The importance of on-board processing

Abstract

3-D marine seismic surveys acquire ever larger volumes of data, and use increasingly complex deployments of multiple streamers and source arrays to reduce costs and increase efficiency. The result of such large volumes of data presents serious problems of acquisition quality control and processing turnaround. The rapid development of on-board processing systems has enabled these problems to be addressed directly, by providing comprehensive features for quality control, smoothing the path for final data processing, and providing access to 3-D data volumes at an early stage. Apart from the processing power provided by the modern workstation computer, the key elements in this development are the availability of real-time data links with the recording system, and the provision of similar linkages to the real-time and post-processed navigation data. These linkages enable real-time processing of a significant subset of the 3-D data in the form of a stack of the near offset traces (typically 6- or 12-fold) of all subsurface lines recorded simultaneously in multiple source and streamer acquisition. The stack traces are assigned appropriate mid-point co-ordinates and stored in the form of a 3-D volume. The 3-D data may be viewed as in-line, cross-line or time-slice profiles at any time during the survey (and the processing), which allows the correct functioning of many key acquisition sub-systems to be verified. The 3-D volume may be migrated on-board, or soon after completing the acquisition of the date, allowing rapid access to 3-D migrated results, and providing a basis for initial interpretation and velocity model building. The on-board processing system thus brings together all aspects of the 3-D survey ? acquisition, processing and interpretation.