Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Mobile detection system for submarine gas hydrate seepage area
Wei Wang, XueYu Ren, Xiaoqing Peng, JiaWang Chen*, Jin Guo, Ying Wang
Ocean college, Zhejiang University, Zhoushan, China
Zhoushan, ZheJiang, China

convenient mobile detection (Tryon, MD, 1999). At present, there arefew researches on mobile detection platforms that can be used on theseabed. Therefore, the development of a mobile detection platform
equipped with various sensors such as methane, carbon dioxide,dissolved oxygen, temperature and salt depth, and fidelity samplingsystem and testing technology for the seawater-sediment interface, indepth understanding of regional methane seepage flux and its impact on
the ocean The environmental impact mechanism can make up for theblank of ocean exploration technology and provide important support
for cold spring research and environmental monitoring of hydrate trial
mining (Leifera, I, 2005).

ABSTRACTA mobile seabed detecting system for the seawater-sediment interface
is developed and introduced in this paper, which can conduct mobile
monitoring and on-site sampling, and realize chemical analysis of thefluid in submarine methane leakage areas. The functions of the mobile
detecting system are verified by a sets of laboratory tests, which canconduct in-situ detecting and sampling (pore water and sediment) under
4500 m water depth. The proposed detecting platform can provide
important technical support for evaluating and detecting theenvironmental impacts of the methane leakage area and cold seeps.

System composition of mobile platform

KEY WORDS: seawater-sediment interface; Mobile detection
platform; low perturbation sampling; Environmental monitoring.

The mobile platform consists of a power system, a monitoring system,a control system, and a sampling system. Power is provided byhydraulic means, and 8 hydraulic thrusters are arranged in vector,
which can flexibly adjust the attitude. The buoyancy of the platform
can be adjusted according to the task performed and the weight of theequipment on board. At the same time, a very rich interface is reserved
for the electronic cabin, user interface box and hydraulic system for theexpansion and optimization of subsequent functions. The monitoring
system is mainly composed of cameras, LED lights, compass, depth
gauge, altimeter and various sensors on board. The control system
consists of a host computer and a hydraulic actuator. The host computer
is connected to the electronic cabin of the mobile platform through an
optical transceiver and a photoelectric composite cable to control thesampling and detection of the platform. The sampling system is mainlycomposed of a manipulator and a sediment sampler, a pore water
sampler and a bottom water sampler.

INTRODUCTION
Methane seepage is closely related to gas hydrate resources and cancause complex ecological effects (Phrampus, BJ, 2012). It has
important resource and environmental research significance. As thegate for methane seepage to the ocean, the seawater-sediment interface
is the area where the physical, chemical and biological characteristicsof the ocean change the most. The rising methane undergoes a series ofbiogeochemical reactions at this interface, which significantly changes
the marine environment (Michaelis, W,2002). The interface is thebest carrier for methane seepage research. International research on
methane seepage on this interface is mainly based on fixed-point longterm monitoring (Santschi, P, 1990), but the detection of regional
methane seepage is relatively blank (Feng, D, 2018). The reason is thatthe mobile detection and high-fidelity sampling technology of thisinterface are relatively scarce, and the related fluid testing technology It
is also relatively weak, which limits the in-depth study of the evolutionof the geological environment system in the methane seepage area(Himmler, T, 2013). The earliest mobile underwater detection platform
developed in the world is the Detroit Rover of the United States, which
can last up to 6 months under the sea (Faure, K,2010). The Phoenix
mobile detection platform developed by Japan has a diving depth of upto 8178m (Liang, Q, 2017). Compared with the current ROV system,
the underwater mobile detection platform can realize flexible and983