Impact of Heterogeneity on the Transient Gas Flow Process in Tight Rock

Bao Jia, Jyun-Syung Tsau, Reza Barati and Fan Zhang
Additional contact information
Bao Jia: Department of Chemical and Petroleum Engineering, University of Kansas, Lawrence, KS 66045, USA
Jyun-Syung Tsau: Department of Chemical and Petroleum Engineering, University of Kansas, Lawrence, KS 66045, USA
Reza Barati: Department of Chemical and Petroleum Engineering, University of Kansas, Lawrence, KS 66045, USA
Fan Zhang: Department of Geology, University of Kansas, Lawrence, KS 66045, USA

Energies, 2019, vol. 12, issue 18, 1-12

Abstract: There exits a great challenge to evaluate the flow properties of tight porous media even at the core scale. A pulse-decay experiment is routinely used to measure the petrophysical properties of tight cores including permeability and porosity. In this study, 5 sets of pulse-decay experiments are performed on a tight heterogeneous core by flowing nitrogen in the forward and backward directions under different pressures under pore pressures approximately from 100 psi to 300 psi. Permeability values from history matching are from about 300 nD to 600 nD which shows a good linear relationship with the inverse of pore pressure. A preferential flow path is found even when the microcrack is absent. The preferential path causes different porosity values using differential initial upstream and downstream pressure. In addition, the porosity values calculated based on the forward and backward flow directions are also different, and the values are about 1.0% and 2.3%, respectively, which is the primary novelty of this study. The core heterogeneity effect significantly affects the very early stage of pressure responses in both the upstream and downstream but the permeability values are very close in the late-stage experiment. We proposed that that there are two reasons for the preferential flow path: the Joule–Thomson effect for non-ideal gas and the core heterogeneity effect. Based on the finding of this study, we suggest that very early pressure response in a pulse-decay experiment should be closely examined to identify the preferential flow path, and failure to identify the preferential flow path leads to significant porosity and permeability underestimation.

Keywords: pulse-decay; heterogeneity; transient flow; preferential flow path; tight porous media (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2019
References: View complete reference list from CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
https://www.mdpi.com/1996-1073/12/18/3559/pdf (application/pdf)
https://www.mdpi.com/1996-1073/12/18/3559/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jeners:v:12:y:2019:i:18:p:3559-:d:268036

Access Statistics for this article

Energies is currently edited by Ms. Agatha Cao

More articles in Energies from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().