Ultrasonic compressional wave velocities and absorption have been measured for Berea sandstone as a function of different nitrogen gas and brine saturations at 103.3-bar net confining pressure. The results of this experiment show larger absorption for partially gas/brine-saturated sandstone than for either complete gas or complete brine saturations. These results are in agreement with suggestions made by some early experimenters and with recently reported resonance data on Vycor glass and ultrasonic measurements on Berea sandstone. These results suggest the possible use of sonic logging as a means of detecting bypassed gas production in older hydrocarbon producing wells.