Oil Flow Rate Research Articles

A comprehensive mathematical model for spontaneous imbibition in oil-saturated fractured tight sandstones: Incorporating fracture distribution, displacement pressure, gravity, and buoyancy effects

This paper presents a generalized mathematical model that comprehensively characterizes the flow behavior of matrix nanopores and natural/hydraulic fractures in tight oil reservoirs during spontaneous imbibition. The model incorporates various influencing factors such as fracture distribution, displacement pressure gradient, gravity, and buoyancy. The complex pore structure of tight oil reservoirs, including nanopores and natural microfractures, presents a challenge in developing an accurate mathematical model for predicting flow behavior. The proposed model considers the fractal characteristics of pores and fractures and accounts for many factors to predict cumulative oil production, oil flow rate, and oil recovery factor during imbibition flow. Experimental data on fractured tight sandstones are used to validate the model, and sensitivity analyses are conducted to assess the influence of pore structure parameters, fracture distribution, and fluid properties on imbibition behavior. The findings reveal that gravity and buoyancy effects become more prominent under low interfacial tension. Fracture distribution significantly impacts imbibition behavior, with critical values for fractal dimensions, fracture numbers, and apertures determining the extent of their influence. Higher contact angles and increased oil phase viscosity result in reduced imbibition efficiency. In pressure-driven displacement processes, larger fractures preferentially produce crude oil, and the higher pressure gradients result in shorter imbibition processes. The proposed model offers insights into the imbibition oil recovery mechanism in tight oil reservoirs and can contribute to improved recovery factors.

Sustainable developments in near-dry electrical discharge machining process using sunflower oil-mist dielectric fluid.

In this study, a near-dry electrical discharge machining (NDEDM) process has been conducted using compressed air mixed with a low quantity of biodegradable refined sunflower oil (called oil-mist) to investigate the machining characteristics. The Box-Behnken method looks at how oil flow rate (OR), air pressure (AR), spark current (SC), and pulse width (PW) affect gas emission concentration (GEC), material removal rate (MRR), and surface roughness (SR). The TOPSIS (The Technique for Order of Preference by Similarity to the Ideal Solution) technique estimates the parameter optimal set for the best machining characteristics. The optimal machining parameters have been used to examine the microstructure of the machined surfaces using a scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS) analysis. The 0.981mg/min of GEC, 55.145mg/min of MRR, and 2.43µm of surface roughness have been attained by the 14ml/min flow rate, 7bar of air pressure, 10 A spark current, and 48µs pulse duration of the sun-flower oil-mist NDEDM process.

STANDART DISPLACEMENT CHARACTERISTICS AS AN EXPRESS METHOD FOR ANALYSIS AND MONITORING OF OIL FIELD DEVELOPMENT

The main task currently facing oil companies is to increase the efficiency of oil production in conditions of depletion of traditional reserves. The deposits of the West Siberian oil and gas basin are mainly at the third and fourth stages of development (final), which are characterized by a deterioration in oil flow rates, an increase in the water content of the extracted products, as well as the involvement of hard-to-recover reserves in the development. Field development specialists need to respond promptly to the events that led to a decrease in oil production in a short time in the absence of creating a complete geological and hydrodynamic model. Consequently, there is a need to develop a methodology that will allow you to quickly identify and localize problem areas of the development object in order to optimize costs, and most importantly, increase or maintain target production for maximum reserves production. In this regard, it is proposed to use the synergy of the developed approaches - the division of development objects into blocks and the construction of reference characteristics of displacement. The blocks, in turn, allow you to analyze the development of the object most reliably, and carry out calculations much faster. The reference characteristics of displacement show themselves as a tool that allows you to evaluate the effectiveness of flooding during the development of an object with a formed reservoir pressure maintenance system, also demonstrates the production of reserves, the effectiveness of flooding and production. In this study, an algorithm for analyzing the development of the block is considered in detail, both from the energy state and the development of reserves, according to which geological and technical measures for the intensification of production are determined.

