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Hemrin oilfield consists of three domes (Albufudhul, Nukhaila and Allas) from NW to SE. This field produces the petroleum from main Tertiary reservoirs (Euphrates, Jeribe and Dhiban formations). Formation water analyses of Tertiary reservoir reflect high variation and differences in chemical and physical properties between Albufudhul, Nukhaila, and Allas domes. The present study suggests that this variation resulted by percolation of surface waters (rain water) through the fractures present in Hemrin anticline, which lead to devastation of petroleum quality. For this reason, this study highlights the hydrogeochemistry of Tertiary reservoir formation water as a result percolation of surface waters.

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Faraj ALSulaiman is a chief geologist at field division in NOC, Ministry of Oil, Kirkuk, Iraq. He received his BSc. Degree from Mosul University in general geology, and MSc. And PhD. Degrees in structural geology from Baghdad university, in 1989, 1998 respectively. Since 2000, he joined NOC as a supervisor for logging operation and interpretation.

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