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Francisco M. Vargas - One of the best experts on this subject based on the ideXlab platform.
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Experimental Investigation of Asphaltene Deposition in A Transparent Microchannel
Proceeding of First Thermal and Fluids Engineering Summer Conference, 2020Co-Authors: Y. Zhuang, Francisco M. Vargas, John C. Chai, Afshin Goharzadeh, Nevin Thunduvila Mathew, Sibani Lisa BiswalAbstract:This study is focused on experimental investigation of Asphaltene Deposition in a vertical transparent microchannel. Heptane-induced Asphaltene precipitation is utilized to precipitate dissolved Asphaltene particles in crude oil and form Asphaltene particles in ambient temperature and standard atmospheric pressure. These Asphaltene particles deposit gradually on the surface of microchannels. The key parameters that influence the mechanism of Asphaltene Deposition are the ratio of crude oil to n-heptane and experimental elapsed time. At a constant flowrate, the amount of Asphaltene deposited on a transparent channel wall is quantified using a new flow visualization technique based on reflected light intensity and image analysis. Asphaltene precipitation and Deposition strongly affect the reflected light intensity through the change of mixture color. Experimental results show that Asphaltene Deposition process might follow three stages, (i) small Asphaltene particle Deposition at the beginning of the experiment, (ii) a rapid and continuous Deposition increase after few hours and (iii) a decrease on Deposition rate in the system at the end of the experimentation. The experimental results regarding different mixing ratios illustrate that Deposition increases with the increasing of the concentration of n-heptane. Continuous Asphaltene Deposition can be represented by light intensity in terms of experimental elapsed time. An empirical fitting in logarithmic trend is plotted and can be used for further numerical simulations. These results provide useful information on behavior of Asphaltene Deposition in diverse parameter setting conditions and are useful in developing and validating numerical model.
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Mitigation of Asphaltene Deposition by Re-injection of dead oil
Fluid Phase Equilibria, 2020Co-Authors: A. T. Khaleel, Mohammed I. L. Abutaqiya, Caleb J. Sisco, Francisco M. VargasAbstract:Abstract Asphaltene Deposition is a common flow assurance problem in the oil and gas industry. During oil production, changes in pressure, temperature, and composition may induce precipitation as Asphaltenes become unstable in the oil. Precipitated Asphaltenes can then deposit on the inner walls of the production tubing and restrict or even completely block the flow of oil. In this work, we propose a novel chemical-free technique to mitigate Asphaltene Deposition, where dead oil collected at the surface is recycled to reduce Asphaltene precipitation. The stabilization effect of the dead oil reinjection is investigated from a thermodynamic perspective using PC-SAFT EOS. Four crude oils from the literature are investigated, and it is found that the Asphaltene unstable region and precipitated amounts reduce significantly upon reinjection of dead oil. The simulation results suggest that, depending on the amount of reinjection and the oil characteristics, Asphaltene precipitation can be eliminated by simply reinjecting dead oil.
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Modeling of Asphaltene Deposition in a Packed Bed Column
Energy & Fuels, 2019Co-Authors: Narmadha Rajan Babu, Francisco M. VargasAbstract:Asphaltene deposit buildup in production pipelines and subsea flowlines greatly affects the production rate of oil and, hence, is a major concern for the upstream oil and gas industry. To better understand the behavior of Asphaltenes under different production scenarios and operating conditions, the physics of Asphaltene Deposition and effectively develop mitigation strategies to overcome this problem, experimental techniques, and modeling methods are extremely important. Recently, Deposition tests using a packed bed column have been performed to measure and quantify Asphaltene Deposition in the laboratory. This work focuses on the development of a modeling technique to simulate the process of Asphaltene Deposition occurring in the packed bed column. A computational fluid dynamics model has been developed to analyze the multi-step process of Asphaltene phase separation, aggregation, diffusion, and Deposition. Three-dimensional transient flow simulations have been performed using an indigenous in-house fin...
