阿曼盆地北部埃迪卡拉系—寒武系油气勘探目标及前景：基于E-C 转换期的构造与沉积证据

作为全球古老含油气盆地的代表，阿曼盆地埃迪卡拉系—寒武系含油气系统（下组合）具有典型的复杂地质构造背景与深层特性，勘探难度大。在阿曼盆地北部油气地质特征（烃源岩、油源对比、构造圈闭等）已有研究基础上，梳理与解剖晚新元古代—早古生代全球古构造背景与埃迪卡拉纪—寒武纪转换期（E-C期）沉积格局，探讨并分析阿曼盆地北部深层油气勘探潜力与风险。研究表明：（1）游离于原特提斯洋的华南板块于早古生代初期向东冈瓦纳大陆北缘的俯冲聚合使阿曼（阿拉伯）盆地与四川（上扬子）盆地在埃迪卡拉纪（震旦纪）—寒武纪构造—沉积特征上具有相似性；（2）阿曼盆地北部深层地震剖面揭示了早寒武世发育的典型张性构造，暂命名为“北阿曼拉张槽”；（3）拉张槽两侧古地貌高地具有优质（潜在）白云岩储层（Buah组、Birba组）的发育条件，拉张槽的形成有利于槽内Ara群U/Athel组、Dhahaban组等优质烃源岩的沉积。深层油气地质特征评价指示阿曼盆地北部（5区）下组合具有良好的油气勘探前景。

Tectonic and Sedimentary Evidences for Oil and Gas ExplorationTargets and Prospects of the Ediacaran-Cambrian Petroleum Systemsin the Northern Oman Basin (Block 5)

As one of the most representative petroliferous basins worldwide with the development of ancient petroleum systems, the Ediacaran-Cambrian petroleum systems in the northern Oman Basin has typical geological features of complex tectonics in deep strata. This results in the difficulty of oil and gas exploration. Based on the study of the petroleum geology characteristics (including source rocks, oil-source correlation, structural traps, etc), combined with addressing global paleo-tectonic background during the Late Neoproterozoic-Early Paleozoic and sedimentary patterns of the Ediacaran-Cambrian transition period, this study analyzed the exploration potential and risk of the regional petroleum systems in the northern Oman Basin. Results showed that the subduction and aggregation of the South China Block (distant from the Proto-Tethys Ocean) towards to the northern edge of the Gondwana Continent in the Early Paleozoic caused the Oman (Arabia) Basin and the Sichuan (Upper Yangtze) Basin share similar tectonic and sedimentary features during the Ediacaran (Sinian)-Cambrian. The interpretation of the deep seismic profiles revealed a typical extensional structure in the Early Cambrian northern Oman Basin, temporarily termed as “North Oman intracratonic sag”. The paleogeomorphic highlands on both sides of the intracratonic sag develop potentially high-quality dolomite reservoirs, e.g., the Buah and Birba formations. The formation of intracratonic sag is conducive to the deposition of highquality source rocks such as the U/Athel and Dhahaban formations. Petroleum geology evaluation of deep strata indicated that the low assemblage of the northern Oman Basin (Block 5) has good oil and gas exploration prospects.