The ups and downs of ocean-bottom seismic processing: Applications of wavefield separation and up-down deconvolution

Abstract

A key advantage of acquiring multicomponent data using ocean-bottom sensors, whether using cables or nodes, is the ability to separate the wavefield into up- and downgoing parts. This opens up a host of attractive possibilities such as mirror imaging using the downgoing wave, attenuating receiver-side multiples using the upgoing wave only, or combining both up- and downgoing waves to completely remove the free-surface effect using up-down deconvolution. We focus here on the latter.

Data matching for free-surface multiple attenuation by multidimensional deconvolution

“…Especially in complex environments, 3‐D SRME has proven to be a superior demultiple method (van Dedem & Verschuur 2005; Aaron et al 2010; Dragoset et al 2010). Inversion‐based methods such as MDD can also be extended to 3‐D and early applications to OBC data have been reported (Wang et al 2010). The proposed data matching algorithm might be extended to 3‐D too, which will be challenging though, due to poor sampling in the cross‐line direction.…”

“…Inversion-based methods such as MDD can also be extended to 3-D and early applications to OBC data have been reported (Wang et al 2010). The proposed data matching algorithm might be extended to 3-D too, which will be challenging though, due to poor sampling in the cross-line direction.…”

“…It has been shown that multidimensional deconvolution (MDD) of the upgoing wavefield with the downgoing wavefield at the receiver level yields a reflection response without surface‐related multiples (Amundsen 2001; Frijlink et al 2011). This method has been applied to remove multiples from ocean bottom cable (OBC) data by various authors (Holvik & Amundsen 2005; Wang et al 2010). To improve convergence, additional sparsity constraints can be imposed, as is done in estimation of primaries by sparse inversion (EPSI, van Groenestijn & Verschuur 2009; Lin & Herrmann 2010).…”

Directional interpolation of multicomponent data

“…The available simulated data did not include a dense crossline sampling of the depth derivative. However, it is well known that if both P and Z are known, the weighted average of the two should effectively attenuate ghosts (deghosting by PZ summation) (Wang et al 2010). A more refined deghosting can be expressed in the Fourier domain and accounts for directionality effects (Amundsen, Weglein and Reitan 2013).…”

Deep water Ocean-Bottom Node Processing - A West of Shetland Case Study

“…Processing the upgoing wavefield optimally nonetheless still requires the downgoing data for updown deconvolution (Wang et al, 2010) which attempts to simultaneously remove free-surface multiples and recover the reflectivity series of the Earth (Figure 2). After the subsequent tau-px-py reverse transform to the t-x-y domain, residual multiple attenuation was performed using a surfacerelated multiple modelling (SRMM) and adaptive subtraction technique (Pica et al, 2006), which used the downgoing data as the reflectivity model.…”