Molecular Diffusion Calculations in Simulation of Gasfloods in Fractured Reservoirs

Mohebbinia, Saeedeh; Wong, Terry

doi:10.2118/182594-ms

Cited by 16 publications

(3 citation statements)

References 22 publications

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“…The reservoir model is shown in Figure 3. Mohebbinia and Wong [46] have pointed out that molecular diffusion would be dominated in the low-permeability fractured reservoirs when gravitational drainage is inefficient. Hence, only diffusion mechanism was included in this work.…”

Section: Base Casementioning

confidence: 99%

Cyclic CH4 Injection for Enhanced Oil Recovery in the Eagle Ford Shale Reservoirs

Zhang

Yang

et al. 2018

Energies

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Gas injection is one of the most effective enhanced oil recovery methods for the unconventional reservoirs. Recently, CH4 has been widely used; however, few studies exist to accurately evaluate the cyclic CH4 injection considering molecular diffusion and nanopore effects. Additionally, the effects of operation parameters are still not systematically understood. Therefore, the objective of this work is to build an efficient numerical model to investigate the impacts of molecular diffusion, capillary pressure, and operation parameters. The confined phase behavior was incorporated in the model considering the critical property shifts and capillary pressure. Subsequently, we built a field-scale simulation model of the Eagle Ford shale reservoir. The fluid properties under different pore sizes were evaluated. Finally, a series of studies were conducted to examine the contributions of each key parameter on the well production. Results of sensitivity analysis indicate that the effect of confinement and molecular diffusion significantly influence CH4 injection effectiveness, followed by matrix permeability, injection rate, injection time, and number of cycles. Primary depletion period and soaking time are less noticeable for the well performance in the selected case. Considering the effect of confinement and molecular diffusion leads to the increase in the well performance during the CH4 injection process. This work, for the first time, evaluates the nanopore effects and molecular diffusion on the CH4 injection. It provides an efficient numerical method to predict the well production in the EOR process. Additionally, it presents useful insights into the prediction of cyclic CH4 injection effectiveness and helps operators to optimize the EOR process in the shale reservoirs.

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Section: Base Casementioning

confidence: 99%

Cyclic CH4 Injection for Enhanced Oil Recovery in the Eagle Ford Shale Reservoirs

Zhang

Yang

et al. 2018

Energies

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“…All models are assumed as no flow boundary condition. Mohebbinia et al [50] stated that molecular diffusion transportation is important in tight rocks. According to the previous study, the range of measured CO 2 diffusion coefficients in Decane is about 1.97 × 10 −5 to 1.26 × 10 −4 cm 2 /s when the temperature is 100 • F and pressure is up to 850 psi [51].…”

Section: Resultsmentioning

confidence: 99%

Simulation Study of CO2 Huff-n-Puff in Tight Oil Reservoirs Considering Molecular Diffusion and Adsorption

Zhang

2019

Energies

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CO2 injection has great potentials to improve the oil production for the fractured tight oil reservoirs. However, Current works mainly focus on its operation processes; full examination of CO2 molecular diffusion and adsorption was still limited in the petroleum industry. To fill this gap, we proposed an efficient method to accurately and comprehensively evaluate the efficiency of CO2-EOR process. We first calculated the confined fluid properties with the nanopore effects. Subsequently, a reservoir simulation model was built based on the experiment test of the Eagle Ford core sample. History matching was performed for the model validation. After that, we examined the effects of adsorption and molecular diffusion on the multi-well production with CO2 injection. Results illustrate that in the CO2-EOR process, the molecular diffusion has a positive impact on the oil production, while adsorption negatively impacts the well production, indicating that the mechanisms should be reasonably incorporated in the simulation analysis. Additionally, simulation results show that the mechanisms of molecular diffusion and adsorption make great contributions to the capacity of CO2 storage in tight formations. This study provides a strong basis to reasonably forecast the long-term production during CO2 Huff-n-Puff process.

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“…In the suggested model, the gradient of chemical potential is considered as the driving force. Also, the implementation of the simulations that consider diffusion using various solution methods has been examined by Mohebbinia and Wong [32]. Also, optimal performance is achieved by the partially implicit approach.…”

Section: Introductionmentioning

confidence: 99%

Numerical modeling of molecular diffusion and convection effects during gas injection into naturally fractured oil reservoirs

Gholamian

Ehsani

Nikookar

et al. 2021

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

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Gas injection into a naturally fractured oil reservoir keeps the reservoir pressure and increments the initial recovery from the reservoir. The main aim of this work was to develop a numerical model to calculate the mass transfer (molecular diffusion and convection) between a gas injected in the fracture and residual fluid (gas and oil) in a matrix block. The dual continuum model is applied to describe flow behaviour and fluid recovery in porous media. Finally, the model is validated by comparing the outcomes with the results of two experimental works available in the literature. The mathematical model results are in agreement with the laboratory data including recovery of each component, saturation profile, and the pressure gradient between matrix and fracture. Modeling results show that after 25 days of N2 injection, the lighter and heavier components (C1 and C5) are recovered about 51% and 39%, respectively. These amounts for CO2 injection are 49% and 27%. It is found that the convection mechanism has a great effect on preventing the pressure drop of the reservoir during injection operations. In the nitrogen injection, without considering the convection, after 30 days, the matrix pressure reaches 1320 Psi from 1479 Psi but after 30 days, considering the convection, the pressure reaches 1473 Psi from 1479 Psi.

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Molecular Diffusion Calculations in Simulation of Gasfloods in Fractured Reservoirs

Cited by 16 publications

References 22 publications

Cyclic CH4 Injection for Enhanced Oil Recovery in the Eagle Ford Shale Reservoirs

Cyclic CH4 Injection for Enhanced Oil Recovery in the Eagle Ford Shale Reservoirs

Simulation Study of CO2 Huff-n-Puff in Tight Oil Reservoirs Considering Molecular Diffusion and Adsorption

Numerical modeling of molecular diffusion and convection effects during gas injection into naturally fractured oil reservoirs

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