Page 177 - Fundamentals of Gas Shale Reservoirs

ThE ROlE OF TEcTOnIc AcTIVITIES On PORE PRESSuRE In ShAlES 157

Well#1 Well#1
3
DTC, NCT_Son ( s/ft) Density (g/cm )
140 120 100 80 60 40 1.95 2.15 2.35 2.55 2.75 2.95
2255 2255

2275 2275
2325 2325

2375 2375

TVD (m) 2425 TVD (m) 2425

2475
2475
2525 Met 2525 ZDEN
NCT_Son
2575 DTC 2575 CNC
PPG_Son
2625 ECD 2625

2675 2675
0.30 0.40 0.50 0.60 0.70 0.80 0.45 0.25 0.05 –0.15
Por press grad, Mud Wt and ECD (psi/ft) Porosity (%)

Well#1 Well#1
GR (API) PEF
0 100 200 300 0 5 10 15 20
2225 2225

2275 2275

2325 2325

2375 2375

TVD (m) 2425 TVD (m) 2425

2475
2475
2525 2525 PEF
GR
2575 CALX 2575 Resistivity

2625 2625
2675 2675
6 11 16 0.2 2 20 200
CAL (in.) Resistivity (ohm)
FIGURE 7.20 Estimated pore pressure, mud weight, and equivalent circulation density gradients as well as log data against depth over the
Kockatea Shale in Well #1.

make a significant contribution to overpressure generation. and is largely oriented EW. The analysis was combined with
This belief is reached from analyzing the complicated analysis of well log data responses and with the high magni-
geology of the study area in conjunction with the trajectory tude of overpressure that caused a reversal in the vertical
of the principal stress (S ) that acts in a horizontal plane effective stress (Fig. 7.24).
hmax