THE OPERATION OF BOREHOLE LOGGING EQUIPMENT IN BOREHOLES CONTAINING SALINE SOLUTIONS

摘要

It is shown that an electrochemical potential can be developed between the armour of the logging cable and the borehole casing when the hole contains a saline fluid. Spurious indications on the instrument are attributed to noise pulses generated when this galvanic cell is short circuited by probe movement;the effect is investigated in some detail. Simple modifications to the Type 1417A instrument circuit are described which permit discrimination against galvanic noise. The modified equipment has been proved satisfactory on a field test.