扎格罗斯盆地油气成藏特征及分布规律

扎格罗斯盆地是我国油气公司海外勘探的重要区域。基于最新油气田资料,系统分析了盆地的油气地质特征,总结了油气分布规律,并探讨了其主控因素。结果表明扎格罗斯盆地主要发育志留系、三叠系、侏罗系和白垩系四套主力烃源岩及古近系次要烃源岩,其中白垩系烃源岩贡献最大。碳酸盐岩是盆地的主要储层类型,从二叠系至中新统均有分布,其中上白垩统班吉斯坦(Bangestan)群和渐新统-下中新统阿斯马里组(Asmari)是主力产层;碎屑岩为次要储层,大部分位于土耳其境内的托罗斯褶皱带内。受造山运动挤压褶皱作用控制,盆地主要发育背斜构造圈闭,且油气总体上表现出垂向运移的特征。分析认为迪兹富勒坳陷、基尔库克坳陷和帕卜德赫坳陷蕴含了盆地绝大多数的油气资源,且新生界和白垩系的油气最为富集,其分布规律主要受控于烃源岩展布、圈闭分布、断层和裂缝发育程度及区域盖层的共同作用。

Hydrocarbon accumulation features and distribution of oil and gas in the Zagros Basin

The Zagros Basin is an important overseas exploration area. Based on the latest data of oil and gas fields, the petroleum geology characteristics were systematically analyzed, the distribution rule was summarized, and the controlling factors were discussed. The results show that the main source rocks of Silurian, Triassic, Jurassic and Cretaceous and the secondary source rocks of Paleogene were developed in Zagros Basin, of which the Cretaceous source rocks contribute the most. Reservoirs in the Zagros Basin are predominantly carbonate, which are distributed from Permian to Miocene. The most significant reservoirs are the Upper Cretaceous Bangestan Group and the Oligocene-Lower Miocene Asmari Formation. Clastic rocks are secondary reservoirs, most of which are located in the Tauros suture zone in Turkey. Controlled by orogenic compression and folding, anticlinal structural traps were mainly developed in the basin, and oil and gas migrated vertically in general. The analysis shows that the Dezful, Kirkuk and Pabdeh depression contain most of the oil and gas resources in the basin, while the Upper Cenozoic and Cretaceous strata are the most abundant. The distribution of oil and gas is jointly controlled by the development of source rocks, anticline traps, faults and fractures, as well as regional seals.