库车坳陷西段盐构造及其与油气的关系

Salt tectonics in the western Kuqa Depression and its relation to oil and gas distribution

根据断层相关褶皱理论和盐构造理论 ,结合地面地质调查和地震剖面的精细解释 ,厘定了库车坳陷西段下第三系库姆格列木群的膏盐岩层系的盐上、盐下和盐间构造样式、分布及形成机理。其中典型盐构造样式有盐核背斜、外来盐、盐枕、盐焊接和断层焊接、盐缩颈、盐成凹陷和“鱼尾”构造。盐构造的形成分两个阶段 ,即早期初始形成阶段 ( 65～ 1 64Ma)和晚期挤压构造定型阶段( 1 64Ma前后 )。变形早期盐上层的重力滑动和顺层挤压决定了克拉苏构造带盐上、盐下不同的构造组合 ,秋立塔克构造带受滑脱传力作用 ,构造样式与盐层厚度和断层交切方式等有关。结合石油地质资料 ,讨论了盐构造的油气分布规律 ,并预测了有利勘探区带。

According to the theories of fault-associated folds and salt tectonics,and based on the field work and seismic data interpretation for the western Kuqa Depression,the tectonic styles of the overburden,the salt sequence and the substrate,and their distribution,and formation mechanism were determined.The typical salt tectonic styles include salt cored anticlines,allochthonous salt,salt pillows,salt(fault) welds,salt necking,salt-associated depressions and 'fish-tail'structures.The evolution of salt tectonics can be divided into two stages of early inceptive deformation (65～1.64 million years) and late compression deformation (about 1.64 million years).The two kinds of deformation,gravity sliding and layer-parallel compression in the early stage determined structural assemblages of the Kelasu tectonic belt.Deformation and tectonic styles in Qiulitake tectonic belt were caused by compression transmitted though the overburden detachment and were controlled by the thickness of salt layer and the crossed way of back thrust faults,respectively.The petroleum implication of the salt structures was discussed,and potential exploration areas were forecasted,based on some petroleum data.