Wave Equation Receiver Deghosting

Current solutions to receiver deghosting generally involve making complementary measurements of the wavefield or, alternatively, involve estimation of data not recorded due to ghost interference. Both solutions offer challenges in practice today. For marine streamer data, although multimeasurement streamers are commercially available, it is still on a somewhat limited basis and existing p-wave data and conventional acquisition could benefit from accurate single-measurement deghosting. In the second case, statistical estimates of the unrecorded frequencies near the ghost notches can be confounded by a variety of factors. Our approach to up/down wavefield separation does not require complementary measurements – we demonstrate the method on pressure-only data – nor does it rely on statistical estimation of the missing spectral components. Instead, we use the wave equation to compute directly the up and downgoing wavefields between the receiver and the surface. This migration-like approach only assumes that the upcoming wavefield is causal with respect to the downgoing wavefield, a good assumption if certain types of noise such as the direct arrivals are removed from the recorded wavefield. Moreover, our method exposes the underlying physics of the problem and thereby allows for complexities such as variable water velocity, variable sea surface and complex wavefields.