Boreholes averaging 70m each were logged with the High Resolution Optical Televiewer® and the High Resolution Acoustic Televiewer®, 3-Arm Caliper, Temperature Conductivity and Impeller Flowmeter. The purpose of this geophysical logging was to gather information on the fracture network together with the elevations of groundwater inflows to the boreholes. The results will be used to determine how each borehole will be completed as necessary with monitoring infrastructure.
To detect groundwater flows in the borehole column the team turned to the flowmeter. Logging the probe at a range of speeds allows detection of flowrate. The probe is equipped with lightweight helical impellers mounted on double sapphire bearings. The impellers contain magnets which actuate Hall-effect switches within the probe to detect impeller rotation.
The probe can identify ingress/egress points for flow and from open fractures for geotechnical projects. Combined with the optical and acoustic televiewers the flowmeter can determine the exact depths of these flow points.
Image shows High Resolution Optical Televiewer® detailing a fracture.
