A marine seismic acquisition system that provides a full ‘ghost-free’ solution

Abstract

Dual sensor streamer technology has previously been developed to remove the receiver sea surface reflection (or ghost) from seismic data. However, seismic data contains two sea surface reflections, on both receiver side and source side. This paper describes a time and depth distributed source design that, in combination with dual sensor streamer technology, provides a full ‘ghost-free’ solution. The time and depth distributed source described in this paper is divided into sub-sources, where each sub-source is deployed at a specific depth and fired with specific fire time delays. Depths of sub-sources are chosen such that the ghost functions are complementary, thereby avoiding deep notches in the spectrum and providing a high signal to noise ratio (S/N) over a large bandwidth. The combination of dual sensor streamers and the time and depth distributed source is an acquisition-based solution that enables the removal of both the source and the receiver ghosts at an early stage in the pre-processing sequence. This has an advantage in following processing steps such as de-multiple, velocity analysis and so on, and produces ghost-free pre- stack as well as post- stack data.