Measurement of gas diffusivity in heavy oils

Zhang, Y.P.; Hyndman, Caroline L.; Maini, Brij B.

doi:10.1016/s0920-4105(99)00031-5

Cited by 231 publications

(142 citation statements)

References 5 publications

Supporting

Mentioning

137

Contrasting

Order By: Relevance

“…The observed variation range of the effective diffusion coefficients in this study were either lower or in range of reported molecular diffusion coefficients in literature for carbon dioxide, and light alkanes (e.g. methane, ethane, propane, and butane) in heavy oils and bitumens (Schmidt et al, 1982;Zhang et al, 2000;Upreti and Mehrotra, 2002;Creux et al, 2005;Yang and Gu, 2006;Cuthiell et al, 2006). On this basis, it can be concluded that the convective dispersion or velocity-dependent effects are playing a minor role in the mass transfer phenomena in the conducted Vapex experiments, and molecular diffusion is the main mass transfer mechanism.…”

Section: Diffusion Coefficientsupporting

confidence: 58%

Interplay of Capillarity, Drainage Height, and Aqueous Phase Saturation on Mass Transfer Rate of Solvent Vapor into Heavy Oil

et al. 2011

View full text Add to dashboard Cite

Performance of the vapor extraction process is strongly dependent on the efficiency of the mass transfer rate between the solvent and heavy oil or bitumen. Therefore, realistic approximation of diffusion and convective dispersion occurring on the edge of the vapor chamber is required for reliable prediction of production rates in this process. Studies conducted at extremely high permeabilities (>200 D) have reported up to four orders of magnitude increase in the solvent diffusion/dispersion rates between the solvent and heavy oil, such increases could result in unrealistic overestimation of the performance of this process at real reservoir conditions. To address this shortcoming, a comprehensive experimental study was designed and conducted to systematically investigate the interplay of capillarity, drainage height, and aqueous phase saturation on efficiency of mass transfer rate in permeability range similar to western Canadian heavy oil and bitumen reservoirs (i.e. 5.1-6.5D). In order to experimentally simulate the vapor extraction process, a new experimental approach was developed to eliminate the effect of pressure disturbances occurring during the course of experiment (20-45 days) and investigate the interplay between studied parameters in a gravity dominant system. In this study, measured stabilized drainage rates per unit length of porous media (9.17×10 -7 -3.33×10 -5 cm 3 /s/cm) revealed functionality with drainage height, specific pore surface area of the porous medium, and presence of aqueous phase at higher capillarities. Moreover, analytical modeling was conducted to determine the effective diffusion/dispersion coefficient, which showed convective dispersion is not playing a prominent role in mixing between solvent and heavy oil as it was proposed by studies conducted in high permeabilities. In addition, comparison between the stabilized drainage rates of oil in absence or presence of water saturation confirmed that the presence of water phase enhances the drainage rates at higher capilarities, which is in contradiction with previous studies investigating the effect of aqueous phase saturation on mass transfer rate in higher permeabilities. This paper provides indepth knowledge of the impact of three major parameters that affect the rate of the mass transfer between heavy oil and solvent, and that are necessary for realistic modeling of the performance of the vapor extraction process.

show abstract

Section: Diffusion Coefficientsupporting

confidence: 58%

Interplay of Capillarity, Drainage Height, and Aqueous Phase Saturation on Mass Transfer Rate of Solvent Vapor into Heavy Oil

et al. 2011

View full text Add to dashboard Cite

show abstract

“…Unchanged pressure readings indicated the equilibrium state. However, the time required to reach the equilibrium is considerably long, and it is arguably more accurate to use linear regression method to predict the equilibrium pressure [17]. After each test, Valve #4 was slowly opened to release the pressurized H 2 S into the fume hood.…”

Section: Methodsmentioning

confidence: 99%

“…The physical significance of the solutions is not obvious, and the exact analytical solutions cannot be obtained without knowing the specific values of D g , k 1 , and/or k −1 . For a much simpler case, Zhang et al [17] employed nonlinear regression to numerically fit their experimental data.…”

Section: Theorymentioning

confidence: 99%

See 1 more Smart Citation

The diffusion coefficient of H2S in liquid sulfur

et al. 2011

Fluid Phase Equilibria

View full text Add to dashboard Cite

“…On the other hand, Saboorian' s [21] results showed that the non-equilibrium boundary condition does not affect the gas diffusion process significantly; however it is more realistic physically. Most of the previous studies [22][23][24][25][26] have been conducted utilizing pressure decay method for calculating diffusion coefficient and interface mass transfer coefficient. Although this technique requires a simple experimental setup, it is time-consuming, and since pressure reduces monotonically during the process, the effect of pressure on diffusion coefficient cannot be determined [27,28].…”

Section: Introductionmentioning

confidence: 99%

Interfacial resistance in CO2-normal alkane and N2-normal alkane systems: An experimental and modeling investigation

Nikkhou

Keshavarz

Ayatollahi

et al. 2014

Korean J. Chem. Eng.

View full text Add to dashboard Cite

Gas-liquid systems are one of the most common systems which appear in hydrocarbon reservoirs; therefore, the investigation of the interfacial properties and effect of temperature and pressure on these systems is crucial for optimizing the plan of production. In this study, interfacial resistances for N 2 -alkane and CO 2 -alkane systems were estimated at different pressures and temperatures. A model was developed to calculate interfacial resistance using the equilibrium and dynamic interfacial tension data which were measured by pendant drop technique at different pressures and temperatures. Interfacial resistances were estimated for a temperature range from 313 to 393 K and pressures from 0.34 to 41.7 MPa. The results showed that interfacial resistance in N 2 -alkane and CO 2 -alkane systems decreased at higher pressure. Moreover, In N 2 -alkane systems, the interfacial resistance decreases as the temperature increases; however, in CO 2 -alkane system the interfacial resistance depends on the diffusion and solubility interactions; it will decrease, increase or remain constant.

show abstract

Measurement of gas diffusivity in heavy oils

Cited by 231 publications

References 5 publications

Interplay of Capillarity, Drainage Height, and Aqueous Phase Saturation on Mass Transfer Rate of Solvent Vapor into Heavy Oil

Interplay of Capillarity, Drainage Height, and Aqueous Phase Saturation on Mass Transfer Rate of Solvent Vapor into Heavy Oil

The diffusion coefficient of H2S in liquid sulfur

Interfacial resistance in CO2-normal alkane and N2-normal alkane systems: An experimental and modeling investigation

Contact Info

Product

Resources

About