The subsea oil and gas industry strives at having systems which last for the entire service life of a field without needing intervention. Consequently, a high level of reliability, among other things, is a prerequisite. Thus, the equipment supplier must assure that the reliability of their products is sufficiently high. For achieving highly reliable equipment comprehensive design, manufacturing, testing, installation and maintenance policies are required, because reliability calculations alone cannot deliver reliable equipment.
Industry uses a myriad of methods to design out all possible faults and provide the evidence required for the reliability assurance (Yasseri, 2015). The focus of this paper is on outlining a framework to achieve highly reliable subsea production equipment. The paper takes the full advantage of model-based systems engineering and describes methods to design out of system's vulnerabilities.
The subsea industry aims for "Quality by design" which means designing the production system at development stage to consistently ensure a predefined quality at every stage of the system lifecycle. Various industry codes assure that quality is built into the production system, implying that testing alone cannot be relied on to ensure a facility's availability. Systems engineering can provide the necessary framework for implementing quality by design, continuous improvement, and risk management.
Systems engineering approach to equipment & systems qualifications includes:
Design qualification/review
Acquisition
Vendor/contractor selection
Monitoring and control; through Master Project Plan
It is the responsibility of the designer, construction manager and systems engineers to ensure that all "agreed" design requirements are met during:
Installation,
Start-up and commissioning,
Qualification and routine monitoring.
There are a few industry codes, e.g. DNV-RP-A203, API-RP-17 N and Q, which recommend processes termed the "Technology Qualification Program", (TQP), for the qualification of the subsea systems. The process of the Technology Qualification (TQ) is similar in all these publications. As referenced in API 17A, the specific term "Technology Qualification" is defined in DNV-RP-A203:2011 (Section:2.1.): Technology qualification is the process of providing the evidence that a technology will function within specified operational limits with an acceptable level of confidence.
