uSeismic Sonde In-Borehole Acoustic Compressional (P) & Shear (S) Velocity Measurements

Sonde Specifications Piezoelectric P wave transducer Geophone S wave transducer Wide range of independent gain control Acquisition Period 5 msec to 80 msec Adjustable spacing between energy source and receivers Operates in fast hard rocks and slow formations Dipole energy source to record normal and complementary S signals Data acquisition hardware and software available Data processing software available

Operating Conditions Sonde is suspended in the borehole, no clamping Requires water\mud filled borehole Source is built into the sonde, no surface source require Can operate in PVC cased borehole

P Waveform Presentation Near P wave is shown in red Far P wave is shown in blue X axis is in milliseconds

P Waveforms In Fast Formation

P Waveforms In Slow Formation

S Wave Acquisition Transmitter Operation Transmitter fires first in Normal mode then Complementary mode. Produces complementary signals at the S receivers Aids in identification of S waves.

S Wave Presentation Red and Orange signals are the near receiver Normal & Complementary signals. Blue & light blue are far receiver Normal & Complementary signals. X Axis is in milliseconds

S Waves in fast formation

S Waves In Slow Formation Observe the normal and complementary nature of the signals. Observe the presence of P waves at around 2 msec on the near receiver.

Processing Software Features Imports the industry standard SEG2 files recorded during acquisition Provides semblance correlation tools for determining time offset between near and far receivers. Calculates velocities for both P & S signals Exports results in several formats, including industry standard LAS format.

Sonde showing major components The spacing between the transmitter and the receiver array can be adjusted by adding isolators of different lengths on top of the transmitter.

GeoVista uSeismic Sonde Sonde Dimensions Sonde diameter 50mm Sonde weight 14 kgs Sonde length 4.1 metres This is the basic length without extra isolator sections installed. Pressure rating 50 Bar as standard. Can be oil filled for higher pressure ratings. GeoVista uSeismic Sonde

11/10/2018 GeoVista 2014