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Journal of Chemistry
Volume 2015 (2015), Article ID 391851, 11 pages
Research Article

The Applicability of Different Fluid Media to Measure Effective Stress Coefficient for Rock Permeability

1State Key Laboratory of Oil and Gas Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China
2Xinjiang Oilfield Company, China National Petroleum Corporation, Xinjiang 834000, China

Received 6 December 2014; Revised 28 February 2015; Accepted 28 February 2015

Academic Editor: Agus Sasmito

Copyright © 2015 Ying Wang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Effective stress coefficient for permeability (ESCK) is the key parameter to evaluate the properties of reservoir stress sensitivity. So far, little studies have clarified which ESCK is correct for a certain reservoir while rock ESCK is measured differently by different fluid media. Thus, three different fluids were taken to measure a fine sandstone sample’s ESCK, respectively. As a result, the ESCK was measured to be the smallest by injecting nitrogen, the largest by injecting water, and between the two by brine. Besides, those microcharacteristics such as rock component, clay mineral content, and pore structure were further analyzed based on some microscopic experiments. Rock elastic modulus was reduced when water-sensitive clay minerals were encountered with aqua fluid media so as to enlarge the rock ESCK value. Moreover, some clay minerals reacting with water can spall and possibly block pore throats. Compared with water, brine can soften the water sensitivity; however, gas has no water sensitivity effects. Therefore, to choose which fluid medium to measure reservoir ESCK is mainly depending on its own exploitation conditions. For gas reservoirs using gas to measure ESCK is more reliable than water or brine, while using brine is more appropriate for oil reservoirs.