Page 41 - Well Control for Completions and Interventions

Introduction and Well Control Fundamentals 33

Method 1: Using Table 1.5:
Select the correction factor at the intersection of depth (left hand col-
umn) and gas SG (top row). Multiply the chosen correction factor by the
SITP:
1:284 3 2500 5 3210 psi:

! !
SITP Depth
Method2 : Using theequation BHP5SITP1 2:5Þ
ð
100 1000
! !
2500 9000
ð
BHP525001 2:5Þ
100 1000
BHP525001ð2:5Þ3ð25Þ3ð9Þ53062:5psi
SITP 1
Using theequation Ratio 5 0:0000343SG3TVD
BHP 2:718
1
2:718 0:00003430:839000
1
50:7829
2:718 0:2448
2500=0:782953193:33psi:

0:018773SG3TVD
Z3T
Using theequation SITP3e
!
0:0187730:839000
50:21657
0:963ð1901460Þ
25003e 0:21657 53104:5psi:

1.1.7 Underbalance and overbalance pressure

If hydrostatic pressure in a well is higher than the reservoir pressure, the
difference is called overbalance pressure, or simply overbalance. Conversely,
if reservoir pressure is more than hydrostatic pressure, the difference is
called underbalance.
Monitoring and controlling overbalance and underbalance pressure is
a critical element of well control. Most completion and workover