Page 290 - Well Control for Completions and Interventions

Well Kill, Kick Detection, and Well Shut-In 283

Initial pump pressure ðmechanical tubing burst limitÞ 5 tubing burst limit
tubing hydrostatic pressure at packer

7 Calculate maximum pump pressure (tubing burst mechanical limit)
at the end of the kill
At the end of the kill, the highest pump pressure than can be applied at
the surface is tubing burst limit, minus the HP of the kill fluid in the
tubing at packer depth. This is a worst-case assumption, and makes no
allowance for the HP in the annulus.
Final pump pressure ðmechanical tubing burst limitÞ 5 tubing burst limit
tubing hydrostatic pressure at packer

7.4.3 Bullhead procedure
If a rig is on location, the mud pumps are normally used to kill the well.
However, a bullhead kill can be carried out using a mobile pumping unit
before the rig arrives on location. This can bring about significant cost
savings.
Outline procedure:
1. Hook up a temporary treating (Chiksan) line from the pumping
equipment to the Christmas tree. Fluid is usually pumped via the kill
wing or swab cap. The treating line should be fitted with non-return
valves close to the tree, as well as a pressure relief valve. The line must
be secured.
2. If there are holes in the tubing and simultaneous injection of kill fluid
is required, or if pressure needs to be applied to the annulus to reduce
tubing burst loading, a second temporary line will need to be made
up to the production (A) annulus side outlet valve. The line should be
fitted with a non-return valve close to the wellhead, as well as a pres-
sure relief valve. The line must be secured.
3. The lines should be tested before pumping begins. Test pressure must
exceed the maximum anticipated pump pressure by a suitable margin,
typically a 10% excess, or 500 psi, whichever is greater.
4. Begin to pump kill fluid at a rate high enough to push produced fluids
in the tubing back into the formation. In practical terms, the pump
rate will be as high as possible whilst remaining below the fracture