AUTOFLUID MODULE AS AN INNOVATIVE AND POWERFUL TECHNIQUE FOR HYDROCARBON IDENTIFICATION IN MATURE FIELDS WITH WIDE RANGE WATER SALINITY VARIATION

摘要

Hydrocarbon identification in oil and gas fieldsrnlocated in Mahakam area is challenging due tornvarying formation water salinity both vertically asrnwell as laterally. In the same field, the verticalrnvariation of formation water salinity is much widerrnthan lateral variation, which is in the range of 1 to 35rnkppm. The water salinity value directly affects thernformation resistivity measurement, the lower salinityrnresulting in higher resistivity values.rnHydrocarbon identification is commonly performedrnby using single resistivity cut-off. If formationrnresistivity is higher than cut-off, it is indicative of arnhydrocarbon-bearing zone. This simple methodrnworks well in a field with low variation of formationrnwater salinity, but in the fields in Mahakam area thisrnmethod results in hydrocarbon misidentification duernto the wide range of formation water salinity. Forrnproper fluid identification, a high number of wirelinernfluid analysis tools per well is routinely run inrnMahakam fields.rnA new interpretation technique, referred to as AutornFluid, has been developed, the technique of which isrnbased on the evaluation of all past fluid analysesrnresults of all existing wells in order to get morernprecise fluid identification, and with the ultimate aimrnto optimize the number of fluid analysis points to bernacquired in new wells. Fluid interpretation isrngenerated automatically by applying a resistivityrnbaseline curve varying with depth. The method hasrnbeen blindly-tested in a number of recently drilledrnwells and the results are matching with Fluid analysisrnacquisition and perforation results.rnThis paper details the method of this technique andrnits application in Mahakam fields, East Kalimantan,rnand further provides a new alternative powerful toolrnto be applied in mature fields in other areas outsidernMahakam.