In the North Sea’s turbulent offshore environment, TotalEnergies needed a connection that would deliver beyond standard reliability for its project. Vallourec proposed its new VAM® SLIJ-3 semi-flush connection, designed to tolerate critical loads for offshore use.
Looking to expand and improve operations in the North Sea, energy supplier TotalEnergies prepared for further rigorous conditions in the offshore region. Faced with temperatures of up to 215°C, the energy major also saw the possibility of mud permeating the formation during the drilling phase of the well. This permeation results in gas leakage from the formation. TotalEnergies thus required a gas-tight, heat-resistant connection, with robust drilling capabilities in the event of these mud losses and necessary sealability performances inside and outside of the casing. They thus turned to Vallourec for a solution meeting all of these requirements.
Asking for external gas tightness was a truly unique request. The formation TotalEnergies would be drilling through was much like white chalk in terms of makeup, so the drilling pressure is very near to the pressure at which the rock starts to be permeated. If the pressure is even slightly more than it should be, there will be mud losses.
Vallourec first introduced VAM® SLIJ-3 to TotalEnergies in 2017, providing details on the new connection and its increased performance rating in comparison to their earlier model, VAM® SLIJ-II. Over time, information was exchanged with regards to the development of this new connection. TotalEnergies, who were aware of the very real possibility of mud permeation and gas release, saw VAM® SLIJ-3 as a suitable connection for this application.
Representing the latest generation in a legacy of reliability, VAM® SLIJ-3 inherits the advanced thread design of industry standby connection VAM® SLIJ-II. For superior performance in ultra-deep offshore environments, it is equipped with higher torque capacity, a metal-to-metal seal for internal and external pressure resistance and increased compression and tension capabilities.
Put to the test
To verify performance quality, Vallourec worked with TotalEnergies to devise a testing protocol that would simulate the demands that VAM® SLIJ-3 would come up against in the North Sea. TotalEnergies needed to see that the connection would be externally gas-tight. The challenge here is that any external pressure is generally never done with the medium of gas, but with fluid, which is less susceptible to leakage than gas.
The research and development (R&D) team at the Vallourec Research Center in Aulnoye-Aymeries, France, collaborated with TotalEnergies to create a test specifically encompassing these variables. The physical testing was witnessed by the TotalEnergies Drilling Engineer heading the project, Vallourec engineers and a Third Party Inspector representative from TotalEnergies. Two steps of the test took place within the R&D facility: one at 195° C, the other at 215° C.
VAM®
SLIJ-3 successfully met the requirements of the testing protocol. This process was a genuine joint effort in which the customer was actively involved. Both parties share equal pride in the successful results.
Coming out on top
With an outstanding story behind its first delivery in the North Sea, VAM® SLIJ-3 has now exceeded its abilities as the highest-performance semi-flush casing connection to date. Application of the connection in other regions, such as the Gulf of Mexico, where more than 45,000 joints have been successfully installed, speaks to global circulation to come.