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Francisco M. Vargas – 1st expert on this subject based on the ideXlab platform
Experimental Investigation of Asphaltene Deposition in A Transparent MicrochannelProceeding of First Thermal and Fluids Engineering Summer Conference, 2020Co-Authors: Y. Zhuang, John C. Chai, Francisco M. Vargas, 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.
Mitigation of Asphaltene Deposition by Re-injection of dead oilFluid 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.
Modeling of Asphaltene Deposition in a Packed Bed ColumnEnergy & 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…
Walter G Chapman – 2nd expert on this subject based on the ideXlab platform
An integrated model for Asphaltene Deposition in wellbores/pipelines above bubble pressuresJournal of Petroleum Science and Engineering, 2018Co-Authors: Q. Guan, John C. Chai, Francisco M. Vargas, Walter G Chapman, Sibani Lisa Biswal, Afshin Goharzadeh, 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.
A unidirectional one-dimensional approach for Asphaltene Deposition in large length-to-diameter ratios scenariosJournal of Petroleum Science and Engineering, 2018Co-Authors: Q. Guan, John C. Chai, Francisco M. Vargas, Walter G Chapman, Sibani Lisa Biswal, Afshin Goharzadeh, 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.
Effect of the Gas Composition and Gas/Oil Ratio on Asphaltene DepositionEnergy & 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…
Shahab Ayatollahi – 3rd expert on this subject based on the ideXlab platform
mechanistic study to investigate the effects of different gas injection scenarios on the rate of Asphaltene Deposition an experimental approachFuel, 2020Co-Authors: Hossein Dashti, Peyman Zanganeh, Shahin Kord, Shahab Ayatollahi, 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.
Prediction of Asphaltene Deposition during turbulent flow using heat transfer approachPetroleum 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.
An Experimental Investigation and Prediction of Asphaltene Deposition during Laminar Flow in the Pipes Using a Heat Transfer ApproachIranian 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.