地学前缘 ›› 2023, Vol. 30 ›› Issue (4): 112-127.DOI: 10.13745/j.esf.sf.2022.10.23

• 深层陆相碎屑岩常规油气地质 • 上一篇    下一篇

松辽盆地梨树断陷构造沉积学特征及发育机制

王宏语1(), 李瑞磊2, 朱建峰2, 张浩宇1   

  1. 1.中国地质大学(北京) 能源学院, 北京 100083
    2.中国石化东北油气分公司, 吉林 长春 130062
  • 收稿日期:2022-08-07 修回日期:2022-09-10 出版日期:2023-07-25 发布日期:2023-07-07
  • 作者简介:王宏语(1973-),男,博士,教授,博士生导师,主要从事含油气盆地沉积学、层序地层学教学与科研工作。E-mail: wanghy@cugb.edu.cn
  • 基金资助:
    国家自然科学基金面上项目(42072175)

Tectono-sedimentary characteristics and formation mechanism of the Lishu rift depression, Songliao Basin

WANG Hongyu1(), LI Ruilei2, ZHU Jianfeng2, ZHANG Haoyu1   

  1. 1. School of Energy Resources, China University of Geosciences (Beijing), Beijing 100083, China
    2. Northeast Oil and Gas Branch of Sinopec, Changchun 130062, China
  • Received:2022-08-07 Revised:2022-09-10 Online:2023-07-25 Published:2023-07-07

摘要:

梨树断陷是一个具有复杂构造沉积特征的箕状断陷湖盆,在松辽盆地深层断陷群中具有代表性。本文以大量的三维地震与钻井资料为基础,通过构造解释与沉积学分析,揭示该区整个断陷过程中的构造与沉积特征,总结其演化规律,分析其控制因素,明确盆地的构造沉积学特征及演化机制;一方面为该区深层储层与圈闭预测研究提供地质依据,另一方面也为松辽盆地其他断陷的构造沉积学深入研究提供实例参考。研究表明,早白垩世的左旋拉伸应力背景及数次挤压构造活动造就了该区断陷过程中发育了多个亚构造阶段,经历了由断陷初期的多个“小而陡”的次级小断陷,向强烈断陷期的一个“西断东超”统一箕状断陷湖盆,再向断陷晚期的“盆缓、域广”浅水湖盆的演化历程。在断陷期的不同阶段,不整合面类型多样、成因各异;初始裂陷阶段区域地层抬升与断块掀斜均有发生,造成不整合的多类型样式;强烈断陷期更多发育断块旋转、掀斜造成的角度不整合;而在断陷晚期,平行不整合占据了更大的不整合面积比例,体现了地层整体抬升与沉降的结果。盆地沉积充填经历了由湖-扇沉积体系向辫状河体系的演变过程;强烈断陷阶段的各层序呈现“低位域逐渐萎缩,高位域所占比例不断增大”的层序结构变化特征;裂陷晚期层序则以“横向连续、纵向加积”为主要层序结构特征。

关键词: 梨树断陷, 构造沉积学, 盆地结构, 不整合, 沉积充填, 层序地层结构, 控制因素

Abstract:

The Lishu rift depression is a typical wedge-shaped rift lake basin in the Songliao Basin with complex tectono-sedimentary features. This paper, based on tectono-sedimentary analysis using large amounts of 3-D seismic and drilling data, reveals the tectono-sedimentary characteristics and evolution, main controlling factors and formation mechanism of the rift depression. The results provide, on the one hand, a geological basis for the reservoir prediction in this area, and on the other hand, a practical reference for the relevant, in-depth studies of other rift depressions in the Songliao Basin. The Lishu rift depression experienced three sub-rift phases under left-handed tensile stress and multi-extrusion tectonic activities in the Early Cretaceous. It evolved from a small rift sag with few small, steep secondary rifts in the early rift stage, to a lacustrine basin with wedge-shaped half graben, bound by the Sangshutai fault along its western side, in the intense rifting phase, then to the shallow lake basin in the late rifting phase. Each of the sub-rift phases exhibited varied basin configuration and palaeo-geomorphological features. In the early rifting phase, both surface uplifting and fault-block tilting occurred, resulting in various types of unconformities. In the intense rifting phase, angular conformities were more developed due to fault-block rotation and tilting. While in the late-rifting phase paraconformities dominated, reflecting regional uplifting and subsidence. During basin evolution, sedimentary systems in the basin transitioned from lake delta to braided river systems. The sequence stratigraphic framework of the intense-rifting phase was characterized by upward “gradual shrinking of low system tracts (LST) and continuing expansion of high system tracts (HST)”; whilst late-rifting sequence featured transverse continuous sediment deposition and longitudinal alluvial accumulation.

Key words: Lishu rift depression, tectono-sedimentology, basin configuraiton, unconformity, sedimentary filling, sequence stratigraphic framework, control factors

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