Rabbit Ears and FWI
In some cultures the rabbit's foot is believed to bring good fortune. However, it's the ears that increase discovery success. PGS Full Waveform Inversion uses back scattered seismic energy, known in the trade as rabbit ears, to build high-resolution velocity models at greater depths. This enables better inversions for robust ranking and more reliable derisking of prospects.
The PGS FWI solution uses diving waves, refractions and reflections together to deliver deep velocity model updates in a stable manner without relying on very long offsets. Conventional FWI high wavenumber artifacts and cycle skipping problems are avoided by using a combination of a clever imaging condition and elegant regularization within the inversion scheme.
The advantage of including the rabbit ears is shown in the illustration below. Traditional transmission FWI requires extremely long offsets to provide reasonably deep velocity updates. The 'banana' transmission FWI kernel only affects quite shallow depths. Velocity updates at larger depths will require much longer offsets. In contrast, reflection FWI and the use of the rabbit ears clearly provides much deeper velocity updates for the same offset.
The area updated for a particular source-receiver offset (5 km here) using two types of FWI solution. 'Transmission FWI' uses diving waves and refractions, while 'Reflection FWI' uses back scattered energy (rabbit ears) and enables much deeper velocity model updates.