塔里木盆地库车坳陷克拉苏构造带西部盐相关构造变形

Deformation characteristics of salt tectonics in the western part of the Kelasu structural beltin the Kuqa Depression, Tarim Basin

库车前陆盆地克拉苏构造带为塔里木盆地油气勘探重点领域,其天然气资源量超万亿立方米,但长期受困于含盐褶皱冲断带构造变形复杂等问题,导致研究区构造圈闭落实难度大。基于三维地震资料精细解释,构建构造几何学地质模型,解析克拉苏构造带横向盐相关构造样式以及构造组合特征。研究结果表明,克拉苏构造带西部分别发育阿瓦特段盐上单斜—高幅度厚盐枕—盐下高幅叠瓦+堆垛构造,博孜段盐上单斜—盐焊接+低幅盐枕—盐下低幅叠瓦+冲起构造,大北段盐上单斜+逆冲断裂—盐焊接+盐背斜—盐下低幅叠瓦+堆垛背斜构造,表现出横向上“东西分段”,纵向上“差异叠置”构造特征。结合膏岩岩层横向差异展布特征和主干断裂叠置关系,揭示阿瓦特、博孜和大北段走向构造分段差异主要取决于先存构造和盐岩厚度的不均匀性。

The western area of Kelasu structural belt in Kuqa foreland basin is a key area of oil and gas explora⁃tion in Tarim Basin,with natural gas resources of more than one trillion cubic meters.However,it has long been trapped in the problems of complex structural deformation in the western part of the salt-bearing fold thrust belt,which makes it difficult to implement structural traps in the study area.This article is based on the precise interpretation of three-dimensional seismic data in the research area,constructing a two-dimensional geometric structural geological model,and analyzing the lateral salt related structural styles and structural combination characteristics of the Kelasu salt bearing fold thrust belt.The research results indicate that in the western part of the Kelasu Structural belt,there are respectively the development of the Awat segment monocline-thick salt pil⁃low-high amplitude imbricate/stacking structure,the Bozi segment monocline-salt welding+low amplitude salt pillow-imbricate/pop up structure and the Dabei segment monocline+thrust fault-salt welding+salt anti⁃cline-imbricate/stacking anticline structure,reflecting a horizontal“east-west segmentation”.Vertically,there are structural features of“differential overlap”.To establish a three-dimensional structural model of the research area,and to further combine the lateral differential distribution characteristics of gypsum layers and the stacking relationship of main faults,it is indicated that the differences in structural segmentation of the Awat,Bozi,and Dabei blocks mainly depend on the preexisting structures and the non-uniform characteristics of salt thickness.