hi...
i got a problem on wellhead flowline model.
the wellhead is quite near to flowline compact manifold about 4-5 metres.i modelled from wellhead and anchored at the mating flange since compact manifold is under VENDOR skid. then, the output analysis shows the load at mating flange point is exceed the allowable load.i tried to do some 'try & error' on support location but the loads still exceeds.the rocking motion for wellhead is +155mm and -25mm.

the allowable load for compact manifold are:
Fx :500N
Fy : 5000N
Fz : 3500N

This is where the "engineering" and "experience" aspects of "pipe stress analysis" come into play. You will have to determine the reason for the overload, then modify your system to alleviate these loads.

There isn't anything "magical" you can do with the software to lower the flange loads.

hi,
regarding wellhead flowline, we can't re-route the system as space is limited.are there any suggestions?

If you're overloaded, something has to change.

To mizstress81,
As Richard Ay states, something has to change. Three categories for considering changes would be
1) stiffness of the piping and supports,
2) input loads, ie. wellhead "rocking", weight, thermal growth
3) allowable loads at compact manifold
The 4-5 meters between the wellhead and the compact manifold would usually allow some space for a flexible routing of the piping. If more pipe length is needed for an expansion loop, consider running the piping past the compact manifold and then double back to the connection on compact manifold. Use vertical space also, if available, for expansion loop. Straight routing of pipe may look clean, but it is not flexible! The supports and locations must carry weight loads AND restrain movements (guide, stop) to limit forces to the compact manifold. If the piping is "anchored at the mating flange" then any piping flexibility of skid piping is not taken advantage for system analysis. Last resort for adding flexibilty to piping would insert a flexible joint between wellhead and the compact manifold. The design pressure required may exceed the capability of common flexible joints. The piping supports design with the flexible joint would need to be engineered by an experienced user. There would be continuing safety and maintenance concerns with any flexible joint in wellhead service.
The input load of wellhead "rocking" of 155 mm x -25 mm needs a reality check. Is this from wave-induced motion? Is restraining the wellhead permitted? The structural base of skid might be connected to wellhead structure to have both move together. Differential movements would then be reduced.
The allowable loads for compact manifold might need to be increased by strengthened design from the vendor. The FX allowable is particularly small. (The allowables are more reasonable than some TEMA heat exchangers with ridiculous zero allowable loads.) Perhaps the skid connection could be made more flexible on the vendor side of his piping design and supports. More likely, robust supports on a heavier construction compact manifold would result in larger allowables for your benefit. This would be a matter of cost.