Naomi Kato

Autonomous Spilled Oil and Gas Tracking Buoy System and Application to Marine Disaster Prevention System: Part 1

This paper describes the ongoing project on autonomous spilled oil and gas tracking buoy system and application to marine disaster prevention system for 5 years since FY2011. Objectives of this project are as (1)autonomous tracking and monitoring of spilled plumes of oil and gas from subsea production facilities by an underwater buoy robot, (2)autonomous tracking of spilled oil on the sea surface and transmission of useful data to a land station through satellites in real time by multiple floating buoy robots, (3)improvement of the accuracy of simulations for predicting diffusion and drifting of spilled oil and gas by incorporating the real-time data from these robots. To realize (1) and (2) objectives, we have developed an autonomous underwater robot named SOTAB-I, and an autonomous surface vehicle named SOTAB-II. To realize (3) objective, Data fusion methods in the simulation models incorporating real time measured data not only from a SOTAB-I for gas and oil blowouts, but also from multiple SOTAB-IIs for spilled oil drifting on sea surface were developed.

Spilled Oil Tracking Autonomous Buoy

We are developing Spilled Oil Tracking Autonomous Buoy System (SOTABS), which is composed of a land base and several spilled oil tracking autonomous buoys (SOTAB), to detect and track spilled oil autonomously, sending real time data around them to the land base. This paper firstly deals with steady sailing performance of SOTAB-II with a sailboat shape for tracking spilled oil on the sea surface by controlling the rudder angle, and the area and direction of the sail, and then sea trials using a model of SOTAB-II with a cylindrical buoy shape to obtain its fundamental characteristics on motion.

Development of Spilled Oil and Gas Tracking and Monitoring Autonomous Buoy System and its Application to Marine Disaster Prevention

In this paper, the recent developments in the ongoing project on spilled oil and gas tracking autonomous buoy system and its application to marine disaster prevention system are described. The objectives of the project mainly consist of (1) autonomous tracking and monitoring of spilled plumes of oil and gas from sub-sea production facilities, (2) autonomous tracking of spilled oil on the sea surface and transmission of useful data to a land station through satellites in real time, (3) improvement of the accuracy of real-time simulations as well as prediction of the diffusion and drifting of spilled oil and gas.

Effect of Liquid-Gas Interaction on Plume Structure in Blowout Flow

Multiphase flow simulation for oil and gas blowout in water is performed to investigate the effect of liquid-gas interaction on the plume structure. The mass and momentum balance equations were solved for each phase, and the interactions were considered with the Euler-Euler approach. To consider the interphase interaction between two dispersed phases in the oil-gas-water three-phase system, we applied the drag force between oil and gas in the momentum equation. A series of numerical results showed that the interaction between the two dispersed phases affected the velocity distribution of the gas and oil phases in the multiphase plume. These results suggested that the gas-oil interaction might affect the traveling time of gas and oil in an actual marine environment.

Depth Control of AUV Using a Buoyancy Control Device

A new method for depth control was developed for a spilled oil and blow out gas tracking autonomous buoy robot called SOTAB-I by adjusting its buoyancy control device. It is aimed to work for any target depth. The new method relies on buoyancy variation model with depth that was established based on experimental data. The depth controller was verified at sea experiments in Toyama bay in Japan and showed good performance. The method could further be adapted to altitude control by combining the altitude data measured from bottom tracking through a progressive depth control. The method was verified by a simulating program and showed that the algorithm succeeded to bring the robot to the target altitude.

Construction of Guidance and Control System and GUI of an Autonomous Underwater Robot SOTAB-I

Abstract Heavy disasters of oil spill bring enormous damage on the ocean environment as well as regional economies. To know when, where and how much the spilled oil and gas float up on the sea surface, and where the floating oil on the sea surface drift ashore, we need information of advection, diffusion and dispersion of underwater oil and gas, and its prediction. This paper describes the guidance and control system and GUI of the underwater robot SOTAB-I (SOTAB; Spilled Oil Tracking Autonomous Buoy) that tracks spilled oil autonomously and gathers oceanographic data.