Difference between revisions of "Fault imaging"

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This page is currently being authored by a student at the University of Houston.  This page will be complete by July 2018.
 
 
 
Fault imaging is the process in which [[Fault|faults]] are processed, identified, and visualized in various ways while conducting seismic exploration. There are multiple motivations for seismically imaging faults. Generally, the goal is to better understand the structural geology of an area, which can range in scale from basin to small-scale reservoir modeling of single formations.   
 
Fault imaging is the process in which [[Fault|faults]] are processed, identified, and visualized in various ways while conducting seismic exploration. There are multiple motivations for seismically imaging faults. Generally, the goal is to better understand the structural geology of an area, which can range in scale from basin to small-scale reservoir modeling of single formations.   
  
== Fault terminology and identification in the subsurface ==
+
== Fault terminology ==
 
Source 1: Structural Geology textbook by Haakon Fossen
 
Source 1: Structural Geology textbook by Haakon Fossen
 
+
[[File:Fault types.png|thumb|Figure 1: Types of faults]]
A [[fault]] is "any surface or narrow zone with visible shear displacement along the zone" (Fossen). It is comprised of a hanging wall and a footwall as seen in the '''figure'''.   
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A [[fault]] is "any surface or narrow zone with visible shear displacement along the zone" (Fossen). It is comprised of a hanging wall and a footwall in non-vertical faults like the normal and thrust faults as seen in the Figur The hanging wall is above the fault plane and "hangs" on the fault zone, while the footwall is below the fault zone.e 1.   
  
 
A fault's displacement is described by its heave in the horizontal axis and throw in the vertical axis. Calculating this throw will be discussed in the following section.  
 
A fault's displacement is described by its heave in the horizontal axis and throw in the vertical axis. Calculating this throw will be discussed in the following section.  
  
== Fault interpretation in seismic exploration ==
+
== Fault importance and interpretation in seismic exploration ==
[[File:Great South Basin NZ Seismic Line.PNG|200px]]
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Faults are very important in the petroleum exploration industry for many reasons. They can behave as a [https://www.slb.com/services/technical_challenges/geomechanics/reservoir_management/fault_seal_analysis.aspx seal] or a conduit for hydrocarbon transportation to a [[wikipedia:Structural_trap#Fault_trap|trap]]. If a fault trap has a large enough volume to store oil and gas, it can become economically viable to drill and produce. When geoscientists interpret seismic data, the most straightforward way to identify a fault is by seeing a significant displacement in a set of seismic reflectors. It does not take a highly trained eye to see the many faults in the New Zealand seismic line if Figure 2. 
Discussion of traps and seals caused by faulting
 
  
calculating throw
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[[File:Great_South_Basin_NZ_Seismic_Line.PNG|200px]]
  
 
velocity modeling corrections
 
velocity modeling corrections
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=== Fault Shadow ===
 
=== Fault Shadow ===
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[[File:Fault shadow.jpeg|thumb|Fault Shadow Illustration]]
 +
Fault shadow is an issue that occurs in seismic imaging that is caused by the formations in the hanging wall having a lower seismic velocity than the rocks in the footwall. This occurs from the faulting itself, and since the hanging wall layers have a slower velocity than the [https://www.slb.com/services/seismic/geophysical-processing/velocity-modeling/seismic-velocity-model.aspx velocity model] predicted, it lowers the layers in the footwall. This can be corrected mathematically by updating seismic velocity models and correctly identifying the slower rocks.
  
 
== Sources ==
 
== Sources ==
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Practical Seismic Data Analysis by Hua-Wei Zhou
 
Practical Seismic Data Analysis by Hua-Wei Zhou
  
Elements of Petroleum Geology by Richard Selley
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Elements of Petroleum Geology by Richard Selley  
 
 
== First heading ==
 
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{| class="wikitable"
 
| This || Produces
 
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| <nowiki>== This ==</nowiki> || '''This'''
 
|-
 
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Start with a brief bit of background about the subject. Relate it to other topics, using plenty of links. Create links with a pair of square brackets around key technical words and phrases.
 
