Ship-Based Exploration of Submarine Gas Hydrates and Environmental Monitoring with Multibeam Echo Sounders

摘要

Submarine gas hydrate deposits exist in almost all continental slopes. However, the dimensions and storage conditions of these deposits are insufficiently documented. Economically interesting deposits are often associated with gas flares in the water column which can be detected by multibeam echo sounders. During the production of methane and a possible future long-term storage of carbon dioxide in the deposits, ship-based multibeam techniques are also important for environmental monitoring and site safety verification. Developed as a result of the German research project SUGAR (Submarine Gas Hydrate Reservoirs), the ELAC SeaBeam 3030/3050 multibeam echo sounders provide a wide functional scope for the identification of gas flares: The online visualization of high-resolution water column image (WCI) data, automatic object detection, frequency-modulated signals and an automatic cyclical steering of the transmitted swaths during stationary vessel operations are very helpful to detect gas flares. ELAC SeaBeam 3050 systems have been successfully applied on scientific cruises regarding the detection of submarine gas hydrates, the analysis of gas flares caused by volcanic gas discharge and the investigation of abandoned drilling wells.