Abstract

The gas chromatography ratios using high speed chromatograph are most applicable to fluid type identification in real-time analysis. These ratios are calculated and plotted in real-time to provide an immediate input of the formation fluid characters while drilling. The values, relationships and separation of these ratio curves are used to determine the hydrocarbon fluid type, relative changes in oil gravity, gas wetness as well as the actual gas/oil and oil/water contacts. The comparison of relative concentrations of the various hydrocarbon species seen in a chromatograph has diagnostic value in estimating the quality of a hydrocarbon reservoir. The data obtained from gas ratio analysis is also useful in stratigraphic correlation using distinct characteristic of hydrocarbons to identify the reservoir boundaries, even when no lithological facies boundary is evident.