Geochemical Evaluation of oils and possible source rocks in oil fields located in the west margin of qatar - kazerun fault

A comprehensive geochemical investigation is carried out on samples selected from five oil fields , located in the west margin of qatar-kazarun fault. These oilfields were vargesi , dara, sulabdar , garangan and gachsaran . The preliminary and complimentary geochemical analysis such as roch - eval pyrolysis , GC and GC-MS were carried out on rock samples for organic matter quality , kerogen typing maturation , and source rock ranking . biomarker studies also were carried out on oil samples . geochemical correlations were made between oil and rock analyses results. geochemical study results revealed that gadvan and kazhdomi formations are considered as stuitable sources for oil generation in dara and sulabdar oil fields. gadvan formation showed a good source rock property and have fair to good organic carbon richness. kazhdomi formation also exhibits the same characteristics in dara and gachsaran fields. similar results can be seen for fahlyian and surmeh formations in garangan and asmari and sarvak formations in gachsaran field. pabdeh and gurpi formations in studied oil fields have poor to fair generation potential which is similar to kazhdomi formation of nargesi field. in general an increasing maturity trend can be seen from nargesi toward gachsaran field. based on rock -Eval and biomarker results kerogen of source focks are dominantly of type II and III indicating an open marine organic matter with little terrestrial input, which are deposited in anoxic conditions.

Keywords:

rock - eval pyrolysis , gas chromatography (GC) , biomarker , petroleum system.