USE OF RESISTIVITY LOGS TO CALCULATE WATER SATURATION AT PRUDHOE BAY

At the time of this work, induction- and porosity-log measurements wer e available in more than 180,000 ft of hydrocarbon column from 428 wel ls. Water saturations were determined from this areally and vertically extensive database after calibration to oil-base-core (OBC)-derived w ater saturations. This paper presents the method used to calibrate the log data to the OBC water saturations and reviews the methods used to derive resistivity and formation factor values. It also presents fiel d measurements of as-received core-plug resistivity and water-saturati on values from two oil-base-mud (OEM)-cored wells. Comparisons are pre sented with both field water saturations and ''routine'' electrical-pr operty measurements on extracted plugs.