Numerical simulation of two-phase heat and mass transfer for fractured reservoir based on projection-based embedded discrete fracture model (pEDFM)

The embedded discrete fracture model (EDFM), among different flow simulation models, achieves a good balance between efficiency and accuracy. In the EDFM, micro-scale fractures that cannot be characterized individually need to be homogenized into the matrix, which may bring anisotropy into the matrix. However, the simplified matrix–fracture fluid exchange assumption makes it difficult for EDFM to address the anisotropic flow. In this paper, an integrally embedded discrete fracture model (iEDFM) suitable for anisotropic formations is proposed. Structured mesh is employed for the anisotropic matrix, and the fracture element, which consists of a group of connected fractures, is integrally embedded in the matrix grid. An analytic pressure distribution is derived for the point source in anisotropic formation expressed by permeability tensor, and applied to the matrix–fracture transmissibility calculation. Two case studies were conducted and compared with the analytic solution or fine grid result to demonstrate the advantage and applicability of iEDFM to address anisotropic formation. In addition, a two-phase flow example with a reported dataset was studied to analyze the effect of the matrix anisotropy on the simulation result, which also showed the feasibility of iEDFM to address anisotropic formation with complex fracture networks.

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The embedded discrete fracture model for two-phase flow involving the capillary pressure discontinuities in low-permeability reservoir

Journal of Physics Conference Series ◽

10.1088/1742-6596/1549/4/042017 ◽

2020 ◽

Vol 1549 ◽

pp. 042017

Author(s):

Zhanke Li ◽

Weidong Cao ◽

Zhifeng Liu ◽

Min Wang ◽

Jinbiao Yu ◽

...

Keyword(s):

Capillary Pressure ◽

Two Phase Flow ◽

Fracture Model ◽

Low Permeability ◽

Phase Flow ◽

Two Phase ◽

Discrete Fracture Model ◽

Low Permeability Reservoir ◽

Discrete Fracture

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A Discrete Fracture Modeling Approach for Analysis of Coalbed Methane and Water Flow in a Fractured Coal Reservoir

Geofluids ◽

10.1155/2020/8845348 ◽

2020 ◽

Vol 2020 ◽

pp. 1-15

Author(s):

Tianran Ma ◽

Hao Xu ◽

Chaobin Guo ◽

Xuehai Fu ◽

Weiqun Liu ◽

...

Keyword(s):

Water Flow ◽

Coalbed Methane ◽

Fluid Transport ◽

Fracture Model ◽

Phase Flow ◽

Two Phase ◽

Discrete Fracture Model ◽

Discrete Fracture ◽

Fractured Coal ◽

Cbm Production

As a complex two-phase flow in naturally fractured coal formations, the prediction and analysis of CBM production remain challenging. This study presents a discrete fracture approach to modeling coalbed methane (CBM) and water flow in fractured coal reservoirs, particularly the influence of fracture orientation, fracture density, gravity, and fracture skeleton on fluid transport. The discrete fracture model is first verified by two water-flooding cases with multi- and single-fracture configurations. The verified model is then used to simulate CBM production from a discrete fractured reservoir using four different fracture patterns. The results indicate that fluid behavior is significantly affected by orientation, density, and fracture connectivity. Finally, several cases are performed to investigate the influence of gravity and fracture skeleton. The simulation results show that gas migrates upwards to the top reservoir during fluid extraction owing to buoyancy and the connected fracture skeleton plays a dominant role in fluid transport and methane production efficiency. Overall, the developed discrete fracture model provides a powerful tool to study two-phase flow in fractured coal reservoirs.

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Numerical Study on Flow and Heat and Mass Transfer in Pulsating Heat Pipe

ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer ◽

10.1115/mnhmt2019-4012 ◽

2019 ◽

Author(s):

Jian-Hong Liu ◽

Fu-Min Shang ◽

Nikolay Efimov

Keyword(s):

Numerical Simulation ◽

Mass Transfer ◽

Heat Pipe ◽

Gas Phase ◽

Heat And Mass Transfer ◽

Mixture Model ◽

Volume Fraction ◽

Pulsating Heat Pipe ◽

Two Phase ◽

Pipe Model

Abstract Numerical simulation was performed to establishing a two-dimensional pulsating heat pipe model, to investigate the flow and heat transfer characteristics in the pulsating heat pipe by using the Mixture and Euler models, which were unsteady models of vapor-liquid two-phase, based on the control-volume numerical procedure utilizing the semi-implicit method. Through comparing and analyzing the volume fraction and velocity magnitude of gas phase to decide which model was more suitable for numerical simulation of the pulsating heat pipe in heat and mass transfer research. It was showed there had gas phase forming in stable circulation flow in the heating section, the adiabatic section using the Mixture and Euler models respectively, and they were all in a fluctuating state at 10s, besides, the pulsating heat pipe had been starting up at 1s and stabilizing at 5s, it was all found that small bubbles in the heat pipe coalescing into large bubbles and gradually forming into liquid plugs and gas columns from the contours of volume fraction of the gas phase; through comparing the contours of gas phase velocity, it could be seen that there had further stably oscillating flow and relatively stabler gas-liquid two-phase running speed in the pulsating heat pipe used the Mixture model, the result was consistent with the conclusion of the paper[11] extremely, from this it could conclude that the Mixture model could be better simulate the vaporization-condensation process in the pulsating heat pipe, which could provide an effective theoretical support for further understanding and studying the phase change heat and mass transfer mechanism of the pulsating heat pipe.

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