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evaluation of solvents for in situ Asphaltene Deposition remediation
Fuel, 2019Co-Authors: Jun Kuang, Jianxin Wang, Josiah Yarbrough, Shayan Enayat, Nigel Edward, Francisco M. VargasAbstract:Abstract Upon the formation and the accumulation of the deposits, cost-effective cleaning strategies should be applied to remediate and remove the organic solids. The injection of aromatic solvents, usually know as solvent wash, is one of the commonly used techniques to re-dissolve the deposited Asphaltenes in the well. To select and develop the best solvents and the most appropriate solvent soaking conditions for Asphaltene remediation, a re-dissolution test apparatus using a packed bed column was introduced to evaluate the solvents for in-situ Asphaltene Deposition remediation under more realistic production conditions. The solvency power of three aromatic solvents and four commercial solvents was determined and compared. Under the current experimental conditions, the injection of p-xylene re-dissolves 31.3% and 69.8% more deposits than the same volume of toluene and aromatic naphtha (A150). Additionally, the solvent wash by toluene/diesel mixture (50/50 by volume) and diesel significantly reduces the re-dissolution efficiency by 31.1% and 74.3% by comparing to toluene. Results also suggest that the screening of chemical solvents based on their solubility parameters may not provide accurate indication on the selection of the best solvent for Asphaltene removal. Furthermore, the effects of aging time, occluded oil, soaking temperature, and soaking time were investigated on the removal of Asphaltene Deposition in the packed bed column. Results show that the existence of the occluded oil during the aging and soaking process weakens the solubility power of the toluene. The solvency power of toluene is enhanced by 11.4% and 24.2% when the soaking temperature increases from 25 °C to 120 °C and the soaking time extends from 1 h to 24 h, respectively. With the proposed technique to assess chemical solvents in the laboratory, the most cost-effective solvent wash strategy can be developed for the in-situ remediation of Asphaltene Deposition in the wellbore.
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Effect of Carbon Steel Corrosion on Asphaltene Deposition
Energy & Fuels, 2018Co-Authors: Mohammad Tavakkoli, Chi-an Sung, Jun Kuang, Andrew Chen, Jeremy Hu, Francisco M. VargasAbstract:In this work, the effect of carbon steel corrosion on Asphaltene Deposition tendency was investigated. A new experimental setup, consisting of a multi-section column made of polytetrafluoroethylene (PTFE), was built and packed with carbon steel spheres, which was then used to quantify the Deposition of Asphaltenes under different conditions. It was found that, in the presence of iron ions in a brine-in-oil emulsion, the amount of deposited material upon the addition of an Asphaltene precipitant, such as n-heptane, was significantly higher than in the case of iron-free brine. In addition, it was observed that Asphaltenes have a higher tendency to deposit on the rust-covered metallic surfaces compared to the clean and smooth carbon steel spheres. Also, increasing the surface roughness can lead to a higher Asphaltene Deposition rate. To reduce the extent of Asphaltene Deposition induced by the tube corrosion, a chelating agent, ethylenediaminetetraacetic acid (EDTA), was added to sequestrate the iron ions. T...
Walter G Chapman - One of the best experts on this subject based on the ideXlab platform.
