Changes

==Episodic leakage of hydrocarbons==

==Episodic leakage of hydrocarbons==

[[file:formation-fluid-pressure-and-its-application_fig5-28.png|thumb|{{figure number|3}After .<ref name=ch05r12>Leonard, R., C., 1993, Distribution of sub-surface pressure in the Norwegian Central Graben and applications for exploration, in Parker, J., R., ed., Petroleum Geology of Northwest Europe: Proceedings of the Geological Society's 4th conference, London, p. 1305–1313.</ref> Copyright: The Geological Society.]]

[[file:formation-fluid-pressure-and-its-application_fig5-28.png|thumb|{{figure number|1}} After .<ref name=ch05r12>Leonard, R., C., 1993, Distribution of sub-surface pressure in the Norwegian Central Graben and applications for exploration, in Parker, J., R., ed., Petroleum Geology of Northwest Europe: Proceedings of the Geological Society's 4th conference, London, p. 1305–1313.</ref> Copyright: The Geological Society.]]

Regional pressure compartment pressures build as a result of hydrocarbon generation and other mechanisms. Intermittent release of hydrocarbons and other fluids occurs when hydrostatic pressure exceeds the fracture gradient of the top seal. Hydrocarbons released from regional pressure compartments charge formations overlying the top seal of the compartment. Subsequent bleed-down of pressure allows temporary rehealing of the fractures. This cycle undoubtedly repeats many times. (David Powley, personal communication).

Regional pressure compartment pressures build as a result of hydrocarbon generation and other mechanisms. Intermittent release of hydrocarbons and other fluids occurs when hydrostatic pressure exceeds the fracture gradient of the top seal. Hydrocarbons released from regional pressure compartments charge formations overlying the top seal of the compartment. Subsequent bleed-down of pressure allows temporary rehealing of the fractures. This cycle undoubtedly repeats many times. (David Powley, personal communication).