I contacted SLB support and they didn't give me any valuable answer that resolve my case:
These are the answers given by SLB:
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Answer 1 :
Hello,

It should be OK, as the WBP's is calculating your average reservoir pressure in the drainage area which should more
then your bottom hole pressure (WBHP).

Please let me know if you need other details.

Best Regards

Answer 2 :
Hello,



There is different reasons why BHP differs from the WBP when a well is not producing:


* BHP is not calculated at all when the well is SHUT. Shut wells are treated as non-existing by the simulator during the dynamic flow calculations (although their potential is calculated and they can be re-opened by WTEST and several other options in ECLIPSE ...)

* If the well status is STOP then the well calculations are performed by the simulator. In this case, the well BHP may be different from the block pressure when there are cross-flows between different layers.

* If the well is not SHUT (and not producing) , it's BHP may be different from BP because BHP and BP have different pressure datum. BHP is referenced to the center of top perforation by default if it is not explicitly defined in item 5 of WELSPECS. BP is expressed with reference to the reservoir datum in EQUIL or DATUM keyword (if defined). To find the pressure at the connection of the well use mnemonic CPR.



I hope this will help.



Best Regards

Answer 3:
Hello,

For the period (history) where the well was closed, the reason of this is may be the fact of having zero rates for all
phases with the status of the well being OPEN in WCONHIST. could you please try to change status of the wells to SHUT
(in WCONHIST keyword) whenever the well is not producing (zero rates) and see the effect.

Please let me know if it helps, if not could you please send me the data file I will try to reproduce the issue.

Best Regards

Answer 4:
Hello,



1- Sometimes when you don’t set your wells status as closed in WCONHIST and they have a rate of zero, it may cause convergence problems in ECLIPSE.



2- From the well inflow performance relationship Q=T*M*(Pavg-Pw-Hw). Where T is the connection transmissibility factor, M is the phase mobility, Pavg is the pressure in the grid block (WBP, WBP5 or WBP), Pw is the bottom hole pressure, and Hw is the well bore pressure head between the connection and the well’s BHP datum depth. If the well is shut at the surface, Q=0, then Pavg=Pw+Hw. So the difference is the well bore pressure head, mostly liquid hydrostatic pressure.





I will check for the history phase why it is showing the same value.





Best Regards

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