scholarly journals Experimental and modeling studies of density and viscosity behavior of a live fluid due to CO2 injection at reservoir condition

2021 ◽  
Vol 76 ◽  
pp. 45
Author(s):  
David C. Santos ◽  
Marina N. Lamim ◽  
Daniela S. Costa ◽  
Ana Mehl ◽  
Paulo Couto ◽  
...  
Keyword(s):  
Volume Change ◽  
Pressure Range ◽  
Excess Volume ◽  
Temperature Gradients ◽  
Co2 Injection ◽  
Maximum Deviation ◽  
Viscosity Behavior ◽  
Predictive Methods ◽  
Predicted Values ◽  
Live Oil

In this study, highly accurate measurements of density and dynamic viscosities of a recombined live oil and its mixture with additional CO2 were performed. The experiments were carried out under pressure and temperature gradients found in Brazilian Pre-salt reservoirs, that is, in the pressure range from (27.6 to 68.9) MPa and at (333.15 and 353.15) K. The assumption of volume change on mixing is evaluated from the experimental results, and the influence of pressure and temperature on the volume change upon mixing is assessed. The densities of mixtures are calculated considering (i) the excess volume approach, and (ii) no volume change. The densities are better correlated using the excess volume approach with Average Absolute Deviations (AAD) of 0.03%. Thirteen mixing rules of viscosity are examined by comparing the predicted values with the experimental viscosity of the recombined live oil + CO2 mixture. The performance of some rules using compositional fractions (molar, volume and weight) is also evaluated. Thus, a total of 28 different ways to calculate the mixture viscosities were tested in this study. The worst result was obtained with Bingham’s method, leading to 148.6% AAD. The best result was obtained from Lederer’s method with 2% AAD and a maximum deviation of 5.8% using volume fractions and the fitting parameter α. In addition, deviations presented by the predictive methods of Chevron, Double log, and Kendall did not exceed 9% AAD, using weight fractions (Chevron and Double log) and molar fractions (Kendall and Monroe).

scholarly journals Study on Cutting Chip in Milling GH4169 with Indexable Disc Cutter

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3135
Author(s):  
Gensheng Li ◽  
Chao Xian ◽  
Hongmin Xin
Keyword(s):  
Chip Thickness ◽  
Cutting Parameters ◽  
Disc Cutter ◽  
Maximum Deviation ◽  
Feed Speed ◽  
Deviation Rate ◽  
Qualitative Relationship ◽  
Predicted Values ◽  
Deformation Coefficient ◽  
And Control

The study and control for chip have a significant impact on machining quality and productivity. In this paper, GH4169 was cut with an indexable disc milling cutter. The chips corresponding to each group of cutting parameters were collected, and the chip parameters (chip curl radius, chip thickness deformation coefficient, and chip width deformation coefficient) were measured. The qualitative relationship between the chip parameters and cutting parameters was studied. The quadratic polynomial models between chip parameters and cutting parameters were established and verified. The results showed that the chip parameters (chip curl radius, chip thickness deformation coefficient and chip width deformation coefficient) were negatively correlated with spindle speed; chip parameters were positively correlated with feed speed; chip parameters were positively correlated with cutting depth. The maximum deviation rate between measured values and predicted values for chip curl radius was 9.37%; the maximum deviation rate for cutting thickness deformation coefficient was 13.8%, and the maximum deviation rate of cutting width deformation coefficient was 7.86%. It can be seen that the established models are accurate. The models have guiding significance for chip control.

scholarly journals Investigation of Oil Recovery in Fractured Carbonate Rock by

2016 ◽  
Vol 6 (1) ◽  
pp. 14
Author(s):  
H. Karimaie ◽  
O. Torsæter
Keyword(s):  
Oil Recovery ◽  
Gas Injection ◽  
Water Injection ◽  
Co2 Injection ◽  
Recovery Method ◽  
Asmari Limestone ◽  
Fractured Carbonate ◽  
Efficient Recovery ◽  
Live Oil ◽  
Non Equilibrium

