塔里木盆地库车坳陷秋里塔格构造带盐构造变形特征与变形机制

As a typical thrust-fold belt in the front of the Kuqa depression, Tarim basin, the Qiulitage structural belt has launched a particular research on the deformation styles of the suprasalt strata (overburden) and constructed some salt structural models. However, because of the influence of thick salt layer, it is more difficult on the research of the structural characteristics and deformation styles in the subsalt strata of the Qiulitage structural belt. The research on the subsalt structures is still relatively weak, and there is still controversial about these previous academic viewpoints. There are still some doubts and difficulties about the research on the formation mechanism of salt structures in Qiulitage structural belt. This proposal, based on abundant seismic profiles, other geophysical data and borehole data, along with field geological investigation, structural geological analyses, analogue modeling，numerical modeling and Particle Image Velocimetry (PIV) technique, will focus on the study of the deformation characteristics and mechanism of salt structures in the Qiulitage structural belt. The aim is to discuss the structural characteristics and deformation styles in the subsalt strata of the Qiulitage structural belt, verify the influence and effect of these subsalt structures on the deformation and evolution of salt structures in the overburden, and construct the structural models of the subsalt strata, discuss the relationship between the segmental structure deformation and the physical properties, spatial distribution of rock salt in the eastern and western Qiulitage structural belt. These works will help to further understand the structural deformation of the Kuqa depression.

塔里木盆地库车坳陷前缘秋里塔格构造带，作为典型的前陆盆地逆冲褶皱带，已经开展了盐上构造层变形样式的精细研究，建立了比较精细的盐上构造模型。然而由于受巨厚盐岩层的影响，秋里塔格构造带盐下基底构造研究的难度大大增加，针对该构造带盐下基底构造的研究目前依然比较薄弱，学术观点也仍然存在比较大的争议，该构造带盐构造研究依然存在没有突破的疑点和难点。本申请将以库车坳陷前缘秋里塔格构造带作为研究区域，借助大量地震、非地震勘探与钻井资料，综合野外地质调查、构造解析、物理模拟和数值模拟实验、以及粒子成像测速（PIV）等方法技术，重点研究该构造带新生代盐构造的变形特征和变形机制，意在探讨构造带内基底构造的特征以及其如何对上覆地层盐构造变形产生影响和控制作用，建立该构造带内盐下基底构造模型，分析构造带东、西段构造分段差异变形与膏盐岩的物性差异和空间分布的相关性，进一步深化和完善对库车坳陷构造变形的认识。

库车坳陷秋里塔格构造带是位于南天山山前前陆盆地南缘的强构造变形带，带内盐构造发育丰富，且具有明显的分段差异性特征。本项目通过野外地质调查及地震资料解析，分析了库车坳陷秋里塔格构造带不同区段内盐构造变形特征，并在此基础上，通过构造物理模拟与离散元数值模拟探讨了以阿瓦特盐推覆体、却勒盐推覆体、米斯坎塔格盐背斜、南、北秋里塔格背斜和东秋里塔格背斜等盐相关构造为代表的库车坳陷前缘秋里塔格构造带盐构造变形演化机制及主要控制因素。项目研究结果表明，除盐上层同构造沉积活动、盐盆地宽度、先存盐底辟、盐盆边界或内部调解走滑断层发育外，盐岩层厚度变化以及盐下基底深部构造活动、盐下深部基底滑脱层分布等均是控制库车坳陷褶皱冲断带盐构造变形的重要因素。在上述多种因素的不同组合作用下，可导致在库车坳陷秋里塔格构造带呈现明显分段差异构造特性。同时本项目还探讨了挤压应力下先存断陷盆地构造反转变形演化特征及其浅部地层褶皱变形特征及应力应变分布特征，以及剥蚀和同构造沉积作用对褶皱冲断带构造变形演化及应力应变分布的影响。研究结果为库车坳陷盐上覆沉积地层中盐相关构造研究，以及盐下褶皱冲断带构造样式、变形传播及动力学机制研究提供了新的思路和理论模型。研究成果对于库车坳陷油气勘探部署和目标层尤其是深部地层的构造解释亦能提供实验理论支撑与资料依据。