Page 293 - Well Control for Completions and Interventions

286 Well Control for Completions and Interventions

Table 7.11 Well data; bullhead kill example
Data Value

Depth (top perforation) 10,499 ft. MD/TVD
Depth (TD) 10,664 ft. MD/TVD
Packer depth 6070 ft. MD/TVD
Liner top 6201 ft. MD/TVD
1
Tubing 4/2 in. 12.6 lb/ft.
1
Liner 4/2 in. 12.6 lb/ft.
Tubing capacity 0.0152 bbls/ft.
API burst pressure 8430 psi
Oil density 6.5 ppg
Gas gradient 0.1 psi/ft.
GOC depth 722 ft. MD/TVD
Annulus fluid density 9.2 ppg
Reservoir pressure 5500 psi
Shut-in tubing pressure (SITP) 2045 psi
Formation fracture equivalent 13.8 ppg
Required overbalance 200 psi

Formation fracture limit at the end of the kill—tubing filled with
kill fluid:
7534psi 2 10:530:052310;499 5 1802
Formation fracture pressure Tubing ðkill fluidÞ hydrostaticpressure Formation limit ðend killÞ

Kill weight hydrostatic 5 10.5 3 0.052 3 10,499 5 5732 psi.
3. Calculate the working tubing burst limit.

8430 3 0:8 5 6744
psi
API burst pressure psi ðnewÞ ð80%Þ
4. Calculate maximum initial and final tubing pressure (mechanical
limits, no back-up).
This assumes the casing is evacuated to the packer.
Initial limit (tubing full of oil and gas):

6744 2 ð722 3 0:1Þ 1 ðð0:052 3 6:5Þ 3 ð6070 2 722ÞÞ
Working burst press
Tubing hydrostatic pressure ðat packerÞ
5 4864 Initial limit ðstart of bullheadÞ