Application of Graptolites and Chitinozoans Reflectance in Maturity Assessment of Lower Paleozoic Formations, Bandar Abbas Area


Research Institute of Petroleum industry


     Maturity assessment of organic matter possess an important role in study and evaluation of petroleum systems in sedimentary basins. Maturity evaluation of lower Paleozoic strata (Seyahou and Sarchahan formations) is restricted by lake of vitrinite particles. Seyahou and Sarchahan Formations, with appropriate geochemical properties, are classified as potential source rocks of hydrocarbons in Persian Gulf Basin. Presence of zooclast in the Seyahou and Sarchahan formations make it possible to evaluate maturity state based on graptolites and other zooclast particles. Based on zooclast reflectance result, Seyahou formation in Faraghun section, with Ro value of more than 1/2%, is entered in wet gas maturity zone, and Sarchahan formation in both Gahkum and Faraghun sections, with Ro value between 1 to 1/2%, are in late oil to early gas window zone. According to this study findings, there is reliable relation between reflectance of chitinozoans and graptolites particles. Correlation coefficient of 0.945 between graptolites and chitinozoans reflectance testify similar maturity trend in these particles. On the other hand, correlation of vitrinite particle reflectance with graptolites reveals that they share common sources.


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