Effect of Crude Oil and Nitrogen Gas Flow Rates on the Time Taken for Flow Initiation of Waxy Crude Oil

Transportation of waxy crude oil in a production pipeline often encountered flow assurance issues, such as wax deposition. In a case where pipeline shutdown is needed, wax deposit is likely to form within the pipelines, which leads to operational complexity during the restart phase. Commonly, crude oil restarts to flow after a significantly high restart pressure is pumped longer than is necessary. This is due to the physical hindrance caused by the solid wax, which requires additional pressure to disintegrate it before achieving a steady crude oil flow. This study aims to investigate the effect of crude oil and nitrogen gas flow rates on the time taken for crude oil flow initiation using a flow loop rig, which is connected to a nitrogen gas injection system. The nitrogen gas was injected into the test section pipeline at predetermined flow rates within specified periods. After 45 min of static cooling, the crude oil gear pump is switched on to build sufficient pressure to initiate the waxy crude oil flow in the pipeline. Additionally, a statistical analysis by the response surface methodology was also performed by Minitab® 19 software. Results show that the maximum reduction in flow initiation is 73.7% at 5 L/min of crude oil and 1 L/min of nitrogen gas. This study reveals that the presence of nitrogen gas improved the pipeline restart phase by minimizing both restart pressure and time taken for flow initiation.

Dual-Modal Electrical Imaging of Two-Phase Flow-Experimental Evaluation of the State Estimation Approach.

Accurate measurement of two-phase flow quantities is essential for managing production in many industries. However, the inherent complexity of two-phase flow often makes estimating these quantities difficult, necessitating the development of reliable techniques for quantifying two-phase flow. In this paper, we investigated the feasibility of using state estimation for dynamic image reconstruction in dual-modal tomography of two-phase oil-water flow. We utilized electromagnetic flow tomography (EMFT) to estimate velocity fields and electrical tomography (ET) to determine phase fraction distributions. In state estimation, the contribution of the velocity field to the temporal evolution of the phase fraction distribution was accounted for by approximating the process with a convection-diffusion model. The extended Kalman filter (EKF) and fixed-interval Kalman smoother (FIKS) were used to reconstruct the temporally evolving velocity and phase fraction distributions, which were further used to estimate the volumetric flow rates of the phases. Experimental results on a laboratory setup showed that the FIKS approach outperformed the conventional stationary reconstructions, with the average relative errors of the volumetric flow rates of oil and water being less than 4%. The FIKS approach also provided feasible uncertainty estimates for the velocity, phase fraction, and volumetric flow rate of the phases, enhancing the reliability of the state estimation approach.

Analysis and Multi-target Optimisation of the Characteristics with Stepped Cavity of the Hybrid Bearing

In this paper, the peak pressure, stiffness, flow rate, and temperature rise of the oil film in the stepped cavity of the hybrid bearing are investigated. The pressure and flow equations for the central section of the stepped cavity and the axial section of the deep and shallow cavity are derived using the simplified Navier-Stokes equations and the boundary conditions of a liquid bearing. Using the control variable method, the influence of the geometrical parameters of the stepped cavity and the process parameters on the oil film characteristics was simulated, and the correctness of the pressure and flow equations was verified. The results show that: the spindle speed is positively correlated with the peak oil film pressure and flow rate; the oil film thickness is negatively correlated with the peak oil film pressure and positively correlated with the flow rate; the depth and width of the shallow cavity are correlated with the peak oil film pressure, but the correlation with the flow rate is low; the maximum error between the theoretical calculation and the simulation analysis is less than 7.3%. The pressure equation and the flow equation are used to establish the objective function with the maximum oil film stiffness, load-bearing capacity, and minimum temperature rise, and the ideal point evaluation function method is used to do a multi-target optimization design to optimize the ladder cavity and obtain the optimal oil cavity geometric parameters. And an 8.75% increase in peak pressure and a 4.1% reduction in temperature rise for the same process parameters.

