Full-Azimuth Marine Acquisition Using the Coil Shooting Technique

摘要

In this paper, we describe a new single-vessel full azimuth (FAZ) seismic acquisition technique named Coil Shooting~*. Whereas conventional marine 3D seismic acquisition records only a narrow azimuth of seismic traces, this new technique acquires FAZ data. We show data examples from extended field trials, review data processing challenges such as noise removal and multiple attenuation, and discuss survey design.The Coil Shooting technique is a development of wide-azimuth (WAZ) acquisition. Over the last five years WAZ has been used extensively in the Gulf of Mexico to produce enhanced images in the subsalt section. However, WAZ marine acquisition using towed-streamer technology still requires the use of multiple vessels (typically three or four vessels). In the North Sea and surrounding areas there are significant advantages in deploying a single vessel, as multivessel operations are subject to availability and logistical constraints. FAZ acquisition records over the full range of azimuths and offsets. In the case of Coil Shooting, this is achieved by sailing the vessel in a series of circles or coils.WAZ and ocean-bottom cable seismic operations are proven techniques for improving illumination. Results from recent modelling and field tests demonstrate that the Coil Shooting technique has similar capabilities. Although the idea of recording while sailing in circles dates from the 1980s, Coil Shooting requires modern streamer positioning and control techniques. We demonstrate that limitations from the 1980s have now been overcome and show that FAZ recording has the potential to improve imaging of geological structures that continue to cause interpretation problems in the European continental shelf, e.g., subsalt, salt flank, and Jurassic tilted fault block structures.