Page 82: of Offshore Engineer Magazine (May/Jun 2015)

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that is available in stackable parts, interface capacity, and network- describing the technology at the ing capabilities.

Marine Construction Europe - Aker’s new electronic drive

Deepwater Development confer- unit is 85cm-high, and can be

Subsea ence in London in March. mounted either horizontally or

Explaining the virtues of Vectus vertically. The unit has an API controls, Larssen said they rep- class 4 standard interface, modu- resent a next-generation subsea lar design, and it can be installed control system, offering a number in up to 4000m (13,120ft) of benefts: Less deployment effort water depth, with up to 2700 and risk, through planning and Nm (Newton metres of torque) confguration tools, and modular maximum torque available. A architecture. subsea gearbox on the unit has

Aker Vectus control system pulled from Larssen MCE DD

Enhanced operational features an API rating from class 7 to 20154 presentation; NB low resolution. Image from Aker Solutions.

include subsea electronics module class 4, suitable for ball valves, (SEM) and maintenance, and advanced performance is provided, Larssen from 2-20in; in a 7in and 3/8in latched condition monitoring systems. Improved says, through better processing power, confguration for use on Xmas trees; in production uptime via planned equip- hence avoiding unplanned shutdown. a step improvement in proactive manage- ment replacement. Three key perfor- DCV operations can also be used in fuid ment of control system health and aim mance indicators are discussed below leakage analysis. to increase uptime by predicting failure including hydraulic pump performance, Combining pump performance with and planning mitigation. A condition subsea control valve utilization and DCV utilization, it is possible to begin monitoring approach also improves the digital communications effciency to identifying imbalances between the understanding of operational perfor- demonstrate the benefts of condition hydraulic fuid demand and supply. Each mance and practices and serves as a monitoring. DCV controlled actuator is designed valuable input in future design of new or

The hydraulic system, from the to consume a fxed volume of hydrau- retroft systems.  hydraulic fuid pumps topside to the lic fuid during each operation cycle. directional control valves (DCVs) subsea, The pump runtime can be converted Claire Zhao is a forms the cardiovascular system of a to hydraulic fuid volume output. The senior engineer at production system. The pumps are the imbalance is thus determined by compar- Clarus Subsea heart of the hydraulic system and are the ing the total volume output by the pumps Integrity Inc., with source of the fuid supply. Frequency and to the total volume consumed by the four years of experi- duration of pump operation to maintain valves. Such imbalance may indicate a ence in risk based required pressure are indicators of system leakage in the system. If additional fow integrity manage- performance. An operational norm can be information can be made available in the ment, non-destructive established by trending pump runtimes hydraulic system, such as on the hydrau- evaluation techniques and riser engineer- and cycles over a period of time. An lic distribution systems, the location of ing. Her project experience includes increasing trend of pump usage translates leakage may be narrowed by performing working with major operators in the Gulf to a growing demand for hydraulic fuid localized mass balance within distribu- of Mexico providing integrity management downstream. With no signifcant changes tion system branches. support and solutions. She holds an M.S. to system confguration, such as startup If the hydraulic system is symbolic in structural analysis of monuments and of additional wells, a leakage in the sys- of the cardiovascular system, then the historical constructions and a BS in civil tem can be a logical conclusion requiring digital communication system repre- engineering. further investigation. sents the production nervous system. As

The DCVs and their companion systems age, response time to commands Dharmik Vadel is a actuators are on the opposite end of the typically increases, commonly referred vice president at hydraulic system. Similar to muscles in to as “sluggish control response.” This Clarus Subsea the body requiring blood to function, is often misdiagnosed as a software Integrity Inc. He the DCVs are the consumers of hydrau- issue, whereas in reality it is due to co-manages techni- lic fuid. Wear on the DCVs is known to decreasing effciency in the electrical/ cal and commercial cause hydraulic fuid leakage over time. optical components. Success and failure areas of Clarus, a

As there are no remediation methods to execute a command from topside are recent spin off from available, they are operated until leak- recorded as success and error messages. 2H Offshore. In his 10 years of service, age rates reach critical levels and the Communication effciency is determined Dharmik has managed multi-platform hydraulic system can no longer provide by dividing the number of successful SURF integrity management projects and suffcient pressure to actuate valves. The messages by total messages recorded. focused on delivering integrity engineer- entire subsea control module (SCM) is Moreover, the degradation rate can be ing solutions. Vadel holds an MS in then replaced. By trending the accumu- used to predict noncompliance with the environmental engineering from lated DCV operation cycles over time, the emergency shutdown response window Oklahoma State University and a wear out date can be estimated allow- based on data trends. bachelor’s degree in civil engineering ing advanced planning for replacement These monitoring algorithms serve as from REC Calicut India.

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