Page 178 - Fundamentals of Gas Shale Reservoirs

158 PORE PRESSuRE PREdIcTIOn FOR ShAlE FORmATIOnS uSInG WEll lOG dATA

Well#3 Well#3
DT, NCT_Son ( s/ft) Porosity (%)
140 120 100 80 60 40 0.45 0.25 0.05 –0.15
1200 1200 1200
NCT_Son SPHI
1300 DTC 1300 1300 LLD
PPG_Son
1400 ECD M wt 1400 1400

1500 1500 1500

1600 1600 1600
Depth (m) 1700 1700 Depth (m) 1700

1800 1800 1800

1900 Kockatea shale 1900 1900
(1799-2037)m MD
2000 2000 2000

2100 2100 2100

2200 2200 2200
0.3 0.4 0.5 0.6 0.7 0.8 0.2 2 20 200 2000
Press grad and mud wt. (psi/ft) Resistivity ( m)

Well#3 Well#3
ROP (m/h) RPM (rpm)
0 20 40 60 80 100 100 150 200 250
1200 1200
ROP RPM
1300 1300 WOB

1400 1400

1500 1500

1600 1600
Depth (m) 1700 Depth (m) 1700

1800 1800

1900 1900
2000 2000

2100 2100
Overpress causes ROP to increase
and WOB to decrease
2200 2200
0 10 20 30
WOB (t)
FIGURE 7.21 Estimated pore pressure, equivalent circulation density gradients, and well log data against depth over the Kockatea Shale
in Well #3.