The process to design and deliver any monitoring system follows several well-defined phases: concept design and sensor selection; performance testing and verification of individual system components; detail design of the system architecture (mechanical and electrical); procurement, manufacturing and system assembly; and finally installation and commissioning. Quality control management and system documentation are common requirements throughout all phases.

This article uses a real-world design case to expound upon the needs and challenges encountered as project development progressed through all design phases. The monitoring architecture consists of a seabed broadband network servicing instrumented monitoring nodes. The primary mission for the system is leak detection, however secondary monitoring missions can be hosted using auxiliary access ports and the available power/data capacity. Although this monitoring network is implemented as an independent system, the site owner (a major energy company) required that the design be fully integrated in the design philosophy and technical requirements for a subsea modification project.

An interesting observation from this case study is that each of the phases have significant challenges, although these challenges do vary in nature and complexity through the phases. As the project progresses, choices made early on often gain increasing significance in later design processes. As an example, in this project the choice of the primary sensing technology later dictated requirements for installation height and verticality relative to seabed, which in turn affected design of the foundation solution for each installation. A second important observation is that a detailed strategy for developing and managing system documentation should be established at the concept phase, as the industry requires stringent and detailed documentation.

The case presented represents the complete design cycle, from initial concept development through final deployment. The experience from this process provides insight in the design process, as well as the technical and administrative challenges associated with developing an underwater monitoring network near offshore installations. This insight is useful for potential system designers, as well as for organizations considering implementing a dedicated scientific monitoring network on or near their infrastructure.

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