A liner lap must be inflow tested. The cement around the liner is a well control barrier. It is designed to prevent flow from a potential source of flow (reservoir zone) into the production casing. Even if a liner top packer is set the liner lap must be tested. For a liner lap to be considered as a barrier it must be tested in the direction of flow.
From Norsok D10 “Wells with a source of inflow/reservoir shall have two independent mechanical well barriers. This also applies to wells which could develop an inflow potential due to injection. Wells with no source of inflow/reservoir shall as a minimum have one mechanical well barrier. For wells with only one mechanical barrier, inflow tests at pre-determined intervals are required to confirm that the well will not flow.”
There are a couple of challenges with regards to inflow testing.
The big challenge with inflow testing is interpretation of the test results. According to well control regulations, inflow tests should be confirmed with a Horner plot of the results with the flow rate recorded so that it can be proven that there is no flow. In hot deep wells this can be a real challenge as the well will continue to flow for a considerable time due to thermal effects.
Creating and interpreting Horner plots is not something that is easy. Most manuals state that a Horner plot must be made, but very few if any provide details on how the plot is to be interpreted.
I have attached guidance for Horner plots and some data from
a well control manual that can be used to try and interpret if the test is
valid.The example data runs for 310 minutes (just over 5 hours) see if you can test that long on a deepwater rig
Sr. Drilling Engineer
PTT Exploration and Production Public Company Limited