Temperature simulation of oil-immersed transformerbased on fluid-thermal coupling

The main components of the transformer face overheating and insulation aging caused by electromagnetic losses, which affect their service life. This paper analyzes an oil-immersed transformer with a rated voltage of 800kV based on heat transfer and fluid dynamics principles. The temperature distribution is carried out by magnetic-thermal coupling simulation. The influence of insulation oil flow rate on temperature is analyzed in the thermal field calculation, and the overall temperature rise of transformer and insulating oil is obtained. It turned out that the highest hot spot of the transformer occurs in the low-voltage winding, and the flow speed of insulation oil between the winding is the fastest.

Enhancement of Heat Dissipation from the Hydraulic System Using a Finned Adaptive Heat Exchanger

The novelty-designed adaptive heat exchanger (AHE) for heat dissipation from the hydraulic system to ambient air has been experimentally investigated. The heated hydraulic oil circulated in rubber hydraulic pipes as working fluid. The heat flow for AHE mounted in the hydraulic circuit was compared with the condition without the AHE. In addition, the contact surfaces of the AHE were coated with a copper-based thermal conductive paste for heat transfer enhancement research. The installation of the AHE in the hydraulic system caused an increase in heat flow by an average of 19.79% compared to the system without AHE, at an oil flow rate of 0.043 kg/s. The AHE with the copper-based thermal conductive paste achieved higher heat flow by an average of 24.93% and 20.49% compared to the circuit without AHE and with AHE, respectively. The installation of the AHE, and AHE with thermal conductive paste, into the hydraulic circuit caused an increase in differences of surface temperatures up to 8.1 °C and 8.3 °C compared to the hydraulic system without AHE. The hydraulic system with AHE achieved 1.3 times and 2.2 times higher the overall heat transfer coefficient compared to the AHE with thermal conductive paste and the system without AHE, respectively. The finned AHE is usable for additional cooling of working fluid (oil, coolant, fuel) in various machines and equipment without the necessity of interrupting the pipelines. Adaptability of the AHE allows it to be mounted on flexible hoses in the required location with the possibility of changing the number of heat exchange segments.

EVALUACIÓN ASISTIDA POR COMPUTADORA DE LA EXTRACCIÓN DE SOLVENTES PARA HIDROCARBUROS LIVIANOS USANDO DIÓXIDO DE CARBONO

Different process of separation was used in the chemical industry, in particular, extraction is a process used to increase the quality of resins in oil removing impurities like organics solids and heavy metals. Supercritical carbon dioxide offers high selectivity at the end of the extraction process of light hydrocarbons from heavy oils mixture. A simulation technique in Aspen Plus ®software was used to develop the process and sensitivity analysis of the extraction configuration. The simulation of extraction process includes two output streams: the first one, a top stream (unpaved oil), and the second one a bottom stream (asphalt residue). A steady state methodology was implemented for process simulation. The sensitivity analysis was used to assess the influence of variables such as solvent flow rate, temperature and pressure. It was found a significant increase in the flow rate of unpaved oil when the solvent flow rate is increased. Optimal extraction values were selected depending on temperature and pressure effects over the process. An increase in temperature directly enhances the quality of API gravity. In certain occasions, an increase in pressure affects the light oils extraction because of product drag.

A novel experimental rig to investigate the effect of the refrigerant on the oil supply of a variable capacity reciprocating compressor

The oil pumping plays a key role in the reliability and efficiency of compressors adopted in refrigeration systems. However, the investigations available in the literature on this subject do not consider the presence of the refrigerant and its effects on the oil supply. This paper reports the development of a novel experimental rig to measure the flow rate provided by the oil pump of a hermetic variable capacity reciprocating compressor considering the presence of the refrigerant in contact with the lubricating oil. A visualization system was also developed to investigate the transient outgassing phenomenon that takes place in the oil supply system when a sudden depressurization occurs, such as during the compressor startup. Measurements were carried out with the AB ISO VG 5 oil and the R-600a as the refrigerant fluid under different pairs of evaporating and condensing temperatures and compressor speed. Considering that the AB ISO VG 5 oil and air are immiscible, tests were also performed with air to isolate the effect of the refrigerant fluid on the oil supply. The results show that the oil flow rate is decreased due to the presence of refrigerant, with this effect becoming slightly stronger as the evaporating temperature is increased. The visualization system revealed that the outgassing brought about by the solubility between oil and refrigerant fluid has the potential to temporarily interrupt the oil supply.

