Page 53: of Marine Technology Magazine (November 2019)

Image: Trendsetter Vulcan Offshore

An artist’s rendering shows a typical tethered BOP installation.

The Wellhead Fatigue Mitigation System uses four anchors sequent time work is done on the well and then translate that to provide foundations for the tensioner units, tensioners that to fatigue damage, they’ll know exactly how they’re using up mount onto the anchors, connection points on the BOP, and a the fatigue life.”

BOP/riser monitoring system. The monitoring system com- The system has been used on multiple projects by a major prises SMART unit sensors mounted onto the BOP and lower operator since 2016, and Tamarind Resources recently con- riser, which measure acceleration and angular velocity and tracted TVO to provide its Wellhead Fatigue Mitigation Sys- transmit the data to a hydro-acoustic dunker deployed from tems offshore New Zealand.

the surface. The dunker is connected to a topside computer TVO is a team of engineers with deep experience in ? oating that uploads data to a cloud-based portal. The software pro- systems. Jim Maher, who was a spar product manager at Tech- vides analysis of the motions and translates it into accumu- nip for many years and was president at Horton Deepwater, lated fatigue for the well system. founded TVO.

Chell says the tethering technology also has the potential “If you know what you want to do, anybody can help you. to mitigate the effects of dynamic positioning (DP) drive-off/ If you have no idea what you want to do, we can usually help drift-off, and so is applicable for operators with a deepwater you ? gure that out,” Maher says. “For problems that have no semi or drillship on contract but also want to work in much apparent solutions, we develop the concept and then deliver.” shallower water. Tethering will reduce the bending associated Brown? eld needs are an interesting part of the Gulf of Mexi- with a DP drive-off event and extend the operability of DP co due to the aging of the ? oating systems, he says. As tieback vessels into shallower water. The tethering system will also technology improves, he expects operators to opt for subsea increase the watch circle and allow operators to work in more tiebacks when they can.

severe weather conditions, he adds. “What we’re getting involved in is ? eld development plan- “Some operators are also thinking about using this technol- ning and component delivery for the riser systems to come ogy for tethering, starting during the exploration phase,” he onboard existing facilities to provide some secondary recov- says. “If they monitor and tether from day one and every sub- ery,” Maher says.

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