渤中凹陷北部弧形断层构造特征及地质意义

渤中凹陷周缘是重要的油气聚集带，而其北部至今尚未有油气田发现，断层与油气具有密切关系，不仅控制着圈闭的形成和演化，也是油气运移的重要通道之一，因此，开展断层构造特征的研究具有重要意义。通过精细解析渤中凹陷北部三维地震资料，对其断层发育特征、活动特征、成因机制以及石油地质意义进行了详细分析。研究结果表明，渤中凹陷北部发育层间、阶梯状的弧形正断层。在垂向上，断层的活动强度具有中间强两边弱的特征，在平面上，断层演化为简单侧向生长模式。综合分析断层的生长指数和断开层位，认为断层活动时期主要为东二下段第II期到东二上期。断层的形成演化过程可以划分为4个阶段，包括断层孕育期、断层活动期、断层迁移期和断层静止期。指出重力滑动作用和走滑作用共同控制了弧形断层生长发育过程。探讨了断层形成演化对油气成藏的控制作用，认为弧形断层的生长发育有利于滚动背斜圈闭的形成，控制了砂体的层数和厚度，促进烃源岩与储层沟通，有利于油气聚集成藏。

Arc Fault Characteristics and Implications for Petroleum Geology in the North of Bozhong Depression

The periphery of Bozhong Depression is an important oil-gas accumulation zone, but no oil-gas fields have been found in the north of Bozhong Depression so far. Faults are closely related to oil-gas, not only a controlling factor of the formation and evolution of traps, but also one of the important channels of oil-gas migration. Therefore, it is of great significance to study the structural characteristics of faults. Based on the detailed analysis of the three-dimensional seismic data in the north of Bozhong Depression, this paper analyzes the characteristics of fault development, activity, genetic mechanism and petroleum geological significance. The research results show that there are interlayer and stepped normal arc faults in the north of Bozhong Depression. In the vertical direction, the activity intensity of the fault is strong in the middle and weak on both sides. In the horizontal direction, the fault evolves into a simple lateral growth mode. Based on the comprehensive analysis of the fault growth index and faulted horizon, it is considered that the fault activity period should be from II segment of the Ed₂^L to the deposition of the Ed₂^U. The process of fault evolution is divided into four stages, including fault incubation period, fault activity period, fault migration period and fault static period. It is pointed out that both gravity sliding and strike sliding control the growth and development of arc fracture. It is considered that the growth and development of arc-shaped faults are beneficial to the formation of rolling anticline traps, to the control of the number and thickness of sand bodies, to the promotion of the communication between source rocks and reservoirs, and to the accumulation of oil and gas.