Experimental and numerical performance assessment of a hybrid parabolic dish collector with photovoltaic for a distiller

ABSTRACT Environmental pollution has been rising recently, and so clean water needing has also increased. People could have easy access to pure water in all environments and conditions. This study is the solar tracking parabolic dish collector with produced pure water independent of electricity (off-grid). This system is fully renewable and autonomous. This system possesses a receiver, a boiler, a condenser, six 1000 mm diameter parabolic dish collectors, and 1 kW photovoltaic (PV) collectors. Thermal oil uses as the working fluid in the experiments. The experiment measured solar radiation, air temperature, air velocity, oil inlet and outlet temperatures, oil flow rate, receiver side surface temperatures, and instantaneous amount of pure water. Numerical and thermal analysis of the receiver in the experimental setup carry out. ANSYS Fluent 18.1 uses for numerical analysis. Energy and exergy analysis calculates the receiver for pure water production rate. The time interval when the system operates at high performance determines. In this study investigates the behavior of some exergetic indicators on the performance of the experimental setup, the cost of the experimental setup, and the enviro-economic impact of the parabolic dish-type collector. For this purpose, some exergetic factors such as the exergy effect, environmental impact factor, waste exergy rate, improvement potential, and exergetic sustainability index examine. The receiver’s improvement potential is between 1700 and 3000 W. In addition, the sustainability index, waste exergy rate, and environmental impact factor range from 0.32 to 0.36, 0.90 to 0.94, and 2.6 to 3.0, respectively.

A non-nuclear inline densitometer for multiphase flows

Multiphase flowmeters are used in the oil-and-gas industry to measure real-time flow rates of oil, gas, and brine, flowing simultaneously as a non-homogeneous mixture, in a pipeline from wellhead to separator. Since these flow rates cannot be measured directly, they are inferred from other measurements including mixture density. Mixture density is commonly measured using nuclear densitometers which can be problematic in terms of safety and maintenance. This paper details the development—concept and experimental validation—of a non-nuclear inline densitometer that measures multiphase mixture density using pressure sensors. A comprehensive flow-loop test was conducted at a commercial facility to evaluate the technology under a wide range of flow conditions—flow rates 1000 to 10000 bpd, gas fractions 0% to 96%, water cuts 0% to 100%, with a synthetic oil as liquid hydrocarbon, methane as gas medium, two water salinities—totaling nearly 300 test points. The results from this experimental validation—specifically, the technology’s accuracy and operating envelope—point to a groundbreaking practical solution to a long-standing problem.

Thermal characteristics of a 90-mm bore cylindrical roller bearings for aerospace applications: All-steel versus hybrid bearings

Modern aircraft engines have to meet rigorous requirements such as thrust to weight ratio, efficiency and new regulations related to environment protection. These requirements affect all engine modules and components, including rolling element bearings. The latter have to withstand severe operating conditions because of the high thermal impact due to elevated rotational speeds and loads. In this study, two test campaigns were carried out under realistic operating conditions of load, speed, and oil flow rate to investigate and compare the thermal characteristics of two distinct cylindrical roller bearings: a hybrid bearing featuring silicon nitride (Si3N4) rollers and an all-steel bearing. Each bearing was instrumented with an array of thermocouples around its circumference to determine temperature profile under various test conditions. In addition, oil supply and drain temperatures were also measured to estimate the power loss. The experiments were conducted on a high-speed rolling-element test rig operating at speeds up to 30,000 rpm and under radial loads of up to 4500N.

