Vertical Seismic Profiling

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Exploration Technique: Vertical Seismic Profiling

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): 60.986,098 centUSD
0.061 kUSD
6.098e-5 MUSD
6.098e-8 TUSD
/ foot
Median Estimate (USD): 76.227,622 centUSD
0.0762 kUSD
7.622e-5 MUSD
7.622e-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: Energy Source Needed, Source and Receiver spacing, Terrain, Size
Dictionary.png
Vertical Seismic Profiling:
Vertical Seismic Profile (VSP) is a technique of seismic measurements used for high resolution seismic imaging. It can also be used for correlation with surface seismic data providing velocity information and information for processing such as deconvolution parameters. The defining characteristic of a VSP is that the detectors are in a borehole.
Other definitions:Wikipedia Reegle


 
Introduction
In the most common type of Vertical Seismic Profiling (VSP), 3C geophones or 3C accelerometers are placed in the borehole to record first arrival energy and reflected seismic energy originating from a seismic source at the surface. The direct arrivals are used to generate the velocity model and the reflected energy is used to image the geologic formation including the reservoirs.
 
Use in Geothermal Exploration
VSP can be applied to geothermal exploration through the calibration and refinement of surface seismic methods in order to better constrain the subsurface model. VSP assists in providing calibration parameters such as identification of seismic reflectors, defining reflector dip, adjusting reflection coefficients, and improved knowledge of appropriate seismic data processing inputs such as deconvolution operators and amplitude decay functions.[1]

Also, VSP has been applied to geothermal wells to determine fracture content, fracture orientation and fracture spacing in a geothermal well.[2]


 
Field Procedures
There are numerous methods for acquiring a vertical seismic profile (VSP).

  • Zero-offset VSPs have sources close to the wellbore directly above receivers.
  • Offset VSPs have sources some distance from the receivers in the wellbore.
  • Walkaway VSPs feature a source that is moved to progressively farther offset and receivers held in a fixed location.
  • Walk-above VSPs accommodate the recording geometry of a deviated well, having each receiver in a different lateral position and the source directly above the receiver.
  • Salt-proximity VSPs are reflection surveys to help define a salt-sediment interface near a wellbore by using a source on top of a salt dome away from the drilling rig.
  • Drill-noise VSPs, also known as seismic-while-drilling (SWD) VSPs, use the noise of the drill bit as the source and receivers laid out along the ground.
  • Multi-offset VSPs involve a source some distance from numerous receivers in the wellbore. 3D and 4D VSP surveys have become more common since 1998 when the first long down hole seismic array became available.

3D and 4D VSP surveys have become more common since 1998 when the first long down hole seismic array became available.


 
Physical Properties













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