差异构造演化控制倾斜油水界面之实例——伊朗雅达油田

针对中东地区油藏普遍存在油水界面倾斜的特征,以伊朗雅达(Yada)油田为例对其成因进行探讨。通过对层序界面三维地震资料精细解释,以及系统的构造演化分析,认为研究区油气成藏关键期集中于新生代扎格罗斯前陆盆地演化阶段,而该阶段经历了多期较强烈的南北向差异性构造活动,在扎格罗斯东西向持续挤压背景下,后期南北向构造反转形成的长轴背斜圈闭对早期古油藏短轴背斜圈闭进行改造,从而形成了油水界面倾斜、继承性构造高点含油幅度最大、构造反转越强油水过渡带跨度越大等特征的非稳态油气藏。结果表明,研究区南北向差异性构造演化控制了油气成藏模式和油藏形态。

Control Effects on the Tilted Oil-water Contact Caused by Differential Structural Evolution:A Case of Yada Oilfield,Iran

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.