"Any HPHT stuff, because of the loads involved, you have to have so much metal in these things that it's just massive," Gibbs says.
The raw form for the main BOP body itself weighed in at 70,000 pounds, making it one of the largest pieces of equipment ever machined at the Cameron facility in Beziers, France.
"During manufacturing, the equipment they were making was very close to the limits of the machines they were making these things on," Shimonek says.
Cameron is working to develop a method that avoids the use of ﬂanges to connect the pieces of the BOP.
"We don't have a solution, but we'll get there," Gibbs says.
Drill pipe for high-pressure reservoirs is thicker, with a larger diameter, and often made of higher-grade material. The BOP must be able to cut that pipe, and the force needed increases in response to both the pipe but also the reservoir pressure itself.
"That's one of the biggest challenges," Gibbs says.
One deep but small well required heavy wall pipe with higher yield strength "than any pipe we'd ever seen before", Shimonek recalls. Typical yield strength is 105,000 psi yield, while the heavy wall pipe in question had 160,000 psi yield. The ram operators had to become very large.
Cameron increased the standard operating pressure from 3000 psi to 5000 psi. This change helped obtain the needed force. However, this higher force required some of the other components of the BOP to be redesigned to carry the higher loads. The trick then became balancing out the required shear force with the ultimate capacity of every component in the BOP.
Increasing the operating cylinder area, increasing the maximum operating pressure, and using higher strength materials enabled the company to accomplish the required increase in force.
"We had to come up with different ways to get a lot more force than we were used to," Shimonek says.