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An integrated model for Asphaltene Deposition in wellbores/pipelines above bubble pressures
Journal of Petroleum Science and Engineering, 2018Co-Authors: Q. Guan, Francisco M. Vargas, John C. Chai, Walter G Chapman, Afshin Goharzadeh, Sibani Lisa Biswal, M. ZhangAbstract:Abstract Asphaltene has been recognized as the cholesterol of petroleum for decades due to its precipitation and Deposition in oil production, transportation and processing facilities, causing tremendous losses to the oil industry each year. This work presents a numerical model to predict Asphaltene Deposition in wellbores/pipelines. A Thermodynamic Module is developed to model Asphaltene precipitation, based on the sequential stability-testing-and-phase-split-calculation method using Peng-Robinson equation of state with Peneloux volume correction. A Transport Module is developed to model fluid transport, Asphaltene particle transport and Asphaltene Deposition, according to basic conservation laws. Using a thermodynamic properties look-up table, these two modules are linked to each other to account for the effects of a finite deposit layer thickness on the coupled flow fields and Deposition process. In this article, verification and validation of the Thermodynamic Module are first carried out. Then, the integrated model is utilized to study Asphaltene Deposition problems in an actual oilfield where the Asphaltene deposit layer profile is reasonably accurately predicted. This case shows that the presented model has great potential as a predicting tool to assist reservoir engineers in assessing Asphaltene Deposition risks in wellbores/pipelines.
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A unidirectional one-dimensional approach for Asphaltene Deposition in large length-to-diameter ratios scenarios
Journal of Petroleum Science and Engineering, 2018Co-Authors: Q. Guan, Francisco M. Vargas, John C. Chai, Walter G Chapman, Afshin Goharzadeh, Sibani Lisa Biswal, M. ZhangAbstract:Abstract Asphaltene Deposition in wellbores has been recognized as the cholesterol of petroleum for decades causing billions of dollars in losses to the oil and gas industry every year. This necessitates great efforts in precise and fast forecasting of the production problems induced by Asphaltene Deposition. From perspective of the large length-to-diameter ratios of wellbores and the unidirectional nature of the crude oil flow, this work presents a numerical procedure to predict the coupled velocity, pressure and concentration distribution in a transient one-dimensional one-way framework. This procedure is general-purpose for flow passages of large aspect ratios with the precipitation rate, aggregation rate and Deposition rate embedded in known forms. In this numerical procedure, the governing equations are solved using the finite volume method on a regular mesh arrangement with fully implicit spatial and temporal schemes. For verification purpose, a few cases having exact solutions are studied. Then, application of the presented procedure to capillary Asphaltene Deposition is illustrated where good agreement is achieved between the simulation results and the experimental measurements. This case demonstrates that the proposed procedure can be used to investigate oilfield Asphaltene problems and assist reservoir engineers in assessing the potential Asphaltene Deposition risk in wellbores.
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Effect of the Gas Composition and Gas/Oil Ratio on Asphaltene Deposition
Energy & Fuels, 2017Co-Authors: Ali A. Alhammadi, Jianxin Wang, Jefferson L Creek, Francisco M. Vargas, Yi Chen, Walter G ChapmanAbstract:Arterial Deposition of Asphaltene is a major flow assurance issue in pipelines and wellbores. The numerous compounds constituting crude oils are mutually soluble at reservoir conditions, but precipitation can occur with changes in the pressure, temperature, or composition. As the pressure and temperature change through the wellbore, Asphaltenes can precipitate and potentially deposit. Unfortunately, remediation by solvent soaks is expensive; hence, the need to forecast the potential risk of Asphaltene Deposition. In this paper, a previously reported simulation tool, Asphaltene Deposition tool (ADEPT), is used to predict the magnitude and location of Asphaltene deposits in flow lines and wellbores. ADEPT is to be used to gauge the frequency and location of deposits and how often intervention will be needed. The phase behavior of Asphaltene is described by the perturbed-chain statistical associating fluid theory equation of state, while the transport equations are coupled with kinetic rates of precipitation...
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revisiting Asphaltene Deposition tool adept field application
Energy & Fuels, 2012Co-Authors: Anjushri S Kurup, Jianxin Wang, Jill S Buckley, Jefferson L Creek, Hariprasad J Subramani, Walter G ChapmanAbstract:Asphaltenes tend to deposit in reservoir, well tubing, flow lines, separators, etc., causing significant production losses. Asphaltenes are originally stable in crude oil at reservoir conditions. However, changes in temperature, pressure, and/or composition may cause Asphaltenes to precipitate and potentially deposit onto the surfaces of a flowing conduit. There are several publications in the literature that discuss modeling of Asphaltene phase behavior in oil as well as development of Deposition models to simulate Asphaltene Deposition profiles along a flow path. In this paper, a previously reported Asphaltene Deposition tool (ADEPT) is used to study the Deposition in a subsea pipeline in the Gulf of Mexico. This is the first demonstration of an Asphaltene Deposition simulator that has been used in a fully predictive manner. All of the required kinetic parameters used for Deposition predictions were experimentally measured. A new methodology to scale up the Deposition constant measured from a small-scal...
