Construction, Validation, and Application of Digital Oil: Investigation of Asphaltene Association Toward Asphaltene-Precipitation Prediction

SPE Journal ◽  
2018 ◽  
Vol 23 (03) ◽  
pp. 952-968 ◽  
Author(s):  
S.. Sugiyama ◽  
Y.. Liang ◽  
S.. Murata ◽  
T.. Matsuoka ◽  
M.. Morimoto ◽  
...  
Keyword(s):  
Experimental Data ◽  
Liquid Phase ◽  
Crude Oil ◽  
Md Simulation ◽  
Heavy Fraction ◽  
Liquid Density ◽  
Asphaltene Precipitation ◽  
Viscosity Change ◽  
Light Crude Oil ◽  
Wide Range

Summary Digital oil, a realistic molecular model of crude oil for a target reservoir, opens a new door to understand properties of crude oil under a wide range of thermodynamic conditions. In this study, we constructed a digital oil to model a light crude oil using analytical experiments after separating the light crude oil into gas, light and heavy fractions, and asphaltenes. The gas and light fractions were analyzed by gas chromatography (GC), and 105 kinds of molecules, including normal alkanes, isoalkanes, naphthenes, alkylbenzenes, and polyaromatics (with a maximum of three aromatic rings), were directly identified. The heavy fraction and asphaltenes were analyzed by elemental analysis, molecular-weight (MW) measurement with gel-permeation chromatography (GPC), and hydrogen and carbon nuclear-magnetic-resonance (NMR) spectroscopy, and represented by the quantitative molecular-representation method, which provides a mixture model imitating distributions of the crude-oil sample. Because of the low weight concentration of asphaltenes in the light crude oil (approximately 0.1 wt%), the digital oil model was constructed by mixing the gas, light-, and heavy-fraction models. To confirm the validity of the digital oil, density and viscosity were calculated over a wide range of pressures at the reservoir temperature by molecular-dynamics (MD) simulations. Because only experimental data for the liquid phase were available, we predicted the liquid components of the digital oil at pressures lower than 16.3 MPa (i.e., the bubblepoint pressure) by flash calculation, and calculated the liquid density by MD simulation. The calculated densities coincided with the experimental values at all pressures in the range from 0.1 to 29.5 MPa. We calculated the viscosity of the liquid phase at the same pressures by two independent methods. The calculated viscosities were in good agreement with each other. Moreover, the viscosity change with pressure was consistent with the experimental data. As a step for application of digital oil to predict asphaltene-precipitation risk, we calculated dimerization free energy of asphaltenes (which we regarded as asphaltene self-association energy) in the digital oil at the reservoir condition, using MD simulation with the umbrella sampling method. The calculated value is consistent with reported values used in phase-equilibrium calculation. Digital oil is a powerful tool to help us understand mechanisms of molecular-scale phenomena in oil reservoirs and solve problems in the upstream and downstream petroleum industry.

Fuel Droplet Evaporation in a Supercritical Environment

2002 ◽  
Vol 124 (4) ◽  
pp. 762-770 ◽  
Author(s):  
G. S. Zhu ◽  
S. K. Aggarwal
Keyword(s):  
Experimental Data ◽  
Phase Equilibrium ◽  
Ambient Pressure ◽  
Droplet Surface ◽  
Fuel Vapor ◽  
Phase Solubility ◽  
Liquid Density ◽  
Ambient Temperatures ◽  
Droplet Vaporization ◽  
Wide Range

