Abstract: The velocity of seismic wave and P-and S-wave velocity ratio are controlled by many factors.Therefore porosity obtained from Wyllie and Pickett formula has limitations and errors.To overcome these problems, 69 rock samples in western Junggar basin were selected and shaliness of clastic rock measured on thin section.Moreover, P- and S-wave velocity of rock samples saturated with oil and water were measured in lab.The results showed that velocity of seismic wave and P- and S-wave velocity ratio are direct proportion to porosity and shiliness of rock ;while veloci ty of seismic wave is more sensitive to porosity than to shaliness, and both parameters are more sensi tive to shaliness of sample saturated with water than to that of sample saturated with oil.This result has guidance to lateral prediction of reservoir.

Key words: Reservoir, Shaliness, Seismic wave, P-wave velocity, S-wave velocity, PV-SV, Correlation analyses