Oil Flow Rate Increases Research Articles

Prediction of technological indicators of selective water isolation of water-watered wells by nanostructured gel

In this work the composition forming nanostructured gel, which does not change phase permeability of oil, easily penetrating into water-saturated depth of the formation in watered wells, effectively closing the drainage channels, is established, the possibilities of its rapid heating up to formation temperature, gel formation within a certain time in contact with water depending on the concentration of the selected composition and with its use of involvement in the development of residual oil reserves, which are in watered wells, are investigated at injection of this composition into the well. As an optimal variant of well isolation in terrigenous reservoirs of oil fields it is suggested to use nanocomposite on the basis of silicate gel (with the content of liquid glass 4 % (modulus 3.1), 0.6 % of hydrochloric acid and 0.063 % of metal nanoparticles). The mechanism of selective isolation of water flow in production wells is based on the fact that when the composition is injected into the production well, part of its volume gets into the oil-saturated layer, and the rest – into the water-saturated layer. The composition is distributed in proportion to the permeability of the layers. In the process of well development the composition in the oil-saturated layer is removed, and in the water-saturated layer it retains its isolating properties. The greater the volume of injected fluid, the greater the isolation factor and pressure gradient. The isolation factor is directly proportional to the volume injected. Gel formed in the water-saturated layer corresponding to the volume of the injected composition reduces the phase conductivity on water at least 30 times. Practically does not change the phase conductivity by oil. On the basis of the calculation model including physical and chemical characteristics of selective isolation process taking into account real field conditions, the influence of possibility to isolate bottomhole zone of wells by gel on technological indicators of its operation was estimated. Thus, when putting into operation a well after isolation by water, the production of which was flooded with water, in the initial moments there was a sharp increase in oil flow rate (2–3 times), and at the subsequent stage – a slight decrease in the rate, compared to the flow rate before isolation, the effective time of development or flushing was about 150 days.

Simulation Study on the Motion Characteristics and Influencing Factors of Fiber Impurity Particles in Oil Flow in a Typical Distributed Electric Field

There have been many studies on the motion and aggregation characteristics of fiber impurities in insulation oil under static conditions. However, there are few studies on the motion characteristics of fiber impurities in insulation oil under flow conditions. In large power transformers, insulation oil is constantly in a state of flow. As a result, the motion characteristics of fiber impurities suspended in the insulation oil are even more complex due to the effects of oil flow. This study constructed a multi-physics field model for single-particle fibrous impurities in solid-liquid two-phase flow and systematically analyzed its motion characteristics. The study shows that the collision frequency between fiber impurity particles and electrodes with the same effective area is negatively correlated with the degree of electric field distortion. The maximum particle velocity and collision frequency of fibrous impurities in both uniform and slightly non-uniform electric fields show an almost linear relationship with the particle size radius. Additionally, the slope of the relationship decreases gradually with an increase in oil flow rate. With the increase of particle size, under the same flow velocity, an increase in the maximum velocity of the fibrous particles and the number of collisions with the electrodes. thereby increasing the probability of fibrous impurities transferring charge between the electrodes. Compared to the motion characteristics of fibrous impurity particles under static conditions, oil flow mainly affects the collision frequency between fibrous impurity particles and electrodes, reducing the probability of particle transfer.

Slip Characteristics in Cylindrical Roller Bearings. Part I: Influence of Cage Type on Rolling Set Slip

AbstractThe slip behavior of four cage types was studied for an NU215 cylindrical roller bearing under radial forces lower than the minimum recommended by the manufacturer by performing force, speed, and oil flow ramp tests. In comparison, a specially designed full complement bearing was also tested as an alternative to the caged bearing variant. All the tested bearings started to operate slip-free at higher forces than those recommended by the bearing manufacturers. In addition to that, the increase in oil flowrate or rotational speed would increase the set slip under insufficient radial forces. Single-part outer-ring-guided brass cage experienced lower slip than its two-part equivalent while roller guidance possessed the least slip tendency among the tested cages. The polyamide cage offered the lightest weight reduction at the expense of a higher slip, whereas the full complement bearings also offer higher load-carrying capacity at the expense of higher slip.

