or 65%. Based on the estimates given in this paper, it is proposed to consider the development of low- permeable layers and residual oil resources as priority areas for the development of hard-toextract oil reserves. Their successful development will ensure the effective development of about half of the industrial oil reserves. Increasing the efficiency of development of low-permeable layers will attract several billion tons of industrial oil reserves for development.

Lessons Learned in Horizontal Well Workovers and Sand Cleanouts, in Cerro Negro Field, Venezuela

Summary The Orinoco Oil Belt in Venezuela contains the largest known deposits of heavy oil in the world, and Cerro Negro is part of the fields in this area. However, the sand production is a major issue which affects the oil production in this field. There are some major issues that stand in the way of the proper cleanout of these wells. These problems include low reservoir pressure, geometry of the wells, and extremely high oil viscosity. Another major problem is the presence of big pieces of progressing cavity pumps (PCP) elastomers, some metallic parts from pressure and temperature sensors configuration, and other metallic parts from previous workover rig operations, encountered during cleanout operations. As a result of these difficulties, some of the past jobs performed in this field were unsuccessful. After these unssuccessful jobs, a campaign of recent multiple sand cleanout jobs was planned in the Cerro Negro field. Numerous difficulties arose during these jobs. These issues were largely due to the presence of big pieces of PCP elastomers and metallic parts. An additional issue was the low reservoir pressure. Due to the size of the casing/liner and the horizontal section, the annulus fluid velocity obtained was insufficient. Therefore, several techniques were applied to overcome these problems. One of these methods was to use reverse circulation for the sand cleanout in the 9-5/8-in. slanted casing section, while circulation was still possible to obtain a higher fluid velocity. Afterward, once the circulation was lost, a special stroking pump was used alongside a large string of tubing to store large amounts of sand and debris. This tool was also used to recover pieces of PCP elastomers and other metallic parts. This tool uses a piston pump to create a vacuum effect, and fluid circulation is not needed for the cleanout. Without this innovative stroking pump, it would have been almost impossible to recover these large pieces. This was the first time this innovative tool was used in these types of wells. When the open horizontal 7-in. production zone was reached, coiled tubing (CT) was used with the proper proportion of diesel and nitrogen to obtain enough fluid velocity and the proper equivalent density. In the end, when necessary, a smaller reliner was run depending on the information obtained during the analysis of the grain sizes. Some techniques were applied to run the reliner successfully in an old and worn out casing, where the geometry of the well and high doglegs caused difficulties. The challenges to complete the cleanout of the well with lost circulation problems included a large annulus area in the highly slanted and horizontal sections, the extremely high oil viscosity, and the presence of large pieces of PCP and metallic parts. These challenges were overcome by using different methods such as the special stroking pump, reverse circulation in the 9.625-in. section, and CT with the proper diesel and nitrogen proportions. Additionally, to keep sand production under control in the cleaned wells, a smaller reliner was run. Finally, these workover jobs were finalized to bring these wells back into production successfully. The oil production results of these operations are shown in this paper, and demonstrated that it is possible to retrieve the production in the sanded wells of the Orinoco Belt in a profitable way.

