Modeling Technique of Asphaltene Precipitation Min Li; Min Li Southwest Petro Ins and The Key Lab for Special Reservoir Development Search for other works by this author on: This Site Google Scholar Ping Guo; Ping Guo Southwest Petro Ins and The Key Lab for Special Reservoir Development Search for other works by this author on: This Site Google Scholar Shilun Li Shilun Li Southwest Petro Ins and The Key Lab for Special Reservoir Development Search for other works by this author on: This Site Google Scholar Paper presented at the SPE Permian Basin Oil and Gas Recovery Conference, Midland, Texas, May 2001. Paper Number: SPE-70048-MS https://doi.org/10.2118/70048-MS Published: May 15 2001 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Get Permissions Search Site Citation Li, Min, Guo, Ping, and Shilun Li. "Modeling Technique of Asphaltene Precipitation." Paper presented at the SPE Permian Basin Oil and Gas Recovery Conference, Midland, Texas, May 2001. doi: https://doi.org/10.2118/70048-MS Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex Search nav search search input Search input auto suggest search filter All ContentAll ProceedingsSociety of Petroleum Engineers (SPE)SPE Permian Basin Oil and Gas Recovery Conference Search Advanced Search AbstractStudy of three phase equilibrium has been seen from many literatures. Most research onmodeling ofasphaltene precipitation has remained in qualitative description stage. Even though quantitative calculation of asphaltene precipitation can be seen from some reports. However, quantitative calculation of asphaltene precipitation with three phase flash algorithm is unstable because gas-liquid-solid material balance equations is highly non-linear equations. In the light of general view that there are not heavy hydrocarbons with high molecular weight including asphalt in gas phase, technique of stable asphaltene precipitation calculation is put forward by the paper. The recommended technique in the paper separates gas-liquid-solid equilibrium into two parts: gas-liquid and liquid-solid equilibrium. Liquid phase is a bridge between gas and solid phase and solid precipitates always from liquid phase. Gas-liquid equilibrium is described through EOS and fugacity of asphaltene determined from gas-liquid equilibrium should be compared and accord with fugacity of pure solid phase of asphaltene. In this way, modeling of three phase equilibrium becomes easier and more stable. The validation of the model with experimental data is described also in the paper. Additionally, the paper puts forward gas-liqiud-asphaltene material balance equations which can be deduced from general three phase material balance equations and are not similar to them in forms.IntroductionDuring oil production, Asphaltene precipitation will cause serious problems because it can result in plugging of the formation, wellbore and production facilities. Many literatures1,2,3,4 gave the description of asphaltene problems and remedies throughout the world. Currently, many cleaning methods of wellbores are being improvised to maintain production, but these methods are time-consuming and expensive. Asphaltene precipitation also occurs frequently during enhanced-oil-recovery by gas injection which impedes seriously the oil recovery. A model for predicting asphaltene precipitation is highly desirable because it would allow the design of production plan with which asphaltene precipitation can be minimized.Some literatures5,6 presented modeling technique of asphaltene precipitation with EOS. The presented technique can give quantitative calculation of asphaltene precipitation with three phase flash algorithm7. The quantitative calculation with three phase algorithm is unstable because of highly non-linear equations of three phase material balance equations.According to generic opinion that there are not heavy hydrocarbons with high molecular weight including asphalt in gas phase, new technique of asphaltene precipitation calculation is presented in the paper. The suggested technique in the paper separates vapor-liquid-solid equilibrium into two parts -vapor/liquid and liquid/solid equilibrium. Liquid phase is a bridge between gas and solid phase and solid precipitates always from liquid phase. Vapor/liquid equilibrium is described through EOS and fugacity of asphaltene calculated from vapor/liquid equilibrium should be compared and accord with fugacity of pure solid phase of asphaltene. modeling of asphaltene precipitation with the present technique becomes stable. The validation of the model with experimental data is also proved in the paper.Mechanism of Asphaltene PrecipitationMany literatures8,9,10,11 hold the same view that asphaltenes are heavy hydrocarbons which are in colloidal suspension in the oil, stabilized by resins adsorbed on their surface. Changes in pressure, temperature and composition may cause asphaltene precipitation. The mechanism of asphaltene precipitation is still under investigation. There are two possibilities2:the asphaltene/resin micelles precipitate essentially unaltered andthere is a dissociation of the asphaltene/resin micelles which cause the asphaltene precipitation. Keywords: equation, upstream oil & gas, equilibrium, hydrocarbon, asphaltene, fraction, oilfield chemistry, asphaltene fugacity, precipitation, scale remediation Subjects: Production Chemistry, Metallurgy and Biology, Improved and Enhanced Recovery, Inhibition and remediation of hydrates, scale, paraffin / wax and asphaltene This content is only available via PDF. 2001. Society of Petroleum Engineers You can access this article if you purchase or spend a download.
A new organic‐inorganic phase transition material (CH 3 NH 3 ) 4 [InCl 6 ]Cl ( 1 ), has been successfully synthesized and characterized. The compound undergoes a reversible first‐order phase transition at Curie temperature Tc=284 K, accompanied with a wide hysteresis of 12 K, which investigated by differential scanning calorimetry (DSC). The temperature dependence of the dielectric permittivity discloses an obvious step‐like dielectric anomaly. Single crystal X‐ray diffraction reveals that the order‐disorder transition of the [InCl 6 ] 3– anion and the methylammonium cation were the main factor drove the phase transition from high temperature phase with the space group P 2/ m to low temperature phase with the space group P 2/ n . This finding indicates that In‐based organic–inorganic hybrids compounds can be used to build phase transition materials, which broaden the way for exploring dielectric switching materials.
Abstract Identifying environmentally inert, ferromagnetic two-dimensional (2D) materials with high Curie temperatures ( T c ) down to the single layer limit has been an obstacle to fundamental studies of 2D magnetism and application of 2D heterostructures to spin-polarized devices. To address this challenge, the growth, structure and magnetic properties of a 2D Cr-silicate single layer on Pt(111) was investigated experimentally and theoretically. The layer was grown by sequentially depositing SiO and Cr followed by annealing in O 2 . Scanning tunneling microscopy (STM), low-energy electron diffraction (LEED), and low energy electron microscopy all indicated a well-ordered layer that uniformly covered the surface, with STM and LEED indicating that the silicate relaxed to its favored lattice constant. Further experimental characterizations demonstrated that the Cr was nominally 3+ but with a lower electron density than typical trivalent Cr compounds. Comparison with theory identified a Cr 2 Si 2 O 9 structure that resembles a single layer of a dehydrogenated dioctahedral silicate. Magnetic circular dichroism in x-ray absorption spectroscopy revealed a ferromagnetically ordered state up to at least 80 K. Theoretical analysis revealed that the Cr in a dehydrogenated Cr-silicate/Pt(111) is more oxidized than Cr in freestanding Cr 2 Si 2 O 9 H 4 layers. This greater oxidation was found to enhance ferromagnetic coupling and suggests that the magnetism may be tuned by doping. The 2D Cr-silicate is the first member of a broad series of possible layered first-row transition metal silicates with magnetic order; thus, this paper introduces a new platform for investigating 2D ferromagnetism and the development of magnetoelectronic and spintronic devices by stacking 2D atomic layers.
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