Single-Well And Cross-Well Seismic Imaging

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Exploration Technique: Single-Well And Cross-Well Seismic Imaging

Exploration Technique Information
Exploration Group: Downhole Techniques
Exploration Sub Group: Borehole Seismic Techniques
Parent Exploration Technique: Borehole Seismic Techniques
Information Provided by Technique
Lithology: Rock unit density influences elastic wave velocities.
Stratigraphic/Structural: Structural geology- faults, folds, grabens, horst blocks, sedimentary layering, discontinuities, etc.
Hydrological: Combining compressional and shear wave results can indicate the presence of fluid saturation in the formation.
Thermal: High temperatures and pressure impact the compressional and shear wave velocities.
Cost Information
Low-End Estimate (USD): 30.493,049 centUSD
0.0305 kUSD
3.049e-5 MUSD
3.049e-8 TUSD
/ foot
Median Estimate (USD): 54.885,488 centUSD
0.0549 kUSD
5.488e-5 MUSD
5.488e-8 TUSD
/ foot
High-End Estimate (USD): 106.7110,671 centUSD
0.107 kUSD
1.0671e-4 MUSD
1.0671e-7 TUSD
/ foot
Time Required
Low-End Estimate: 1 days0.00274 years
24 hours
0.143 weeks
0.0329 months
/ job
Median Estimate: 2 days0.00548 years
48 hours
0.286 weeks
0.0657 months
/ job
High-End Estimate: 3 days0.00821 years
72 hours
0.429 weeks
0.0986 months
/ job
Additional Info
Cost/Time Dependency: Depth, Resolution
Dictionary.png
Single-Well And Cross-Well Seismic Imaging:
Single well seismic imaging (SWSI) is the application of borehole seismic sources and receivers on the same string within a single borehole in order to acquire CMP type shot gathers. Cross well seismic places sources and receivers in adjacent wells in order to image the interwell volume.
Other definitions:Wikipedia Reegle


 
Introduction
Single well seismic and cross-well seismic methods are both seismic methods in which the source and the receivers are placed down a borehole. During a single well seismic imaging (SWSI) survey, a line with the source and receivers is lowered down one borehole. There can be numerous configurations of the source and receivers. During a cross-well seismic survey the seismic source is lowered down one well and a receiver array is lowered down an adjacent well. To see an animated video (made by Schlumberger) of the cross-well seismic method click here.
 
Use in Geothermal Exploration
Single well seismic methods can be used to detect vertical or near vertical geologic structures, such as permeable fractures, faults, and geologic /stratigraphic boundaries.[1] Cross-well seismic methods are useful for determining both horizontal and vertical geologic structures between two wells. The method can be used to identify fractures, faults, stratigraphic boundaries, and calculate seismic velocities, which can give clues about rock type and porosity.

Applications of borehole seismic methods are hydrofracture monitoring, fracture mapping, and validation of drilling paths during horizontal drilling activities.[1]

 
Related Techniques

 
Field Procedures
Conceptual drawing of the cross-well seismic method.[2]
Conceptual drawing of a single well seismic imaging system integrated with Electromagnetic sensors. The system is designed to image up to 50 m from the borehole.[3]

 
Physical Properties


 
Best Practices
Typically a cross-well seismic survey will provide more valuable data because the seismic waves are allowed to travel from well to well through much more rock providing information on a larger portion of the subsurface. Single well seismic methods are useful when there is only one borehole or the boreholes are spread too far apart for cross-well surveys.[1]









 
References
  1. 1.0 1.1 1.2 Thomas M. Daley,Ernest L. Majer,Roland Gritto,Jerry M. Harris. 2000. Progress and issues in single well seismic imaging. In: 70th Annual International Meeting of the Society of Exploration Geophysicists, Expanded Abstracts; 2000/01/01; N/A. N/A: N/A; p. 1552-1555
  2. AAPG Data Pages/Search and Discovery. Online Journal for E&P Geoscientists [Internet]. 2012. [cited 2013/10/15]. Available from: http://www.searchanddiscovery.com/documents/geophysical/harris_langan/images/figure_2.htm
  3. U.S. Department of Energy. Oil & Natural Gas Projects Exploration and Production Technologies [Internet]. [cited 2013/10/15]. Available from: http://www.netl.doe.gov/technologies/oil-gas/Petroleum/projects/EP/Explor_Tech/P225.htm




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