Saturation of porous rock and measurement of the B coefficient

R. Y. Makhnenko, Joseph F Labuz

Research output: Chapter in Book/Report/Conference proceedingConference contribution

8 Scopus citations

Abstract

Laboratory testing of fluid-saturated rock is often needed to properly duplicate field conditions, where pores in rock are filled with a liquid. It is desirable that laboratory specimens be fully saturated, because it reduces the number of unknown parameters and allows calculation of some of the rock's poroelastic moduli. However, full saturation is difficult to achieve in rock specimens because of the air bubbles trapped in pores. In order to dissolve air bubbles, back pressure can be applied to the specimens, decreasing the size of air bubbles and reducing the time needed to dissolve them in water. A process to saturate Berea sandstone is presented. Skempton's B coefficient was measured at each increment of back pressure while keeping the effective mean stress approximately the same. A B-value that was constant and independent of the magnitude of the back pressure indicated full saturation. The maximum B achieved for the sandstone at 5 MPa effective mean stress was 0.58. This value was confirmed by calculation of Skempton's coefficient from other poroelastic parameters. Moreover, full saturation was assured by the measurement of a constant P-wave velocity with increasing back pressure.

Original languageEnglish (US)
Title of host publication47th US Rock Mechanics / Geomechanics Symposium 2013
Pages679-684
Number of pages6
StatePublished - Dec 1 2013
Event47th US Rock Mechanics / Geomechanics Symposium 2013 - San Francisco, CA, United States
Duration: Jun 23 2013Jun 26 2013

Publication series

Name47th US Rock Mechanics / Geomechanics Symposium 2013
Volume1

Other

Other47th US Rock Mechanics / Geomechanics Symposium 2013
Country/TerritoryUnited States
CitySan Francisco, CA
Period6/23/136/26/13

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