柴达木盆地英雄岭构造带新生代隆升过程与油气成藏效应

Cenozoic Uplift Processes and Hydrocarbon Accumulation Effects in the Yingxiongling Tectonic Belt in Qaidam Basin

英雄岭构造带是柴达木盆地内部最大的正向构造单元,构造带及周缘蕴育了丰富的油气资源。针对构造带地质结构认识不清、初始隆升时间认识不统一、形成过程和机制不明确等问题,通过构造解析、构造演化、构造模拟、埋藏史与生烃史恢复等手段,以钻井和连片三维地震数据为基础,以时间为主线,以构造活动期次为节点,以主干地震剖面为纲,以具体构造为目,从几何学和运动学方面揭示英雄岭构造带三维空间结构和形成过程。研究表明:英雄岭构造带空间上具有南北分带展布、东西分段相接、垂向上下分层叠置的特征;新生代以来构造带演化经历了古近纪断坳、新近纪早期初始隆升和新近纪晚期—第四纪调整定型3个阶段,演化过程具有自南向北、自西向东逐次扩展的特点,构造演化与油气成藏紧密相关;青藏高原隆升背景下特殊的盆地边界条件、内部结构和应力场变换可为英雄岭构造带成藏模式建立和下一步有利勘探方向选择提供参考。

Yingxiongling Tectonic Belt is the largest positive tectonic unit within the Qaidam Basin,and the tectonic zone and its periphery are rich in oil and gas resources.To address the problems of unclear understanding of the geological structure of the tectonic belt,inconsistent understanding of the initial uplift time,and unclear formation process and mechanism,the following understandings were reached by means of tectonic analysis,tectonic evolution,tectonic simulation,and restoration of the burial and hydrocarbon history,based on the drilling wells and the continuous 3D seismic data,and by using the time as the main line,the tectonic activity period as the node,the main seismic section as the outline,and the specific tectonics as an item to reveal the 3D spatial structure and the formation process of the Yingxiongling Tectonic Belt from the geometrical and kinematical perspectives:Yingxiongling Tectonic Belt is characterized by spatial spreading of north-south zoning,east-west segmentation,and vertical up-and-down layering superposition;since the Cenozoic era,the tectonic zone has gone through three phases:Paleoproterozoic fault depression,the initial uplift in the early Neoproterozoic,and the late Neoproterozoic-Quaternary adjustment and stereotyping,and the evolution process has been characterized by the expansion from the south to the north and from the west to the east,and the tectonic evolution has been closely related with the hydrocarbon accumulation;the special boundary conditions of the basins,the internal structure,and the transformations of the stress field in the background of the uplift of the Tibetan Plateau can provide references for the establishment of the hydrocarbon accumulation model of Yingxiongling Tectonic Belt and the selection of a favorable direction of the next step of the exploration.