Extend wellhead fatigue life
Updated: Mar 16, 2021
CAN technology provides a reliable wellhead foundation with radically improved stability compared to conventional wellheads.
Due to fatigue related issues, the wellhead system is widely recognized as the “weak link” in conventional well design. To meet the new 2021 NORSOK standards, it is imperative for operators to take steps to protect and extend wellhead fatigue life.
Protecting the wellhead during installation
With DP operated deep-water drilling rigs increasingly being used on shallow water wells, there is an underlying threat of “drift off” as well as a reduction in fatigue life of the wellhead. During drilling, the forces and bending moments placed on wellhead can be critical and cause damage, both in terms of fatigue and structural limits.
The CAN-WSS (Wellhead Saver System) is designed to mitigate these risks by re-directing the bending forces from the BOP directly to the well foundation (CAN). It protects the wellhead, including associated welds and extension pipes from over-bending and over-stressing, resulting in extended fatigue life.
While installed, the CAN overcomes fatigue issues with less, or no risk, of fatigue issues; and removes the risk of reduced operations time, which can occur due to fatigue.
Addressing wellhead fatigue
Once installed, CAN technology continues to protect the wellhead and deliver a reliable well foundation with radically improved stability compared to conventional wellheads. In the 28 projects carried out to date, CAN has a proven inclination of < 1 deg.
As intermediate between the well construction and the soil, CAN technology removes uncertainties like top of cement, cement quality, and point of fixity. This results in more reliable fatigue modelling which decreases risk and improves overall fatigue life.
The CAN has also enabled jetting in conductors in Norwegian Sea soil conditions. Here, soft seabed soil conditions may rapidly increase in strength to firm, non-jettable clays, thus stopping further conductor penetration. The verified load capacity of the CAN allows us to safely shorten the length of the jetted conductor.
How CAN compares to conventional wellheads
CAN technology offers a smarter well foundation for both exploration and production wells.