A full wavefield approach to marine survey planning

Conventional processing of 3D marine seismic data based on primary reflections can suffer from strong acquisition related footprint. The problem manifests as gaps in the data because the water bottom and shallow features lack full illumination in shallow water data. The phenomenon is most obvious at the water bottom and gradually heals with increasing depth. This degradation of the shallow image is particularly problematic for surveys that target geohazard evaluation. Furthermore, accurate and continuous water bottom information can be crucial for multiple removal techniques that are required for successful imaging of deeper targets (Brittan et al., 2011). Separated wavefield imaging is a technique that has been developed to image the subsurface using any order of sea-surface multiples (Whitmore et al., 2010). The method requires the separation of upgoing and downgoing wavefields using multi-sensor marine streamer recordings (Carlson et al., 2007). By considering sea-surface reflections, receivers act as virtual sources, which provide increased lateral illumination and angular diversity compared to primary only reflections (Figure 1). Lu et al. (2013) demonstrated that imaging with sea-surface multiples is a valuable tool, providing a continuous water bottom image by reducing the acquisition related footprint and gives improved resolution of shallow structures. Separated wavefield imaging can therefore be used to obtain high-quality images from data acquired using operationally efficient acquisition configurations.