柴达木盆地新生代不同层次构造特征

Characteristics of Structures of Various Levels in the Qaidam Cenozoic Basin

应用柴达木盆地地震、非地震资料进行综合解释研究发现,新生代盆地深、浅层构造存在较大差异,盆地沉积在不同时期受到不同构造格局的控制。古近系受近东西向构造控制,新近系受北西向构造控制,显示了柴达木盆地新生代为不同时期受不同方向构造控制的大型叠合盆地。盆地地层深、浅层构造变形特征不同,深层表现为陡倾的逆冲断裂构造,以断块构造为主要特征;中浅层表现为滑脱褶皱与滑脱断裂构造;地表在背斜核部发育斜列展布的正断层构造。盆地经历了多旋回沉积和多方式的后期改造,不同的构造组合形成了不同的储油气构造模式,认识这一点对于盆地深层的油气勘探,特别是寻找隐蔽油气藏具有重要意义。

The deep and shallow structural frameworks are quite different in the Qaidam Cenozoic basin according to a comprehensive interpretation of seismic and non-seismic data. In different stages, the basin sedimentation is controlled by different structural frameworks. The nearly E-W-trending structures controlled the basin sedimentation in the Paleogene and the NW-trending structures controlled the basin sedimentation in the Neogene. It is indicated that the Qaidam Cenozoic basin is a large superposed basin controlled by structures of different directions in different stage. The characteristics of structural deformation in the deep and shallow strata are different. The fault-block structure mainly develops in the deep strata with reverse basement faults. Decollement folds and faults develop in the middle-shallow strata and the normal faults developed in the core of anticlines are diagonal combination on the surface. The basin experienced multi-cycle sedimentary evolution and later deformations of various types. Different structure combination forms different structural reservoir model. It is very important to recognize these for oil and gas exploration in deep basins, especially for the concealed reservoir exploration.