Changes

==Pore pressure variations==

==Pore pressure variations==

Pore pressure (p) is not always a smooth curve.<ref name=ch10r26>Engelder, T., and J. Leftwich, 1993, An analysis of geopressure profiles from south Texas: the search for higher quality reservoirs in the Tertiary sections of the Gulf Coast: AAPG Hedberg Research conference, unpublished abstract.</ref> Decompaction is controlled in part by the permeability of sediment layers. Shales adjacent to high-permeability layers may undergo rapid decompaction while thick shale sequences with no immediate access to high-permeability layers will decompact more slowly and have high pore pressures. Local variations in pore pressure may be important in evolving seal integrity during basin subsidence.

Pore pressure (p) is not always a smooth curve.<ref name=ch10r26>Engelder, T., and J. Leftwich, 1993, An analysis of geopressure profiles from south Texas: the search for higher quality reservoirs in the Tertiary sections of the Gulf Coast: AAPG Hedberg Research conference, unpublished abstract.</ref> [[Decompaction]] is controlled in part by the permeability of sediment layers. Shales adjacent to high-permeability layers may undergo rapid decompaction while thick shale sequences with no immediate access to high-permeability layers will decompact more slowly and have high pore pressures. Local variations in pore pressure may be important in evolving seal integrity during basin subsidence.

==Effect of water depth, stratigraphy, and facies changes==

==Effect of water depth, stratigraphy, and facies changes==