System solves old seabed acquisition problems

Sercel has launched SeaRay, a new data acquisition system specifically designed for redeployable, cost-effective four-component (4-C) seabed seismic acquisition in water depths down to 985 ft (300 m). An optional smaller and lighter cable has also been designed to permit full operational capability in water depths of less than 300 ft (91 m) where smaller and shallower draft vessels are commonly deployed.

The SeaRay data acquisition system is designed for redeployable, cost-effective 4-C seabed seismic acquisition in water depths down to 985 ft (300 m). (Image courtesy of Sercel)

A key feature of SeaRay is the integration of a single hydrophone with Sercel’s newly designed 428XL DSU3 (three-component Digital Sensor Unit) into one sensor package. This sensor unit is insensitive to tilt and provides excellent vector fidelity that is far superior to the gimbaled geophones that were frequently used in older systems. Each 4-C sensor is packaged inside a customized aluminum-bronze casting called a flatpack. The flatpack design provides sensor and wiring protection from the environment, including most handling systems, and provides superior mechanical coupling of the sensor to the seabed. Its flat profile and weight negates the potential to move or roll from its desired location once in-situ. The holes in the flatpack ensure excellent acoustic coupling of the hydrophone and provide a means of settling into soft sands and muds.

By use of MEMS (Micro Electro Mechanical System) sensor technology, SeaRay provides broader bandwidth, lower distortion and extended dynamic range compared with older systems. The low-frequency response of the sensor unit is much better than that of typical fixed or gimbaled geophone systems (resonant frequencies ~14 Hz or 10 Hz, respectively) and, hence, is ideally matched to the low-frequency requirements of many surveys that are being acquired for very deep objectives, for example, subsalt imaging in the Gulf of Mexico.