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development and application of an Asphaltene Deposition tool adept for well bores
Energy & Fuels, 2011Co-Authors: Anjushri S Kurup, Jianxin Wang, Jill S Buckley, Jefferson L Creek, Francisco M. Vargas, Subramani J Hariprasad, Walter G ChapmanAbstract:Asphaltenes often tend to deposit in reservoirs, flow lines, separators, and other systems along production lines causing significant production loss due to restricted oil flow or damages caused to the units and instruments used along the flow lines. Asphaltenes are typically stable in the oil; however, changes in conditions such as temperature or pressure or compositional changes can trigger the phase separation and resultant Deposition of these Asphaltenes on the surfaces encountered along the flow. Hence, it is required to be able to forecast the possibility of precipitation of Asphaltenes for given operating conditions and quantify the amount of Deposition. In this work, the development of an Asphaltene Deposition tool (ADEPT) that can predict the occurrence and calculate the magnitude and profile of Asphaltene Deposition in a well bore is discussed. The simulator consists of a thermodynamic module and a Deposition module. The thermodynamic module uses the Perturbed Chain Statistical Associating Fluid...
Shahab Ayatollahi - One of the best experts on this subject based on the ideXlab platform.
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mechanistic study to investigate the effects of different gas injection scenarios on the rate of Asphaltene Deposition an experimental approach
Fuel, 2020Co-Authors: Hossein Dashti, Peyman Zanganeh, Shahab Ayatollahi, Shahin Kord, Amirpiran AmiriAbstract:Abstract Asphaltene Deposition during enhanced oil recovery (EOR) processes is one of the most problematic challenges in the petroleum industry, potentially resulting in flow blockage. Our understanding of the Deposition mechanism with emphasis on the rate of the Asphaltene Deposition is still in its infancy and must be developed through a range of experiments and modelling studies. This study aims to investigate the rate of Asphaltene Deposition through a visual study under different gas injection scenarios. To visualise the Asphaltene Deposition, a high-pressure setup was designed and constructed, which enables us to record high-quality images of the Deposition process over time. Present research compares the effects of nitrogen (N2), carbon dioxide (CO2) and methane (CH4) on the rate of Asphaltene Deposition at different pressures. The experimental results in the absence of gas injection revealed that the rate of Asphaltene Deposition increases at higher pressures. The results showed that the rate of Asphaltene Deposition in the case of CO2 injection is 1.2 times faster than CH4 injection at 100 bar pressure. However, N2 injection has less effect on the Deposition rate. Finally, it has been concluded that the injection of CO2 leads to more Asphaltene Deposition in comparison with CH4 and N2. Moreover, the experimental results confirmed that gas injection affects the mechanism of Asphaltene flocculation and leads to the formation of bigger flocculated Asphaltene particles. The findings of this study can help for a better understanding of the mechanism of the Asphaltene Deposition during different gas-EOR processes.
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Prediction of Asphaltene Deposition during turbulent flow using heat transfer approach
Petroleum Science and Technology, 2018Co-Authors: Farhad Salimi, Shahab Ayatollahi, Mohsen Vafaie SeftieAbstract:ABSTRACTIn this study, Asphaltene Deposition from crude oil has been studied experimentally using a test loop and prediction using theoretical study under turbulent flow (Reynolds numbers below 5000). The effects of many parameters such as oil velocity, surface temperature and concentration of flocculated Asphaltene on the Asphaltene Deposition were investigated. The results showed that Asphaltene Deposition thickness increases with increasing both surface temperature and concentration of flocculated Asphaltene and decreasing oil velocity. Thermal approach was used to describe the mechanisms involved in this process and the results of data fitting showed that there are good agreements between the results of the proposed model and the measured Asphaltene Deposition rates.
