Changes

'''System:''' Stratigraphic

'''System:''' Stratigraphic

 

:'''Regime:''' Depositional

* '''Regime:''' Depositional

:Trap boundaries are created primarily by depositional processes and can involve igneous rocks as well as sedimentary rocks. Three classes are recognized, based on whether the trap involves an isolated reservoir, an updip pinch-out, or depositional relief on top of the reservoir.

* Trap boundaries are created primarily by depositional processes and can involve igneous rocks as well as sedimentary rocks. Three classes are recognized, based on whether the trap involves an isolated reservoir, an updip pinch-out, or depositional relief on top of the reservoir.

::'''Class:''' Isolated (local) depositional reservoirs

 

::Reservoir rock is partially or completely isolated by sealing rocks, which provide top, side, and often bottom seals. These traps are often of limited areal extent, with trap closure defined largely by reservoir distribution.

<list-item>'''Class:''' Isolated (local) depositional reservoirs</list-item><list-item>Reservoir rock is partially or completely isolated by sealing rocks, which provide top, side, and often bottom seals. These traps are often of limited areal extent, with trap closure defined largely by reservoir distribution.

:::'''Subclass:''' Sandstone reservoirs

 

:::Partially or completely isolated by seal.

<list-item>'''Subclass:''' Sandstone reservoirs</list-item><list-item>Partially or completely isolated by seal.</list-item><list-item>'''Subclass:''' Carbonate reservoirs</list-item><list-item>Partially or completely isolated by seal.</list-item><list-item>'''Subclass:''' Igneous reservoirs</list-item><list-item>Partially isolated by seal.</list-item></list-item><list-item>'''Class:''' Depositional pinch-outs</list-item><list-item>Depositional processes form an updip pinch-out of permeable rock into impermeable rock. Trap closure is usually created by an updip re-entrant of the pinch-out boundary or by a combination of the pinch-out with other trap elements, such as tectonic nosing or [[hydrodynamics]]. Pinch-out boundaries typically involve top, side, and bottom seals.

:::'''Subclass:''' Carbonate reservoirs

 

:::Partially or completely isolated by seal.

<list-item>'''Subclass:''' Regional sandstone pinch-outs</list-item><list-item>Regional updip pinch-outs of sandstone into an impermeable facies such as shale or anhydrite.</list-item><list-item>'''Subclass:''' Local sandstone pinch-outs</list-item><list-item>Local updip pinch-outs of sandstone into an impermeable facies such as shale or anhydrite.</list-item><list-item>'''Subclass:''' Regional carbonate pinch-outs</list-item><list-item>Regional updip pinch-outs of carbonate into an impermeable facies such as shale or anhydrite.</list-item><list-item>'''Subclass:''' Local carbonate pinch-outs</list-item><list-item>Local updip pinch-outs of carbonate into an impermeable facies such as shale or anhydrite.</list-item></list-item><list-item>'''Class:''' Depositional relief traps</list-item><list-item>Process forms positive relief on top of the reservoir; this topographic relief between top seal and reservoir creates the trap closure.

:::'''Subclass:''' Igneous reservoirs

 

:::Partially isolated by seal.

<list-item>'''Subclass:''' Sandstone depositional relief traps</list-item><list-item>'''Subclass:''' Carbonate depositional relief traps

::'''Class:''' Depositional pinch-outs

 

::Depositional processes form an updip pinch-out of permeable rock into impermeable rock. Trap closure is usually created by an updip re-entrant of the pinch-out boundary or by a combination of the pinch-out with other trap elements, such as tectonic nosing or [[hydrodynamics]]. Pinch-out boundaries typically involve top, side, and bottom seals.

<list-item>'''Style:''' Carbonate reservoirs sealed by shale</list-item><list-item>'''Style:''' Carbonate reservoirs sealed by tight carbonate</list-item><list-item>'''Style:''' Carbonate reservoirs sealed by evaporites</list-item></list-item></list-item>

:::'''Subclass:''' Regional sandstone pinch-outs

:::Regional updip pinch-outs of sandstone into an impermeable facies such as shale or anhydrite.

:::'''Subclass:''' Local sandstone pinch-outs

:::Local updip pinch-outs of sandstone into an impermeable facies such as shale or anhydrite.

:::'''Subclass:''' Regional carbonate pinch-outs

:::Regional updip pinch-outs of carbonate into an impermeable facies such as shale or anhydrite.

:::'''Subclass:''' Local carbonate pinch-outs

:::Local updip pinch-outs of carbonate into an impermeable facies such as shale or anhydrite.

