Changes

  | part    = Critical elements of the petroleum system

  | part    = Critical elements of the petroleum system

  | chapter = Sedimentary basin analysis

  | chapter = Sedimentary basin analysis

  | frompg  = 4-1

  | frompg  = 4-50

  | topg    = 4-123

  | topg    = 4-52

  | author  = John M. Armentrout

  | author  = John M. Armentrout

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch04/ch04.htm

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch04/ch04.htm

Certain types of hydrocarbon [[trap]]s are more commonly associated with a particular [[Depositional systems tracts|depositional systems tract]]. Identifying the [[Sea_level_cycle_phase_and_systems_tracts#Highstand_systems_tracts|highstand]], [[Sea_level_cycle_phase_and_systems_tracts#Lowstand_systems_tracts|lowstand]], or [[Sea_level_cycle_phase_and_systems_tracts#Transgressive_systems_tracts|transgressive]] systems tract and the specific depositional environments within each lets us predict possible [[reservoir]], [[seal]], and [[Calculating charge volume|charge system]] for each potential trap.

Certain types of hydrocarbon [[trap]]s are more commonly associated with a particular [[Depositional systems tracts|depositional systems tract]]. Identifying the [[Sea_level_cycle_phase_and_systems_tracts#Highstand_systems_tracts|highstand]], [[Sea_level_cycle_phase_and_systems_tracts#Lowstand_systems_tracts|lowstand]], or [[Sea_level_cycle_phase_and_systems_tracts#Transgressive_systems_tracts|transgressive]] systems tract and the specific depositional environments within each lets us predict possible [[reservoir]], [[seal]], and [[Calculating charge volume|charge system]] for each potential trap.

[[file:Systems_Tracts.jpg|thumb|400px|left|Systems tracts: Highstand, transgressive, and lowstand. Modified from Vail.<ref name=ch04r99></ref> From Snedden and Sarg.<ref name=Sneddedandsarg_2008>Snedden, John W., and J. F. (Rick) Sarg, Seismic Stratigraphy-A Primer on Methodology, Search and Discovey Article #40270 (2008).</ref>]]

[[file:Systems_Tracts.jpg|thumb|400px|Systems tracts: Highstand, transgressive, and lowstand. Modified from Vail.<ref name=ch04r99></ref> From Snedden and Sarg.<ref name=Sneddedandsarg_2008>Snedden, John W., and J. F. (Rick) Sarg, Seismic Stratigraphy-A Primer on Methodology, Search and Discovey Article #40270 (2008).</ref>]]

==Methods==

==Methods==

[[file:sedimentary-basin-analysis_fig4-27.png|500px|thumb|{{figure number|8}}Seismic reflection profile schematic. Copyright: Armentrout;<ref name=ch04r6 /> courtesy Gulf Coast SEPM.]]

[[file:sedimentary-basin-analysis_fig4-27.png|500px|thumb|{{figure number|8}}Seismic reflection profile schematic. Copyright: Armentrout;<ref name=ch04r6 /> courtesy Gulf Coast SEPM.]]

Using seismic reflection geometries to suggest relative sea level phase requires confidence in the coeval character of seismic reflections. The first downhole occurrence of ''Glob alt (Globoquadrina altispira'', bold arrows) in [[:file:sedimentary-basin-analysis_fig4-27.png|Figure 8]] suggests a correlation cross-cutting the seismically imaged clinoforms. If the ''Glob alt'' occurrences are coeval, the seismic reflections are time transgressive.

Using [[Reflection configuration patterns|seismic reflection geometries]] to suggest relative sea level phase requires confidence in the coeval character of seismic reflections. The first downhole occurrence of ''Glob alt (Globoquadrina altispira'', bold arrows) in [[:file:sedimentary-basin-analysis_fig4-27.png|Figure 8]] suggests a correlation cross-cutting the seismically imaged clinoforms. If the ''Glob alt'' occurrences are coeval, the seismic reflections are time transgressive.

Note that the first downhole well-cutting sample occurrence of the bioevent ''Glob alt'' is at the interface of outer [http://www.onr.navy.mil/focus/ocean/regions/bluewater1.htm neritic] and upper [http://www.thefreedictionary.com/bathyal bathyal] [[Fossil assemblage|biofacies]], except in the two southern wells, A446-1 and A267-1, where the first occurrences occur within stratigraphic intervals containing bathyal biofacies. ''Glob alt'' is a [http://www.thefreedictionary.com/planktonic planktonic] [http://www.ucmp.berkeley.edu/foram/foramintro.html foraminifer] normally found associated with open marine faunas and floras interpreted as upper bathyal [[Fossil assemblage|assemblages]]. The occurrences of ''Glob alt'' coincident with the first upper bathyal biofacies assemblage suggests a facies-controlled top, depressed below the true extinction top by environmental factors. The two occurrences within upper bathyal biofacies are interpreted as true [[Wikipedia:Bioevent |extinction events]]. These true extinction events correlate with a seismic reflection, suggesting that specific reflection approximates a time line and can be used to extend the ''Glob alt'' extinction event datum (2.8 Ma) northward toward the basin margin (see Armentrout & Clement<ref name=ch04r10>Armentrout, J., M., Clement, J., F., 1990, Biostratigraphic calibration of depositional cycles: a case study in High Island–Galveston–East Breaks areas, offshore Texas: Proceedings, Gulf Coast Section SEPM 11th Annual Research Conference, p. 21–51.</ref>).

Note that the first downhole well-cutting sample occurrence of the bioevent ''Glob alt'' is at the interface of outer [http://www.onr.navy.mil/focus/ocean/regions/bluewater1.htm neritic] and upper [http://www.thefreedictionary.com/bathyal bathyal] [[Fossil assemblage|biofacies]], except in the two southern wells, A446-1 and A267-1, where the first occurrences occur within stratigraphic intervals containing bathyal biofacies. ''Glob alt'' is a [http://www.thefreedictionary.com/planktonic planktonic] [http://www.ucmp.berkeley.edu/foram/foramintro.html foraminifer] normally found associated with open marine faunas and floras interpreted as upper bathyal [[Fossil assemblage|assemblages]]. The occurrences of ''Glob alt'' coincident with the first upper bathyal biofacies assemblage suggests a facies-controlled top, depressed below the true extinction top by environmental factors. The two occurrences within upper bathyal biofacies are interpreted as true [[Wikipedia:Bioevent |extinction events]]. These true extinction events correlate with a seismic reflection, suggesting that specific reflection approximates a time line and can be used to extend the ''Glob alt'' extinction event datum (2.8 Ma) northward toward the basin margin (see Armentrout & Clement<ref name=ch04r10>Armentrout, J., M., Clement, J., F., 1990, Biostratigraphic calibration of depositional cycles: a case study in High Island–Galveston–East Breaks areas, offshore Texas: Proceedings, Gulf Coast Section SEPM 11th Annual Research Conference, p. 21–51.</ref>).

[[Category:Critical elements of the petroleum system]]  

[[Category:Critical elements of the petroleum system]]  

[[Category:Sedimentary basin analysis]]

[[Category:Sedimentary basin analysis]]