Acquisition and Processing of a High Resolution 3D Seismic Survey – Offshore Netherlands

This paper describes the data acquisition and processing of a 3D high resolution seismic (HRS) survey acquired off-shore Rotterdam, the Netherlands. Target of the survey was the upper 1000 meters in the vicinity of a candidate CO2 storage site.

The acquisition concept was based on deployment of six 24-channel streamers in combination with two seismic sources operating in ‘flip-flop’ mode. Exact positioning of the spread was achieved using multiple GPS nodes and ship gyro.

Major differences from conventional seismic processing practice include retaining frequencies up to 300 Hz, having short intervals between sources and receivers, and relatively large static shifts. Processing included removing the source signature with an inverse filter. Correcting for data gaps by using super-gather distance weighted smoothing. Pre-stack time migration, followed by full and offset-limited stacks. The new deployment concept resulted in high-quality 3D images with the resolution and dense coverage that is required to identify and delineate shallow anomalies and structures related to gas presence and migration paths. Based on this first demonstration,we expect that 3D HRS can be developed into a viable technology for a broad range of applications related to off-shore site investigation, risk assessment, and exploration for shallow targets.