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262 Applied Petroleum Geomechanics

Figure 7.21 Pore pressure profile in the Macondo well (redrawn from Pinkston, 2018)
with downhole mud weight (APD) and LOT, FIT. p n and p p are the normal pressure and
pore pressure.

a similar behavior, i.e., the reservoir pressure regression occurred compared
to adjacent shales and isolated sands owing to lateral drainage in the
reservoir (Zhang et al., 2008).
The leak-off test (LOT) and formation integrity test (FIT) data points
(related to fracture gradient) from BP’s report (BP, 2010) are also plotted in
Fig. 7.21. It shows that the drilling window between pore pressure and
fracture gradient is very narrow in some sections although the maximum
fracture gradient is greater than 16 ppg (the value of FIT tested at 17,082 ft
TVD ss).
7.5.3 Abnormal pressures in the Scotian Shelf, Canada

The Scotian Basin is located beneath the outer part of the Scotian Shelf,
offshore Nova Scotia, eastern Canada. The gas-bearing sandstones in the
Cretaceous and upper Jurassic formations are the major target in the basin.
Overpressures are encountered throughout the Scotian Shelf south of the