This manual introduces the function and theory of Geotech Borehole Resistivity (BR) system, including the composition, operation method, maintenance method, etc.
The Geotech Borehole Resistivity (BR) System is designed for logging shallow vertical wells. It enables the user to obtain Spontaneous Potential (SP) curves and normal and lateral resistivity curves. The system is hand-operated, with the well probe manually lowered and raised in the well to record data point by point.
| Reel capacity | approximately 500 feet (152 m) |
|---|---|
| Maximum depth with extender | 1000 feet (305 m) |
| Cable breaking strength | 320 pounds (145 kg) |
| Resistivity range (normal .25 ft) | 1000 ohm feet |
| Resistivity range (normal 2.5 ft) | 10,000 ohm feet |
| Resistivity range (normal 10 ft) | 40,000 ohm feet |
The Self-Potential Dial balances out the SP which always exists between any pair of potential electrodes. Balance is indicated when the meter needle goes to zero.
The instrument should be calibrated at the start of the logging operation and after every 50 feet (15 m) of logging.