::'''Class:''' Depositional relief traps

::Process forms positive relief on top of the reservoir; this topographic relief between top seal and reservoir creates the trap closure.

:::'''Subclass:''' Sandstone depositional relief traps

:::'''Subclass:''' Carbonate depositional relief traps

::::'''Style:''' Carbonate reservoirs sealed by shale

::::'''Style:''' Carbonate reservoirs sealed by tight carbonate

::::'''Style:''' Carbonate reservoirs sealed by evaporites

==Families==

==Families==

'''Regime:''' Depositional reservoirs

'''Regime:''' Depositional reservoirs

 

:'''Class:''' Isolated depositional reservoirs

* '''Class:''' Isolated depositional reservoirs

::'''Subclass:''' Isolated carbonate reservoirs

 

:::'''Superfamily:''' Marine carbonate reservoirs

<list-item>'''Subclass:''' Isolated carbonate reservoirs

::::'''Family:''' Open-shelf (high-energy) carbonates

 

:::::'''Subfamily:''' Shoal

<list-item>'''Superfamily:''' Marine carbonate reservoirs

::::::'''Variety:''' Oolite

 

::::::'''Variety:''' Skeletal

<list-item>'''Family:''' Open-shelf (high-energy) carbonates

::::'''Family:''' Tidal-zone carbonates

 

:::::'''Subfamily:''' Tidal channel

<list-item>'''Subfamily:''' Shoal

::'''Subclass:''' Isolated sandstone reservoirs

 

:::'''Superfamily:''' Marine sandstone traps

<list-item>'''Variety:''' Oolite</list-item><list-item>'''Variety:''' Skeletal</list-item></list-item></list-item><list-item>'''Family:''' Tidal-zone carbonates

::::'''Family:''' Shallow-water sandstone reservoirs

 

:::::'''Subfamily:''' Beach

<list-item>'''Subfamily:''' Tidal channel</list-item></list-item></list-item></list-item><list-item>'''Subclass:''' Isolated sandstone reservoirs

:::::'''Subfamily:''' Barrier island

 

:::::'''Subfamily:''' Offshore bar

<list-item>'''Superfamily:''' Marine sandstone traps

::::'''Family:''' Deepwater sandstone reservoirs

 

:::::'''Subfamily:''' Turbidites

<list-item>'''Family:''' Shallow-water sandstone reservoirs

:::::'''Subfamily:''' Turbidite channel

 

:::::'''Subfamily:''' Submarine fans

<list-item>'''Subfamily:''' Beach</list-item><list-item>'''Subfamily:''' Barrier island</list-item><list-item>'''Subfamily:''' Offshore bar</list-item></list-item><list-item>'''Family:''' Deepwater sandstone reservoirs

:::'''Superfamily:''' Alluvial sandstone reservoirs

 

::::'''Family:''' Fluvial

<list-item>'''Subfamily:''' Turbidites</list-item><list-item>'''Subfamily:''' Turbidite channel</list-item><list-item>'''Subfamily:''' Submarine fans</list-item></list-item></list-item><list-item>'''Superfamily:''' Alluvial sandstone reservoirs

:::::'''Subfamily:''' Channel

 

::::::'''Variety:''' Deltaic

<list-item>'''Family:''' Fluvial

::::'''Family:''' Deltaic

 

:::::'''Subfamily:''' Distributary channel

<list-item>'''Subfamily:''' Channel</list-item><list-item>'''Variety:''' Deltaic</list-item></list-item><list-item>'''Family:''' Deltaic

::'''Subclass:''' Isolated igneous reservoirs

 

:::'''Superfamily:''' Intrusive igneous bodies

<list-item>'''Subfamily:''' Distributary channel</list-item></list-item></list-item></list-item><list-item>'''Subclass:''' Isolated igneous reservoirs

::::'''Family:''' Intrusive sills

 

:'''Class:''' Depositional pinch-outs

<list-item>'''Superfamily:''' Intrusive igneous bodies

::'''Subclass:''' Sandstone pinch-outs

 

:::'''Superfamily:''' Marine sandstone pinch-outs

<list-item>'''Family:''' Intrusive sills</list-item></list-item></list-item>

::::'''Family:''' Shallow marine

* '''Class:''' Depositional pinch-outs

::::Updip pinch-out of shallow marine sands into lagoonal or basinal shales and silts.

 

:::::'''Subfamily:''' Barrier bar

<list-item>'''Subclass:''' Sandstone pinch-outs

::::::'''Variety:''' Pinch-out into lagoonal shale

 

::::::'''Variety:''' Pinch-out into marine shale

<list-item>'''Superfamily:''' Marine sandstone pinch-outs</list-item><list-item>'''Family:''' Shallow marine</list-item><list-item>Updip pinch-out of shallow marine sands into lagoonal or basinal shales and silts.