Acid treatment of carbonate reservoir with a new dual action microemulsion: Selection of optimal application conditions

Complex emulsifying systems based on acid have been widely used in petroleum production. The advantage of these agents is that the rock dissolution rate is slow and the corrosion activity is reduced. This allows acid to penetrate deeper into the reservoir to increase the drainage area of the well while reducing the destructive impact on the surface of downhole equipment. This work is a continuation of the study of a unique acid emulsion for stimulation of carbonate reservoirs, which is already common in the fields in Russia. The new emulsion has a dual action, capable of forming wormholes in the bottomhole area and dissolving paraffin. The application of a single composition significantly reduces the cost of oil production. The main advantage of the technology is that it does not require workover crew when performing the treatment. The accumulated production experience in the implementation of acid treatments without the workover crew can evaluate whether this technology can be further popularized, showing a very broad prospect. We substantiated the selection criteria of candidate wells for stimulation of reservoir by double-action emulsion. The groups of effective and ineffective operations were determined by linear discriminant analysis. We can identify the factors that determine the final effectiveness of the measure through the analysis of field data. In order to ensure that the predicted value is highly consistent with the actual value, We developed a statistical model to estimate the potential increase in oil flow rate after acidizing. The model was piloted on two wells, which can better justify the design of measures and increase their final efficiency by 17–23%. The results confirm that acidizing technology of carbonate reservoir without workover crew is an excellent alternative to standard acidizing, characterized by reduced operating well time and improved profitability.

Controlled deep perforation by radial drilling of channels with the "Perfobur" technical system to intensify the reservoir inflow

The paper presents a technology for controlled deep penetrating perforation using the Perfobur technical system to intensify inflow by drilling radial channels 69 mm in diameter, up to 25 metres in length. This technology was first applied to a carbonate reservoir in the Bashkirian tier, characterised by high heterogeneity and close proximity of bedrock water.
 An adjacent well, close to the acid fracture well, with identical reservoir properties, was selected. Well "A" was acid fractured and well "B" was drilled using Perfobur technology with two directional channels, each 14 metres in length. In well "B", after drilling the channels, hydrochloric acid solution was injected through a special hydromonitor nozzle at two points. A total of 48 m3 of acid was injected into the "B" well.
 Comparing the results of well "B" with the well where the hydrofracturing was performed allow speaking about high efficiency of the controlled radial drilling technology. The ability to predict the channel trajectory, knowledge of its actual trajectory in combination with acid treatment of the reservoir using hydromonitor nozzle at a considerable distance from the reservoir allows achieving a significant increase in oil flow rate with lower water cut of the produced oil.

On the Effect of Supplied Flow Rate to the Performance of a Tilting-Pad Journal Bearing—Static Load and Dynamic Force Measurements

Abstract Rotating machinery relies on engineered tilting-pad journal bearings (TPJB) to provide static load support with minimal drag power losses, safe pad temperatures, and ensuring a rotor-dynamic stable rotor operation. End users focus on reducing the supplied oil flow rate into a bearing to both lower operational costs and to increase drive power efficiency. This paper presents measurements of the steady-state and dynamic forced performance of a TPJB whilst focusing on the influence of supplied oil flow rate, below and above a nominal condition (50% and 150%). The test bearing has five pads, slenderness ratio L/D = 0.4, spherical pivots with pad offset = 50%, and a preload –0.40, with a clearance to radius ratio (Cr/R) ≈ 0.001 at room temperature. The bearing is installed under a load-between-pads (LBP) orientation and has a flooded housing with end seals. The test conditions include operation at various shaft surface speeds (32 m/s–85 m/s) and specific static loads from 0.17 MPa to 2.1 MPa. A turbine oil lubricates the bearing with a speed-dependent flow rate delivered at a constant supply temperature. Measurements obtained at a steady thermal equilibrium include the journal static eccentricity and attitude angle, the oil exit temperature rise, and the pads' subsurface temperatures at various locations, circumferential and axial. The rig includes measurement of the drive torque and shaft speed to produce the bearing drag power loss. Dynamic force coefficients include stiffness, damping, and virtual-mass coefficients. As expected, the drag power and the lubricant temperature rise depend mainly on shaft speed rather than on applied load. A reduction in oil flow rate to 50% of its nominal magnitude causes a modest increase in journal eccentricity, a 15% reduction in drag power loss, a moderate raise (6 °C) in pads' subsurface temperatures, a slight increase (up to 6%) in the direct stiffnesses, and a decrease (up to 7%) in direct damping coefficients. Conversely, a 1.5 times increase in oil flow rate causes a slight increase (up to 9%) in drag power loss, a moderate reduction of pads' temperatures (up to 3 °C), a maximum 5% reduction in direct stiffnesses, and a maximum 10% increase in direct damping. The paper also presents comparisons of the test results against predictions from a thermo-elastohydrodynamic (TEHD) lubrication model. In conclusion, a 50% reduced oil flow rate only causes a slight degradation in the test bearing static and dynamic force performance and does not make the bearing operation unsafe for tests with surface speed up to 74 m/s. As an important corollary, the measured bearing drag power differs from the conventional estimate derived from the product of the supplied flow rate, the lubricant-specific heat, and the oil exit temperature rise.