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An Experimental Investigation and Prediction of Asphaltene Deposition during Laminar Flow in the Pipes Using a Heat Transfer Approach
Iranian Journal of Oil and Gas Science and Technology, 2017Co-Authors: Farhad Salimi, Shahab Ayatollahi, Mohsen Vafaie SeftieAbstract:In this study, Asphaltene Deposition from crude oil has experimentally and theoretically been studied using a test loop and an accurate temperature monitoring during a laminar flow. The effects of oil velocity and surface temperature on the thickness of Asphaltene Deposition were investigated. The results show that Asphaltene Deposition thickness increases by increasing surface temperature. As the oil velocity increased, less Deposition was noticed in this experimental study. The thermal approach was used to describe the mechanisms involved in this process, and the results of data fitting showed that there was good agreement between the results of the proposed model and the measured Asphaltene Deposition rates. Moreover, the theoretical study of Deposition process showed that the rate of Asphaltene Deposition was inversely related to velocity, which was proved by the experimental results.
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Effects of Native and Non-Native Resins on Asphaltene Deposition and the Change of Surface Topography at Different Pressures: An Experimental Investigation
Energy & Fuels, 2015Co-Authors: Farhad Soorghali, Ali Zolghadr, Shahab AyatollahiAbstract:Asphaltene Deposition during oil production and transportation causes extensive damage to reservoirs and wellhead equipment. In this study, the effects of native and non-native resins as well as those of their mixtures on the Asphaltene Deposition process are investigated. A novel pressure, volume, and temperature (PVT) visual cell is used to check the effect of resin on Asphaltene Deposition at different pressures and reservoir temperatures. Two Iranian crude oil samples with different potentials of Asphaltene Deposition (low and high) were used in these tests. During depressurizing in the presence of native and non-native resins, the amount of Asphaltene deposited was measured. To monitor any changes in surface topography, the atomic force microscopy (AFM) technique was used in this study. The results show that the amount of Asphaltene deposited decreases as the amount of resin increases; however, less Asphaltene is deposited when the resin mixture is used than when the native resin is used. At high rat...
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effect of resins on Asphaltene Deposition and the changes of surface properties at different pressures a microstructure study
Energy & Fuels, 2014Co-Authors: Farhad Soorghali, Ali Zolghadr, Shahab AyatollahiAbstract:Asphaltene Deposition has hindered oil production from asphaltenic oil reservoirs through Deposition in reservoir rock and surface facilities. This paper investigates the effect of resin on Asphaltene Deposition at different pressures. To investigate the Asphaltene Deposition in the presence of resins at reservoir temperature and different pressures, a pressure, volume, and temperature (PVT) visual cell was designed. A high-resolution microscope and image processing software were used to detect and determine the amount of deposited Asphaltene as well as its size distribution at different conditions. Two types of Iranian crude oils with different potential of Deposition (low and high) were used in this work. In the first stage, the amount of Asphaltene Deposition and the changes of surface properties were recognized through the depressurizing process with and without the presence of resins in the fluid. The wettability changes as a sign of surface properties were studied by contact angle measurement, and a...
Jefferson L Creek - One of the best experts on this subject based on the ideXlab platform.
