Difference between revisions of "Reflection configuration patterns"
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==Discontinuous reflector patterns== | ==Discontinuous reflector patterns== | ||
− | Five types of discontinuous reflector patterns that help interdepositional systems are shown in [[:file:exploring-for-stratigraphic-traps_fig21-25.png|Figure 2]]. Hummocky strata may be discontinuous point bars and crevasse splays. Chaotic reflectors suggest coarse-grained fluvial or [[turbidite]] channel fills. Contorted features may be shale-prone debris | + | Five types of discontinuous reflector patterns that help interdepositional systems are shown in [[:file:exploring-for-stratigraphic-traps_fig21-25.png|Figure 2]]. Hummocky strata may be discontinuous [[Lithofacies_and_environmenta|l_analysis_of_clastic_depositional_systems#Braided_and_meandering_fluvial_deposits|point bars and crevasse splays]]. Chaotic reflectors suggest coarse-grained [http://www.merriam-webster.com/dictionary/fluvial fluvial] or [[turbidite]] channel fills. Contorted features may be shale-prone [[debris flow]]s. Precise identification of depositional environments requires integration with other data. |
[[file:exploring-for-stratigraphic-traps_fig21-26.png|300px|thumb|{{figure number|3}}Prograding reflectors and their possible depositional significance. After Mitchum et al.<ref name=ch21r31 />]] | [[file:exploring-for-stratigraphic-traps_fig21-26.png|300px|thumb|{{figure number|3}}Prograding reflectors and their possible depositional significance. After Mitchum et al.<ref name=ch21r31 />]] |
Revision as of 21:30, 24 October 2014
Exploring for Oil and Gas Traps | |
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Series | Treatise in Petroleum Geology |
---|---|
Part | Predicting the occurrence of oil and gas traps |
Chapter | Exploring for stratigraphic traps |
Author | John C. Dolson, Mike S. Bahorich, Rick C. Tobin, Edward A. Beaumont, Louis J. Terlikoski, Michael L. Hendricks |
Link | Web page |
Store | AAPG Store |
Groups of configuration patterns
Reflection configuration patterns can be divided into three groups:
- Parallel—including subparallel and divergent
- Discontinuous
- Prograding—caused by lateral accretion of strata
![](/images/thumb/5/54/Exploring-for-stratigraphic-traps_fig21-24.png/300px-Exploring-for-stratigraphic-traps_fig21-24.png)
Parallel reflector patterns
Parallel reflections include subparallel, wavy, and divergent. Parallel, subparallel, and wavy reflectors suggest uniform depositional rates on a uniformly subsiding surface, such as a shelf or basin plain. Divergent reflectors suggest lateral variations in depositional rates or progressive tilting of a depositional surface. Figure 1 shows reflection configurations for this group.
![](/images/thumb/e/e3/Exploring-for-stratigraphic-traps_fig21-25.png/300px-Exploring-for-stratigraphic-traps_fig21-25.png)
Discontinuous reflector patterns
Five types of discontinuous reflector patterns that help interdepositional systems are shown in Figure 2. Hummocky strata may be discontinuous l_analysis_of_clastic_depositional_systems#Braided_and_meandering_fluvial_deposits|point bars and crevasse splays. Chaotic reflectors suggest coarse-grained fluvial or turbidite channel fills. Contorted features may be shale-prone debris flows. Precise identification of depositional environments requires integration with other data.
![](/images/thumb/c/c9/Exploring-for-stratigraphic-traps_fig21-26.png/300px-Exploring-for-stratigraphic-traps_fig21-26.png)
Prograding reflector patterns
One of the most common depositional features observed in seismic sections are clinoforms manifested in a configuration pattern called offlap. Clinoforms are progradational strata that form through the progressive development of gently sloping surfaces. Paleowater depths can be interpreted from the height of prograding clinoforms. Figure 3 shows prograding reflectors and their possible depositional significance.
![](/images/thumb/e/e7/Exploring-for-stratigraphic-traps_fig21-27.png/300px-Exploring-for-stratigraphic-traps_fig21-27.png)
Channel fill patterns
Channels are expressed in seismic sections as negative relief features truncating the underlying strata. Fill patterns are shown in Figure 4.
See also
- Seismic facies analysis
- Basics of seismic facies analysis
- Seismic facies mapping
- Analyzing individual reflectors
- Techniques for enhancing seismic facies analysis
- Analyzing lithofacies
- Petrophysical analysis of lithofacies
References
- ↑ 1.0 1.1 1.2 1.3 Mitchum, R., M., Vail, P., R., Sangree, J., B., 1977, 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: AAPG Memoir 26, p. 117–133.