A dynamic fractal permeability model for heterogeneous coalbed reservoir considering multiphysics and flow regimes

Jianwei Tian, Jishan Liu, Derek Elsworth, Yee Kwong Leong, Wai Li, Jie Zeng

Research output: Chapter in Book/Conference paperConference paper

Abstract

Heterogeneous pore structure is critically important for unconventional gas recovery. In this paper, a dynamic fractal permeability model is proposed to investigate the interplay between heterogeneous pore structures and gas transport for coal seam gas reservoir. In this model, pore diameter and fractal dimension of pore size distribution are dynamically changing as a result of the variation of effective stress. Besides, based on fractal approach, a new Klinkenberg coefficient that dynamically changes with pore pressure is employed to incorporate the non-Darcy effect. This dynamic permeability model is applied to couple Multiphysics in coal seam gas recovery process. The impacts of these fractal parameters on permeability evolution are explored through a benchmark reservoir simulation. The numerical results exhibit good agreements with experimental data. The simulation results indicate that: (1) the dynamic permeability model matches better with experimental data than other homogeneous models, especially in low-pressure stage; (2) reservoir with larger initial fractal dimension is more sensitive to pressure depletion; (3) fractal dimension would change more dramatically when initial porosity is relatively smaller; (4) Klinkenberg coefficient increases with the decreasing of reservoir pore pressure during gas depletion. In summary, the dynamic permeability model predicts permeability evolution well in gas production process and provide some fundamental insights into the implications of reservoir heterogeneity on gas transport in reservoir simulation.

Original languageEnglish
Title of host publicationProceedings of the 7th Unconventional Resources Technology Conference
DOIs
Publication statusPublished - 2019
EventSPE/AAPG/SEG Unconventional Resources Technology Conference 2019, URTC 2019 - Denver, United States
Duration: 22 Jul 201924 Jul 2019

Conference

ConferenceSPE/AAPG/SEG Unconventional Resources Technology Conference 2019, URTC 2019
CountryUnited States
CityDenver
Period22/07/1924/07/19

Fingerprint

Fractals
Fractal dimension
Gases
Pore pressure
Pore structure
Recovery
Pore size
Porosity
Coal bed methane

Cite this

Tian, J., Liu, J., Elsworth, D., Leong, Y. K., Li, W., & Zeng, J. (2019). A dynamic fractal permeability model for heterogeneous coalbed reservoir considering multiphysics and flow regimes. In Proceedings of the 7th Unconventional Resources Technology Conference https://doi.org/10.15530/urtec-2019-250
Tian, Jianwei ; Liu, Jishan ; Elsworth, Derek ; Leong, Yee Kwong ; Li, Wai ; Zeng, Jie. / A dynamic fractal permeability model for heterogeneous coalbed reservoir considering multiphysics and flow regimes. Proceedings of the 7th Unconventional Resources Technology Conference. 2019.
@inproceedings{2f36a3b52a38472c83aec110e8c4e944,
title = "A dynamic fractal permeability model for heterogeneous coalbed reservoir considering multiphysics and flow regimes",
abstract = "Heterogeneous pore structure is critically important for unconventional gas recovery. In this paper, a dynamic fractal permeability model is proposed to investigate the interplay between heterogeneous pore structures and gas transport for coal seam gas reservoir. In this model, pore diameter and fractal dimension of pore size distribution are dynamically changing as a result of the variation of effective stress. Besides, based on fractal approach, a new Klinkenberg coefficient that dynamically changes with pore pressure is employed to incorporate the non-Darcy effect. This dynamic permeability model is applied to couple Multiphysics in coal seam gas recovery process. The impacts of these fractal parameters on permeability evolution are explored through a benchmark reservoir simulation. The numerical results exhibit good agreements with experimental data. The simulation results indicate that: (1) the dynamic permeability model matches better with experimental data than other homogeneous models, especially in low-pressure stage; (2) reservoir with larger initial fractal dimension is more sensitive to pressure depletion; (3) fractal dimension would change more dramatically when initial porosity is relatively smaller; (4) Klinkenberg coefficient increases with the decreasing of reservoir pore pressure during gas depletion. In summary, the dynamic permeability model predicts permeability evolution well in gas production process and provide some fundamental insights into the implications of reservoir heterogeneity on gas transport in reservoir simulation.",
author = "Jianwei Tian and Jishan Liu and Derek Elsworth and Leong, {Yee Kwong} and Wai Li and Jie Zeng",
year = "2019",
doi = "10.15530/urtec-2019-250",
language = "English",
booktitle = "Proceedings of the 7th Unconventional Resources Technology Conference",