This paper reports a numerical investigation of the transcritical droplet vaporization phenomena. The simulation is based on the time-dependent conservation equations for liquid and gas phases, pressure-dependent variable thermophysical properties, and a detailed treatment of liquid-vapor phase equilibrium at the droplet surface. The numerical solution of the two-phase equations employs an arbitrary Eulerian-Lagrangian, explicit-implicit method with a dynamically adaptive mesh. Three different equations of state (EOS), namely the Redlich-Kwong (RK), the Peng-Robinson (PR), and Soave-Redlich-Kwong (SRK) EOS, are employed to represent phase equilibrium at the droplet surface. In addition, two different methods are used to determine the liquid density. Results indicate that the predictions of RK-EOS are significantly different from those obtained by using the RK-EOS and SRK-EOS. For the phase-equilibrium of n-heptane-nitrogen system, the RK-EOS predicts higher liquid-phase solubility of nitrogen, higher fuel vapor concentration, lower critical-mixing-state temperature, and lower enthalpy of vaporization. As a consequence, it significantly overpredicts droplet vaporization rates, and underpredicts droplet lifetimes compared to those predicted by PR and SRK-EOS. In contrast, predictions using the PR-EOS and SRK-EOS show excellent agreement with each other and with experimental data over a wide range of conditions. A detailed investigation of the transcritical droplet vaporization phenomena indicates that at low to moderate ambient temperatures, the droplet lifetime first increases and then decreases as the ambient pressure is increased. At high ambient temperatures, however, the droplet lifetime decreases monotonically with pressure. This behavior is in accord with the reported experimental data.

Fuel Droplet Evaporation in a Supercritical Environment

1999 ◽  
Author(s):  
G. S. Zhu ◽  
S. K. Aggarwal
Keyword(s):  
Experimental Data ◽  
Phase Equilibrium ◽  
Ambient Pressure ◽  
Droplet Surface ◽  
Fuel Vapor ◽  
Phase Solubility ◽  
Liquid Density ◽  
Ambient Temperatures ◽  
Droplet Vaporization ◽  
Wide Range

This paper reports a numerical investigation of the transcritical and supercritical droplet vaporization phenomena. The simulation is based on the time-dependent conservation equations for liquid and gas phases, pressure-dependent variable thermophysical properties, and a detailed treatment of liquid-vapor phase equilibrium at the droplet surface. The numerical solution of the two-phase equations employs an arbitrary Eulerian-Lagrangian, explicit-implicit method with a dynamically adaptive mesh. Three different equations of state (EOS), namely the Redlich-Kwong (RK), the Peng-Robinson (PR) and Soave-Redlich-Kwong (SRK) EOS, are employed to represent phase equilibrium at the droplet surface. In addition, two different methods are used to determine the liquid density. Results indicate that the predictions of RK-EOS are significantly different from those obtained by using the RK-EOS and SRK-EOS. For the phase-equilibrium of n-heptane-nitrogen system, the RK-EOS predicts higher liquid-phase solubility of nitrogen, higher fuel vapor concentration, lower critical-mixing-state temperature, and lower enthalpy of vaporization. As a consequence, it significantly overpredicts droplet vaporization rates, and underpredicts droplet lifetimes compared to those predicted by PR- and SRK-EOS. In contrast, predictions using the PR-EOS and SRK-EOS show excellent agreement with each other and with experimental data over a wide range of conditions. A detailed investigation of the transcritical droplet vaporization phenomena indicates that at low to moderate ambient temperatures, the droplet lifetime first increases and then decreases as the ambient pressure is increased. At high ambient temperatures, however, the droplet lifetime decreases monotonically with pressure. This behavior is in accord with the reported experimental data.

MD Simulation of Crosslinked Epoxy Resin at Different Temperatures

2012 ◽  
Vol 602-604 ◽  
pp. 747-750
Author(s):  
Miao Zhang ◽  
Ping Yang
Keyword(s):  
Experimental Data ◽  
Epoxy Resin ◽  
Md Simulation ◽  
Md Simulations ◽  
Atomic Scale ◽  
Electronic Packages ◽  
Powerful Method ◽  
Wide Range ◽  
Different Temperatures ◽  
The Cross

Epoxy resin is widely used in many electronic packages, the ability to predict properties of cross linked epoxy resin before experiments will facilitate the process of materials design. Molecular dynamics (MD) is a powerful method that can simulate the materials at atomic scale and it can be used to predict the performance and properties of a wide range of materials. In this work, the properties of the cross-linked epoxy resin compound at high temperature were studies by MD simulations. The relations of the glass transition temperature (Tg) and properties of the cross-linked epoxy resin were investigated. The results show that Tg can be estimated by the plot of non-bond energy at different temperatures, and consist with the experimental data.

