Periodical Investigations of Methane Plumes on Research Vessels with ROV onboard, sponsored and operated individually by a private company
Abstract
Since 2015, recovery techniques of methane hydrate have been considered and developed in Japan as a national policy. On the other hand, even though investigations of surface layer methane hydrate are being used as an indicator for naturally seeping methane plumes, expenses for researches and observations regarding its structure and seeping amount are not included in the budget by the government. This connects to the current situation of the number of related reports being so few. Understanding the details of naturally seeping methane plumes from in situ investigations is necessary in order to consider the resource utilization and the environmental impact.
Purpose The purpose of this study is to continue total and periodical observations on methane plumes, and report the details to the government and the people to gain an understanding of methane plume investigations and recovery techniques in order to undertake this project as our national policy. Method Perform 8 experiments using ROV and 6 experiments using acoustic instruments along with other devices onboard the research vessel In situ experiment at methane seeping sea areas using ROV Methane gas recovery with specially made gas collecting device Methane and nitrogen generation using specially made gas generating device and retrieval of acoustic data Acoustic observation of methane particles to examine the relation between plumes and seeps Acoustic observation of methane particles gushing from seeping points Observation of methane density using methane sensor Recovery experiment to examine the amount of naturally seeping methane particles Observation of phase changes of methane particles Measurement of methane density and hydrogen sulfide from water samples On-board experiments Relation between atmospheric methane density and underwater plumes using atmospheric methane sensor Methane plume observation using multibeam sonar Methane plume observation using scientific echosounder Water quality analysis with CTD Measurement of methane density and hydrogen sulfide from water samples Observation of stratum under seafloor (gas chimneys) using sub bottom profiler Result Consideration Investigations were performed from June 13 to 19, 2019 at Umitaka Spur in the Sea of Japan. Details of each experiment will be reported during the presentation at AGU. Acknowledgement I would like to express my gratitude to the crew members and the engineers of Kaiyomaru No. 1 and also, to Sekimosuke Shoten for the specially made experiment instruments.- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMOS51A..07A
- Keywords:
-
- 3002 Continental shelf and slope processes;
- MARINE GEOLOGY AND GEOPHYSICS;
- 3004 Gas and hydrate systems;
- MARINE GEOLOGY AND GEOPHYSICS;
- 3045 Seafloor morphology;
- geology;
- and geophysics;
- MARINE GEOLOGY AND GEOPHYSICS;
- 3050 Ocean observatories and experiments;
- MARINE GEOLOGY AND GEOPHYSICS