}

Tian, J, Liu, J, Elsworth, D, Leong, YK, Li, W & Zeng, J 2019, A dynamic fractal permeability model for heterogeneous coalbed reservoir considering multiphysics and flow regimes. in Proceedings of the 7th Unconventional Resources Technology Conference. SPE/AAPG/SEG Unconventional Resources Technology Conference 2019, URTC 2019, Denver, United States, 22/07/19. https://doi.org/10.15530/urtec-2019-250

A dynamic fractal permeability model for heterogeneous coalbed reservoir considering multiphysics and flow regimes. / Tian, Jianwei; Liu, Jishan; Elsworth, Derek; Leong, Yee Kwong; Li, Wai; Zeng, Jie.

Proceedings of the 7th Unconventional Resources Technology Conference. 2019.

Research output: Chapter in Book/Conference paperConference paper

TY - GEN

T1 - A dynamic fractal permeability model for heterogeneous coalbed reservoir considering multiphysics and flow regimes

AU - Tian, Jianwei

AU - Liu, Jishan

AU - Elsworth, Derek

AU - Leong, Yee Kwong

AU - Li, Wai

AU - Zeng, Jie

PY - 2019

Y1 - 2019

N2 - Heterogeneous pore structure is critically important for unconventional gas recovery. In this paper, a dynamic fractal permeability model is proposed to investigate the interplay between heterogeneous pore structures and gas transport for coal seam gas reservoir. In this model, pore diameter and fractal dimension of pore size distribution are dynamically changing as a result of the variation of effective stress. Besides, based on fractal approach, a new Klinkenberg coefficient that dynamically changes with pore pressure is employed to incorporate the non-Darcy effect. This dynamic permeability model is applied to couple Multiphysics in coal seam gas recovery process. The impacts of these fractal parameters on permeability evolution are explored through a benchmark reservoir simulation. The numerical results exhibit good agreements with experimental data. The simulation results indicate that: (1) the dynamic permeability model matches better with experimental data than other homogeneous models, especially in low-pressure stage; (2) reservoir with larger initial fractal dimension is more sensitive to pressure depletion; (3) fractal dimension would change more dramatically when initial porosity is relatively smaller; (4) Klinkenberg coefficient increases with the decreasing of reservoir pore pressure during gas depletion. In summary, the dynamic permeability model predicts permeability evolution well in gas production process and provide some fundamental insights into the implications of reservoir heterogeneity on gas transport in reservoir simulation.

AB - Heterogeneous pore structure is critically important for unconventional gas recovery. In this paper, a dynamic fractal permeability model is proposed to investigate the interplay between heterogeneous pore structures and gas transport for coal seam gas reservoir. In this model, pore diameter and fractal dimension of pore size distribution are dynamically changing as a result of the variation of effective stress. Besides, based on fractal approach, a new Klinkenberg coefficient that dynamically changes with pore pressure is employed to incorporate the non-Darcy effect. This dynamic permeability model is applied to couple Multiphysics in coal seam gas recovery process. The impacts of these fractal parameters on permeability evolution are explored through a benchmark reservoir simulation. The numerical results exhibit good agreements with experimental data. The simulation results indicate that: (1) the dynamic permeability model matches better with experimental data than other homogeneous models, especially in low-pressure stage; (2) reservoir with larger initial fractal dimension is more sensitive to pressure depletion; (3) fractal dimension would change more dramatically when initial porosity is relatively smaller; (4) Klinkenberg coefficient increases with the decreasing of reservoir pore pressure during gas depletion. In summary, the dynamic permeability model predicts permeability evolution well in gas production process and provide some fundamental insights into the implications of reservoir heterogeneity on gas transport in reservoir simulation.

UR - http://www.scopus.com/inward/record.url?scp=85072921733&partnerID=8YFLogxK

UR - https://www.spe.org/events/en/2019/conference/19apur/spe-aapg-seg-asia-pacific-unconventional-resources-technology-conference.html

U2 - 10.15530/urtec-2019-250

DO - 10.15530/urtec-2019-250

M3 - Conference paper

BT - Proceedings of the 7th Unconventional Resources Technology Conference

ER -

Tian J, Liu J, Elsworth D, Leong YK, Li W, Zeng J. A dynamic fractal permeability model for heterogeneous coalbed reservoir considering multiphysics and flow regimes. In Proceedings of the 7th Unconventional Resources Technology Conference. 2019 https://doi.org/10.15530/urtec-2019-250