Influences of Asphaltene Precipitation on Capillary Pressure and Pore Size Distribution of Carbonate Reservoirs

Shedid, Shedid A.

doi:10.1081/lft-100105270

Cited by 14 publications

(15 citation statements)

References 4 publications

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“…In all pores, there is consistently a 3–4-μm-thick asphaltene layer, whereas in increasingly smaller pores (especially with pore radii smaller than 60 μm) the asphaltene deposition thickness becomes increasingly thicker. This higher sensitivity of the smaller pores to asphaltene deposition was also observed by Shedid, who attributed this phenomenon to the reduction of the surface area open to flow. From the above observations and interpretations, we speculate that the asphaltene deposition is a coupled effect of both the gradual surface adsorption and pore blockage.…”

Section: Discussionsupporting

confidence: 77%

Asphaltene Deposition Preference and Permeability Reduction Mechanisms in Oil Reservoirs: Evidence from Combining X-ray Microtomography with Fluorescence Microscopy

Xiao

Zeng

et al. 2017

Energy Fuels

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Asphaltene deposition in oil reservoirs during acid stimulation, natural depletion, and CO2 injection may cause intense formation damage and reduced productivity. Gaining a better understanding of the asphaltene deposition mechanisms and their influence on the reservoir permeability reduction will contribute to the prevention of reservoir damage and the optimization of development schemes. Although numerous models and experiments have been applied to simulate the asphaltene deposition process and evaluate the reservoir permeability loss, few analyses have been performed on natural samples from oil reservoirs undergoing asphaltene deposition. Moreover, permeability reduction simulation due to asphaltene deposition has not yet been performed in three-dimensional (3D) microscale pore systems. In this work, sandstone samples were collected from natural oil reservoirs with asphaltene deposition and analyzed by both X-ray tomography and fluorescence microscopy to identify the asphaltene. A Navier–Stokes simulator and pore network model are used to study the 3D pore spaces and to calculate the permeabilities and pore radius distributions. Ideal asphaltene deposition models are applied in the 3D pore spaces to simulate the influences of surface adsorption and pore blockage on the permeability reduction. By comparing the calculation results of the ideal models and natural samples, we found that the asphaltene deposition is a coupled effect of the surface adsorption and the pore blockage, which causes a weaker permeability loss than that from the ideal single factor models.

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Section: Discussionsupporting

confidence: 77%

Asphaltene Deposition Preference and Permeability Reduction Mechanisms in Oil Reservoirs: Evidence from Combining X-ray Microtomography with Fluorescence Microscopy

Xiao

Zeng

et al. 2017

Energy Fuels

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“…Therefore, it is possible to infer v and k 1 with enough experimental data in core tests; v can be estimated with the following expression: v = 1 t normalc where t c is time, from this time permeability no suffer any alteration. We used experimental data in core tests reported by Minssieux, Shedid, and Ali and Islam to validate the mathematical model developed in this work to represent the precipitated asphaltene trapped process. Figures − show the experimental data reported in the literature and those obtained by eq .…”

Section: Resultsmentioning

confidence: 99%

“…The processes of asphaltene precipitation and deposition in porous media have a substantial effect on oil flow during primary oil production and enhanced oil recovery processes; − it is well-known that during primary production stage of a reservoir, oil flows through regions with the minor resistance (i.e., porous matrix and fractures), and the impulse force arising the fluids movement between the porous spaces of rock is a pressure difference in the rock−fluid system. The natural depletion of a reservoir may cause the precipitation and flocculation phenomena of organic solids (asphaltenes or waxes) diminishing the productivity of well during primary oil recovery. ,,,− …”

Section: Introduction and Reviewmentioning

confidence: 99%

“…In general, field experiences − ,− ,,− and laboratory tests on coreflooding ,− ,− have demonstrated that any operation carried out in the oilfield (i.e., drilling, cementation, completion, workover, production, injection of fluid, acid stimulation, and hydraulic fracturing) is a potential source of damage to well productivity. Although the way in which well productivity may be damaged varies from operation to operation, the researches and diagnosis of specific problems have led to the conclusion that formation damage is usually associated with the transport of fine solids, chemical reactions, and thermodynamic considerations. ,, …”

