TEMPERATURE
Temperature is sensed by a fully encapsulated AD590 temperature sensor
Located in the stainless steel probe at the bottom of the tool. The sensor produces a current directly related to the temperature.
All temperature logs should be recorded on the down run of the borehole to avoid disturbing the temperature equilibrium between hole fluids and the formation. Temperature logs are used in the determination of water level, detection of casing leaks, fluid entry or exit detection. Heat flow anomalies and minute fluid or gas leaks will also be readily detected.
FLUID CONDUCTIVITY
The Fluid Conductivity measurement is made by a four-electrode alternating current system. The voltage of operation is kept well below the dissociation voltage of water, so the fluid will behave as an ohmic resistance.
A current is applied to the fluid between two electrodes at each end of a non-conducting rod, and the voltage generated by this is measured between a pair of electrodes placed on the same rod. The current is then passed through a reference resistor to generate a voltage that drives a voltage-controlled oscillator. This operates in a manner that takes into account the voltage between the measure electrodes so that the output frequency is proportional to the ratio of the current in the fluid and the voltage across the electrodes.
The method enables contact potentials and electrode polarisation to play no part in the measurement. Although the voltage and current used both vary with the conductivity encountered, since both are measured and held constant during the brief measure period, the ratio always represents the conductivity.
Specifications
Detector Sensor array Solid State Temp Sensor and Electrode Range 0-70 Deg C / 0-400mS/m Calibration Baths of known temperature Units of measure Deg C or F and mS/m Communication Pulse Nominal Current 40 Power at Sonde (VDC) 40 Pressure Rating (KPg/PSI) 21000/3000 Temp Rating ( Degrees C) 0-60 Diameter (mm) 43 Length (mm) 900 Weight (Kg) 3.6
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