 
 
== Second heading ==
 
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You can add as many sections as you think you need to 'spiral out' from the core of the topic. Use judgment to decide when to split out a separate article.
 
 
 
=== Subheading ===
 
In longer articles, it may make sense to have another level of headings. There are not many occasions when you will need to use '''H4''' headings (four '''=''' signs), so don't go there unless it's unavoidable. Never use more than four.<ref>Matt Hall, 2013, pers. comm. Sorry, this is the best reference I can find.</ref>
 
  
 
== References ==
 
== References ==
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{{reflist}}
 
{{reflist}}
  
== See also ==
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*  
Most articles should have a '''See also''' section, containing a list of other closely related articles ''in this wiki''.
 
 
 
* [[Closely related article]]
 
  
 
== Important Papers ==
 
== Important Papers ==
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* [[Wikipedia:Wikipedia:How to structure the content|Wikipedia:How to structure the content]] — Wikipedia article about structuring content
 
* [[Wikipedia:Wikipedia:How to structure the content|Wikipedia:How to structure the content]] — Wikipedia article about structuring content
 
== Categories ==
 
Categories are listed at the very bottom of the article.
 
 
[[Category: Help]]
 
[[Category: Help]]
 
== Additional help ==
 
{{Special:Prefixindex/Help:}}
 

Latest revision as of 12:21, 13 December 2018

Fault imaging is the process in which faults are processed, identified, and visualized in various ways while conducting seismic exploration. There are multiple motivations for seismically imaging faults. Generally, the goal is to better understand the structural geology of an area, which can range in scale from basin to small-scale reservoir modeling of single formations.

Fault terminology

Source 1: Structural Geology textbook by Haakon Fossen

File:Fault types.png
Figure 1: Types of faults

A fault is "any surface or narrow zone with visible shear displacement along the zone" (Fossen). It is comprised of a hanging wall and a footwall in non-vertical faults like the normal and thrust faults as seen in the Figur The hanging wall is above the fault plane and "hangs" on the fault zone, while the footwall is below the fault zone.e 1.

A fault's displacement is described by its heave in the horizontal axis and throw in the vertical axis. Calculating this throw will be discussed in the following section.

Fault importance and interpretation in seismic exploration

Faults are very important in the petroleum exploration industry for many reasons. They can behave as a seal or a conduit for hydrocarbon transportation to a trap. If a fault trap has a large enough volume to store oil and gas, it can become economically viable to drill and produce. When geoscientists interpret seismic data, the most straightforward way to identify a fault is by seeing a significant displacement in a set of seismic reflectors. It does not take a highly trained eye to see the many faults in the New Zealand seismic line if Figure 2.

Great South Basin NZ Seismic Line.PNG

velocity modeling corrections

Processes of seismic imaging of faults

Ray-based Seismic Modeling

Post vs pre-migration

seismic attributes

Common issues

Fault Shadow

Fault Shadow Illustration

Fault shadow is an issue that occurs in seismic imaging that is caused by the formations in the hanging wall having a lower seismic velocity than the rocks in the footwall. This occurs from the faulting itself, and since the hanging wall layers have a slower velocity than the velocity model predicted, it lowers the layers in the footwall. This can be corrected mathematically by updating seismic velocity models and correctly identifying the slower rocks.

Sources

Correct citations to come

Fault Interpretation During SeismicInterpretation and Reservoir Evaluation: Fractured Reservoirs: Origin, Description, Evaluation by M. E. Badley, B. Freeman, A. M. Roberts, J. S. Thatcher, J. Walsh, J. Watterson, G. Yielding

Fault Shadow Correction Methodology P. Julien1, J. L. Broyer2, O. Bernet-Rollande3

Advances in Seismic Fault Interpretation Automation* By Randolph Pepper1 and Gaston Bejarano1

Structural Geology texbook by Haakon Fossen

Practical Seismic Data Analysis by Hua-Wei Zhou

Elements of Petroleum Geology by Richard Selley

References

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Important Papers

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External links

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