Tie-back packers are generally run in the following circumstances:
- an inflow test has been performed and has failed
- the CBL indicates that a hydrocarbon bearing interval is poorly isolated from the liner lap
- time savings are envisaged. In this case the packer could be run integrally with the liner hanger.
The inflow test must be repeated after the installation of a tie-back packer. Should the inflow test still fail, the office team shall be informed to decide on the next course of action. However special cases (eg., minimum liner lap length not achieved) shall be considered separately.
Test Pressure Limitation
The maximum hydrostatic pressure at the tie-back packer during testing shall not exceed the sum of the casing injection test pressure (CITP) plus the hydrostatic pressure due to a column of water in the annulus. This is proposed to avoid tie-back failures when in communication with low pressure zones. While testing the packer, pressure shall be limited to a hydrostatic pressure not exceeding the hydrostatic pressure with original mud + 2 500 psi to avoid damage to cement outside casing or previous casing shoe limit pressure test + 500psi whichever is lower.
When to Run an Integral Liner Packer
In certain cases, when hole conditions indicate no potential for future problems, considerable time savings are achieved by running the CPH tie-back packer integral with the liner hanger.
There are however cases when the integral liner packer should not be set:
- If losses occur during displacing of cement exceeding 50 % of the excess cement volume used, do not set the packer nor reverse circulate out POOH till above TOC and flush the string.
- If the cement is not fully displaced and all indications are that the cement has not filled up the liner lap.