Experimental investigation of the parameters that affect droplet size and distribution for design calculations of two-phase separators

The critical design parameter when sizing a separator is the size of oil droplets in the water phase. This study improves the design of a separator by investigating the parameters that control droplet size, frequency, and distribution.Experimental work was performed to investigate the effect of flow rates and oil layer thickness on these parameters. Experiments were performed using a transparent laboratory separator to allow the measurement of droplet properties. The Design of the Experiment (DOE) method with the Taguchi analysis was applied to investigate statistically if droplet properties are solely a function of the independent variables or if they interact.The findings show that the results can be modelled using Gaussian distributions. Droplet size distribution and the number of droplets produced are functions of the interaction between oil flow rate and oil pad thickness. The oil flow rate dominates the droplet size though layer thickness has a minor effect. The number of droplets (Frequency) increases with both oil and water flow rates but decreases with oil pad thickness. There are clear interactions between all variables resulting in different droplet frequencies for combined effects. The distribution of the droplet sizes is controlled by oil layer thickness, where the spread is seen to rise with thickness. However, interactions between the fluid flows and oil pad thickness give rise to different droplet distributions if either variable were changed on its own.

A method for assessing the effectiveness of water isolation works based on the development of a hydrodynamic model

An important task at the stage of designing any activity related to oil recovery enhancement (in the present case repair and isolation works), is process modeling, in particular, hydrodynamic modeling. Modeling is used to forecast the parameters of oil recovery as s function of the implemented technology at the design stage. As a result, the cost of works performed can be reduced and the profitability and success rate of the planned activities can be assessed. The paper considers the assessment of technological and economic effects using the developed two-phase hydrodynamic model simulating oil-saturated and water-bearing layers. Discussed are the calculated values and relationship between skin factor and various isolation factors. The graphs of oil flow rate and water cut as functions of the material isolation factor are given. Keywords: water isolation; hydrodynamic model; skin factor; isolation factor; water inflow.

Improving the Recovery of Hydrocarbons in a Well in the Gullfaks Field by Injecting Sequestrated CO2

The Gullfaks field was discovered in 1978 in the Tampen area of the North Sea and it is one of the largest Norwegian oil fields located in Block 34/10 along the western flank of the Viking Graben in the northern North Sea. The Gullfaks field came on stream in 1986 and reached a peak of production in 2001. After some years, a decrease in production was noticed due to the decrease in pressure in the well. The goal of this paper is to improve the production of a well located in Gullfaks field by injecting CO2 through coiled tubing. The use of the CO2 injection method is due to the fact that it is a greenhouse gas, and its production in the atmosphere contributes to global warming. It is important to reduce its emission into the atmosphere and to boost the production of oil in the well. The CO2 is injected through the coil tubing to lighten the hydrostatic column and allow the fluid to move from the tubing to the surface. The completion and PVT data are processed in Pipesim and Prosper softwares. By integrating a number of calculations by using the nodal analysis methods and gas injection methods, the results obtained show that the well is not producing and by injecting sequestrated CO2 at the flow rate of 1.482 MMScft/d with an injection pressure of 2500 psig, the oil flow rate provided by the coiled tubing gas injection is 900 Stb/d. The profitability of the project is achieved over a period of 20 years with a net present value (NPV) of $11948858.5 and a return on investment after 5 years 2 weeks.

Dynamic Heat Dissipation Model of Distributed Parameters for Oil-Directed and Air-Forced Traction Transformers and Its Experimental Validation

A traction transformer with narrow oil channels is usually cooled with the ODAF or "Oil Directed Air Forced" method, where its temperature greatly depends on the Joule heat of windings, the conjugate heat transfer in the transformer, and the secondary heat release via oil cooler, together with the oil flowrate generated by oil pump. Neither the thermal-electric analogy nor the CFD simulation approach is qualified to predict the temporal and spatial temperature variations in this type of transformer. In the current work, the distributed parameter models are built for traction transformers and oil coolers with the assumption of a one-dimensional temperature field in the oil flow direction, respectively. Then, the two models are combined with the lumped parameter ones of oil pumps and pipes via the flow rate, temperature and pressure continuities at their interfaces, resulting in the derivation of the dynamic heat dissipation model of oil-directed and air-forced traction transformers. Additionally, an efficient algorithm is proposed for its numerical solution, and the temperature rise experiment is performed for model validation. Finally, the fundamental of dynamic heat dissipation in traction transformers is investigated with the current numerical model and the effects of ambient temperature are studied.