Coking of high-viscosity water-containing oil

Objectives. A characteristic feature of oil production is an increase in the volume of highviscosity bituminous oil. In Russia, technologies based on the use of water vapor are used for their extraction. The use of such technologies leads to a large amount of water in the product stream from the production well. Preparation of oil for processing involves its stabilization, desalination, and dewatering. Since the densities of the extracted oil and the water contained in it are comparable, traditional preparation schemes for processing of high-viscosity bituminous oil are ineffective. One of the possible solutions to the problem involving such oil in the fuel, energy, and petrochemical balance is to use a coking process at the first stage of its processing. This aim can be achieved by studying the influence of the process conditions of coking high-viscosity water-containing oil on the yield and characteristics of the resulting products.Methods. Coking of oil with a density of 1.0200 g/cm3 at 50 °C and with 18 wt % water content was carried out in a laboratory installation in a “cube.” A hollow cylindrical apparatus was used as a reactor and was placed in a furnace. The temperature and pressure in the reactor were maintained at 500–700 °C and 0.10–0.35 MPa, respectively.Results. An increase in the coking process temperature results in an increase in the amount of gaseous products, a decrease in the amount of the coke generated, and a higher dependence of the amount of liquid products on temperature with a maximum yield at 550–600 °C. The process temperature also affects the composition of liquid products. At a lower temperature, the amount of gasoline and kerosene fractions in liquid products is higher. With an increase in pressure, a higher amount of gaseous products, coke, and low-molecular-weight hydrocarbon fractions in liquid products could also be obtained. The characteristics of the coke produced in the coking process are similar to those of commercially produced grades. It is noted that when coking water-containing oil, up to 98% of the emulsion water goes with liquid products, and the remaining amount of water remains in the formed coke.Conclusions. Results showed the possible application of the coking process at the initial stage of processing high-viscosity bituminous oil. In this case, the dewatering stage is significantly simplified since the technological scheme of delayed coking allows the separation of the gasoline fraction from water.

The Role of Immiscible Fingering on the Mechanism of Secondary and Tertiary Polymer Flooding of Viscous Oil

Immiscible viscous fingering in porous media occurs when a low viscosity fluid displaces a significantly more viscous, immiscible resident fluid; for example, the displacement of a higher viscosity oil with water (where μo > > μw). Classically, this is a significant issue during oil recovery processes, where water is injected into the reservoir to provide pressure support and to drive the oil production. In moderate/heavy oil, this leads to the formation of strong water fingers, bypassed oil and high/early water production. Polymer flooding, where the injected water is viscosified through addition of high molecular weight polymers, has often been applied to reduce the viscosity contrast between the two immiscible fluids. In recent years, there has been significant development in the understanding of both the mechanism by which polymer flooding improves viscous oil recovery, as well as in the methodologies available to directly simulate such processes. One key advance in modelling the correct mechanism of polymer oil recovery in viscous oils has been the development of a method to accurately model the “simple” two-phase immiscible fingering (Sorbie in Transp Porous Media 135:331–359, 2020). This was achieved by first choosing the correct fractional flow and then deriving the maximum mobility relative permeability functions from this. It has been proposed that central to the polymer oil recovery is a fingering/viscous crossflow mechanism, and a summary of this is given in this paper. This work seeks to validate the proposed immiscible fingering/viscous crossflow mechanism experimentally for a moderately viscous oil (μo = 84 mPa.s at 31 °C; μw = 0.81 mPa.s; thus, (μo/μw) ~ 104) by performing a series of carefully monitored core floods. The results from these experiments are simulated directly to establish the potential of our modified simulation approach to capture the process (Sorbie, et al., 2020). Both secondary and tertiary polymer flooding experiments are presented and compared with the waterflood baselines, which have been established for each core system. The oil production, water cut and differential pressure are then matched directly using a commercial numerical reservoir simulator, but using our new “fractional flow” derived relative permeabilities. The use of polymer flooding, even when applied at a high water cut (80% after 0.5 PV of water injection), showed a significant impact on recovery; bringing the recovery significantly forward in time for both tertiary and secondary polymer injection modes—a further 13–16% OOIP. Each flood was then directly matched in the simulator with excellent agreement in all experimental cases. The simulations allowed a quantitative visualisation of the immiscible finger propagation from both water injection and the banking of connate water during polymer flooding. Evidence of a strong oil bank forming in front of the tertiary polymer slug was also observed, in line with the proposed viscous crossflow mechanism. This work provides validation of both polymer flooding’s viscous crossflow mechanism and the direct simulation methodology proposed by Sorbie et al. (Transp Porous Media 135:331–359, 2020). The experimental results show the significant potential for both secondary and tertiary polymer flooding in moderate/heavy oil reservoirs.

