Reserve Recalculation Using Hydrocarbon Interpretation from Gas Chromatograph (GC) Ratios in JR-23 Field, Northeast Jav

The very first indication of reservoir’s fluid characteristics can be interpreted using chromatograph gases as reported on mud logs. In other hand, this chromatograph interpretation can confirm what type of hydrocarbon places in the reservoir. In prior study, the characteristic of well log data in this field show that the reservoir contains gas cap in the upper part and oil zone below the gas cap zone. This gas cap interpretation effect the oil reserve and recovery factor in this field become unrealistic. Since the ratio of methane to the heavier hydrocarbon component (ethane, propane, butane and pentane) is indicative of gas, oil and water productive potential, therefore those ratios show us what is the actual fluid type contained in reservoir. Thus in otherhand this methode can be used to interpret hydrocarbon type in reservoir. From the gas chromatograph ratios comparison, the fluid type in the Zone A is light oil with high gas solution contain instead of dry gas as concluded in the prior study. This new interpretation lead us to give reserve and recovery factor calculation more realistic.