Changes

Micropermeable leakage is difficult to predict from rock properties because [[wettability]] and permeability of seals are poorly known in exploration settings. Micropermeable leakage can be geophysically and geochemically detected where it occurs at a moderately rapid rate in a dynamic basinal environment, as in the preceding example.

Micropermeable leakage is difficult to predict from rock properties because [[wettability]] and permeability of seals are poorly known in exploration settings. Micropermeable leakage can be geophysically and geochemically detected where it occurs at a moderately rapid rate in a dynamic basinal environment, as in the preceding example.

Leakage by any mechanism obviously goes through a drainage stage when the seal leaks like a micropermeable seal. Because micropermeable leakage can be slow, it is more likely to destroy old rather than young accumulations. Many fields not filled to the spill point in oil basins with former prolific generation (such as those along the Aylesworth anticline in the Anadarko basin) were probably once filled to the spill point and have since leaked to their present contacts. Marginal seal lithologies such as argillaceous carbonates or silt-stone are more likely to suffer micropermeable leakage than accumulations under salt or claystone seals.<ref name=ch11r11>Grunau, H., 1987, A worldwide look at the cap rock problem: Journal of Petroleum Geology, vol. 10, p. 245–266.</ref>

Leakage by any mechanism obviously goes through a drainage stage when the seal leaks like a micropermeable seal. Because micropermeable leakage can be slow, it is more likely to destroy old rather than young accumulations. Many fields not filled to the spill point in oil basins with former prolific [[Petroleum generation|generation]] (such as those along the Aylesworth anticline in the Anadarko basin) were probably once filled to the spill point and have since leaked to their present contacts. Marginal seal lithologies such as argillaceous carbonates or silt-stone are more likely to suffer micropermeable leakage than accumulations under salt or claystone seals.<ref name=ch11r11>Grunau, H., 1987, A worldwide look at the cap rock problem: Journal of Petroleum Geology, vol. 10, p. 245–266.</ref>

==See also==

==See also==