Abstract：Complexity of reservoir of volcanic rocks brings a great difficulty of basic petrophysical study in volcanic rocks. In order to strengthen the basic petrophysical study of volcanic rocks and improve seismic volcanic reservoir prediction, we measures P-wave velocity, S-wave velocity and density of 105 rock samples and 16 kinds of lithologies in the states of dry, full gas and full water saturation under simulating real formation temperature and pressure conditions. Then we study influences of the following factors such as temperature, (static rock) pressure, pore fluid pressure, different fluids' saturations on P-wave and S-wave velocities, analyze petrophysical parameter characteristics of different lithologies and rocks with different fluids for the purpose of direct identification of volcanic lithology and reservoirs. As the result shows, cross plots of density and P-wave velocity can distinguish basic, neutral and acidic rocks, and cross plots of P-wave velocity and S-wave velocity ratio can distinguish water and gas.
