库车坳陷含夹层盐构造变形物理模拟

Physical modeling analysis on salt structure deformation with interbeded layers in Kuqa Depression

张希晨 罗良 杨克基 于小霞 解荣波 罗凌烟 2

中国石油大学（北京）油气资源与探测国家重点实验室，北京 102249 中国石油大学（北京）地球科学学院，北京 102249

State Key Laboratory of Petroleum Resource and Prospecting, China University of Petroleum, Beijing 102249, China Department of Geology, China University of Petroleum, Beijing 102249, China

最新的钻井、测井资料显示，库车坳陷古近系库姆格列木组盐层并非纯盐，而是由4套夹层组成。文中依据地层组合特征，设计出含夹层塑性层模型进行物理模拟研究，揭示各夹层的差异变形规律、与围岩的相互作用，以及脆性夹层变形机理。实验结果表明：底部塑性层被盐下断裂刺入，吸收逆冲位移量后刺穿上覆砂层进入顶部硅胶层；石英砂层初期受到上下塑性层剪切作用，发育密集小褶皱，然后在盐下断层下盘的弱应力区折叠增厚，形成复杂褶皱，受盐下断块逆冲位移差异控制；顶部塑性层流动最强烈，滑脱作用显著增加了盐上变形距离，底辟拱升促使上覆层褶皱变形；顶部微玻璃珠层在背斜核部发生弯流作用。由此论证了含夹层塑性层是研究库车地区盐构造的必要前提。

Latest drilling and logging data indicate the Paleogene Kumugeliemu Formation is not pure salt in Kuqa Depression, it is composed of 4 interlayers. Based on stratigraphy assemblage, the interbeded ductile layer model is devised to physically simulate the evolution of four different interlayers. This model reveal differential deformation in 4 interlayers, interaction between the ductile layer and the strata beneath and above salt, and deformation mechanism of competent interlayer. Test results show that the bottom ductile layer was pierced by faults from sub-salt strata, absorbing a large number of thrust displacements. This layer also pierced overlying sand interlayer into top ductile layer. The sand interlayer was subjected to shear action of the surrounding ductile layers, and the dense minor folds were developed. Its intensive thickening usually occur in the footwall of the sub-salt faults with complex folds, which was controlled by violent thrust action from sub-salt strata. The top ductile layer is a significant decollement with the intense flow, expanding the range of deformation and promotes folds in the upper-salt strata. The top micro glass bead layer bent and flowed in the core of anticline. Interbeded layers is an necessary prerequisite for the study of salt structures in Kuqa Depression.

10.6056/dkyqt201803011