炭素繊維強化プラスチックを用いた深海掘削用軽量マリンライザーの検討

抄録

The marine riser with carbon fiber reinforced plastics (CFRP) is under developing for deepwater drilling, especially for deep sea drilling vessel CHIKYU owned and operated by Japan Agency for Marine-Earth Science and Technology (JAMSTEC). Previous steel riser is so heavy that water depth for drilling with CHIKYU is limited up to 2,500 m, which is far below CHIKYU's final water depth goal for drilling, 4,000 m. Therefore, new marine riser with much lighter material is required and CFRP is the best candidate. Moreover, high stiffness is requreid for riser materials due to prevent large vibration even in case of storm condition. To fulfill this requirement, pitch-based carbon fiber is more desirable because of its higher stiffness coming from higher graphitization. Our early stage of case study shows that water depth over 4,000 m can be achieved with pitch-based CFRP riser. Present assignments and recent developing program is also discussed briefly.