Difference between revisions of "Fluid-composition trap regime"

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! Regime || Class || Subclass || Family
 
! Regime || Class || Subclass || Family
 
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| rowspan = 4 | ''Fluid-composition traps''; Result from a chemical property of the trapped oil or gas. || rowspan = 3 | ''Viscosity traps;'' Petroleum can be trapped by the presence of barriers created by highly [[Wikipedia:Viscosity|viscous]] oil ([[asphalt]], [[tar]]) or solid hydrocarbons ([[albertite]], [[gilsonite]], or [[grahamite]]). || ''Tar Seals'' || ''Bacterial degradation;'' Updip tar seal created by [[bacteria degradation]] of the hydrocarbons, preferentially removing the [[lighter fractions]].
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| rowspan = 4 | ''Fluid-composition traps''; Result from a chemical property of the trapped oil or gas. || rowspan = 3 | ''[[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]]). || ''Tar Seals'' || ''Bacterial degradation;'' Updip tar seal created by [[bacteria degradation]] of the hydrocarbons, preferentially removing the [[lighter fractions]].
 
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| colspan = 2 | ''Disseminated;'' Tar or asphalt fills the pores of [[shale]]s, [[sandstone]]s, or [[carbonate]]s. These traps are often called [[tar sands]], [[oil shale]]s, bituminous sandstones, or bituminous limestones.
 
| colspan = 2 | ''Disseminated;'' Tar or asphalt fills the pores of [[shale]]s, [[sandstone]]s, or [[carbonate]]s. These traps are often called [[tar sands]], [[oil shale]]s, bituminous sandstones, or bituminous limestones.
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| colspan = 2 | ''Veins;'' 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.
 
| colspan = 2 | ''Veins;'' 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.
 
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| colspan = 3 | ''Coal-bed methane;'' [[Coal bed]]s trap large volumes of [[Wikipedia:Methane|methane]], where most is [[Wikipedia:Adsorption|adsorbed]] onto internal surfaces of [[micropore]]s or along [[cleat face]]s. [[Coalification]] generates methane along with water, [[Wikipedia:Carbon dioxide|carbon dioxide]], and [[Wikipedia:Carbon monoxide|carbon monoxide]].
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| colspan = 3 | ''[[Coal bed methane]];'' [[Coal]] beds trap large volumes of [[Wikipedia:Methane|methane]], where most is [[Wikipedia:Adsorption|adsorbed]] onto internal surfaces of [[micropore]]s or along [[cleat face]]s. [[Coalification]] generates methane along with water, [[Wikipedia:Carbon dioxide|carbon dioxide]], and [[Wikipedia:Carbon monoxide|carbon monoxide]].
 
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[[Category:Traps, trap types, and the petroleum system]]  
 
[[Category:Traps, trap types, and the petroleum system]]  
 
[[Category:Classification of exploration traps]]
 
[[Category:Classification of exploration traps]]
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[[Category:Treatise Handbook 3]]

Latest revision as of 16:31, 13 April 2022

Exploring for Oil and Gas Traps
Series Treatise in Petroleum Geology
Part Traps, trap types, and the petroleum system
Chapter Classification of exploration traps
Author Richard R. Vincelette, Edward A. Beaumont, Norman H. Foster
Link Web page
Store AAPG Store

Fluid-composition traps are controlled by the physical or chemical properties of the trapped fluids themselves. The insolubility, immiscibility, and density contrasts between hydrocarbons and water are major factors that allow hydrocarbons to concentrate into subsurface accumulations. Therefore, in its purest sense, all hydrocarbon accumulations have fluid-composition trapping elements. However, for classification purposes, fluid-composition traps are those in which unique properties of the hydrocarbons provide trapping mechanisms.

Classes and families

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

Regime Class Subclass Family
Fluid-composition traps; Result from a chemical property of the trapped oil or gas. 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). Tar Seals Bacterial degradation; Updip tar seal created by bacteria degradation of the hydrocarbons, preferentially removing the lighter fractions.
Disseminated; Tar or asphalt fills the pores of shales, sandstones, or carbonates. These traps are often called tar sands, oil shales, bituminous sandstones, or bituminous limestones.
Veins; 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.
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

External links

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