柴达木盆地西部古近系湖侵体系域及其相关储集体

基于对柴西地区钻孔岩心、显微镜下矿物组成和特征的观察、地震测线的处理和解释、地质和地球物理资料及其它资料的综合分析，完成了柴达木盆地柴西古近系层序地层学与隐蔽油气藏预测研究。柴达木盆地基底的构造格架及不同位置发育的深大断裂及其所决定的古地理与古气候等条件共同控制了沉积相带在时空上的展布。湖盆构造演化对沉积演化有明显的控制作用。多个不整合层序界面发育多期碎屑物质供给，但沉积物供给并不充分。可容空间持续存在，导致湖侵体系域十分发育。在湖侵体系域发育期间，柴达木盆地西部古近系易于形成与湖侵体系域相关的油气储集体及油气藏：三角洲前缘砂体上倾尖灭岩性油气藏、湖相碳酸盐岩裂缝性油气藏、深湖浊积砂岩透镜体隐蔽油气藏、层序界面控制的隐蔽油气藏以及构造断层控制的复合隐蔽油气藏。

TRANSGRESSIVE SYSTEM TRACTS AND RELATED RESERVOIR BODIES OF PALEOGENE IN WESTERN QAIDAM BASIN

Based on observation of core and thin section, SEM analysis and seismic interpretation of the Paleogene in western Qaidam Basin, the study on sequence stratigraphy and forecast of subtle oil reservoirs of the Paleogene is completed. The basement structural framework and large deep faults in different locations and related palaeogeography and palaeoclimate controlled distribution of sedimentary facies. The basin tectonics controlled sedimentary evolution obviously. Multiple unconformities led to multiple clastic sediment supply to the basin, but the supply was not sufficient to fill up the basin. Continuous existence of accommodation space led to well-developed lacustrine transgressive system tracts(LTST). During deposition of lacustrine transgressive systems tracts, the oil reservoirs and pools related to LTST were easily formed in the Paleogene of western Qaidam Basin, which included delta front sandstone updip wedging-out lithologic pools, carbonate fissure pools, deep-lake turbidite pools, subtle pools near to sequence boundary and composite subtle pools controlled by structure and fault.