Pore structure and surface property design of silicon carbide membrane for water-in-oil emulsification

In recent years, ceramic membranes have been applied as emulsification media in preparing emulsified heavy oils for residue fluid catalytic cracking units. In this case, silicon carbide (SiC) material is used for harsh environments due to its excellent chemical and thermal stabilities. Herein, a superhydrophobic SiC emulsified functional membrane was prepared by using an in-situ sintering method and subsequent grafting modification. The open porosity of these prepared membranes can be controlled from 26% to 48%, and the water contact angle of the membranes under oil was approximately 170°. The decrease of open porosity improved the bending strength of the membranes and also affected the emulsification performance. The size of water droplets decreased from 1.16 μm to 0.98 μm as the open porosity decreased from 48% to 26%. Moreover, the SiC membranes exhibited high flux and stability during the preparation of water-in-oil (W/O) emulsions, and the fouled membranes can be conveniently and effectively regenerated by ultrasonic cleaning with ethanol. Hence, the SiC membranes produced W/O emulsions with small droplets in harsh environments, such as the emulsification of heavy oil and high-viscosity oil at high temperature. • Pore structure and surface property of SiC membranes were successfully tailored. • High bending strength and excellent underwater superhydrophobicity were achieved. • Open porosity was revealed to dominate the membrane emulsification performance. • SiC membranes showed high flux and stability in preparing water-in-oil emulsions. • SiC membranes can be effectively regenerated by ultrasonically cleaning in ethanol.

Evaluation of Waterflooding Performance in Carbonate Reservoirs with High-Viscosity Oil in the Volga-Ural Petroleum Province

Evaluation of Waterflooding Performance in Carbonate Reservoirs with High-Viscosity Oil in the Volga-Ural Petroleum Province

Numerical study of hydrodynamic herringbone-grooved journal bearings combined with thrust bearings considering thermal effects

Abstract Hydrodynamic herringbone-grooved journal bearings (HGJBs) are analyzed by solving Navier–Stokes and energy equations. It is well known that the load capacity of hydrodynamic bearings may be affected by high temperatures and low oil viscosity. Therefore, the main objective of this study is to understand the pressure distribution of hydrodynamic HGJBs under different oil viscosity and eccentricity ratios. In this paper, 3 different configurations are studied, namely, a HGJB, a combined HGJB and thrust bearing, and a combined HGJB and grooved thrust bearing. The bearing characteristics, such as load capacity and attitude angle that vary with different eccentricity ratios, are also discussed. The results show that the load capacity of the bearing decreases with increasing temperature. The pressure difference also increases as the eccentricity ratio increases. The high-pressure region is concentrated at the tip of the groove for the HGJB. In addition, the combined HGJB and grooved thrust bearing can be used to stabilize the journal because of the low attitude angle. These findings may help and facilitate the design of hydrodynamic bearings suitable for working in warm and hot environments in the future.

Cationic guar gum-kaolin coated combined superhydrophilic and oleophobic nylon textile for efficient oil separation from wastewater

The treatment of wastewater polluted by oils and organic solvents has becoming a global environmental issue. Superhydrophobic separation materials have been widely developed to solve the problems, these materials are easily fouled by high viscosity oil fouling, causing the decrease of separation efficiency. Developing the materials with high hydrophilicity and oleophobicity in air via a facile and inexpensive approach is vital to address the oily water problems. Herein, a guar hydroxypropyltrimonium chloride-perfluorononanoate/kaolin (GHTC-PFN/KL) coated nylon textile (NT) was fabricated via a facile dip-coating approach. The obtained textiles reveal good superhydrophilicity, high oleophobicity in air, and low oil adhesion. By virtue of their special wettability, the functionalized textiles without any pre-wetting allow water to pass but preventing the passage of oils, which enables the textiles to be utilized for the selective separation to water/oil mixtures. The separation efficiencies for different oils are more than 96.7%. The modified textiles are capable of separating the oils employed with acidic, alkaline, salty solutions and hot water. Especially, a large quantity of water underoil is able to be continuously separated in situ via the multilayered textile tube at vacuum system. Simple preparation steps, scalable process and low cost make the as-prepared textile an ideal candidate for dealing with oily wastewater and purifying water-containing oil.