大水深掘削ライザーの技術課題と展望 ２，０００ｍ水深における掘削ライザーシステムの構築

Abstract

A joint study has been created for the development and the operation of a deep water drilling riser in Japan. For the realization of the project, innovative and advanced technologies are required. This paper provides a description of the project and its goals.The current world record of 2, 328m for deep water riser drilling was established in 1988 in the Gulf of Mexico. As only five wells have been drilled deeper than 2, 000m, riser drilling operations in these water depths cannot yet be considered an established technology.Four primary new research areas are required.The first is the development of a new deep water riser analysis program that will include the effects of liquid inside the riser and the vibration caused by vortex shedding.The second is a control optimization program using thrusters installed on the riser string. This will be effective for both the drilling mode and reentry mode. The program will account for and control, using both the riser and the vessel motions, helping to shorten operational downtime.The third is the research and development of new materials for the riser. Titanium, hybrid materials, and composites will be each studied to optimize the vesel and the drilling riser equipment.Fourth, for the safety of the operation personnel and the preservation of the vessel in extreme weather conditions, the concept of a near surface disconnectable riser system will be studied.The joint study, conducted by the Technology Research Center of the Japan National Oil Corporation, includes the Japan Drilling Company, Mitsui Engineering & Shipbuilding, and Mitsubishi Heavy Industries. The research and development will continue over a period of six years, with the ultimate goal of serving oil companies, drilling contractors, and related industries.