吴伟，周永，冯阵东，等.准噶尔盆地齐古背斜深浅层泥岩裂缝发育差异性及其制约下油气保存条件［J］.河南理工大学学报（自然科学版），2024，43（2）：49-56.

WU W，ZHOU Y，FENG Z D，et al.Differences in the development of deep and shallow mudstone fractures in Qigu anticline in the Junggar Basin and their constraints on oil and gas preservation conditions［J］.Journal of Henan Polytechnic University（Natural Science），2024，43（2）：49-56.

准噶尔盆地齐古背斜深浅层泥岩裂缝发育差异性及其制约下油气保存条件

吴伟1，周永1，冯阵东2，鲁雪松3，卓勤功3，刘惟庆1，王光绪1

1.河南理工大学 资源环境学院，河南 焦作 454000；2.河南理工大学 安全科学与工程学院，河南 焦作 454000；3.中国石油勘探开发研究院，北京 100083

摘要: 前陆冲断带油气资源丰富，但复杂构造作用下盖层封闭能力的差异阻碍油气勘探进程。目的 针对准噶尔盆地南缘冲断带地表油气泄露严重且勘探不足的问题，方法以齐古背斜深浅泥岩盖层为研究对象，在明确地层模型的基础上，结合测井资料反演与实测数据，构建研究区力学参数数值模型，运用有限元方法对齐古背斜古、今构造应力场进行模拟，并将获取的应力场数据与裂缝参数理论相结合，分析盖层的裂缝形成时期，计算现今应力场对盖层裂缝的改造结果。结果 结果表明：齐古背斜古、今应力分布受控于埋深、构造位置、断裂走向和断裂汇聚位置；现今应力场下，齐古背斜浅部盖层不易破裂，只对古构造应力场形成的裂缝起改造作用；深浅盖层裂缝发育程度差异大，背斜高点裂缝发育可能是造成浅部油气泄漏的主要原因；裂缝带在断层附近更发育，断层带附近裂缝渗透率远大于正常地层的，可能为深部油气向浅层运移甚至散失提供通道；深部盖层相对稳定，盖层条件不是制约准南下组合勘探成败的关键因素。结论 研究结果可为准噶尔盆地南缘冲断带深部油气勘探提供一定参考。

关键词:地应力；裂缝预测；盖层评价；数值模拟；侏罗系；齐古背斜

doi:10.16186/j.cnki.1673-9787.2021120118

基金项目:国家自然科学基金资助项目（41872112）

收稿日期: 2022/12/29

修回日期: 2023/02/28

出版日期:2024/03/25

Differences in the development of deep and shallow mudstone fractures in Qigu anticline in the Junggar Basin and their constraints on oil and gas preservation conditions

WU Wei1，ZHOU Yong1，FENG Zhendong2，LU Xuesong3，ZHUO Qingong3，LIU Weiqing1，WANG Guangxu1

1.School of Resources & Environment， Henan Polytechnic University，Jiaozuo 454000，Henan，China；2.College of Safety Science and Engineering，Henan Polytechnic University，Jiaozuo 454000，Henan，China；3.Petro China Research Institute of Petroleum Exploration and Development，Beijing 100083，China

Abstract: The foreland thrust belt is rich in oil and gas resources，but the differences in the sealing capacity of the caprock under the action of complex structures has hindered the process of oil and gas exploration. Objectives Aiming at the current situation of surface oil and gas seriously leakage and insufficient exploration in the thrust belt in southern Junggar basin， Methods the deep and shallow mudstone caprock of Qigu anticline was taken as the research object.Based on the stratigraphic model，combined with logging data inversion and actual measurement data，a numerical model of the mechanical parameters of the study area was constructed，and the finite element method was used to simulate the paleo and present tectonic stress fields in the Qigu anticline.The obtained stress field data was combined with fracture parameter theory to analyze the formation period of fractures in the caprock and calculate the transformation results of the current stress field on the fractures in the caprock. Results The results showed that the paleo and present stress distributions of the Qigu anticline were all controlled by buried depth，tectonic location，fault strike，and fault convergence location；under the current stress field，the shallow caprock of Qigu anticline was not easy to break，and only played a role in reforming the fractures formed by the paleotectonic stress field；the degree of fracture development in deep and shallow caprocks varied greatly，and the development of fractures at high points of the anticline may be the main cause of shallow oil and gas leakage；the fracture zone was more developed near the fault，and the fracture permeability near the fault zone was much higher than that of the normal formation，which may provide a channel for the migration and even loss of deep oil and gas to the shallow layer；the deep caprock was relatively stable，and the caprock condition wass not the key factor to restrict the success of exploration in the lower Junggar Basin.Conclusions The research results can provide some references for deep oil and gas exploration in the thrust belt of the southern margin of the Junggar Basin.

Key words:in-situ stress；fracture prediction；caprock evaluation；numerical simulation；Jurassic；Qigu anticline