Changes

  | part    = Predicting the occurrence of oil and gas traps

  | part    = Predicting the occurrence of oil and gas traps

  | chapter = Exploring for stratigraphic traps

  | chapter = Exploring for stratigraphic traps

  | frompg  = 21-1

  | frompg  = 21-50

  | topg    = 21-68

  | topg    = 21-51

  | author  = John C. Dolson, Mike S. Bahorich, Rick C. Tobin, Edward A. Beaumont, Louis J. Terlikoski, Michael L. Hendricks

  | author  = John C. Dolson, Mike S. Bahorich, Rick C. Tobin, Edward A. Beaumont, Louis J. Terlikoski, Michael L. Hendricks

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch21/ch21.htm

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch21/ch21.htm

==Objective==

==Objective==

The objective of basin-fill analysis is to integrate [[sequence stratigraphy]], geometrical analysis, seismic facies analysis, and lithofacies analysis to produce paleogeographic maps of depositional sequences.

The objective of basin-fill analysis is to integrate [[sequence stratigraphy]], geometrical analysis, [[seismic facies analysis]], and [[lithofacies]] analysis to produce [[Mapping paleogeography|paleogeographic maps]] of [[Depositional sequence identification|depositional sequence]]s.

==Procedure==

==Procedure==

Below is a suggested procedure for basin-fill analysis.

Below is a suggested procedure for basin-fill analysis.

# Make a chronostratigraphic chart for the basin.

# Combine [[Sequence stratigraphy|sequence stratigraphic]] interpretations from seismic sections with sequence stratigraphic interpretations from well log [[cross section]]s.

# Make [[Paleogeography|paleogeographic]] maps of depositional sequences.

# Identify the best locations for traps using a combination of paleogeography and sequence stratigraphy.

| Make a chronostratigraphic chart for the basin.

|-

| Combine sequence stratigraphic interpretations from seismic sections with sequence stratigraphic interpretations from well log cross sections.

|-

| Make paleogeographic maps of depositional sequences.

| Identify the best locations for traps using a combination of paleogeography and sequence stratigraphy.

==Chronostratigraphic charts==

[[file:exploring-for-stratigraphic-traps_fig21-33.png|500px|thumb|{{figure number|1}}Chronostratigraphic chart (A) correlated with a chart showing relative sea level changes (B). From Mitchum and Vail;<ref name=ch21r31 /> courtesy AAPG.]]

A chronostratigraphic chart is a correlation chart with geologic time as the Y-axis and distance across the area of interest as the X-axis. A dip-oriented chronostratigraphic chart should be made. But we also should consider making strike-oriented chronostratigraphic charts, depending on the complexity of the stratigraphic section. A chronostratigraphic chart shows the following:<ref name=ch21r31>Mitchum, R., M., Vail, P., R., Sangree, J., B., 1977, [http://archives.datapages.com/data/specpubs/seismic1/data/a165/a165/0001/0100/0117.htm Seismic stratigraphy and global changes in sea level, part 6: stratigraphic interpretations of seismic reflection patterns in depositional sequences], in Payton, C., E., ed., Seismic Stratigraphy and Applications to Hydrocarbon Exploration: [http://store.aapg.org/detail.aspx?id=1157 AAPG Memoir 26], p. 117–133.</ref>

 

A chronostratigraphic chart is a correlation chart with geologic time as the Y-axis and distance across the area of interest as the X-axis. A [[dip]]-oriented chronostratigraphic chart should be made. But we also should consider making [[strike]]-oriented chronostratigraphic charts, depending on the complexity of the stratigraphic section. A chronostratigraphic chart shows the following:<ref name=ch21r31>Mitchum, R. M., P. R. Vail, J. B. Sangree, 1977, [http://archives.datapages.com/data/specpubs/seismic1/data/a165/a165/0001/0100/0117.htm Seismic stratigraphy and global changes in sea level, part 6: stratigraphic interpretations of seismic reflection patterns in depositional sequences], in C. E. Payton, ed., Seismic Stratigraphy and Applications to Hydrocarbon Exploration: [http://store.aapg.org/detail.aspx?id=1157 AAPG Memoir 26], p. 117–133.</ref>

* Apparent geologic time of each sequence and time gaps between sequences

* Apparent geologic time of each sequence and time gaps between sequences

* Relationships of sequences to bounding unconformities, highlighting areas of onlap, downlap, toplap, and truncation

* Relationships of [[Depositional sequence|sequences]] to bounding [[Unconformity|unconformities]], highlighting areas of [http://www.glossary.oilfield.slb.com/en/Terms.aspx?LookIn=term%20name&filter=onlap onlap], [http://www.glossary.oilfield.slb.com/en/Terms/d/downlap.aspx downlap], [http://homepage.ufp.pt/biblioteca/Seismic/Pages/Page22.htm toplap], and truncation

* Relationships and correlation of parasequences to a sequence

* Relationships and correlation of [[Parasequences (fourth- and fifth-order sequences)|parasequences]] to a sequence

* Distribution of facies

* Distribution of [[facies]]

Chronostratigraphic charts aid in stratigraphic mapping by showing facies relationships across the basin in terms of time so that paleogeographic maps can be made. They are also useful for structural analysis.

Chronostratigraphic charts aid in stratigraphic mapping by showing facies relationships across the basin in terms of time so that [[Paleogeography|paleogeographic]] maps can be made. They are also useful for structural analysis.

[[:file:exploring-for-stratigraphic-traps_fig21-33.png|Figure 1]] is an example of a chronostratigraphic chart (A) correlated with a chart showing relative sea level changes (B).

[[:file:exploring-for-stratigraphic-traps_fig21-33.png|Figure 1]] is an example of a chronostratigraphic chart (A) correlated with a chart showing relative sea level changes (B).

==Combining well and seismic data==

==Combining well and seismic data==

Combining well and [[seismic data]] is simple once the correlation between the two is established. [[Synthetic seismogram]]s establish these correlations. By combining lithofacies with seismic facies, stronger interpretations of the sedimentary section can be made away from well control. Seismic fades allow accurate correlation of lithofacies between wells. Lithofacies allow more detailed interpretation of seismic parameters, such as reflection patterns.

Combining well and [[seismic data]] is simple once the correlation between the two is established. [[Synthetic seismogram]]s establish these correlations. By combining [[lithofacies]] with [[Seismic facies mapping|seismic facies]], stronger interpretations of the sedimentary section can be made away from well control. Seismic facies allow accurate correlation of lithofacies between wells. Lithofacies allow more detailed interpretation of seismic parameters, such as [http://wiki.seg.org/wiki/Dictionary:Reflection reflection] patterns.

==See also==

==See also==

[[Category:Exploring for stratigraphic traps]]

[[Category:Exploring for stratigraphic traps]]

[[Category:Basin modeling]]

[[Category:Basin modeling]]