Taking Yada Oilfield as an example, this paper discussed the cause of reservoirs with tilted oil-water contact which is a widespread characteristic in the Middle East. Through 3D fine seismic interpretation of sequence boundary and systematic analysis of structural evolution, it is shown that the Zagros foreland basin in Cenozoic, which has suffered strong, multi-phase, N-S trending differential structural evolution, is the critical period of hydrocarbon accumulation. With the persistent E-W compression of Zagros, the earlier paleo-anticline trap in short axis is transformed later by the anticlinal trap in long axis as a result of structural inversion, therefore, specific reservoirs are formed with the characteristics of tilted oil-water contact, and longest oil-bearing column in sustained structural high, and longest oil-water transitional zone in stronger inversed structural high. The results show that N-S differential structural evolution has controlled the hydrocarbon accumulation pattern with tilted oil-water contact.