Deep-ocean mining R&D took a direct approach to the development of deep-ocean systems and technology at the 6,000-m ocean depth with an equivalently long pipe, bypassing the offshore industry's step-by-step approach to going deeper from a short pipe. Such a fresh approach — with some risk — led this R&D to its success. Some of the experiences (among those published) from the deep-ocean tests and research with a long pipe deployed from a ship provided benefit and confidence to the offshore industry's endeavor of going deeper. When going deeper with a longer pipe, the varying surface-to-oceanfloor physical environmental properties play a larger role in the coupled ship-pipe-equipment dynamics and behavior, thrust power and integrated ship-pipe control. While now going to deeper water with a longer pipe, some technical issues appear to have been overlooked. Some of the associated critical issues and design/operational parameters as the industry goes from deep to still deeper with shorter pipe and associated longer pipes are discussed.
In the past 40 years the offshore petroleum industry has taken a stepby- step approach to its technology and system development and operation from deep to deeper water: a lower-risk approach. It has been guessing and identifying and learning many unknowns while going deeper and deeper with a longer riser or pipe. In meeting the new challenges, it has been coming up with innovative engineering concepts and solutions for design, installation and operations, although taking much longer time. For the deep-ocean mining R&D at the 6,000-m ocean depth in the 1970s, the development teams of the advanced commercial deep-ocean mining systems and technology had to take the approach of starting the technology and system development directly from the deep ocean depth. Cost and time were the key factors.