RE: Apoligies30 Jan 2025 17:41
there is no, or very little cement in the annulus, just mud or production fluid. the cement is between open hole and and outside of the casing, it should be all the way to the surface. tubing will be lowered into the annulus and the first (lowest) zone to be tested isolated by bridges or packer assemblies. when done a cement plug will be set then move up to the next zone. connection to each zone is through tubing with the annulus isolated by packers, i.e. the space from the exterior of the tubing to the inside of the casing....the annulus.
the perf guns are lowered through the tubing and out the end which sits in the top packer, the perf guns are now in the annulus opposite the zone to be tested, sealed by a cement plug below and the packer above. there are a bunch of safety checks for integrity usually in the form of pressure tests. subsequent flow is controlled at the surface same way you control the water at the end of a garden hose. the weight of the fluid in the annulus will stop any flow up the annulus.....this is a bad thing!
all a long time ago....that's how i remember it from my floater days.
nb cement is pure cement powder, blows through pipes (chic sans) to cement unit with compressed air, mixed with water by the cement hand, advancer or ******ers added as required, samples taken in paper cups on regular basis, pumped down the hole through the drill pipe or tubing fills from bottom up the space as above.....all watched by a nervous company man.