The purpose of the three experiments described in this paper is to investigate the efficiency of secondary andtertiary gas injection in fractured carbonate reservoirs, focusing on the effect of equilibrium gas,re-pressurization and non-equilibrium gas. A weakly water-wet sample from Asmari limestone which is the mainoil producing formation in Iran, was placed vertically in a specially designed core holder surrounded withfracture. The unique feature of the apparatus used in the experiment, is the capability of initializing the samplewith live oil to obtain a homogeneous saturation and create the fracture around it by using a special alloy whichis easily meltable. After initializing the sample, the alloy can be drained from the bottom of the modified coreholder and create the fracture which is filled with live oil and surrounded the sample. Pressure and temperaturewere selected in the experiments to give proper interfacial tensions which have been measured experimentally.Series of secondary and tertiary gas injection were carried out using equilibrium and non-equilibrium gas.Experiments have been performed at different pressures and effect of reduction of interfacial tension werechecked by re-pressurization process. The experiments showed little oil recovery due to water injection whilesignificant amount of oil has been produced due to equilibrium gas injection and re-pressurization. Results alsoreveal that CO2 injection is a very efficient recovery method while injection of C1 can also improve the oilrecovery.

scholarly journals Using Markov Chains to Predict Productivity of Maize in Iraq for the Period (2019-2025)

2021 ◽  
Vol 8 (5) ◽  
pp. 1
Author(s):  
L.A.F. Al-Ani ◽  
A.D.K. Alhiyali
Keyword(s):  
Markov Chains ◽  
Historical Data ◽  
Unit Area ◽  
Recent Past ◽  
Predictive Values ◽  
The Third ◽  
Predictive Methods ◽  
Horizontal Expansion ◽  
Predicted Values ◽  
The Impact

The research aims to predict the productivity of one of the most important major crops in Iraq, which is Maize, using Markov chains, which is one of the most important predictive methods that depend on relatively recent historical data and based mainly on previous data that is not far away. This is the advantage that Markov chains have, as relying on somewhat old historical data may negatively affect the predicted values. The results of the research showed the superiority of the third state to predict the productivity of Maize depending on the availability of Markov chains prediction conditions for this state. The results of the research also showed the continued decline in productivity for the coming years, as well as the impact of the predictive values on changes in the cultivated area more than changes in production, which confirms the existence of horizontal expansion at the expense of vertical expansion, that is, there is no intensification of production per unit area. The research also found that the actual values of productivity have approached the estimated values of the following years, and the matter applies to the convergence of these results for the subsequent years with the previous years, which confirms the accuracy of the method of Markov chains, in other words that what happened in the recent past had a clear impact in the future near.

Pressure Effects on the Optical Properties of LuVO4:Eu3+ Nanoparticles

2017 ◽  
Vol 75 ◽  
pp. 1-10 ◽  
Author(s):  
Brana Jovanić ◽  
Marco Bettinelli ◽  
Bozidar Radenković ◽  
Marijana Despotović-Zrakić ◽  
Fabio Piccinelli ◽  
...  
Keyword(s):  
High Pressure ◽  
Fluorescence Lifetime ◽  
Pressure Range ◽  
Room Temperature ◽  
Emission Spectra ◽  
Pressure Effects ◽  
Predicted Values ◽  
Line Positions ◽  
Effect Of Hydrostatic Pressure ◽  
The Eu

The effect of hydrostatic pressure (varying up to 110 kbar) at the room temperature on three lines at 594nm, 615nm and 619nm positions in emission spectra and fluorescence lifetime t of the Eu3+ for 0-2 line (5D0→7F2 transition) in LuVO4: Eu3+ nanoparticles was studied. The results showed that the increase of the pressure induced lines red shift towards longer wavelengths for all considered lines with different rate. Also, the fluorescence lifetime τ for 5D0 → 7F2 transition nonlinearly decreased with pressure in the considered pressure range. Line positions and fluorescence lifetime τ, were explained by a model which took into account the effect of high pressure on: refractive index of crystal; compression, polarizability of the crystal and individual ions. Satisfactory agreement between measured and theoretical predicted values with error less than 2% was obtained.

RBF Prediction Model Based on EMD for Forecasting GPS Precipitable Water Vapor and Annual Precipitation

2013 ◽  
Vol 765-767 ◽  
pp. 2830-2834 ◽  
Author(s):  
Yan Ping Liu ◽  
Yong Wang ◽  
Zhen Wang
Keyword(s):  
Rbf Neural Network ◽  
Precipitable Water ◽  
Annual Precipitation ◽  
Maximum Deviation ◽  
Atmospheric Sciences ◽  
Precipitation Forecasting ◽  
Mode Function ◽  
Mode Decomposition ◽  
Proposed Model ◽  
Predicted Values

The forecast of precipitations is important in meteorology and atmospheric sciences. A new model is proposed based on empirical mode decomposition and the RBF neural network. Firstly, GPS PWV time series is broken down into series of different scales intrinsic mode function. Secondly, the phase space reconstruction is done. Thirdly, each component is predicted by RBF. Finally, the final prediction value is reconstructed. Next, the model is tested on annual precipitation sequence from 2001 to 2010 in northeast China. The result shows that predictive value is close to the actual precipitation, which can better reflect the actual precipitation change. From 2001 to 2010, the maximum deviation of the predicted values never exceeds 4%. The testing results show that the proposed model can increase precipitation forecasting accuracies not only in GPS PWV but also in annual precipitation.

