关键词: 克拉苏构造带, 克深构造段, 解释模型, 石油地质条件

Abstract: A number of oil and gas structures were found in Keshen structural segmentation of Kelasu structural belt, such as KL2, KS2 and KS1. The structural model is under argument because this segmentation is located in the foreland thrust belt with complicated structural deformations. Based on the previous understanding and with the help of surface outcrop and drilling data, a T-Q full level interpretation was made on 3D data of Keshen segmentation. The structural interpretation model of this structural segmentation was re-established to study the petroleum geological characteristics of this segmentation. The research results indicated that deformation characteristic of Keshen structural segmentation is vertically layered and south-north division of belts. It is vertically divided into four structural layers - suprasalt layer, salt layer, subsalt layer and basement layer. There are three main structural patterns developed in this area, such as thrust fault with the related folds, salt contractive structure and strike-slip structure. Of those, the structural pattern of subsalt layer is gradually turned into cap decollement structural pattern from high-angle basement curled structural pattern from the north to the south. The present-day structure of Keshen segmentation was shaped mainly in the middle and late periods of Cenozoic era and experienced four development stages, such as Late Permian-Triassic foreland basin, Jurassic-Cretaceous sag basin, Paleocene-Miocene weak contractive flexure basin and Pliocene-Quaternary intra-continental foreland basin. The practice of exploration showed that this area, with favorable conditions of good cap-rock, thick reservoir, large structure, strong injection and late accumulations, was the important target for foothill natural gas exploration in Kuqa Depression.