Title: Klinkenberg Effect and Effective Pressure for Gas Permeability of Tight Sandstones

Abstract

Gas permeability k_g of tight sandstones was measured while cycling pore pressure, Pf, and confining pressure, P_c, using two different procedures. Firstly, we cycled the pore pressure from a minimum value close to atmospheric pressure to a maximum one slightly lower than P_c, while keeping the Pc constant. Secondly, P_f and P_c were simultaneously varied so as to keep the difference, P_c - P_f, constant. Significant effects owing to slip flow were observed when the gas pressure was lower than about 5 MPa. Klinkenberg plots showed that, under constant P_c, gas permeability kg decreased linearly for high values of 1/P_f, reached a minimum and then sharply increased as 1/P_f approached zero. Under constant P_c - P_f, k_g again decreased linearly in the high limit of 1/P_f and showed additional decrease in the low 1/P_f limit. The linear segments in both procedures indicate that k_g in tight sandstones was subject to slip flow at low values of P_f, while the curved segments revealed the sensitivity of permeability to effective pressure when Pf became comparable in magnitude to confining pressure. The effective pressure coefficient α was estimated and generally appeared to be a well-defined decreasing function of the pressure difference P_c -more » P_f. We modified the Walsh permeability model for fissured rocks to include slip-flow effects and obtained satisfactory fits to the experimental data for the samples with lowest porosities and highest pressure-sensitivities. This observation suggests that the intrinsic permeability of these rocks was controlled by inter- and/or intra-granular crack-like pores.« less

Authors:

Xiao, Wenlian  ^[1];

• Search DOE PAGES for author "Xiao, Wenlian"
• Search DOE PAGES for ORCID "0000-0001-7184-8760"

Bernabé, Yves  ^[2];

• Search DOE PAGES for author "Bernabé, Yves"
• Search DOE PAGES for ORCID "0000-0003-3489-3882"

Evans, Brian  ^[2];

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• Search DOE PAGES for ORCID "0000-0003-0324-0969"

Mok, Ulrich ^[2]; Zhao, Jinzhou ^[1]; Ren, Xiyao ^[1]; Chen, Meng ^[1]

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+ Show Author Affiliations

1. Southwest Petroleum Univ., Chengdu (China). State Key Lab. of Oil and Gas Reservoir Geology and Exploitation
2. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Earth, Atmospheric and Planetary Sciences Dept.

Publication Date:

Mon Jan 28 00:00:00 EST 2019

Research Org.:

Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences, and Biosciences Division

OSTI Identifier:

1515257

Alternate Identifier(s):

OSTI ID: 1496915

Grant/Contract Number:  

FG02-97ER14760; FG01‐09ER14760

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Geophysical Research. Solid Earth

Additional Journal Information:

Journal Volume: 124; Journal Issue: 2; Journal ID: ISSN 2169-9313

Publisher:

American Geophysical Union

Country of Publication:

United States

Language:

English

Subject:

58 GEOSCIENCES; gas permeability; Klinkenberg plots; effective pressure; pressure sensitivity; tight sandstones