海相油气地质2025，Vol.30Issue(2)：167-176,10.DOI:10.3969/j.issn.1672-9854.2025.02.007
库车坳陷白垩系沉积前古地貌及对沉积的控制作用
Pre-Cretaceous paleogeomorphology and its control effect on sedimentation in Kuqa Depression
摘要
Abstract
Paleogeomorphology plays an important controlling role in the spatial distribution characteristics of sedimentation.Based on the structural restoration of 16 typical north-south geological profiles by using balanced cross-section techniques,the pre-Cretaceous paleogeomorphology in Kuqa Depression has been reconstructed,and its control effect on sedimentation has been analyzed.Firstly,based on the calculation of the shortening amount of the balanced profile,the northern boundary of the pre-Cretaceous sedimentary basin in Kuqa Depression is calculated.Then,based on the restored thickness data of the Cretaceous stratum,the pre-Cretaceous paleogeomorphology of Kuqa Depression is mapped.Finally,a paleogeological map of the Kuqa Depression at the end of the Jurassic is compiled based on the restored balanced profile,and the controlling effect of paleogeomorphology on sedimentation is analyzed.The results show that:(1)The north-south geological profile of the Kuqa Depression has a structural shortening amount ranging from 3.74 to 26.02 km since the Early Cretaceous,with a structural shortening rate ranging from 3.76%to 24.74%.The structural deformation is mainly concentrated in the mountainous areas of the southern Tianshan Mountains.Based on the calculation according to the angle between the geological profile and the normal to the structural strike,the current basin boundary has shifted southwards by a minimum of 3.70 km and a maximum of 25.19 km compared to the pre-Cretaceous boundary.(2)The pre-Cretaceous paleogeomorphology is characterized by alternating uplift and depression,which can be divided into Wensu uplift,Baicheng low uplift,central subsidence area,Yangxia slope,and Yangdong low uplift from west to east.The uneven structural compression stress on the north and south sides of the Kuqa Depression,as well as the lithological differences in the internal sedimentary strata,led to the occurrence of east-west zoning characteristics of paleogeomorphology.(3)Paleogeomorphology controls the development of two sets of sedimentary systems in the Early Cretaceous Yageliemu Formation in Kuqa Depression.The northern sedimentary system develops fan delta on the east and west sides of the depression,and braided river delta in the middle of the depression.In the northern sedimentary system,the Kelasu structural belt is the favorable development area of structural hydrocarbon reservoirs,and the Yiqikelike structural belt and Yangxia sag are the favorable development areas of stratigraphic-lithologic hydrocarbon reservoirs.The southern sedimentary system develops mainly small near-source fan deltas,and stratigraphic lithologic reservoirs.关键词
古地貌/平衡剖面/去压实校正/沉积体系/白垩系/库车坳陷Key words
paleogeomorphology/balanced profile/decompaction correction/depositional system/Cretaceous/Kuqa De-pression分类
石油、天然气工程引用本文复制引用
莫涛,王珂,王俊鹏,金文正..库车坳陷白垩系沉积前古地貌及对沉积的控制作用[J].海相油气地质,2025,30(2):167-176,10.基金项目
本文受国家自然科学基金企业创新发展联合基金集成项目"环青藏高原盆山体系动力学与天然气富集机理"(编号:U22B600002)和中国石油天然气集团有限公司基础性前瞻性重大科技专项"叠合盆地中下组合油气成藏与保持机制研究"(编号:2023ZZ02)联合资助 （编号:U22B600002）