::::'''Family:''' Deep marine

 

:::::'''Subfamily:''' Turbidite

<list-item>'''Subfamily:''' Barrier bar

:::::Updip pinch-out of marine turbidite sandstone into marine shale.

 

:::'''Superfamily:''' Lacustrine sandstone pinch-outs

<list-item>'''Variety:''' Pinch-out into lagoonal shale</list-item><list-item>'''Variety:''' Pinch-out into marine shale</list-item></list-item><list-item>'''Family:''' Deep marine

::::'''Family:''' Lacustrine delta pinch-out

 

::'''Subclass:''' Carbonate pinch-outs

<list-item>'''Subfamily:''' Turbidite</list-item><list-item>Updip pinch-out of marine turbidite sandstone into marine shale.</list-item></list-item></list-item><list-item>'''Superfamily:''' Lacustrine sandstone pinch-outs

:::'''Superfamily:''' Marine carbonate pinch-outs

 

::::'''Family:''' Tidal zone

<list-item>'''Family:''' Lacustrine delta pinch-out</list-item></list-item></list-item><list-item>'''Subclass:''' Carbonate pinch-outs

:::::'''Subfamily:''' Tidal-flat carbonate pinch-out

 

::::::'''Variety:''' Pinch-out into silts and shales

<list-item>'''Superfamily:''' Marine carbonate pinch-outs

::::::'''Variety:''' Pinch-out into tight dolomites and anhydrite

 

::::'''Family:''' Open shelf (high energy)

<list-item>'''Family:''' Tidal zone

:::::'''Subfamily:''' Carbonate bank pinch-out

 

::::::'''Reservoir variety:''' Rudistid limestone bank

<list-item>'''Subfamily:''' Tidal-flat carbonate pinch-out

::::::'''Seal variety:'''

 

:::::::'''Top:''' Marine shale

<list-item>'''Variety:''' Pinch-out into silts and shales</list-item><list-item>'''Variety:''' Pinch-out into tight dolomites and anhydrite</list-item></list-item></list-item><list-item>'''Family:''' Open shelf (high energy)

:::::::'''Side:''' Tight shelf limestone

 

:'''Class:''' Depositional relief

<list-item>'''Subfamily:''' Carbonate bank pinch-out

::'''Subclass:''' Sandstone

 

:::'''Superfamily:''' Eolian sandstone reservoirs

<list-item>'''Reservoir variety:''' Rudistid limestone bank</list-item><list-item>'''Seal variety:'''

::::'''Family:''' Dune

 

:::'''Superfamily:''' Marine sandstone reservoirs

<list-item>'''Top:''' Marine shale</list-item><list-item>'''Side:''' Tight shelf limestone</list-item></list-item></list-item></list-item></list-item></list-item>

::::'''Family:''' Deep water

* '''Class:''' Depositional relief

:::::'''Subfamily:''' Turbidite fan

 

::'''Subclass:''' Carbonate

<list-item>'''Subclass:''' Sandstone

:::'''Superfamily:''' Marine carbonate reservoirs

 

::::'''Family:''' Bioherms

<list-item>'''Superfamily:''' Eolian sandstone reservoirs

::::Trap results from depositional relief created by porous organic carbonate buildup sealed by overlying and adjacent tight lithologies. These buildups are commonly referred to as reefs. A wide variety of reef traps have been described and classified based upon both the environment of deposition and geometry of the carbonate reservoir. Oil and gas have been trapped in barrier reefs, fringing reefs, platform reefs, atoll reefs, patch reefs, pinnacle reefs, reef mounds (or mud mounts), and carbonate banks (James and Gelsetzer, 1989). These terms can be used as subfamilies, as noted below. If a more detailed classification is needed, varieties can be established based upon the facies and genesis of the sealing units surrounding the buildups.

 

:::::'''Subfamily:''' Pinnacle reefs

<list-item>'''Family:''' Dune</list-item></list-item><list-item>'''Superfamily:''' Marine sandstone reservoirs

:::::High-relief, circular or ovoid mounds created by upward grown of carbonate frame-building organisms in basinal setting. Reef typically contains a significant amount of high-energy carbonate detritus (grain-stones, wackestones) as well as boundstones and framestones. Reef width is less than 10% of height (James and Geldsetzer, 1989).

 

:::::'''Subfamily:''' Platform reefs

<list-item>'''Family:''' Deep water</list-item><list-item>'''Subfamily:''' Turbidite fan</list-item></list-item></list-item><list-item>'''Subclass:''' Carbonate

:::::Larger reefal carbonate buildup in which lateral dimensions are measured in kilometers and in which reef width is more than 10 times reef height (James and Geldsetzer, 1989).

