Role of The Diagensis in Evolution of Fat'ha Formation as Petroleum Cap Rocks

Petrographical, petrophysical and facies studies of seven surface and subsurface locations of Fat'ha Formation from Mosul area and Kirkuk oil field, reveal that the diagensis played an important role in the evolution of the nodular sulfate as petroleum cap rocks; and this role increases with an increase of diagenetic growth and compaction. The occasional presences of bitumen inclusions within both, nodules and the host material of some sulfate bed bases is thought to be formed due to early leakage of the hydrocarbon through the host material. This leakage was gradually diminished and finally stopped due to the growth and the packing of the sulfate nodules and the disappearance of the most of the host material.