The porosities of core samples from the Natural Buttes 21 in Uinta County, Utah, have been measured in the laboratory using three techniques. Two techniques involve a helium porosimeter, and the third requires that the sample be saturated with kerosene and the difference between the saturated and the dry weight used as an indication of the porosity. The best method for determining porosity in the laboratory has not been selected. Initial results of determining porosities of intervals from the Natural Buttes 21 well using wireline logs indicate that the porosities calculated from the density logs might be too low if standard procedures are used. Matrix densities needed to calculate the correct porosities using the density logs were higher than normally used in the tight western gas sands. The error in calculating the porosity from the density log could underestimate the volume of gas-in-place in the tight western gas sands.