Tomoki Taniguchi

A Feasibility Study on Hybrid Use of Ocean Renewable Energy Resources Around Japan

This paper addressed assessing feasibility of hybrid use of ocean renewable energy, such as wave and wind energy around Japanese coast. At first, wave and wind energy theoretical potentials were calculated and, in the second step, correlation coefficient between wave and wind energy was computed around Japanese coast. Sea area suitable for hybrid use of ocean renewable energy resources is supposed to have high potential for some types of energy resources. Furthermore, correlation of power generation between wave and wind energy resources should be low because one energy resource needs to complement another one for stabilizing power generation.Based on the assumptions, feasibility of wind and wave energy was evaluated on some sea areas where R&D project are ongoing.Copyright

Experimental Evaluation of VIM on MPSO in Combined Environmental Conditions for Waves and Current

MPSO, mono-column hull type FPSO, is attracting the interest as a floating production system which has high performance for motion and large tank capacity in recent years.The authors had performed a mooring system safety evaluation of a MPSO named ‘MONOBR’ which was assumed to be installed at the Gulf of Mexico in the international collaborative research and development project between PETROBRAS and JOGMEC.There exists a strong current called the Loop current in the Gulf of Mexico. It is known that cylindrical floaters like SPARs or MPSOs sway with the long period and large amplitude in the transverse direction of the current. The motion is called Vortex Induced Motion (VIM), and is caused by vortex shedding from the sidewall of the floater. VIM is one of the important issues in the safety evaluation of mooring system of MPSO.Generally, the combined environmental conditions in which wind, waves and current exist are concerned for the safety evaluation of mooring systems. Therefore, it needs to estimate VIM in waves and current. The authors had performed the VIM measurement tests in order to investigate the estimation method of VIM in waves and current. The results of the VIM measurement test in waves and current and the results of the mooring safety evaluation method using the estimation method of VIM in waves and current are described in this paper.© 2012 ASME

Gas Explosion Analysis for FLNG Plant Layout Design

Recently, the natural gas is expected to be an environmentally friendlier energy and alternative to the nuclear energy. In the social situation, many oil and gas and engineering companies had studied FEEDs (Front End of Engineering Designs) of FLNG (LNG-FPSO) expected to be a new production system for offshore natural gas development in the near future. The FLNG system is no proven technology and there is no FLNG operation, which can make it difficult to design FLNG. Furthermore, it is noted that FLNG designers can’t get enough information for the design.Gas explosion is the technical problems for the topside facilities of FLNG. The objective of this paper is to study the gas explosion for the FLNG design.© 2012 ASME

Wind Effect Estimation in Side by Side Offloading Operation for FLNG and LNG Carrier Ships

Liquid Natural Gas resource development is often conducted worldwide. Recently the drilling area has gradually expanded from shallow sea area to the deep ocean. A Floating LNG facility (FLNG) and a LNG carrier ship (LNG) are assumed to operate in the open sea expected to wind, wave and current. In this situation, an operational capability evaluation of the LNG would be needed to grasp the operational weather limitation. The effect of each weather element, i.e. wind, wave and current, giving manoeuvring effect to ships, is expected to assess exactly as external loads. In such a situation, wind interaction effect under the operating condition that a FLNG and a LNG are in same closed area is not clearly understood. This paper treats and proposes one estimation method of wind load for the operation of side-by-side offloading including interaction effect of a FLNG and a LNG. The proposed wind load estimation method based on the wind tunnel experiments represents the shielding effect of the LNG behind the FLNG. Operational assessment on ship manoeuvring under strong wind is calculated using the proposed wind load method in the final stage.

Basic Design of a Semi-Submersible Rig for Experimental Drilling of Methane Hydrate by “Harmonic Design Tool”

For the growth of demand for utilization of the vast Japanese Economic Exclusive Zone (EEZ), Ministry of Land, Infrastructure, Transport and Tourism of Japan (MLIT) started the R&D project of offshore platform technologies in 2007. National Maritime Research Institute (NMRI) had developed the integrated design support tool, called “Harmonic design tool” for evaluating economical, safety and environmental aspects of the offshore platforms. The tool conducts conceptual design of offshore platforms for seafloor massive sulphides mining, experimental drilling of methane hydrate, combined application of food and energy production. Using the tool, basic design of semi-submersible rig type platform for experimental drilling of methane hydrate is carried out and optimum hull size, predicted steady environmental forces acting on the platform (current, wave, wind forces), thruster specification for Dynamic Positioning System (DPS) such as required thrust force, construction cost are estimated.The purpose of this paper is to evaluate the feasibility of proposed basic design of the platform aspects of stability and position keeping ability. From results of experiments and numerical calculation, it is confirmed that the basic design of the platform proposed by the “Harmonic design tool” is appropriate.Copyright