湖南涟源凹陷构造演化与油气成藏研究

涟源凹陷经历了2个主要构造演化阶段:晚古生代海相碳酸盐岩夹碎屑岩盖层建造和中生代陆相沉积,现今的逆掩冲断构造样式和构造格局基本定型于燕山期。油气藏的形成经历了早、晚两期,早期形成于印支运动主幕,燕山运动主幕遭到破坏,部分经重新分配后形成次生气藏;晚期形成于燕山运动主幕以后,属原生油气藏。涟源凹陷中部褶断带的紧闭背斜是寻找次生气藏的首选区域,而宽缓向斜中的隐伏隆起则是寻找晚期原生油气藏的靶区。

TECTONIC EVOLUTION AND FORMING OF HYDROCARBON RESERVOIR IN THE LIANYUAN DEPRESSION, HUNAN

Based on a discussion of tectonic evolution and forming rules of hydrocarbon reservoirs,the paper thought that the Lianyuan Depression experienced two main stages of tectonic evolution: the marine sedimentary cover depositing from Middle Devonian to Early Triassic, and the continental facies sediments depositing from Middle Triassic. The existed thrust structures and the tectonic framework created in the Indosinian orogeny and fell its pattern in the Yanshanian orogeny. It was also suggested that there were two stages of forming of hydrocarbon reservoirs: the earlier hydrocarbon reservoirs were mainly oil ones which formed in the Indosinian cycle and turned into gas reservoirs in the Early Yanshanian period,then,the reservoirs reformed and became the secondary gas reservoirs in the Middle Yanshanian period. The later hydrocarbon reservoirs were oil and gas ones originally, which formed after the main episode of Yanshanian orogeny. The paper forecasted that the secondary gas reservoirs would be found in anticlines of the central syncline belt and the original oil and gas reservoirs found in buried sub-anticlines of the central syncline belt.