Page 276 - Origin and Prediction of Abnormal Formation Pressures

248 H.H. RIEKE, G.V. CHILINGAR AND J.O. ROBERTSON JR.
Pressure, atms.
Age 300 400 500 600 700 800
I 1 I i I I
5 10 Sail, ],~, gms/I-'"" 20 25 30
I I I I I 9
1000

1500

200C
/-
/
E ?
.. 2500
(.-.
CL l f
(I)
C~
3000
' w/traces of gas "~ / '
rw/t ...... fgas "~,_ ,,~ I ~.
t
d r ~o~ naa?i~a ted ~ ~L '''~ ~ 9-5/8" csg @ 3316 m .....
~
~lt water w/little gas coming out ~ ~) 7"
3500 / /- .f / , / Normal pressure
~ . A / 9
gas w/sali .... ter ~ m a l l y - h t g h pressure
in order to release stuck pipe /
4000 :cessful.
No elect, log below 4040 m salinity data from DST is not ~',,,,,,~
. ,,., reliable as a long interval
/ V/ m was tested
9 Casing shoe
4500 II DST data
- -O-- Salinity curve drawn from DST data
---~- Log derived salinity
--~-- Pressure in atms.
Fig. 10-10. Study on salinity and pressures in the Bodra-l well, Bengal Basin, India. (Modified after Sahay,
1999, fig. 11-26, p. 258.)

(1999) reported that the pressures are approximately 1.2 to 1.4 times the hydrostatic and
the pore fluids encountered in this interval were mainly water and dissolved natural gas.
Fig. 10-l 1 provides the details of the formation pressures, mud weight, temperature and
salinity of the water as obtained by drillstem testing in the Kutch exploratory well.

Songliao Basin, China
A very important modeling study using formation pressure and pore-water chemical
data was performed by He et al. (2000) to delineate the abnormal pressure-chemistry