摘要
在塔里木盆地西部上白垩统—古近系中可识别出7种具典型成因意义的高频旋回层序,根据垂向上的有序叠加方式,可以建立起一个由5个Ⅳ级旋回层序、2个Ⅲ级旋回层序和一个Ⅱ级旋回层序组成的特征层序地层格架.它基本上控制着研究层位中不同沉积相和生储盖组合的时空展布特征.上白垩统在盆地西南缘形成了较厚的高水位体系域开阔台地相灰岩储层,但成岩特征受海水成岩环境控制,胶结作用强烈,致使储层呈低孔低渗特征.古近系在帕米尔山前主要为一套冲积平原-河流沉积体系产物,从中可划分出4种有利的沉积-成岩相带.由于该碎屑岩均处于早成岩阶段B期,成岩环境呈酸性,储集性能明显优于上白垩统灰岩储集层.
Seven high-frequency cyclic sequences with typical genetic implication can be distinguished in the Upper Cretaceous-Eogene in western Tarim basin. According to their vertical stacking patterns, a characteristic sequence stratigraphy can be established, which is composed of five fourth-order cyclic sequences, two third-order cyclic sequences and one second-order cyclic sequence. The sequence stratigraphy fundamentally controls the spatial and temporal distribution of different depositional facies and associations of source, reservoir and cap rocks. The Upper Cretaceous in the southwestern margin of the study area consists of a set of thick limestone reservoirs formed in HST open platform facies. Since the system was influenced by marine diagenetic environment, the reservoir porosity was seriously destroyed by intense cementation. Therefore, the Cretaceous reservoir is low in porosity and permeability. The Eogene is composed of alluvial plain-fluvial facies sediments that are lower and acidic in diagenesis, so the Eogene reservoir properties are much better than those of the Upper Cretaceous. Furthermore, four types of favorable depositional-diagenetic facies could be identified.
出处
《新疆地质》
CAS
CSCD
2002年第z1期26-30,共5页
Xinjiang Geology
基金
中国科学院资源环境领域知识创新工程重大项目(KZCX2-111)
国家(973)项目(G1999043300)资助
关键词
塔里木西部
上白垩统-古近系
层序地层格架
沉积成岩
演化
western Tarim basin
Upper Cretaceous-Eogene
framework of sequence stratigraphy
depositional- diagenetic evolution
