AVO inversion of multicomponent data for P and S impedance

Faranak Mahmoudian, Gary F. Margrave

Procedures to invert P-P and P-S prestack seismic data for underlying compressional and shear wave impedance reflectivity have been developed in the past. A program has been written to perform a joint AVO inversion on PP and PS pre-stack synthetic data in MATLAB. The inversion can be done for pure compressional wave (PP), as well as only converted shear wave (PS data) resulting in PP inversion only and PS inversion only. The program is primarily intended to perform an AVO inversion utilizing a model-based, weighted stacking approach similar to established PP and joint inversion methods. Missing low-frequency components in seismic datasets cause low-cut filtered reflectivity in the inversion process. The inversion program is organized to provide missing low-frequency components of impedance from well log information. The inverted impedance reflectivity results from PP, PS only inversion and joint inversion are compared using synthetic noise-free data. In the noise-free case all three methods have similar performance. In presence of noise, the joint inversion method performs significantly better than the results of PP and PS inversion only.