Thermal Contact Resistance Measurements of Compressed PEFC Gas Diffusion Media

2016 ◽  
Vol 13 (4) ◽  
Author(s):  
Adam S. Hollinger ◽  
Stefan T. Thynell
Keyword(s):  
Fuel Cell ◽  
Contact Resistance ◽  
Pressure Range ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Gas Diffusion ◽  
Temperature Gradients ◽  
Polymer Electrolyte Fuel Cell ◽  
Carbon Paper ◽  
Carbon Cloth

Localized temperature gradients in a polymer electrolyte fuel cell (PEFC) are known to decrease the durability of the polymer membrane. The most important factor in controlling these temperature gradients is the thermal contact resistance at the interface of the gas diffusion layer (GDL) and the bipolar plate. Here, we present thermal contact resistance measurements of carbon paper and carbon cloth GDLs over a pressure range of 0.7–14.5 MPa. Contact resistances are highly dependent upon the clamping pressure applied to a fuel cell, and in the present work, contact resistances vary from 3.5 × 10−4 to 2.0 × 10−5 m2 K/W, decreasing nonlinearly over the pressure range for each material tested. The contact resistances of carbon cloth GDLs are two to four times higher than contact resistances of carbon paper GDLs throughout the range of pressures tested. The data presented here also show that the thermal resistance of the sample is negligible in comparison to the thermal contact resistance. Controlling temperature gradients in a fuel cell is desirable, and the measurements presented here can be used to more accurately predict temperature distribution in a polymer electrolyte fuel cell.

scholarly journals Comparative Analysis of CO2, N2, and Gas Mixture Injection on Asphaltene Deposition Pressure in Reservoir Conditions

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2483 ◽  
Author(s):  
Peng Wang ◽  
Fenglan Zhao ◽  
Jirui Hou ◽  
Guoyong Lu ◽  
Meng Zhang ◽  
...  
Keyword(s):  
Crude Oil ◽  
Pressure Range ◽  
Co2 Injection ◽  
Gas Mixture ◽  
Low Permeability ◽  
Deposition Pressure ◽  
Severe Problem ◽  
Asphaltene Deposition ◽  
Reservoir Conditions ◽  
Buried Hill

CO2 and N2 injection is an effective enhanced oil recovery technology in the oilfield especially for low-permeability and extra low-permeability reservoirs. However, these processes can induce an asphaltene deposition during oil production. Asphaltene-deposition-induced formation damage is a fairly severe problem. Therefore, predicting the likelihood of asphaltene deposition in reservoir conditions is crucial. This paper presents the results of flash separation experiments used to investigate the composition of crude oil in shallow and buried-hill reservoirs. Then, PVTsim Nova is used to simulate the composition change and asphaltene deposition of crude oil. Simulation tests indicate that the content of light components C1-C4 and heavy components C36+ decrease with increasing CO2 and N2 injection volumes. However, the extraction of CO2 is significantly stronger than that of N2. In shallow reservoirs, as the CO2 injection volume increases, the deposition pressure range decreases and asphaltenes are easily deposited. Conversely, the asphaltene deposition pressure of crude oil injected with N2 is higher and will not cause serious asphaltene deposition. When the CO2-N2 injection ratio reaches 1:1, the deposition pressure range shows a significant transition. In buried-hill reservoirs, asphaltene deposition is unlikely to occur with CO2, N2, and a gas mixture injection.

An Evaluation of Tympanometric Estimates of Ear Canal Volume

1981 ◽  
Vol 24 (4) ◽  
pp. 557-566 ◽  
Author(s):  
Janet E. Shanks ◽  
David J. Lilly
Keyword(s):  
Tympanic Membrane ◽  
Direct Measurement ◽  
Middle Ear ◽  
Volume Change ◽  
Pressure Range ◽  
Normal Subjects ◽  
Transmission System ◽  
Ear Canal ◽  
Volume Changes

