Riser Hang Off Collar is a core load-bearing component for riser systems in deepwater oil and gas development. It serves as the critical load-bearing connector linking subsea wellheads to offshore platforms (or Floating Production Storage and Offloading units, FPSOs), playing a pivotal role in ensuring the safety of drilling and production operations.
Core Functions
Load-Bearing Suspension: As its primary function, the collar reliably supports the massive axial weight of the entire riser string and transfers this load to load-bearing structures such as the offshore platform deck or the riser deck of floating units. This prevents the riser from sinking or shifting due to its own weight and the weight of transported media inside.
Auxiliary Protection: In extreme sea conditions, it enables emergency suspension of the riser when integrated with the riser hang-off system. For instance, if a typhoon approaches and there is insufficient time to retrieve hundreds of riser joints back to the deck, the collar can suspend the riser string, allowing the drilling platform to quickly move away from the typhoon path. Simultaneously, it reduces additional stress damage to the riser caused by ocean currents and platform heave. Additionally, some models assist in riser alignment to ensure precision in subsequent operations.
Structural & Operational Features
Structural Design: Most collars adopt a split-type or integral ring-shaped forged steel structure. This design accommodates the outer diameter of the riser, facilitating easy installation and disassembly, while the steel material meets the strength requirements of deep-sea environments with high pressure and severe corrosion. Certain products are also equipped with sealing components to minimize erosion of the connection area by seawater and other media.
Operational Compatibility: It is often used in conjunction with structures like riser guide tubes, transferring riser tension to load-bearing structures via dedicated interfaces. During installation, the split-type collar structure allows for dry-installation suspension and fixation of the riser, minimizing the need for diver intervention and adapting to the unique conditions of deepwater operations.
Typical Application Scenarios
The riser hang-off collar is widely used in oil and gas development projects across various water depths globally, with particular suitability for deepwater and ultra-deepwater drilling, as well as floating production systems. For example: In deepwater drilling operations in typhoon-prone sea areas such as the South China Sea, it is a key component of the riser emergency protection system.
On the riser deck of FPSOs, it is commonly used to suspend and fix steel risers, ensuring stable oil and gas transportation.
