Page 316 - Well Control for Completions and Interventions

Well Kill, Kick Detection, and Well Shut-In 307

7.7.3.2 Example “pressure method” lubricate and bleed well kill
To enable comparisons to be made between the two lubricate and bleed
techniques, the data set used for the constant volume method (Table
7.13) will be used for this constant pressure example. The well is plugged.
The first part of the constant pressure method is identical to constant
volume method (Section 7.7.1.2)
1. Calculate the gas gradient.
5747 2 4911

Gas gradient psi=ft 5 5 0:08 psi=ft
10; 450
2. Calculate kill weight fluid density and gradient (to kill to the plug).
Pressure at the plug is reservoir pressure minus the gas hydrostatic
from the top of the reservoir to the plug depth. Gas gradient is
0.08 psi/ft. (10,450 2 10,250) 3 0.08 5 16 psi. Pressure at plug is
5747 2 16 5 5731 psi.
5731 1 200
Kill fluid ppgÞ 5 5 11:127-11:2 ppg:
ð
10; 250 3 0:052
11:2 ppg 3 0:052 5 0:5824 psi=ft:
3. Calculate the tubing volume (to the plug)

Tubing volume 5 0:0149 3 10; 250 5 152:725 bbls-153 bbls:

4. Stage 1: Fluid is pumped into the well until the maximum wellhead
pressure (5,500 psi) is reached. Increasing pressure will compress the
gas. The amount of gas compression, and therefore the amount of
fluid that can be pumped is calculated using Boyle’s Law.
4911 3 153
Volume to reach P max 5 5 136:61 bbls:
5500
5. The volume of fluid that can be pumped is the original tubing vol-
ume (153 bbls) minus the volume occupied by the compressed gas
(136.61 bbls) 5 16.39 bbls.
6. Pump the calculated volume (16.39 bbls), or until the wellhead pressure
reaches the maximum allowable value (5500 psi). Do not exceed this
value even if not all the calculated amount of fluid has been pumped.
7. Calculate the reduction in hydrostatic head from the volume of fluid
pumped.