Numerical Modeling and Heat Transfer Analysis of Minimum Quantity Lubrication Grinding of Inconel 751

Sustainable Manufacturing has gained a widespread acceptance in today's manufacturing industry. This paper accentuates the need for environment-friendly lubrication with the help of Minimum Quantity Lubrication or Near Dry Machining. Minimum Quantity Lubrication (MQL) uses an atomizing nozzle in order to create fine droplets which on hitting the hot machining zone dissipates the heat and provides lubrication. In contrast to the flood coolant, MQL technology increases the surface area of contact with each droplet hence optimizing the coolant to the maximum extent by reducing harmful fumes, improving cutting performance and favorably reducing coolant consumption. Due to the rotating grinding wheel, a hydrodynamic boundary layer is formed around it, producing a back air flow which possesses enough momentum to oppose the incoming cutting fluid, restricting it to reach the machining zone. Thus, it is of prime importance to penetrate this air cushion forming the boundary layer to effectively cool and lubricate the grinding region. This could be only achieved when the oil droplet velocity is significantly greater than the grinding wheel's tangential velocity. In this work, various parameters including droplet size & velocity have been determined for improving the spray on the basis of flow rate and inlet air pressure in MQL nozzle using commercially available CFD solver Ansys Fluent. Further, Heat Transfer Modeling is also carried out both computationally and analytically in order to find the heat taken away by the MQL oil. The computational results validated the experimental analysis carried out for the droplet diameter and analytical model for the heat flux. Multiphase model DPM was preferred over VOF since it tracks each and every parcel coming out from the injection surface within the computational domain. The oil droplet size if found to be a function of air pressure and flow rate of the atomizer and the Heat flux on workpiece decreased with increase in oil flow rate.

Modeling of heavy oil-water core-annular upward flow in vertical pipes using the two-fluid model

In this work, a one-dimensional, isothermal, pseudo-transient two-fluid mathematical model is presented to simulate heavy oil-water core-annular upward flow. The model consists of mass, momentum and energy conservation equations for each phase, whose numerical solution is based on the finite difference technique with a first order implicit scheme. The model allows compute the profiles of pressure, velocity, volume fraction and temperature of the phases. Various water-wall and interfacial friction factors proposed in literature were evaluated. It was found that: (1) the interfacial friction factor has an important influence on pressure drop computation, (2) the interfacial shear stress is larger as the oil flow rate increases, and (3) to take into account the buoyancy effect, into the water-wall stress, improves the pressure computation. A characteristic analysis to determine the model stability was also developed and it was found that the well-posed region grows as the oil superficial velocity (Jo) increases, and the model is stable for Jo/Jw≥0.75 (Jw is the superficial water velocity). The model is in agreement with experimental data and other models reported in literature. The total pressure drop computations present deviations smaller than 6% from experimental data.

Effects of lubricating oil on the performance of a semi-hermetic twin screw refrigeration compressor

Lubricating oil is often employed in a twin-screw refrigeration compressor for lubricating bearings, sealing leakage paths, cooling refrigerant gas and regulating capacity. In this paper, the effect of lubricating oil on the performance of a semi-hermetic twin-screw refrigeration compressor is investigated. A mathematical model is established and a comprehensive experimental investigation is performed for this purpose. The model is validated using experimental data and then used to investigate the effect on compressor performance of lubricating oil supplied to the suction and discharge end bearings, and returned to the suction pipe. The results show that the compressor performance is reduced as the compensation oil injection flow rate increases in the suction pipe. However, as the compensation oil injection position moves from the suction pipe to a proper compression chamber position, the compressor efficiencies increase as the oil flow rate increases. The results also show that the compressor performance decreases as the oil flow rate increases at the suction end bearing. But the effect on the compressor performance of the lubricating oil supplied to the discharge end bearing depends on the oil temperature. Low temperature oil supplied to the discharge end bearing increases the compressor performance, while high temperature oil lowers the compressor performance. These analyses provide useful information for optimizing lubricating oil distribution to maximize energy efficiency in semi-hermetic twin screw refrigeration compressors.

