Page 65 - Reservoir Geomechanics

a.
OFFSHORE TRINIDAD OFFSHORE TRINIDAD
CENTER OF BASIN GALEOTA RIDGE
2000
Effect of uplift
Adjusted trend
4000 Trend
from
basin
center Top Abnormal
6000
Normal Compaction
Pressure Trend
Depth (ft) 8000

10000

12000 Top Abnormal

14000

16000
200 150 100 50 200 150 100 50
Travel time (µs/ft) Travel time (µs/ft)

b.
OFFSHORE TRINIDAD OFFSHORE TRINIDAD
CENTER OF BASIN GALEOTA RIDGE
2000
Effect of uplift
Adjusted trend
4000
Trend from
basin center
Top Abnormal
6000 Normal Compaction
Pressure Trend
Depth (ft) 8000

10000

12000 Top Abnormal

14000

16000
.2 20 .2 20
Shale resistivity Shale resistivity
Figure 2.15. Data indicating compaction trends in Trinidad as inferred from (a) travel time data and
(b) resistivity data (from Heppard, Cander et al. 1998). Assuming that the deviations from the
normal compaction trends is evidence of overpressure (abnormally low effective stress), both sets
of data indicate an onset of overpressure in the center of the basin at ∼11,500 ft and 5,200 ft in the
vicinity of the Galeota ridge. AAPG C 1998 reprinted by permission of the AAPG whose permission
is required for futher use.