Study On Wide Angle AVA Character Of Cross-well Seismic Data And Waveform Correction

AVA technique is the best technology that uses seismic data to study reservoir quality. Cross-well seismic data contain abundant AVA information, possess high resolution and high S/N, and can be used to solve the problem of reservoir exploration and production.3-D AVA analysis technique is relatively mature, but it is only suitable to small or medium incident angle, which is different in cross-well seismology for bigger incident angle. In this dissertation, on the basis of elastic wave theory and Zoeppritz equation, the simplified reflection coefficient equation for wide incident angle is derived. Control variable method is used to study relationship between wide-angle AVA response and reservoir lithology, velocity, porosity and pore fluid. Simplified equation is used to make synthetic record of cross-well common angle gather in frequency domain. In order to obtain high quality cross-well section, waveform correction methods base on constant phase and waveform correction factor are applied to common angle gather respectively before stack. Model experiments illustrate the validity of simplified equation and reservoir with different lithology, velocity, porosity and pore fluid show different AVA responses. Waveform correction of synthetic data and field data gives excellent results.