scholarly journals Dispersant effectiveness on oil spills – impact of salinity

2006 ◽  
Vol 63 (8) ◽  
pp. 1418-1430 ◽  
Author(s):  
Subhashini Chandrasekar ◽  
George A. Sorial ◽  
James W. Weaver
Keyword(s):  
Experimental Data ◽  
Crude Oil ◽  
Oil Spills ◽  
Refined Oil ◽  
Light Crude Oil ◽  
Mixing Energy ◽  
Oil Dispersant ◽  
Dispersant Effectiveness ◽  
Almost All ◽  
The Impact

Abstract When a dispersant is applied to an oil slick, its effectiveness in dispersing the spilled oil depends on factors such as oil properties, wave-mixing energy, temperature, and salinity of the water. Estuaries represent water with varying salinity, so in this study, three salinity values in the range 10–34 psu were investigated, representing potential salinity concentrations found in typical estuaries. Three oils were chosen to represent light refined oil, light crude oil, and medium crude oil. Each was tested at three weathering levels to represent maximum, medium, and zero weathering. Two dispersants were chosen for evaluation. A modified trypsinizing flask termed a baffled flask was used to conduct the experimental runs. A full factorial experiment was conducted for each oil. The interactions between the effects of salinity and three environmental factors, temperature, oil weathering, and mixing energy, on dispersion effectiveness were investigated. Each experiment was replicated four times in order to evaluate the accuracy of the test. Statistical analyses of the experimental data were performed for each of the three oils independently for each dispersant treatment (two dispersants and oil controls). A linear regression model representing the main factors (salinity, temperature, oil weathering, flask speed) and second-order interactions among the factors was fitted to the experimental data. Salinity played an important role in determining the significance of temperature and mixing energy on dispersant effectiveness for almost all the oil–dispersant combinations. The impact of salinity at different weathering was only significant for light crude oil with dispersant A.

Influence of Temperature and Pressure on Asphaltene Flocculation

1984 ◽  
Vol 24 (03) ◽  
pp. 283-293 ◽  
Author(s):  
A. Hirschberg ◽  
L.N.J. deJong ◽  
B.A. Schipper ◽  
J.G. Meijer
Keyword(s):  
Experimental Data ◽  
Molecular Weight ◽  
Crude Oil ◽  
Pressure Dependence ◽  
Thermodynamic Model ◽  
Molecular Model ◽  
Asphaltene Precipitation ◽  
Skin Model ◽  
Order Of Magnitude ◽  
Specific Project