Liquid buckling in a practical situation

Buckling of an oil filament is observed during the core annular flow of high viscous oil and water, when it encountered a sudden expansion in its flow path. Suitable mathematical equations have been suggested to predict the distance of initiation of buckling from the plane of area change and other characteristics of the deformed oil core. It is proposed that the initiation of buckling depends on the balance of inertial and viscous forces. The model predicts that as the oil flow rate increases, the fluid jet has to travel a larger distance from the plane of area change to initiate buckling. Frequency and radius of the buckled oil filament are also predicted from the model.

Multifractal analysis of inclined oil-water countercurrent flow

Characterizing countercurrent flow structures in an inclined oil-water two-phase flow from one-dimensional measurement is of great importance for model building and sensor design. Firstly, we conducted oil-water two-phase flow experiments in an inclined pipe to measure the conductance signals of three typical water-dominated oil-water flow patterns in inclined flow, i.e., dispersion oil-in-water pseudo-slug flow (PS), dispersion oil-in-water countercurrent flow (CT), and transitional flow (TF). In pseudo-slug flow, countercurrent flow and transitional flow, oil is completely dispersed in water. Then we used magnitude and sign decomposition analysis and multifractal analysis to reveal levels of complexity in different flow patterns. We found that the PS and CT flow patterns both exhibited high complexity and obvious multifractal dynamic behavior, but the magnitude scaling exponent and singularity of the CT flow pattern were less than those of the PS flow pattern; and the TF flow pattern exhibited low complexity and almost monofractal behavior, and its magnitude scaling was close to random behavior. Meanwhile, at short time scales, all sign series of two-phase flow patterns exhibited very similar strong positive correlation; at high time scales, the scaling analysis of sign series showed different anti-correlated behavior. Furthermore, with an increase in oil flow rate, the flow structure became regular, which could be reflected by the decrease in the width of spectrum and the difference in dimensions. The results suggested that different oil-water flow patterns exhibited different nonlinear features, and the varying levels of complexity could well characterize the fluid dynamics underlying different oil-water flow patterns.

Numerical Investigation on a Hydrodynamic Journal Bearing with a Center Circumferential Groove in Cavitation Zone

Center circumferential groove usually exists in cavitation zone or load zone of journal bearing bush to improve bearing performance, but little research has been designed to investigate the effect of CCG in caviatation zone. In order to investigate the CCG effect on the journal bearing performance when it exists in cavitation zone, numerical simulation is carried out using Computational Fluid Dynamics (CFD) software FLUENT. Different CCG angle and width are considered. To carry out this study, a “Full Cavitation” model with a constant cavitation pressure has been used. The energy equation and heat conduction equation have been used for the determination of oil film and bush temperature distributions. Both pressure distribution and maximum bush temperature of the no-groove bearing agrees with experiment dates well. The results show that: cutting a CCG in cavitation zone could increase oil flow rate but has little effect on bearing capacity. As CCG angle or width increased, the oil flow rate increases, the maximum bush temperature first decreases then becomes unchanged.

The Research on Oil-Air Lubrication and Oil Lubrication Used in the Sliding Friction Element

In order to study the effect of oil-air lubrication on sliding friction element, the experiments between oil-air lubrication and oil lubrication have been done by using friction-abrasion testing machine. By means of measuring the temperature rise, the friction coefficient of two different lubrication systems in the same conditions and studying the temperature rise and the friction coefficient of oil-air lubrication with different oil flow rate at the same load and rotating speed level, the results obtained show that when the oil flow rate of oil- air lubrication is equal to 10ml/h, the temperature rise of the element is the same as submerged lubrication caused. As the effect of oil aeration, the friction coefficient of oil-air lubrication is higher. When the load and rotating speed is at 1500N, 210rpm level, as the oil flow rate increases, the temperature rise and friction coefficient of oil-air lubrication element decreases significantly, however, they remain almost unchanged with the increasing of oil supply while the oil flow rate is increased to 15ml/h.

An Experimental Investigation of the Effect of Groove Location and Supply Pressure on the THD Performance of a Steadily Loaded Journal Bearing

This paper aims to present the results of parametric experiments carried out in order to study the influence of groove location and supply pressure on the performance of a steadily loaded journal bearing with a single-axial groove. Hydrodynamic pressure and temperature distributions on the bush surface, shaft temperature, flow rate and bush torque were measured at variable supply pressure, using bushes with a single groove located at three different positions. A series of tests were carried out for variable applied load and rotational speed. The experimental evidence shows that some bearing characteristics are significantly sensitive to changes in groove location and supply pressure. One groove located at 30 degrees in relation to the load line, in the direction of shaft rotation, can conduct to reductions in maximum temperature, maximum hydrodynamic pressure and bush torque, with a moderate increase in oil flow rate. [S0742-4787(00)02801-0]