Tectonic-Sedimentary Evolution and Influence on Reservoir Development of Oilfields in Middle East

A series of large oil fields with structural inversion and tilted oil-water contact are developed near the Zagros thrust belt in the Middle East. According to the Paleotectonic restoration, it experienced four stages of tectonic movement with paleo-high migration after the deposition of Late Cretaceous in H oilfield. Massive porous bioclastic limestone reservoirs were developed in the Khasib, Sadi and Hartha Formation of the Upper Cretaceous, while the complex porosity and strong heterogeneity in the study area severely restrict the further development. The original oil - water contact adjusted during the tectonic evolution because of the tectonic evolution. The results show that since the Late Cretaceous, the Arabian plate and the Eurasian plate had a collision. It can be seen from the structural restored maps that the depositional center migrated along with the plate compression. Because of the migration of paleo-high, the balance of oil and water is disrupted. Due to differences in density of different fluid and gravity, the reservoir was accumulated as a layered reservoir with favorable reservoir in the south of the study area. And the Pliocene-Holocene right-lateral plate torsion may be the main reason for the tectonic reversal, stratigraphic tilting and the break of oil-gas water balance in Halfaya oilfield, West Qurna 1 oilfield, Rumaila Oilfield, Azadegan oilfield, Yada oilfield and Ahwaz oilfield.