Correct relative permeability data from steady-state experiments for capillary end effects

Water-oil relative permeability curves can be obtained from co-injection experiments at steady-state (SS) conditions. The two-phase Darcy's law can be used to calculate the relative permeability directly only when water saturation is constant along the core. However, the capillary end effect (CEE) causes water accumulation or depletion at the end of the core depending upon the wettability. This work modifies the Intercept Method initially proposed by Gupta and Maloney. Similar to their work, we again envisage carrying out a steady-state (SS) co-injection experiment. For each ratio of water to oil flowrate (F=qwqo), we require experiments at different total flowrates. From each run, we obtain pressure drop across the core and average water saturation inside the core.We demonstrate mathematically that a plot of average water saturation vs. reciprocal of oil flowrate gives a straight line whose intercept is the water saturation in the unaffected region. A plot of pressure difference vs. oil flowrate yields a straight line whose slope gives the oil relative permeability which can be used to calculate water relative permeability. It is necessary to perform the SS experiment at least three times for the same F=qwqo (at different oil/water rates). The same procedure is used for other values of F to obtain more data points to construct the relative permeability curves. An experimental step-by-step procedure for experimental engineers to follow is given in appendix C.

Mismatch problem of the model and topology of oil pumping facilities

The mismatch of the model and the topology of real objects is important in modeling technological processes, which is the purpose of this paper. The problem is considered when modeling hot oil pumping in the "Kasymov–Bolshoy Chagan" oil pipeline. In this problem, the topology of objects consists of the linear part of the pipeline and technological equipment (pumps and heating furnaces) of the stations. The accuracy of the simulation results is determined by the calculations of pressure and temperature in the oil pipeline. The pressure in the pipeline is created by pumps at the stations and is determined by the dependence of the pressure and efficiency of the pump on the oil flow rate. These characteristics change depending on the service life of the pump. The identification of the actual dependences of the pressure and efficiency of the pump on the oil flow rate was carried out by the regression analysis of experimental data. The pressure in the linear part is determined by the hydraulic resistance of the pipeline. The actual dependence of the hydraulic resistance coefficient on the Reynolds number and wall roughness was obtained by regression analysis of experimental data. The temperature in the oil pipeline is created at the stations by heating furnaces. The identification of the actual characteristics of the heating furnace was also found by regression analysis of the experimental data. The temperature distribution in the linear part is determined by the heat transfer of oil with the surrounding environment. An undefined parameter for calculating heat transfer is the soil thermal conductivity, which depends on the type of rock and the degree of soil moisture. The soil thermal conductivity is determined in such a way that at a given oil flow rate, oil temperatures at the beginning of the section and soil at the section, the calculated oil temperature at the end of the section has the smallest discrepancy with the actual one. Thus, the determination of the actual dependencies of the objects makes it possible to increase the accuracy of the results of hot pumping modeling and eliminates the mismatches of the model and the topology of the objects.

The study of efficiency of increase of fluid production in long-term developed fields

As is known, one of the most effective methods of increase of oil development for the mature production fields is the forced fluid withdrawal (FFW). In this respect, the bypassed oil, lenses, blind and dead zones, and low-permeable interlayers are involved in the development of non-homogeneous and heavily watered formations. The decision on the employment of FFW should be made only after the study of the correlation between the flow rate of oil, water, fluid, as well as the water cut. With the purpose of the evaluation of the efficiency of FFW application, the researches based on the actual field data of the well operation in Lokbatan and Gala fields of “Azneft” PU have been carried out. Thus, the dependencies of the flow rate of oil, water and water cut of the product on the flow rate of fluid by all reviewed wells have been developed on a system approach and analyzed, as well as the mathematical models have been found. The analysis and estimation calculations justified the capacity of an approximately 7 % increase of oil production due to the forced withdrawal by the reviewed pattern of wells in Gala field. The studies conducted on the field data justify the practicability of the employment of forced fluid withdrawal in the wells operated from the upper stage of Productive Series in Gala field.