Hydrocarbon gas chromatography as indicator of fluids types: A case study of Azhar field, Beni Suef Basin, Egypt

Abstract

Hydrocarbon gas chromatographic investigation is regarded as the initial indicator of a reservoir's fluid properties. This study shows the assessment of fluid types of A/R “A, E, and F” members by using gas chromatographic analysis. The analysis entails examining the gas composition found in the drilling mud. The interpretation of the lighter gas composition (C1-C5) in Azhar A-2 well indicated that the A/R “A” member is characterized by the presence of dry gas or wet gas, where Wh 0.5–17.5, Bh > Wh, and Ch < 0.5. A/R “B” and A/R “C” members are characterized by the presence of wet gas or condensate, where Wh = 0.5–17.5, Bh > Wh, and Ch > 0.5. A/R "D," A/R "E,” and A/R “F” members had been characterized by the presence of oil, where Wh was 17.5–40, Wh > Bh, and Ch > 0.5. The interval in the A/R “F” member from 6605 to 6610ft indicates the presence of residual oil with Wh > 40 in the Azhar A-2 well. A/R “F” Member in Azhar E-1X contains residual oil with Wh > 40 and Bh much less than Wh, indicating poor effective porosity net pay by the integration between gas chromatographic analysis and petrophysical data. In this study, the methane ratio and wet C5 (C1) ratio in the dry gas/wet gas zone are higher than in the oil zone.