摘要
以库车前陆冲断带西部古近系盐岩层系为重点,研究盐构造主应力方向和垂直挤压方向的变形特征,探讨库车前陆冲断带西部盐构造形成的控制因素及其形成机理。通过三维离散元数值模拟方法,以克深和大北工区为例,对库车前陆冲断带西部典型盐构造的形成机制进行分析。研究得出:克深和大北工区的盐构造变形是前展式的,且变形主要集中在山前位置;靠近挤压端基底的早期隆起、先存断裂、同沉积作用以及盐岩层的初始沉积中心,影响了盐构造的形成;垂直挤压方向上,靠近挤压端的盐岩具有较强的侧向流动性,盐岩有向中部运动的速度分量,且越靠近中部运动速率越大,导致盐岩向中部聚集并强烈变形,发育复杂的褶皱样式并出现盐构造与源盐分离的构造组合,局部随逆冲断层冲破地表。相较于二维模拟研究,三维模拟能够完成盐构造主应力方向及其垂直方向的多角度分析,完整认识盐构造形成机制,为盐构造相关油气藏的勘探提供指导。
Taking the Paleogene salt strata in the west of Kuqa foreland thrust belt as study object, the deformation features of salt structure in the compression direction and perpendicular to the compression direction were examined to find out the control factors and formation mechanisms of the salt structures. By using the three-dimensional discrete element numerical simulation method, the formation mechanisms of typical salt structures of western Kuqa foreland thrust belt in Keshen and Dabei work area were comprehensively analyzed. The simulation results show that the salt structure deformation of Keshen and Dabei work areas is piggyback type, with deformation concentrated in the piedmont zone;early uplift near the compression end basement, pre-existing basement faults, synsedimentary process and the initial depocenter of the salt rock affect the formation of the salt structure;in the direction perpendicular to the compression direction, the salt rock near the compression end has stronger lateral mobility and velocity component moving towards the middle part, the closer to the middle, the bigger the velocity will be, so the salt rock will aggregate towards the middle and deform intensely, forming complex folds and separation of salt structure from salt source, and local outcrop out of ground with thrust fault. Compared with 2D simulation, 3D simulation can analyze the salt structure in the principal stress direction and direction perpendicular to the principal stress, give us a full view of the formation mechanisms of salt structure, and guide the exploration of oil and gas reservoirs related to salt structures.
作者
李江海
章雨
王洪浩
王殿举
LI Jianghai;ZHANG Yu;WANG Honghao;WANG Dianju(The Key Laboratory of Orogenic Belts and Crustal Evolution,Ministry of Education,School of Earth and Space Sciences,Peking University,Beijing 100871,China;Institute of Oil and Gas,Peking University,Beijing 100871,China)
出处
《石油勘探与开发》
SCIE
EI
CAS
CSCD
北大核心
2020年第1期65-76,共12页
Petroleum Exploration and Development
基金
国家科技重大专项“大型油气田及煤层气开发”（2016ZX05033002,2016ZX05033001）
关键词
塔里木盆地
库车坳陷
前陆冲断带
盐构造
三维离散元数值模拟
形成机制
Tarim Basin
Kuqa Depression
foreland thrust belt
salt structure
three-dimensional discrete element numerical simulation
formation mechanism
