The buried depth of the gas-producing reservoir in the Kuqa foreland thrust belt of the Tarim Basin exceeds 6000 m. The average matrix porosity of the reservoir is 5.5%, and the average matrix permeability is 0.128 × 10⁻³ μm². In order to reveal the characteristics and effectiveness of ultra-deep fractures and their effects on reservoir properties and natural gas production, outcrops, cores, thin section, image logs and production testing data are used to investigate the effectiveness of tectonic fractures in ultra-deep reservoirs in the Kuqa foreland thrust zone, and the corresponding geological significance for oil and gas exploration and development are discussed. Tectonic fractures in the thrust belt include EW-trending high-angle tensile fractures and NS-trending vertical shear fractures. The former has a relatively high filling rate, while the latter is mostly unfilled. Micro-fractures are usually grain-piercing-through cracks with width of 10–100 microns. In the planar view, the effective fractures are concentrated in the high part and wing zones of the long axis of the anticline, and along the vertical direction, they are mainly found in the tensile fracture zone above the neutral plane. The adjustment fracture zone has the strongest vertical extension abilities and high effectiveness, followed by the nearly EW longitudinal tensile fracture zone, and the netted fracture zone with multiple dip angles. The effectiveness of fracture is mainly controlled by fracture aperture and filling degrees. Effective fractures can increase reservoir permeability by 1–2 orders of magnitude. The higher part of the anticline is associated with high tectonic fracture permeability, which control enrichment and high production of natural gas. The netted vertical open fractures effectively communicate with pores and throats of the reservoir matrix, which forms an apparent-homogenous to medium-heterogeneous body that is seen with high production of natural gas sustained for a long term.

塔里木盆地库车前陆冲断带产气储层埋深超过6000 m。储层平均基质孔隙度为5.5%，平均基质渗透率为0.128×10 ^-3  μm ². 为了揭示超深层裂缝的特征和有效性及其对储层物性和天然气产量的影响，利用露头、岩心、薄片、图像测井和生产测试数据，研究超深层构造裂缝的有效性。讨论了库车前陆冲断带的储层及其相应的油气勘探开发地质意义。逆冲带构造裂缝包括东西向高角度拉伸裂缝和南北向垂直剪切裂缝。前者的填充率比较高，而后者大多是未填充的。微裂纹通常是宽度为 10-100 微米的穿透晶粒的裂纹。在平面视图中，有效裂缝集中在背斜长轴的高部和翼带，沿垂向主要分布在中性面以上的拉伸断裂带。调整裂缝带纵向伸展能力最强、有效性高，其次是近东西向的纵向拉伸裂缝带和多倾角的网状裂缝带。裂缝的有效性主要受裂缝孔径和充填度控制。有效裂缝可以将储层渗透率提高 1-2 个数量级。背斜上部与高构造裂缝渗透率相关，控制天然气的富集和高产。