Offshore/subsea systems

Subsea Technology

Subsea processing is a significant technology that presents and will continue to bring many challenges and opportunities to the industry.

Subsea processing is an enabling technology for deepwater-oilfield development. The primary technologies of interest are fluid separation and pumping. There are also many supporting technologies that must be targeted toward subsea processing, such as flow assurance, controls, power distribution, performance monitoring, maintenance and repair, high-integrity pipeline-protection systems, and high-pressure/high-temperature technology. Subsea processing is a significant technology that presents and will continue to bring many challenges and opportunities to the industry.

Can we safely and economically move traditional field-processing equipment from the surface to the ocean floor? There is a strong incentive to eliminate (or greatly reduce the size of) surface-supported processing facilities; they are expensive and heavy, they can certainly be the long-lead item on a schedule, and they are susceptible to environmental (weather) effects that will affect operations. The biggest advantage to surface processing equipment is that “I can walk up to it and touch it.” Is that advantage worth the cost? This is the starting point for considering subsea processing.

We can compare the development of subsea-processing technologies with that of the more-traditional technologies such as subsea drilling and subsea completions. With 40 years of history, the industry has become comfortable enough with subsea drilling and completions that these technologies have become comparatively standardized, routine, and predictable. The equipment designs for subsea wells, trees, manifolds, and distribution systems have matured, which has reduced the perceived and real risks of subsea field development. This, in turn, has allowed asset owners to forecast development cost more predictably and accurately, which has encouraged subsea investment. We have all heard the lament, “I could sure use that technology, but I cannot take the risk of being the first one to use it.”  Risk reduction has been the key to success for subsea completions. Risk reduction has largely occurred over time by the increasing number of installations, which has led to design improvements through installation and operational lessons learned. The engineering challenge before us is to reduce, mitigate, and eliminate the risks associated with the new technologies. This allows asset owners to justify the incorporation of the new technologies of subsea processing into their projects. The risk categories that must be addressed successfully are safety, quality, and commercial success.

There have been some great successes, some of which are discussed in the following papers. However, there are still many things to be learned. The next generation of engineers will face exciting challenges in bringing these technologies to the market and maturing them to a level of acceptance that we now realize with subsea-completion technologies. I envision that subsea processing will serve as a springboard for new enabling technologies that have yet to even be considered. It will certainly be interesting to watch the continued development and maturing of subsea processing and the associated technologies.

This Month's Technical Papers

Reassessment of Multiphase Pumps for Marginal-Field Development

Subsea Processing and Boosting in Brazil: Future Vision

Qualification of a Subsea Separator With Online Desanding Capability

Recommended Additional Reading

OTC 24307 Steps to the Subsea Factory by O. Økland, Statoil, et al.

OTC 25009 The Future of Electric Controls: Trees and Subsea Processing by Carsten Mahler, OneSubsea, et al.

OTC 25171 Investigation of Next-Generation Subsea Power-Distribution-System Architectures by Yao Duan, FMC Technologies, et al.

Tom Kelly, SPE, is a technical manager for the Western Region Systems Engineering group at FMC Technologies in Houston.  He has been with FMC for 10 years and has worked 40 years in the subsea-equipment industry, designing subsea trees and subsea systems. Kelly holds a bachelor’s degree in mechanical engineering from Texas A&M University. He has been an active member of SPE since 2003 and the American Society of Mechanical Engineers (ASME) since 1977. Kelly has served on the Offshore Technology Conference (OTC)/ASME program subcommittee, which he chaired before accepting a 1-year term as chairperson for the OTC Program Committee in 2005. He holds four patents relating to subsea-equipment designs and has authored or coauthored several OTC papers relating to subsea technology. Kelly remains active in the industry, with continued service to the OTC/ASME program subcommittee, and he serves on the JPT Editorial Committee. Kelly has been a registered professional engineer in Texas since 1982.