Equalisation of christmas trees
In the design process for all wells, consideration should be given to the repressurisation of the Christmas tree after it has been closed in. Several approaches may be taken depending on the circumstances and the design of the well.
In the case of the well being shut in and depressurised with full pressure below the closed SCSSSV, there has to be some means of equalising the pressure across the sub-surface valve before it can be opened.
Repressurisation scenarios
There are several scenarios possible for the repressurisation of a Christmas tree . . .