Reversibility of asphaltene precipitation in porous and non-porous media

Abedini, Ali; Ashoori, Siavash; Torabi, Farshid

doi:10.1016/j.fluid.2011.06.024

Cited by 21 publications

(22 citation statements)

References 18 publications

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“…A series of experiments have been carried out to quantify the asphaltene precipitation and resulting formation damage during enhanced oil recovery processes. A high-temperature high-pressure PVT cell was used to study the effects hydrocarbon solvent dilution ratio, temperature, and pressure on the asphaltene onset and precipitation rate. − Slim tube apparatus was also employed to monitor the pressure fluctuation and flow turbulence as a result of asphaltene precipitation during solvent injection . In addition, high-pressure coreflooding has been applied to estimate permeability reduction as a result of asphaltene deposition during immiscible and miscible CO 2 injection processes. − Asphaltene deposition during the vapor extraction process with propane and butane has been measured using sand-packed physical models. , In addition, the roles of morphology and mineralogy of the rock were analyzed with regard to asphaltene deposition and associated reservoir damage .…”

Section: Introductionmentioning

confidence: 99%

“…23−25 Slim tube apparatus was also employed to monitor the pressure fluctuation and flow turbulence as a result of asphaltene precipitation during solvent injection. 26 In addition, high-pressure coreflooding has been applied to estimate permeability reduction as a result of asphaltene deposition during immiscible and miscible CO 2 injection processes. 27−29 Asphaltene deposition during the vapor extraction process with propane and butane has been measured using sand-packed physical models.…”

Section: Introductionmentioning

confidence: 99%

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Asphaltene Deposition during Bitumen Extraction with Natural Gas Condensate and Naphtha

Abedini

Sharbatian

et al. 2018

Energy Fuels

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Solvent bitumen extraction processes are alternatives to thermal processes with potential for improved economic and environmental performance. However, solvent interaction with bitumen commonly results in in situ asphaltene precipitation and deposition, which can hinder flow and reduce the process efficiency. Successful implementation requires one to select a solvent that improves recovery with minimal flow assurance problems. The majority of candidate industrial solvents are in the form of mixtures containing a wide range of hydrocarbon fractions, further complicating the selection process. In this study, we quantify the pore-scale asphaltene deposition using two commonly available solvent mixtures, natural gas condensate and naphtha, using a microfluidic platform. The results are also compared with those of two typical pure solvents, n-pentane and n-heptane, with all cases evaluated with both 50 and 100 μm pore-throat spacing. The condensate produced more asphaltenes and pore-space damage than the naphtha and exhibited deposition dynamics similar to that of pentane and heptane. This similarity is due to the presence of a large amount of light hydrocarbon fractions in condensate (∼85 wt % of C5s–C7s) dictating the overall deposition dynamics. Naphtha, which contains heavier fractions (∼70 wt % of C8s–C11s) and aromatic/naphthenic components, generated less asphaltenes and exhibited a slower deposition rate, resulting in less pore damage and overall better performance.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Asphaltene Deposition during Bitumen Extraction with Natural Gas Condensate and Naphtha

Abedini

Sharbatian

et al. 2018

Energy Fuels

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“…Asphaltene precipitation could cause serious damages to formations [5][6][7]. This is because the precipitated asphaltene will deposit on to the reservoir rocks, which may cause reservoir plugging and wettability alteration [8,9].…”

Section: Introductionmentioning

confidence: 99%

Formation damage due to asphaltene precipitation during CO₂ flooding processes with NMR technique

Qian

Yang

Dou

et al. 2019

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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In order to quantitatively evaluate the pore-scale formation damage of tight sandstones caused by asphaltene precipitation during CO2 flooding, the coreflood tests and Nuclear Magnetic Resonance (NMR) relaxometry measurements have been designed and applied. Five CO2 coreflood tests at immiscible, near-miscible and miscible conditions were conducted and the characteristics of the produced oil and gas were analyzed. For each coreflood test, the T2 spectrum of the core sample was measured and compared before and after CO2 flooding to determine the asphaltene precipitation distribution in pores. It is found that, the solubility and extraction effect of the CO2 plays a more dominant role in the CO2-EOR (Enhanced Oil Recovery) process with higher injection pressure. And, more light components are extracted and recovered by the CO2 and more heavy components including asphaltene are left in the core sample. Thus, the severity of formation damage influenced by asphaltene precipitation increases as the injection pressure increases. In comparison to micro and small pores (0.1–10 ms), the asphaltene precipitation has a greater influence on the medium and large pores (10–1000 ms) due to the sufficient interaction between the CO2 and crude oil in the medium and large pores. Furthermore, the asphaltene precipitation not only causes pore clogging, but also induces rock wettability to alter towards oil-wet direction.

