Equipment & Software for Geophysical Surveys: Design, Manufacture, Support, Supply

Multi-component downhole seismic array GStreamer

Main features:
  • Multi-component seismic data registration
  • Most compact and lightweight
  • Works in wells with a diameter of 70 to 150 mm
  • Remote clamping without air pump
  • Works in dry and water-filled wells
1 level with 100 m cable
1 level with 100 m cable 2 levels with 100 m cable 4 levels with 100 m cable 8 levels with 100 m cable
Price: on request
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Multi-component downhole seismic array GStreamer is the most compact on the market, cost effective solution for 3C borehole engineering and environmental surveys such as VSP and crosswell tomography. GStreamer is compatible with any modern seismograph, if you do not have any, DAQlink4 can be used for data recording.

We developed an easy-to-operate downhole tool with robust deployment and clamping system. Deployment is performed by placing multi-level 3C geophone array into the borehole without need of additional depressors. Once the borehole array is placed in the well, all units are clamped simultaneously by simply pulling the secure wire, bringing array in operational mode. Comparing to the pneumatic clamping, the use of springs is significantly more advantageous, since it provides excellent clamping of each probe with an anchor-to-weight ratio similar to large VSP systems and does not depend on the relative depth of the modules and different hydrostatic pressure at different depths.

GStreamer is significantly lighter and smaller comparing to electromechanical clamping systems that results in exceptional simplicity of field operations – they can be performed by only one person without use of additional winches.  The absence of electronic components in GStreamer makes it extremely reliable and easy to use.

Each geophone pod housing contains 3 component sensors (2 geophones on each component to increase signal level), combined orthogonally. GStreamer array configuration is quite flexible - it can be manufactured with up to 8 levels, interval between the tools is on the customer’s choice.

Combination of GStreamer array, Jack energy source and SHock borehole source provides modern acquisition setup for compressional (P) and shear (S) waves generation and registration. Registered wavefields are used to determine P- and S-wave velocity profiles which are typically used for Poisson’s ratio and other elastic modulus estimation, required for various engineering applications, such as foundation studies, soil and rock mechanics and earthquake engineering.

Often P wave model estimation would be enough to solve the geological task, using hydrophone WellStreamer. In case wells are not water-filled, it would not be possible to use hydrophone streamers to register seismic signal, while GStreamer works well both in dry and water-filled wells.

The geophone array can be supplied on a reel with slip ring, which allows to leave the equipment plugged into it while winding and unwinding the cable.

VSP and crosshole data processing requires efficient and sophisticated processing flow. RadExPro seismic software provides all necessary algorithms for multi-component data processing – hodogram analysis, 2C/3C component orientation, wavefield separation, velocity modelling, corridor stacking and well tie to reflection seismic data. Velocity model, Quality factor and other attributes can be estimated by seismic tomography in ZondST2d and ZondST3d software. Geodevice provide processing and consultancy services.

Examples of data, acquired by GStreamer and processed in RadExPro software and ZondST2d are shown below.

Raw VSP section, acquired by GStreamer geophone array and P-wave energy source
Vertical (Z-) component. Distance between the borehole and source (sledgehammer) is 5 m. Trace spacing is 1 m, depth range: 5–124 m.
Example of field data for VSP on P- waves, obtained with usage of GStreamer geophone array Example of field data for VSP on P- waves, obtained with usage of GStreamer geophone array
VSP section, acquired by GStreamer geophone array and SH-wave energy source
“Right” and “left” shots were performed using SHock energy source to generate SH+ and SH- polarized seismic gathers. Rotation of the components was performed using 3C orientation routine in RadExPro software and resulted in clear SH-wave energy on X component. Subtraction of reverted polarity gathers enhanced signal-to-noise ratio with removing any residual P-wave energy. Seismic gather after such preprocessing and 3C-orientation is shown. Distance between the borehole and the source (sledgehammer, horizontal blows) is 0.6 m. The trace spacing is 1 m, the depth range: 1–120 m.
Example of field data for VSP on S- waves, obtained with usage of GStreamer geophone array
Raw VSP section, acquired by GStreamer geophone array and SH-wave energy source
Distance between the borehole and source (sledgehammer, horizontal shots) is 0.6 m. Trace spacing is 1 m, the depth range: 1–120 m. VSP section, its amplitude spectrum and extracted S-wave velocity profile are shown.
Example of field data for VSP on SH- waves, obtained with usage of GStreamer geophone array

Geodevice offers equipment for borehole seismic surveys as well as acquisition, education and processing services. 

Number of modules in array

1 - 8 pc

Number of channels in module

3 pc

Compensation coupled geophones

yes

Natural frequency of geophones

12.5 Hz

Maximum operating pressure

15 atm.

Interval between modules in array

1 - 10 m

Maximum diameter of module

60 mm

Borehole diameter range

70 - 150 mm

Clamping force range

1:7 - 1:11

Remote snapping of springs

yes

Operation without plummet in the well

yes

Compatible with linear seismic stations

yes