Downhole Seismic Survey

GT provides wireline borehole seismic services to obtain high resolution data and accurate geological picture of the reservoir, enhancing and supplementing surface seismic data.

 

Velocity Surveys

Downhole travel-time measurements produce accurate time-depth relation and seismic velocity results that can be used to calibrate surface seismic and well log data. The services include:

  • Stationary source velocity survey with near-wellhead source
  • Vertical incidence velocity survey – moving source directly above downhole receiver(s) in deviated wells

 

Vertical Seismic Profiling

VSP images the subsurface near, offset from, or beneath the well to provide critical information which can be directly correlated with well logs and surface seismic sections to improve reservoir analysis.

Downhole seismic method delivers superior data quality using the properties of acoustic waves to measure the velocity of the materials through which the waves travel.

Surveys are conducted by placing one as well as three component geophones at selected depths in the borehole to obtain shear (S) and p-wave (P) profiles of the subsurface.

 

KEY TOOLS:

GEORES Imagine VSP- GEOSPACE

HDShuttle DS-325

AVALON Geochain 48 level digital VSP array

ASR-1 Advanced Seismic Receiver

GRT-1 3-5/8” Gamma Ray Tool

 

Avalon Geochain has proved the complete VSP digital seismic system, operating with up to 48 satellites for maximum logging and recording efficiency. The Geochain VSP array can be run in open and cased holes using standard 7 conductor wireline. The array is based on the well proven ASR-1 downhole geophone and can be used in wells up to 25,000 psi (1,750 bar) and hole sizes from 31⁄2”-22” (89 to 559mm).