Borehole source of SV-waves GeoSV

Borehole electrodynamic source GeoSV is used for generating vertically polarized shear waves (SV) in dry and water-filled wells up to 200 m deep during parallel cross-hole seismic testing (CST) with distance between boreholes 3 - 6 m. To generate P-waves a borehole sparker Pulse is usually used. Both sources require energy source Jack. The multi-wave parallel CST allows to obtain reliable vertical distributions of Vp and Vs in the crosshole medium and to calculate Poisson's ratio, as well as Young's and shear moduli proceeding to the evaluation of physical and mechanical properties.

GeoSV has a pneumatic anchoring system for fixing in a borehole, that allows to generate bipolar shear SV+ and SV- polarized waves. The advantage of using an SV source is the possibility of registering the signal with 3C VSP probe on vertical (Z) component. Thus, polarization analysis for obtaining shear wave data is not required. Source GeoSV fully complies with ASTM D4428/D4428M.

• Physical and mechanical soil properties characterization
• Soil stabilization control
• Engineering surveys for the construction of highly sensitive facilities
• Geotechnical monitoring

• Source GeoSV
• High voltage cable line on a reel
• Pneumatic tube on a reel
• Switchbox
• Energy source Jack connection cable

• Energy source Jack with JackPad remote control
• 3C borehole probe with spring (GStreamer), pneumatic (GStreamer-P) or electromechanical (GStreamer-E) anchoring system
• High frequency seismic station Sigma 4+ or DAQlink 4
• Borehole sparker Pulse
• Borehole hydrophone array WellStreamer
• Borehole inclinometer INCLIS

Parallel CST data obtained with the borehole sparker and source GeoSV. Well distance – 4 m.

From left to right: combination of SV+ and SV- data (Z component of 3C VSP probe); P-wave data (WellStreamer and Pulse); Vertical distribution of velocities of S and P waves.