The test pressure and the justification for this pressure shall be clearly indicated in the testing programme. The casing string shall be tested to the lowest value as dictated by the following pressure:
- the casing/liner design pressure or 75% of the casing/liner burst
- the wellhead design pressure
- the working rating of the BOP
- cement head working pressure rating
- float equipment manufacturer’s test pressure limitation.
Timing
If the casing is not pressure tested immediately after bumping the plugs, the casing shall not be pressure tested until either:
- at least 24 hours have elapsed from the time the cement slurry was in place
or
- the tail slurry samples retained at the surface have set to a rock hard state.
This is to prevent Micro Annuli forming between the casing and cement
General Casing Pressure Testing Procedure
General pressure testing procedure for casing/liner shall be as shown in the following table:
|
Casing/Liner Type |
Testing Procedure |
|
Surface/Intermediate/ Production Casing/liner |
Tests shall be conducted after nippling up and pressure testing the BOP stack, by either:
closing the shear/blind rams and pumping down the choke/kill line or closing the annular preventer or pipe rams around the drill string and pressure testing prior to drilling out the shoe track. |
|
Drive Pipe/Structural Casing (surface wellheads only ) |
Can only be pressure tested against a cement plug (if present) to the rating of the Diverter system (typically 200-300psi ). |
|
Conductor casing (surface wellheads only) |
Shall be pressure tested by closing the pipe rams around the drill string and pressure testing prior to drilling out the cement. |