塔中隆起寒武—奥陶纪碳酸盐岩台地沉积体系与油气成藏条件

CAMBRIAN-ORDOVICIAN CARBONATE PLATFORM SEDIMENTARY SYSTEM AND ITS PETROLEUM ACCUMULATION CONDITIONS IN MIDDLE TARIM UPHEAVAL

由地震、钻井层序地层分析表明,寒武—奥陶纪塔中隆起经历了4种不同的碳酸盐岩台地结构型式的演变,分别为:①早、中寒武世缓坡型碳酸盐岩台地;②晚寒武世—早奥陶世弱镶边斜坡型碳酸盐岩台地;③中奥陶世—晚奥陶世早期孤立型碳酸盐岩台地;④晚奥陶世中晚期淹没型碳酸盐岩台地。4种不同类型的碳酸盐岩台地在沉积特征、沉积相类型和岩石垂向组合序列上有着显著的差异,因而它们有着不同的烃源岩和储盖组合条件。

An analysis of seismic and drill sequence stratigraphy shows that the evolution of Cambrian-Ordovician carbonate platform in the middle of Tarim area undergoes four phases: ① The gentle incline carbonate platform in early-middle Cambrian;②The gentle incline weak trimmed shelf carbonate platform in late Cambrian-early Ordovician;③Isolated carbonate platform in middle-late Ordovician;④Submerged carbonate platform in the intermediate stage of late Ordovician.These carbonate platforms have their own characters of sedimentation.The sedimentary faces types and the assembled sequences that control the rock composition vertically are distinct from each other.Therefore,the four carbonate platforms have different hydrocarbon source rocks and reservoir and caprock assemblage conditions.According to the information of the seismic and drill,we studied the sedimentary characters of the four types of platforms and then make an analysis on them.