Page 304 - Well Control for Completions and Interventions

Well Kill, Kick Detection, and Well Shut-In 297

9. Note the wellhead pressure and pump the same volume of kill
weight fluid as used at the first stage (step 5).
10. Allow time for the fluid to fall in to the well.
11. Bleed dry gas until the pressure is reduced to that recorded before
the second stage was pumped (beginning of step 9). Further reduce
the pressure equivalent to the hydrostatic head of fluid pumped into
the well. The final pressure will be equivalent to the pressure
recorded at the end of step 8/beginning of step 9, plus the increase
in hydrostatic head.
12. Continue to lubricate and bleed until the well is dead. The volume
(and hydrostatic pressure increase) should be the same for each step.

7.7.1.2 Example lubricate and bleed kill using the constant volume
method
A well is to be killed by lubricate and bleed, constant volume method. A
200 psi overbalance is required at the end of the kill. A plug has been
placed close to the end of the tubing. All the necessary data are presented
in (Table 7.13 and Figure 7.19).
1. Calculate the gas gradient.
5747 2 4911

Gas gradient psi=ft: 5 0:08 psi=ft
10; 450

Table 7.13 Data for lubricate and bleed—constant volume
Data Value
WHCIP 4911 psi
Plug depth 10,250 ft.
Packer depth 10,240 ft.
Reservoir depth 10,450 ft. (TVD)
Reservoir pressure 5747 psi
Maximum surface pressure (wellhead mechanical limit) 5500 psi
Tubing size 4/2 in. 13.5 lb/ft.
1
Tubing ID 3.92 in.
Tubing capacity 0.0149 bbls/ft.
Tubing end (tail-pipe) 10,260 ft.
Casing size 7 in. 29 lb/ft.
Casing ID 6.184 in.
Casing capacity 0.0371 bbls/ft.
Kill fluid to give 200 psi overbalance 10.94-11 ppg
Fracture pressure 6950 psi
Safety factor (below fracture pressure) 500 psi