The accuracy of tympanometric estimates of ear canal volume was evaluated by testing the following two assumptions on which the procedure is based: (a) ear canal volume does not change when ear canal pressure is varied, and (b) an ear canal pressure of 200 daPa drives the impedance of the middle ear transmission system to infinity so the immittance measured at 200 daPa can be attributed to the ear canal volume alone. The first assumption was tested by measuring the changes in ear canal volune in eight normal subjects for ear canal pressures between ±400 daPa using a manometric procedure based on Boyle's gas law. The data did not support the first assumption. Ear canal volume changed by a mean of .113 ml over the ±400 daPa pressure range with slightly larger volume changes occurring for negative ear canal pressures than for positive ear canal pressures. Most of the volume change was attributed to movement of the probe and to movement of the cartilaginous walls of the ear canal. The second assumption was tested by comparing estimates of ear canal volume from susceptance tympanograms with a direct measurement of ear canal volume adjusted for changes in volume due to changes in ear canal pressure between +±400 daPa. These data failed to support the second assumption. All tympanometric estimates of ear canal volume were larger than the measured volumes. The largest error (39%) occurred for an ear canal pressure of 200 daPa at 220 Hz, whereas the smallest error (10%) occurred for an ear canal pressure of ±400 daPa at 660 Hz. This latter susceptance value (-400 daPa at 660 Hz) divided lay three is suggested to correct the 220-Hz tympanogram to the plane of the tympanic membrane. Finally, the effects of errors in estimating ear canal volume on static immittance and on tympanometry are discussed.

Measurement of the Speed of Sound in 2,3,3,3-Tetrafluoropropylene (R-1234yf) Liquid Phase with an Ultrasonic Sensor

2014 ◽  
Vol 875-877 ◽  
pp. 588-592
Author(s):  
Lei Gao ◽  
Takuro Shibasaki ◽  
Tomohiro Honda ◽  
Hiroyuki Asou
Keyword(s):  
Liquid Phase ◽  
Speed Of Sound ◽  
Pressure Range ◽  
Pure Water ◽  
Ultrasonic Sensor ◽  
Maximum Deviation ◽  
Subcooled Liquid ◽  
Temperature Range ◽  
Liquid Phases ◽  
Measurement Results

The speeds of sound in near saturated and subcooled liquid phases of R-1234yf have been measured using a ultrasonic sensor. The measurements were conducted at the temperature range from 0 to 80 °C, and the pressure range from 0.316 to 2.52 MPa. In order to validate the ultrasonic sensor, the measurement in pure water at the temperature range from 0 to 80 °C was also performed. The measurement result of water was compared with those calculated from REFPROP (based on IAPWS-95) and PROPATH (based on IAPWS-IF97). The result of water agrees well with that calculated from REFPROP within a maximum deviation of 0.28%, except for that at temperature of 80 °C. And it agrees well also with that calculated from PROPATH within a maximum deviation of ±0.2%. The measurement results for near saturated and subcooled liquid phases of R-1234yf were compared with those calculated from REFPROP and JSRAE thermodynamic table.

Accurate Live Interfacial Tension for Improved Reservoir Engineering Practices

2021 ◽  
Author(s):  
Taha Okasha ◽  
Mohammed Al Hamad ◽  
Bastian Sauerer ◽  
Wael Abdallah
Keyword(s):  
Interfacial Tension ◽  
Liquid Composition ◽  
Fluid Composition ◽  
Ambient Conditions ◽  
Pressure Step ◽  
Reservoir Conditions ◽  
Fluid Characterization ◽  
Predicted Values ◽  
Engineering Practices ◽  
Live Oil

Abstract Current reservoir simulators use interfacial tension (IFT) values derived from dead oil measurements at ambient conditions or predicted from literature correlations. IFT is highly dependent on temperature, pressure and fluid composition. Therefore, knowledge of the IFT value at reservoir conditions is essential for accurate reservoir fluid characterization. This study compares IFT values from dead and live oil measurements and the results of literature predicted values, thereby clearly showing the weakness of existing correlations when trying to predict crude oil IFT. A total of ten live oils was sampled for this study. Using the pendent drop technique, IFT was measured for each oil at different conditions: in the under-saturated region at reservoir pressure and temperature, in the saturated region at reservoir temperature, and for dead oil at ambient conditions. Basic PVT properties such as gas to oil ratio (GOR), gas and liquid composition, density, viscosity and molecular weight were also measured. The bubble point for each oil was identified to define the pressure step in the saturated region for extra IFT measurement. The equilibrium IFT values for the live oils were generally higher than for the corresponding dead oils. For oils where this general trend was not observed, contaminations were found in the crude samples. The use of current literature correlations does not allow to predict correct reservoir IFT. Therefore, this study provides accurate live IFT values for a variety of reservoir fluids and conditions in combination with live oil properties, highly beneficial to reservoir engineers, allowing better oil production planning.

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