Overview

Designed to work with Transition Zone (TZ), Ocean Bottom Cable (OBC) and Dragged Ocean Bottom Cable seismic systems, this system from Sonardyne significantly improves the speed, accuracy and efficiency of positioning marine seismic cables. By using a multimode network of transponders, more accurate hydrophone positions (1-2 metres absolute) can be derived than with traditional ‘first break’ techniques.

Features & Benefits

Acoustic capacity to position 3600 unique hydrophone ground stations in real-time

No connection to the seismic cable required

Uses low cost transponders

Operational in 1 to 500 metres water depth

Transponder Options

The transponders developed for the system are small and lightweight and have been proven to be able to withstand the demanding and varied operational environment of OBC and TZ surveys.

Standard features of the Type 7815 transponder include a depth rating of 500 metres, a unique acoustic ‘address’ enabling thousands of units to be laid in a single deployment and automatic battery voltage monitoring to allow users to better plan their maintenance schedules.

The Lightweight Release Transponder (LRT) is a low cost positioning transponder that when used in conjunction with a rope canister, can assist with the recovery of the seismic cable. By mooring the transponder to the end of the cable, then commanding it to ‘release’ the transponder returns to the surface under positive buoyancy, leaving one end of the rope still attached to the bottom cable.

Software

HydroPos Seismic is the PC software that controls Sonardyne’s OBC/TZ positioning system. The application monitors, time tags and logs raw data received from the vessel’s surface navigation systems (GPS, Gyro etc) and the acoustic transceiver to provide the user with real-time positioning of the transponders as deployed on the ground stations/receivers.

All raw and processed data is stored in a single file to allow easy archiving and transfer of all survey data. In addition, the application enables post processing of all the raw data to enable improved position computation and quality analysis. Various industry standard reports are provided for export from the application.