Interbed Multiple Attenuation Using a Reflectivity Model from Well Logs

OMV E&P and ETAP reprocessed and merged 9 different surveys (5200 km²) acquired in Southern Tunisia. One of the objectives of the reprocessing was to attenuate surface-related and complex interbed multiple energy that interferes with the target area.

Due to the complexity of the interbed multiples generated by two distinct geological layers representing high impedance contrasts, conventional multiple attenuation in the Radon domain is inefficient. Therefore, wavefield extrapolation was chosen to model internal multiples and adaptively subtract from the seismic data.

The modelling of the multiple reflections requires a reflectivity model, which was derived from sonic and density information from 3 pre-selected wells in the 200 km² pilot area. Incorporation of well information, instead of a fast track seismic volume, yields a high-frequency reflectivity model that proves to be useful for both modelling and subtraction.

A comparison after the adaptive subtraction with a VSP confirms that a significant amount of interbed multiples have been attenuated.