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Effect of the Gas Composition and Gas/Oil Ratio on Asphaltene Deposition
Energy & Fuels, 2017Co-Authors: Ali A. Alhammadi, Jianxin Wang, Jefferson L Creek, Francisco M. Vargas, Yi Chen, Walter G ChapmanAbstract:Arterial Deposition of Asphaltene is a major flow assurance issue in pipelines and wellbores. The numerous compounds constituting crude oils are mutually soluble at reservoir conditions, but precipitation can occur with changes in the pressure, temperature, or composition. As the pressure and temperature change through the wellbore, Asphaltenes can precipitate and potentially deposit. Unfortunately, remediation by solvent soaks is expensive; hence, the need to forecast the potential risk of Asphaltene Deposition. In this paper, a previously reported simulation tool, Asphaltene Deposition tool (ADEPT), is used to predict the magnitude and location of Asphaltene deposits in flow lines and wellbores. ADEPT is to be used to gauge the frequency and location of deposits and how often intervention will be needed. The phase behavior of Asphaltene is described by the perturbed-chain statistical associating fluid theory equation of state, while the transport equations are coupled with kinetic rates of precipitation...
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joint industrial case study for Asphaltene Deposition
Energy & Fuels, 2013Co-Authors: Priyanka Juyal, Jianxin Wang, Jill S Buckley, Amy M Mckenna, Rosa I Ruedavelasquez, Jade E Fitzsimmons, Ryan P Rodgers, Murray R Gray, Stephan J Allenson, Jefferson L CreekAbstract:Here, we present a case study on a Wyoming well with known Asphaltene Deposition issues as a result of natural depletion. Field deposits and crude oil from the same well were collected for analysis. Compositional differences between field deposits, lab-generated capillary deposits, and C7-precipitated Asphaltenes were determined by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), and all three samples show similar trends in composition, displayed as plots of aromaticity versus carbon number. An enrichment of highly condensed aromatic molecules for the field deposit is detected with both ultrahigh-resolution mass spectrometry and thermal cracking experiments and could predict Asphaltene Deposition. FT-ICR mass spectral analysis of solvent-extracted fractions suggest different Deposition mechanisms for field deposits (slow Deposition) compared to rapid precipitation in standard Asphaltene preparation protocols that contain trapped maltenes.
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revisiting Asphaltene Deposition tool adept field application
Energy & Fuels, 2012Co-Authors: Anjushri S Kurup, Jianxin Wang, Jill S Buckley, Jefferson L Creek, Hariprasad J Subramani, Walter G ChapmanAbstract:Asphaltenes tend to deposit in reservoir, well tubing, flow lines, separators, etc., causing significant production losses. Asphaltenes are originally stable in crude oil at reservoir conditions. However, changes in temperature, pressure, and/or composition may cause Asphaltenes to precipitate and potentially deposit onto the surfaces of a flowing conduit. There are several publications in the literature that discuss modeling of Asphaltene phase behavior in oil as well as development of Deposition models to simulate Asphaltene Deposition profiles along a flow path. In this paper, a previously reported Asphaltene Deposition tool (ADEPT) is used to study the Deposition in a subsea pipeline in the Gulf of Mexico. This is the first demonstration of an Asphaltene Deposition simulator that has been used in a fully predictive manner. All of the required kinetic parameters used for Deposition predictions were experimentally measured. A new methodology to scale up the Deposition constant measured from a small-scal...
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development and application of an Asphaltene Deposition tool adept for well bores
Energy & Fuels, 2011Co-Authors: Anjushri S Kurup, Jianxin Wang, Jill S Buckley, Jefferson L Creek, Francisco M. Vargas, Subramani J Hariprasad, Walter G ChapmanAbstract:Asphaltenes often tend to deposit in reservoirs, flow lines, separators, and other systems along production lines causing significant production loss due to restricted oil flow or damages caused to the units and instruments used along the flow lines. Asphaltenes are typically stable in the oil; however, changes in conditions such as temperature or pressure or compositional changes can trigger the phase separation and resultant Deposition of these Asphaltenes on the surfaces encountered along the flow. Hence, it is required to be able to forecast the possibility of precipitation of Asphaltenes for given operating conditions and quantify the amount of Deposition. In this work, the development of an Asphaltene Deposition tool (ADEPT) that can predict the occurrence and calculate the magnitude and profile of Asphaltene Deposition in a well bore is discussed. The simulator consists of a thermodynamic module and a Deposition module. The thermodynamic module uses the Perturbed Chain Statistical Associating Fluid...