Section: Introduction and Reviewmentioning

confidence: 99%

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Asphaltene-Induced Precipitation and Deposition During Pressure Depletion on a Porous Medium: An Experimental Investigation and Modeling Approach

Cruz¹,

Argüelles‐Vivas²,

Matías-Pérez³

et al. 2009

Energy Fuels

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Dynamic displacement experiments, simulating temperature and pressure conditions of an oil-bearing formation during primary production stage, were carried out to investigate the processes of asphaltene-induced precipitation and deposition during pressure depletion on a core sample and their effects on the absolute permeability. A representative monophasic-bottom-hole fluid sample and one core of consolidated Bedford limestone were used in coreflood tests. To identify the pressure and temperature conditions at which the asphaltene will begin to precipitate, as well as the bubble-point pressures of the reservoir fluid sample, the light-scattering technique solid detection system (SDS) using a variable volume, visual P V T cell was used. The coreflood test results indicated that the in situ asphaltene precipitation and deposition on porous medium damage absolute permeability and reduce effective porosity as reservoir fluid pressure is reduced until a point near bubble-point pressure. Core impairment, resulting from asphaltene deposition, was found to cause a 24% and 20% loss of initial oil permeability and effective porosity, respectively. A mathematical model, based on the transport of stable particulate suspensions in porous media, for asphaltene deposition was developed and validated directly with experimental results obtained in this investigation, as well as those found in the literature. On the basis of the developed mathematical model, two distinct mechanisms were identified as a consequence of the deposition process, namely, asphaltene adsorption and trapping. The porous medium was represented as a network of sites and bonds, with pore bodies identified as sites and pore throats as bonds. A satisfactory qualitative agreement was observed with the experimental results.

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“…Nasri and Dabir (2010) used pore scale network model of Blunt (1997a,b) and Blunt et al (1992) to simulate two-phase flow under asphaltene deposition. They incorporated the experimental data of water and oil relative permeability represented by Shedid (2001) …”

Section: Introductionmentioning

confidence: 99%

Dynamic Pore Scale Modeling of Asphaltene Deposition in Porous Media

Nikooey

Manshad

Ashoori

2015

Petroleum Science and Technology

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Asphaltene deposition in porous medium is one of important factors in reducing the productivity of oil reservoirs. Reduction of permeability is the main factor, which is also due to reduced pores size or complete closure of them. The authors simulate phase one flow of oil in porous medium using a dynamic pore scale network model. Also asphaltene deposition process is considered based on a scaling equation. Because the greatest amount of precipitation occurs at bubble point pressure condition, we considered boundary conditions of the model in this pressure. The hypothetical model is only a very small element of a real reservoir rock therefore we assumed constant temperature in this process, consequently the main reason of asphaltene precipitation is pressure changes in the pores. Permeability reduction simulated was based on these steps: pore and throat pressure changes were due to fluid flow through the network and asphaltene deposited according to scaling equation. Applying a material balance for each pore/throat gives the volume reduction of pores/throats according to the deposited asphaltene. Due to this change in pores size permeability and porosity of the model is calculated. Repeating these steps over the time gives effect of asphaltene deposition on the primary properties of porous medium.

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Influences of Asphaltene Precipitation on Capillary Pressure and Pore Size Distribution of Carbonate Reservoirs

Cited by 14 publications

References 4 publications

Asphaltene Deposition Preference and Permeability Reduction Mechanisms in Oil Reservoirs: Evidence from Combining X-ray Microtomography with Fluorescence Microscopy

Asphaltene Deposition Preference and Permeability Reduction Mechanisms in Oil Reservoirs: Evidence from Combining X-ray Microtomography with Fluorescence Microscopy

Asphaltene-Induced Precipitation and Deposition During Pressure Depletion on a Porous Medium: An Experimental Investigation and Modeling Approach

Dynamic Pore Scale Modeling of Asphaltene Deposition in Porous Media

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