Detecting a gas reservoir using the ratio of P-wavevelocity to S-wave-velocity
Gas reservoir can be detected using both the real P-wave-velocity to S-wave-velocity ratio which is derived from long source-receiver distance sonic logging data and the converted P-wave-velocity to S- wave-velocity ratio. A gas reservoir exists when the real P-wave-ve- locity to S-wave velocity ratio is lower than the corresponding con- verted velocity ratio. Whereas, no gas reservoir exists when the two velocity ratios are Dearly equal. P-wave-velocity to S-wave velocity ratio method has higher res- olution and accuracy in detecting low porosity carbonate gas reser- voir. Therefore, it is an effective logging detecting method for gas reservoir.