新疆石油地质

新疆石油地质 ›› 2019, Vol. 40 ›› Issue (zk(English) ): 21-26.

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Subsalt Structural Styles of Keshen Section in the Kelasu Tectonic Belt

HOU Guiting1, SUN Shuai1, ZHENG Chunfang1, TANG Yangang2, ZHOU Lu2, MO Tao2   

  1. 1.MOE Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing 100871, China;
    2.Research Institute of Exploration and Development, Tarim Oilfield Company, PetroChina, Korla, Xinjiang 841000, China
  • 收稿日期:2018-08-01 修回日期:2018-09-03 出版日期:2020-01-01 发布日期:2021-05-18

Subsalt Structural Styles of Keshen Section in the Kelasu Tectonic Belt

HOU Guiting1, SUN Shuai1, ZHENG Chunfang1, TANG Yangang2, ZHOU Lu2, MO Tao2   

  1. 1.MOE Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing 100871, China;
    2.Research Institute of Exploration and Development, Tarim Oilfield Company, PetroChina, Korla, Xinjiang 841000, China
  • Received:2018-08-01 Revised:2018-09-03 Online:2020-01-01 Published:2021-05-18
  • About author:HOU Guiting, E-mail: gthou@pku.edu.cn

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摘要： The exploration and development practices in the Cretaceous Bashijiqike formation of the Kelasu tectonic belt in Kuqa depression reveal that the fractures are featured with vertical zonation, which are possibly constrained by neutral surfaces of anticlines. It is necessary to rebuild the structural style of the Kelasu tectonic belt because the present model for structural style classification cann’t explain thevertical zonation of fractures. Selecting the Keshen section of the Kelasu tectonic belt as the study area, taking the interlimb angle of fold asthe main element and combining with the fault combination configuration, the paper rebuilds the subsalt structural styles of the Keshen section in the Kelasu tectonic belt on the basis of 3D seismic interpretation. The results show that the structural styles of the Keshen section canbe divided into 2 types such as gentle fold and open fold according to the interlimb angle of fold; according to the fault combination configuration, the gentle fold is further divided into double-thrust gentle fold, back-thrust gentle fold and recoil gentle fold, and the open fold is divided into double-thrust and back-thrust open folds. The structures to the north of the Keshen fault are imbricate faulted anticlines made up ofopen and gentle folds, and the structures to the south of the Keshen fault are imbricate structures of gentle-fold faulted anticline. The distribution of fractures is closely related to the interlimb angle, the thickness and the distribution range of tension fissure zones in the open foldsare much larger than those in the gentle folds, and faults has an influence on the distribution of the fractures around them. The classificationof the structural style provides a foundation for the further study on the fracture development and genetic mechanism of different structuralstyles.

关键词: Kuqa depression, Kelasu tectonic belt, open fold, gentle fold, interlimb angle, structural style

Abstract: The exploration and development practices in the Cretaceous Bashijiqike formation of the Kelasu tectonic belt in Kuqa depression reveal that the fractures are featured with vertical zonation, which are possibly constrained by neutral surfaces of anticlines. It is necessary to rebuild the structural style of the Kelasu tectonic belt because the present model for structural style classification cann’t explain thevertical zonation of fractures. Selecting the Keshen section of the Kelasu tectonic belt as the study area, taking the interlimb angle of fold asthe main element and combining with the fault combination configuration, the paper rebuilds the subsalt structural styles of the Keshen section in the Kelasu tectonic belt on the basis of 3D seismic interpretation. The results show that the structural styles of the Keshen section canbe divided into 2 types such as gentle fold and open fold according to the interlimb angle of fold; according to the fault combination configuration, the gentle fold is further divided into double-thrust gentle fold, back-thrust gentle fold and recoil gentle fold, and the open fold is divided into double-thrust and back-thrust open folds. The structures to the north of the Keshen fault are imbricate faulted anticlines made up ofopen and gentle folds, and the structures to the south of the Keshen fault are imbricate structures of gentle-fold faulted anticline. The distribution of fractures is closely related to the interlimb angle, the thickness and the distribution range of tension fissure zones in the open foldsare much larger than those in the gentle folds, and faults has an influence on the distribution of the fractures around them. The classificationof the structural style provides a foundation for the further study on the fracture development and genetic mechanism of different structuralstyles.

Key words: Kuqa depression, Kelasu tectonic belt, open fold, gentle fold, interlimb angle, structural style