Abstract A thermodynamic liquid model has been developed to describe the behavior of asphalt and asphaltenes in reservoir crudes upon changes in pressure, temperature, or composition. Asphaltene solubility properties used as input to the model may be obtained from titration experiments on tank oil. High-pressure flocculation experiments confirm the potential of the model. The model appears to be well applicable to conditions at which asphaltenes are associated with resins. The model may be used to identify field conditions where asphalt or asphaltene precipitation will occur. Introduction Scope of study. Miscible flooding with enriched gas or CO has the potential of recovering a significantly larger volume of oil more economically than conventional water flooding. One of the problems in gas drives is asphaltene instability, which might result in plugging or wettability reversal. Asphalt or asphaltenes precipitation may also affect production in the course of precipitation may also affect production in the course of reservoir development by natural depletion. The parameters that govern precipitation appear to be composition of the crude, pressure, temperature, and properties of asphaltenes. For a specific project one can properties of asphaltenes. For a specific project one can investigate the flocculation process experimentally. This proposition is usually impractical because it requires a proposition is usually impractical because it requires a large number of experiments at reservoir conditions of pressure and temperature. Hence, there is a need for a pressure and temperature. Hence, there is a need for a theoretical description using only a limited amount of experimental data to predict precipitation. The search for such a model has been hampered by the widely held notion that asphaltene precipitation is not a (fully) reversible process. Re-examination of experimental information indicates that reversibility of asphaltene precipitation should be considered an open question. If reversible, the process can be described with a thermodynamic model. The aim of the present paper is to demonstrate that flocculation of asphalt and asphaltenes in light crudes (formation of a bituminous phase) can be described with a simple molecular thermodynamic model. The key concepts of asphalt, asphaltenes, and resins are defined in the next section. The model proposed is described in the following section, in which we also review previous studies. We then discuss field experiences. Experimental data are presented on the phase behavior of two light crudes: an Iranian crude oil with an n-heptane asphaltene content of 1.9 wt% (of tank oil) and a North Sea crude with a low (0.3 wt%) asphaltene content (see PVT properties in Tables 1 and 2). We first use the proposed model (Appendix A) to determine the solubility properties of asphaltenes in Crude No. 1, from a series of titration experiments on tank oil. Using, these results, we compare the measured and predicted amounts of asphaltenes precipitated on mixing recombined Crude No. 1 with three potential injection gases (Table 3). We discuss the pressure dependence of asphalt precipitation and compare measured and predicted pressure dependence of the amount of asphalt precipitated from a mixture of crude No. 2 and propane. Possible improvements of the model are also discussed. Finally, the model is used to predict field conditions favorable to asphalt and asphaltene precipitation. Asphaltenes, Resins, and Asphalt. Asphaltenes are defined as the n-heptane insoluble fraction of crude oil obtained following the Inst. of Petroleum (IP) Method Test 143. Resins can be defined as the fraction of crude oil not soluble in ethylacetate but soluble in n-heptane, toluene, and benzene at room temperature. Asphalt is used here as a general term to designate the combination of asphaltenes and resins. Asphalt precipitated by propane can be molten. n-heptane asphaltenes are solid and decompose upon heating. Asphaltenes and resins are heterocompounds and form the most polar fraction of crude oil. Recent studies on asphaltene structure show that the basic asphaltene "molecule" (asphaltene sheet ) has a molecular weight of the same order of magnitude as that of resins (5 × 10 to 10 3 ). Depending on "purity" and concentration asphaltenes form aggregates with a molecular weight of the order of magnitude of 10 to 10 (asphaltene particles ). Resins have a strong tendency to associate with particles ). Resins have a strong tendency to associate with asphaltenes. This reduces the aggregation of asphaltenes, which determines to a large extent their solubility in crude oil. The most common model for asphaltene/resin interaction is the colloidal model. Asphaltene micelles (aggregates) are assumed to be kept in solution (stabilized or peptized) by a layer of resins ("onion-skin model"). peptized) by a layer of resins ("onion-skin model"). However, the studies of Yen, Speight, and Briant provide a basis for developing a molecular model for provide a basis for developing a molecular model for asphaltene/resin interaction. SPEJ P. 283

scholarly journals Cardanol /SiO2 Nanocomposites for Inhibition of Formation Damage by Asphaltene Precipitation/Deposition in Light Crude Oil Reservoirs. Part II: Nanocomposite Evaluation and Coreflooding Test

ACS Omega ◽  
2020 ◽  
Vol 5 (43) ◽  
pp. 27800-27810
Author(s):  
Daniel López ◽  
Juan E. Jaramillo ◽  
Elizabete F. Lucas ◽  
Masoud Riazi ◽  
Sergio H. Lopera ◽  
...  
Keyword(s):  
Crude Oil ◽  
Oil Reservoirs ◽  
Formation Damage ◽  
Asphaltene Precipitation ◽  
Light Crude Oil ◽  
Sio2 Nanocomposites

Effect of pressure and CO2 content on the asphaltene precipitation in the light crude oil

2019 ◽  
Vol 38 (2) ◽  
pp. 116-123
Author(s):  
Jianguang Wei ◽  
Jiangtao Li ◽  
Xiaofeng Zhou ◽  
Xin Zhang
Keyword(s):  
Crude Oil ◽  
Asphaltene Precipitation ◽  
Effect Of Pressure ◽  
Light Crude Oil
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