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on the development of an Asphaltene Deposition simulator
Energy & Fuels, 2010Co-Authors: Francisco M. Vargas, Jefferson L Creek, Walter G ChapmanAbstract:The potential problem of Asphaltene Deposition during oil production has motivated the development of several experimental techniques and theoretical models to understand and predict Asphaltene behavior. Although important progress has been made in this area, prediction of the rate of Asphaltene Deposition remains an unsolved problem. We have previously reported the successful application of the perturbed chain version of the statistical associating fluid theory equation of state (PC-SAFT EOS) in modeling Asphaltene phase behavior under both ambient and reservoir conditions. In this work, we present the development of a simulation tool that simultaneously accounts for Asphaltene precipitation, aggregation, and Deposition. The thermodynamic modeling using the PC-SAFT EOS is coupled with kinetic models and transport equations. The mechanism for Asphaltene precipitation and Deposition, proposed in this work, has been found to be consistent with various experiments and field observations. Furthermore, it also...
Jianxin Wang - One of the best experts on this subject based on the ideXlab platform.
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evaluation of solvents for in situ Asphaltene Deposition remediation
Fuel, 2019Co-Authors: Jun Kuang, Jianxin Wang, Josiah Yarbrough, Shayan Enayat, Nigel Edward, Francisco M. VargasAbstract:Abstract Upon the formation and the accumulation of the deposits, cost-effective cleaning strategies should be applied to remediate and remove the organic solids. The injection of aromatic solvents, usually know as solvent wash, is one of the commonly used techniques to re-dissolve the deposited Asphaltenes in the well. To select and develop the best solvents and the most appropriate solvent soaking conditions for Asphaltene remediation, a re-dissolution test apparatus using a packed bed column was introduced to evaluate the solvents for in-situ Asphaltene Deposition remediation under more realistic production conditions. The solvency power of three aromatic solvents and four commercial solvents was determined and compared. Under the current experimental conditions, the injection of p-xylene re-dissolves 31.3% and 69.8% more deposits than the same volume of toluene and aromatic naphtha (A150). Additionally, the solvent wash by toluene/diesel mixture (50/50 by volume) and diesel significantly reduces the re-dissolution efficiency by 31.1% and 74.3% by comparing to toluene. Results also suggest that the screening of chemical solvents based on their solubility parameters may not provide accurate indication on the selection of the best solvent for Asphaltene removal. Furthermore, the effects of aging time, occluded oil, soaking temperature, and soaking time were investigated on the removal of Asphaltene Deposition in the packed bed column. Results show that the existence of the occluded oil during the aging and soaking process weakens the solubility power of the toluene. The solvency power of toluene is enhanced by 11.4% and 24.2% when the soaking temperature increases from 25 °C to 120 °C and the soaking time extends from 1 h to 24 h, respectively. With the proposed technique to assess chemical solvents in the laboratory, the most cost-effective solvent wash strategy can be developed for the in-situ remediation of Asphaltene Deposition in the wellbore.
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Investigation of Asphaltene Deposition at High Temperature and under Dynamic Conditions
Energy & Fuels, 2018Co-Authors: Jun Kuang, Jianxin Wang, Mohammad Tavakkoli, Josiah Yarbrough, Shekhar Jain, Sunil Ashtekar, Dalia Abdallah, Sameer Punnapala, Francisco M. VargasAbstract:Asphaltene Deposition is one of the major flow assurance problems that can potentially deteriorate due to the current tendencies to produce from the deep-water environment or as a result of enhanced oil recovery operations based on miscible gas injection. The deposited Asphaltenes in the wellbores and on the surface of the oilfield pipelines can impede the productivity of the wells significantly. The comprehensive understanding of the mechanisms and the techniques to control Asphaltene Deposition at high temperature and under dynamic conditions can help resolve this critical issue. Thus, it is imperative to develop reliable, straightforward, and inexpensive tools to investigate the Asphaltene Deposition tendency and the performance of Asphaltene inhibitors in the laboratory. In this work, a new stainless steel packed bed column Deposition system that was inspired by the work of Vilas Boas Favero et al. was successfully developed. The packed bed design allows the feasibility of investigating a variety of f...
