Marine Environmental Protection

Research to Increase Efficiency of Offshore Resource Surveys

Gas hydrates discovered on the seabed at depths of 500m to 1000m hold promise as energy resources that may be used in the future. In conventional surveys, sediment core samples are collected for analysis above the sea surface. However, this compromises the accuracy of gas hydrate quantity estimates (since gas hydrates─which are formed in a seabed environment under conditions of low temperature and high pressure─decompose soon after being brought on board ship), and necessitates the expenditure of a large amount of time and money on surveying and analysis.

This research aims to develop a survey analyzer capable of direct measurement of the constituents and quantity of gas hydrates in situ, in the low temperature, high-pressure deep sea environment in which the gas hydrates exist.

The analyzer under development is for insertion into boreholes on the seabed, and utilizes Raman spectroscopy, which is an established onshore technique used for the analysis of organic matter. The object of the analyzer is to allow direct measurement of methane, ethane, and propane, etc., through the analysis of the inner wall of the borehole.