阿根廷圣豪尔赫盆地油气成藏特征及有利区预测

Petroleum accumulation characteristics and favorable exploration area prediction in San Jorge Basin,Argentina

圣豪尔赫盆地是阿根廷重要的产油气盆地之一,其演化经历了4个阶段,形成三叠纪—早白垩世裂谷和早白垩世—新生代坳陷双层结构。从区域构造沉积演化入手,结合最新钻井资料,对盆地油气成藏特征及控制因素分析后指出,烃源岩主要为上侏罗统—下白垩统Neocomian群和下白垩统D-129组湖相页岩;主要储层为白垩系Chubut群砂岩;Chubut群内的湖相泥页岩构成最重要的盖层;断、拗以及安第斯造山运动形成了丰富的圈闭类型。成熟烃源岩的分布与断裂体系控制油气的富集;河流相砂体控制油气藏规模;油气主要围绕盆地中心呈环带状分布。在此基础上,预测了白垩系Chubut群上部砂岩、白垩系D-129组与上侏罗统—下白垩统Neocomian群的勘探有利区。

The San Jorge Basin is one of the most important prolific petroliferous basins in Argentina. It experienced four tectonic evolution stages and a double-layer structure was formed,which is composed of a rift system formed in the Triassic- Early Cretaceous and a depression system formed in the Early Cretaceous- Cenozoic.Based on the study of regional tectonic and depositional evolution,integrated with the latest drilling data,hydrocarbon accumulation characteristics and controlling factors were studied. The Upper Jurassic- Neocomian Group of the Lower Cretaceous and lacustrine shale in the D-129 Formation of the Lower Cretaceous are the main source rocks. The Cretaceous Chubut Group sandstone is the main reservoir. The Chubut Group lacustrine mud shale is the most important cap. Various trap types were formed due to rifting,depression and the Andean orogeny. Hydrocarbon accumulations were controlled by the distribution of mature source rocks and fault systems. The size of oil and gas pools was controlled by fluvial facies sandstones. Oil and gas distribute circularly around the basin center. The favourable exploration areas for the upper part of the Cretaceous Chubut Group sandstone,the Cretaceous D-129 Formation and the Upper Jurassic- Lower Cretaceous Neocomian Group were predicted.