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Effect of the Gas Composition and Gas/Oil Ratio on Asphaltene Deposition
Energy & Fuels, 2017Co-Authors: Ali A. Alhammadi, Jianxin Wang, Jefferson L Creek, Francisco M. Vargas, Yi Chen, Walter G ChapmanAbstract:Arterial Deposition of Asphaltene is a major flow assurance issue in pipelines and wellbores. The numerous compounds constituting crude oils are mutually soluble at reservoir conditions, but precipitation can occur with changes in the pressure, temperature, or composition. As the pressure and temperature change through the wellbore, Asphaltenes can precipitate and potentially deposit. Unfortunately, remediation by solvent soaks is expensive; hence, the need to forecast the potential risk of Asphaltene Deposition. In this paper, a previously reported simulation tool, Asphaltene Deposition tool (ADEPT), is used to predict the magnitude and location of Asphaltene deposits in flow lines and wellbores. ADEPT is to be used to gauge the frequency and location of deposits and how often intervention will be needed. The phase behavior of Asphaltene is described by the perturbed-chain statistical associating fluid theory equation of state, while the transport equations are coupled with kinetic rates of precipitation...
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joint industrial case study for Asphaltene Deposition
Energy & Fuels, 2013Co-Authors: Priyanka Juyal, Jianxin Wang, Jill S Buckley, Amy M Mckenna, Rosa I Ruedavelasquez, Jade E Fitzsimmons, Ryan P Rodgers, Murray R Gray, Stephan J Allenson, Jefferson L CreekAbstract:Here, we present a case study on a Wyoming well with known Asphaltene Deposition issues as a result of natural depletion. Field deposits and crude oil from the same well were collected for analysis. Compositional differences between field deposits, lab-generated capillary deposits, and C7-precipitated Asphaltenes were determined by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), and all three samples show similar trends in composition, displayed as plots of aromaticity versus carbon number. An enrichment of highly condensed aromatic molecules for the field deposit is detected with both ultrahigh-resolution mass spectrometry and thermal cracking experiments and could predict Asphaltene Deposition. FT-ICR mass spectral analysis of solvent-extracted fractions suggest different Deposition mechanisms for field deposits (slow Deposition) compared to rapid precipitation in standard Asphaltene preparation protocols that contain trapped maltenes.
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revisiting Asphaltene Deposition tool adept field application
Energy & Fuels, 2012Co-Authors: Anjushri S Kurup, Jianxin Wang, Jill S Buckley, Jefferson L Creek, Hariprasad J Subramani, Walter G ChapmanAbstract:Asphaltenes tend to deposit in reservoir, well tubing, flow lines, separators, etc., causing significant production losses. Asphaltenes are originally stable in crude oil at reservoir conditions. However, changes in temperature, pressure, and/or composition may cause Asphaltenes to precipitate and potentially deposit onto the surfaces of a flowing conduit. There are several publications in the literature that discuss modeling of Asphaltene phase behavior in oil as well as development of Deposition models to simulate Asphaltene Deposition profiles along a flow path. In this paper, a previously reported Asphaltene Deposition tool (ADEPT) is used to study the Deposition in a subsea pipeline in the Gulf of Mexico. This is the first demonstration of an Asphaltene Deposition simulator that has been used in a fully predictive manner. All of the required kinetic parameters used for Deposition predictions were experimentally measured. A new methodology to scale up the Deposition constant measured from a small-scal...
