Expanding latch hanger mechanisms should recock when the string is picked up (if accidentally engaged in the BOP's etc.). All liner tools should have OD profiles that do not catch or snag on the inside of conventional BOP's, wellheads or casing connections.
The flowby area on all hangers should be maximised. Either on landed position or while running-in. The shape of the flowby area should resist plugging either with cuttings or with cement.
Wash ports, if required, should be located in the hanger running tool.
Effective seals must be incorporated into the running tool and tie-back tool. These should be in line with threads on the liner joints below.
Effective threads must be incorporated into the running tools and tie-back tools. These should be in line with threads on the liner joints below.
Full operation of running tools and tie-back tools should be accomplished with much less torque than what is required to back off a casing connection.
All internal components must be designed for H2S service.
No welding or plating will be used on the construction or repair of any component that will contain pressure or transfer axial loads or any component that is critical to the operation of the equipment.
Tie-back tools shall be designed for easy stabbing and make up, centralisers must be incorporated onto the tie-back tools SO that all seals and the threads are protected during stabbing.
All components shall be coated to prevent corrosion, in addition, active threads and metal to metal seal surfaces should be coated to prevent galling.