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“…The solvent-reversibility experiments were conducted by observing the pressure drop across an in-line filter in a flow-loop apparatus. Further comprehensive work was performed by Abedini et al to analyze asphaltene reversibility as a function of thermodynamic factors in porous and non-porous media, with triggers of pressure, temperature, and/or liquid composition changes using n -heptane. , …”

Section: Introductionmentioning

confidence: 99%

“…Further comprehensive work was performed by Abedini et al to analyze asphaltene reversibility as a function of thermodynamic factors in porous and non-porous media, with triggers of pressure, temperature, and/or liquid composition changes using n-heptane. 35,36 In our study assuming CO 2 EOR, we evaluated asphaltene reversibility in the near wellbore region and production stream tubing, where the highest asphaltene risk occurs as a result of CO 2 breakthrough under depleted pressure conditions.…”

Section: Introductionmentioning

confidence: 99%

Re-equilibrium of Asphaltenes by Repressurizing after Precipitation in Natural Depletion and CO₂ Enhanced Oil Recovery Schemes

2018

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In a series of isothermal depressurizing tests to measure asphaltene onset pressure (AOP), several depressurizing operations are usually conducted to multiple AOPs using the same lot of fluid subsamples. After one depressurizing operation is finished, the pressure/temperature condition is reset to the initial condition. Then, the next depressurizing run is performed. Before the next run, the fluid sample must equilibrate again by dissolving precipitated asphaltenes from the previous step. According to our many experiences with isothermal depressurizing tests for measuring AOPs, we know that redissolving asphaltenes depends highly upon the characteristics of a fluid sample. Some fluids redissolve asphaltenes quickly, while other samples need a lot of time. This study focused on fluid-dependent asphaltene re-equilibrium during a series of isothermal depressurizing tests. To investigate asphaltene re-equilibrium, the authors re-examined past experimental data for two types of crude oils. In the experiment, continuous power of light transmittance (PLT) was monitored for all stages in the series of AOP measurements. Two series of isothermal depressurizing tests were separately performed to evaluate CO 2 -induced asphaltene risks for two fluid samples. Three or four total steps of depressurizing were conducted in order of CO 2 addition ratios: 0, 20, 40, and 60 mol %. After a depressurizing process finished, pressure was increased above AOP to dissolve precipitated asphaltenes. PLT profiles in equilibrium steps between each depressurizing step were compared from a viewpoint of equilibrium time and/or PLT profile fluctuation. One of the fluids showed quick re-equilibrium of asphaltenes and smooth PLT profiles, whereas the other took much longer to achieve equilibrium and had fluctuating PLT profiles. This information suggested that easyequilibrium-achievable fluids would be a preferred target for CO 2 enhanced oil recovery because of its potential use of pressure control for mitigating asphaltenes. In the case of easy-equilibrium-achievable fluid, when a production problem is caused by asphaltene precipitation, repressurization by temporary shut-in and/or production rate control can be an effective mitigation.Article pubs.acs.org/EF

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Reversibility of asphaltene precipitation in porous and non-porous media

Cited by 21 publications

References 18 publications

Asphaltene Deposition during Bitumen Extraction with Natural Gas Condensate and Naphtha

Asphaltene Deposition during Bitumen Extraction with Natural Gas Condensate and Naphtha

Formation damage due to asphaltene precipitation during CO₂ flooding processes with NMR technique

Re-equilibrium of Asphaltenes by Repressurizing after Precipitation in Natural Depletion and CO₂ Enhanced Oil Recovery Schemes

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Reversibility of asphaltene precipitation in porous and non-porous media

Cited by 21 publications

References 18 publications

Asphaltene Deposition during Bitumen Extraction with Natural Gas Condensate and Naphtha

Asphaltene Deposition during Bitumen Extraction with Natural Gas Condensate and Naphtha

Formation damage due to asphaltene precipitation during CO2 flooding processes with NMR technique

Re-equilibrium of Asphaltenes by Repressurizing after Precipitation in Natural Depletion and CO2 Enhanced Oil Recovery Schemes

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Product

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Formation damage due to asphaltene precipitation during CO₂ flooding processes with NMR technique

Re-equilibrium of Asphaltenes by Repressurizing after Precipitation in Natural Depletion and CO₂ Enhanced Oil Recovery Schemes