hi moverz & sha,

In my last reply, i had mentioned that the sea water depth in our project is 40 meters and this will not cause such a huge thermal displacement.

i am sorry, I forgot that the oil rock will be far deeper from the sea bed. and the production pipe will be of 600 meters or more in length. now it sounds little bit clear to me. then, i collected some sketches which have given me more details.

In the attached sketch for well head arrangement, the conductor is of several pieces with varying dia & legth. these pieces are cemented with the sea bed wall. It shows how these pieces will act as a spring like moverz has told before.

And in the sketch no.2 of jacket assembly, it can be seen that the conductor will have only guides above the sea bed (there is no rest point with steel plate in the structure. the conductor & production pipe is rested with cementing in sea bed only). so the spring action (up & down)will be transfered to the whole assembly including christmas tree which will have further effect on connected pipe line too.

it can be seen clearly in the 3rd sketch for christmas tree. hope now it is more clear regarding how the displacement occurs.

Now, i need a help from you all. Can anyone clarify if a spring support at first support location is mandatory to absord this displacement?
or shall i make no rest support arrangement as the attached isometrics in my previous reply shows? (in this case, i have given no rest supports. i have taken both the connecting ends to well head and manifold as anchors. And a Cnode at the well head end anchor with displacement +-50mm. in the result of analysis, my sagging is less than 6mm and the terminal loads are within limit. in the isometrics you can see the support arrangement is with a gap below pipe. the support wnt rest during operation. only when dismantled during maintenance, it will be rested in the support).

have anyone done such a arrangement before? can anyone provide me a suggestion? i need you people's openion in this regard please.