Fibre optic ocean bottom seismic cable system: from innovation to commercial success

Abstract

Optoplan has been awarded the world's first commercial contract for a fibre optic Ocean Bottom Seismic Cable (OBC) system [1] for permanent reservoir monitoring at the Ekofisk field in the North Sea. An area of 60 sq. km of the seabed will be covered by four component (4C) sensors in 2010. The system consists of i) a top-side (platform) laser interrogation and recording system, and ii) a wet-end system including 200 km of seismic cable with 4000 sensor stations, each containing 4 FBG-based interferometric sensors (three accelerometers and one hydrophone). The wet-end system includes 24000 FBGs and more than 3500km of optical fibres, and will probably be the largest single fibre optic sensor network ever made. The completely passive wet-end part of the system is designed to operate with ultra-high reliability subsea over more than 25 years. The system is expected to significantly enhance the oil and gas recovery of the field. This commercial success is a result of i) Optoplan's long experience and credibility in the field of fibreoptic sensors for the oil and gas industry [2], [3], ii) close collaboration with oil companies and qualification through extensive field testing [4], [5], iii) the establishment of a high capacity supply chain and manufacturing system with innovative automated processes, iv) sensor/manufacturing design for high reliability and good manufacturability with high yield, v) innovative sensor fibre network and instrumentation design [1], [6], [7], [