Hussar converted-wave data processing and analysis

J. Helen Isaac, John C. Bancroft

We processed and inverted converted-wave data acquired during the low-frequency shoot at Hussar, Alberta in September, 2011. The two datasets we selected were generated from dynamite and low-dwell vibroseis sources and were recorded on 3C 10 Hz geophones. The data processing included radial filtering and Gabor deconvolution. The stacked dynamite and vibroseis data both show strong converted-wave reflections. Receiver statics were derived successfully by flattening an horizon picked on a stack of receiver gathers.

Comparison of the stack of vibroseis data obtained through conventional NMO, common conversion point (CCP) stack and post-stack migration and the equivalent offset migration (EOM) stack of the same data show that the EOM method successfully produced a stack of comparable quality. The converted-wave velocity model derived through common scatter point analysis was similar to that obtained through semblance analysis of common conversion point gathers. Thus, EOM shows considerable promise as a method for converted-wave data velocity estimation and migration.

Joint PP-PS model-based inversion was only partially successful. The character ties between the migrated PS data and well data were not easy to make and the registration of the PP and PS data shows that the character match between the two datasets is poor. However, since we clearly have converted-wave data in this area, the dataset will be useful for testing converted-wave processing procedures such as velocity determination, statics estimation and migration, and PP-PS data matching and registration.