Wellhead Support Frame

The most recent addition in the toolbox to combat wellhead fatigue is the “Wellhead Support Frame”. The device is intended for temporary use to divert a major part of the loads inflicted to the well around the wellhead, and therefore will substantially increase the fatigue life of the well.

At the end of the drilling phase the frame is removed and therefore does not provide limitations for other equipment like X-mas Trees and the like.

  • The technology is available for both, exploration and production wells as well as for “old and tired” wells that are supposed to be plugged and abandoned

  • The frame can be installed by a crane vessel or rig

    • Total weight is around 20 mT

    • Connection of wellhead connector to wellhead by work ROV

    • Connection of frame to CAN unit by work ROV

H4 mandrel

Adaptor flange

Wellhead connector

Frame

CAN

Connection struts

The “Wellhead Support Frame” consists of the following main parts:

  • Core
    • Wellhead connector that connects to the HPWHH of the well
    • Adaptor flange

    • H4 mandrel

  • Frame
    • Steel structure that connects rigidly to the core
    • One may describe the locking between the frame and the core as “rigid lockdown” around the wellhead
      • Together with a “rigid lockdown” between LPWHH and HPWHH a solid load path AROUND the wellhead is established
  • Connection struts

    • The struts complete the load path from the core, via the frame, through the struts directly into the CAN

Proven technology applied:

Proven technology applied:

  • Key strategy is to use main parts with a long track record

  • The wellhead connector and the H4 mandrel are provided by Baker Hughes

    • Both parts are in stock at Baker Hughes, Stavanger area

    • Baker receives the adaptor flange from Neodrill, assembles and tests the core before the assembly is returned to Neodrill for integration into the frame

    • The testing includes pressure and seal tests up to required standard in 5k, 10k or 15k according to customer requirements

  • The foundation provided by the CAN has been proven in more than 2 dozen applications

    • Multiple units for production and exploration wells are in stock at Neodrill, Stavanger area

  • The adaptor flange, frame and connection struts are developments of Neodrill

    • Delivery time for engineering adaption, manufacturing, assembly and testing is currently about one year

Consequences for fatigue life

  • It is well known that fatigue life is highly non-linear, a small increase in loads/stresses can result in unproportionally high loss of fatigue life

  • Applying the “Wellhead Support Frame” utilizes this non-linear behavior to our advantage

  • Assuming a conservative load reduction of 50% the benefit for the fatigue life is improved as shown in the table below

PART

Welds, typically between housing and extension

Base material, typically conductor pipe

High grade base material, typically forgings like LP/HPWHH

S/N slop

 

 

 

3

5

6

Original Fatigue Life (nominal)

 

1

1

1

Improved Fatigue Life

(factor of improvement)

8

32

64

Neodrill AS
post@neodrill.com

+47 51 94 59 00

Kanalsletta 4
4033 Stavanger
Norway

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