oa Application of C7 Hydrocarbons Technique to Geochemical Evaluation of Asmari and Bangestan Reservoir Oils in Marun Oilfield

The purpose of this study was to examine the potential of C7 light hydrocarbons as biomarkers for<br>petroleum exploration to geochemical evaluation of Asmari and Bangestan Reservoir Oils in Marun<br>oilfield. The Oils from Asmari and Bangestan reservoirs with a variable δ13C‰ ratio -27.10 to -<br>26.77‰ PDB, and Pristane/Phytane ratio from 0.78 to 0.91 shows the source rock of this oils should<br>be marine Marl-carbonate. The isomeric parameters of C7 included single-branched and multiplebranched<br>heptanes and isomeric pairs, such as nC7/Methylcyclohexane ratio vs. Toluene/nC7 ratio, 2-<br>MH+2, 3-DMP vs. 3-MH+2, 4-DMP, n-Heptane ratio vs. iso-Heptane ratio. The ratios for<br>nC7/Methylcyclohexane and Toluene/nC7 ranged from 1.5 to 1.8 and 0.53 to 1.23, respectively. The n-<br>Heptane value and iso-Heptane value ranged from 30.5 to 39.3 and 1.55 to 1.95 respectively and the<br>iso-alkanes (3RP), cyclopentanes (5RP), cyclohexanes (6RP) ratios ranged from 20 to 47.5%, 10 to<br>15% and 41 to 70% respectively. The use of this technique as a qualitative tool shows that all the oils<br>from the Asmari and Bangestan Reservoirs were Super mature, free of biodegradation and generated<br>from marine Marl-carbonate source.