 

:::::'''Subfamily:''' Patch reefs

<list-item>'''Superfamily:''' Marine carbonate reservoirs

:::::Small, low-relief carbonate mounds developed by frame-building organisms on top of a shelf.

 

:::::'''Subfamily:''' Mud mounds

<list-item>'''Family:''' Bioherms</list-item><list-item>Trap results from depositional relief created by porous organic carbonate buildup sealed by overlying and adjacent tight lithologies. These buildups are commonly referred to as reefs. A wide variety of reef traps have been described and classified based upon both the environment of deposition and geometry of the carbonate reservoir. Oil and gas have been trapped in barrier reefs, fringing reefs, platform reefs, atoll reefs, patch reefs, pinnacle reefs, reef mounds (or mud mounts), and carbonate banks (James and Gelsetzer, 1989). These terms can be used as subfamilies, as noted below. If a more detailed classification is needed, varieties can be established based upon the facies and genesis of the sealing units surrounding the buildups.

:::::Depositional carbonate mounds consisting largely of clean lime mudstone with relatively little macro-fossil debris.

 

:'''Class:''' Supraunconformity traps

<list-item>'''Subfamily:''' Pinnacle reefs</list-item><list-item>High-relief, circular or ovoid mounds created by upward grown of carbonate frame-building organisms in basinal setting. Reef typically contains a significant amount of high-energy carbonate detritus (grain-stones, wackestones) as well as boundstones and framestones. Reef width is less than 10% of height (James and Geldsetzer, 1989).</list-item><list-item>'''Subfamily:''' Platform reefs</list-item><list-item>Larger reefal carbonate buildup in which lateral dimensions are measured in kilometers and in which reef width is more than 10 times reef height (James and Geldsetzer, 1989).</list-item><list-item>'''Subfamily:''' Patch reefs</list-item><list-item>Small, low-relief carbonate mounds developed by frame-building organisms on top of a shelf.</list-item><list-item>'''Subfamily:''' Mud mounds</list-item><list-item>Depositional carbonate mounds consisting largely of clean lime mudstone with relatively little macro-fossil debris.</list-item></list-item></list-item></list-item>

::'''Subclass:''' Onlap pinch-out

* '''Class:''' Supraunconformity traps

:::'''Superfamily:''' Nonmarine erosion surface

 

::::'''Family:''' Sequence-boundary unconformity onlap

<list-item>'''Subclass:''' Onlap pinch-out

:::::'''Subfamily:''' Depositional re-entrant

 

::::::'''Reservoir variety:''' Deltaic sandstone pinch-out

<list-item>'''Superfamily:''' Nonmarine erosion surface

::::::'''Seal variety:'''

 

:::::::'''Top:''' Deltaic shale

<list-item>'''Family:''' Sequence-boundary unconformity onlap

:::::::'''Bottom:''' Subunconformity units

 

::'''Subclass:''' Buttress pinch-outs

<list-item>'''Subfamily:''' Depositional re-entrant

:::'''Superfamily:''' Nonmarine erosional surface

 

::::'''Family:''' Sequence-boundary unconformity buttress

<list-item>'''Reservoir variety:''' Deltaic sandstone pinch-out</list-item><list-item>'''Seal variety:'''

:::::'''Subfamily:''' Pinch-out against erosional ridge

 

::::::'''Reservoir variety:''' Alluvial sandstone

<list-item>'''Top:''' Deltaic shale</list-item><list-item>'''Bottom:''' Subunconformity units</list-item></list-item></list-item></list-item></list-item></list-item><list-item>'''Subclass:''' Buttress pinch-outs

::::::'''Seal variety:'''

 

:::::::'''Top:''' Nonmarine shale

<list-item>'''Superfamily:''' Nonmarine erosional surface

:::::::'''Side:''' Marine shale of subcrop ridge

 

:::::::'''Bottom:''' Marine shale beneath unconformity

<list-item>'''Family:''' Sequence-boundary unconformity buttress

 

<list-item>'''Subfamily:''' Pinch-out against erosional ridge

 

<list-item>'''Reservoir variety:''' Alluvial sandstone</list-item><list-item>'''Seal variety:'''

 

<list-item>'''Top:''' Nonmarine shale</list-item><list-item>'''Side:''' Marine shale of subcrop ridge</list-item><list-item>'''Bottom:''' Marine shale beneath unconformity</list-item></list-item></list-item></list-item></list-item></list-item>

==See also==

==See also==