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Effects of partial liquid/gas saturation on extensional wave attenuation in Berea sandstone
Author(s) -
Yin C.S.,
Batzle M. L.,
Smith B. J.
Publication year - 1992
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/92gl01159
Subject(s) - attenuation , saturation (graph theory) , geology , imbibition , mineralogy , extensional definition , brine , geotechnical engineering , optics , seismology , thermodynamics , physics , mathematics , tectonics , combinatorics , germination , botany , biology
Extensional wave attenuation measurements on Berea sandstone were made during increasing (imbibition) and decreasing (drainage) brine saturations. Measurements on samples with both open‐pore and closed‐pore surfaces were made using the resonant‐bar technique. The frequency dependence was examined using the forced‐deformation method. The attenuation was found to be dependent on saturation history as well as degree of saturation and boundary flow conditions. The sample with open‐pore surface had a larger attenuation which peaked at greater brine saturations than the sample with closed‐pore surface. During drainage, the attenuation reached a maximum at about 90% brine saturation as opposed to about 97% brine saturation during imbibition. The variation of the size and number of air pockets within the rock can account for this discrepancy. The magnitude of the attenuation peak value decreases substantially with decreasing frequency to the extent that no attenuation peak with saturation was apparent at seismic frequencies, say, below 100 Hz.