Changes

The outline below presents the hierarchy and definitions for fluid-composition traps.

The outline below presents the hierarchy and definitions for fluid-composition traps.

'''Regime:''' Fluid-composition traps

'''Regime:''' Fluid-composition traps<br />

 

Result from a chemical property of the trapped oil or gas.

Result from a chemical property of the trapped oil or gas.

 

:'''Class:''' Viscosity traps

* '''Class:''' Viscosity traps

:Petroleum can be trapped by the presence of barriers created by highly viscous oil (asphalt, tar) or solid hydrocarbons (albertite, gilsonite, or grahamite).

* Petroleum can be trapped by the presence of barriers created by highly viscous oil (asphalt, tar) or solid hydrocarbons (albertite, gilsonite, or grahamite).

::'''Subclass:''' Tar seals

 

:::'''Family:''' Bacterial degradation

<list-item>'''Subclass:''' Tar seals

:::Updip tar seal created by bacteria degradation of the hydrocarbons, preferentially removing the lighter fractions.

 

::'''Subclass:''' Disseminated

<list-item>'''Family:''' Bacterial degradation</list-item><list-item>Updip tar seal created by bacteria degradation of the hydrocarbons, preferentially removing the lighter fractions.</list-item></list-item><list-item>'''Subclass:''' Disseminated</list-item><list-item>Tar or asphalt fills the pores of shales, sands, or carbonates. These traps are often called tar sands, oil shales, bituminous sandstones, or bituminous limestones.</list-item><list-item>'''Subclass:''' Veins</list-item><list-item>The solid, essentially infusible form of petroleum is called pyrobitumen. It occurs in veins [[length::1 mm]] to [[length::8 m]] across and appears to have been injected or is a dead seepage.</list-item>

::Tar or asphalt fills the pores of shales, sands, or carbonates. These traps are often called tar sands, oil shales, bituminous sandstones, or bituminous limestones.

* '''Class:''' Coal-bed methane

::'''Subclass:''' Veins

* Coal beds trap large volumes of methane, where most is adsorbed onto internal surfaces of micropores or along cleat faces. Coalification generates methane along with water, carbon dioxide, and carbon monoxide.

::The solid, essentially infusible form of petroleum is called pyrobitumen. It occurs in veins [[length::1 mm]] to [[length::8 m]] across and appears to have been injected or is a dead seepage.

:'''Class:''' Coal-bed methane

:Coal beds trap large volumes of methane, where most is adsorbed onto internal surfaces of micropores or along cleat faces. Coalification generates methane along with water, carbon dioxide, and carbon monoxide.

==See also==

==See also==