this study was aimed at relating the seismic and the electrical properties of tight-gas rocks to their pore-space geometry, permeability, and level of water saturation. here we report results of a laboratory experimental study of wave propagation in cotton valley and spirit river sandstones as a function of partial water saturation (sw) and wave frequency. we find that wave velocities and the velocity ratio are sensitive to the presence of gas. furthermore, wave attenuation is sensitive to the amount of gas in the pore space ultrasonic measurements in tight-gas sands tend to yield higher velocity values, due to the inability of the pore fluid pressure to homogenize during the passage of waves. laboratory measurements were made also of the complex electrical response of selected tight rocks, and compared with normal permeability berea sandstone. the results show that the dielectric property of tight-gas sands is very sensitive to partial water saturation, and may give not only insight into the nature of the pore space, but also provide a practical measure of s/sub w/ in situ. 35 figures, 2 tables. (era citation 08: 023050)