塔里木盆地库车坳陷克深气藏超深层致密砂岩储层天然裂缝发育特征及对水侵的影响

Fracture development characteristics and their influence on water invasion of ultra-deep tight sandstone reservoirs in Keshen gas reservoir of Kuqa Depression, Tarim Basin

徐小童 曾联波 董少群 第五鹏祥 李海明 刘剑忠 韩高松 徐辉 冀春秋

XU Xiaotong ZENG Lianbo DONG Shaoqun DIWU Pengxiang LI Haiming Liu Jianzhong HAN Gaosong XU Hui JI Chunqiu

1. 中国石油大学(北京) 油气资源与工程全国重点实验室, 北京 102249; 2. 中国石油大学(北京) 地球科学学院, 北京 102249; 3. 中国石油大学(北京) 理学院, 北京 102249; 4. 中国石油 塔里木油田分公司 勘探开发研究院, 新疆 库尔勒 841000; 5. 中国石化 西北油田分公司, 乌鲁木齐 830011; 6. 中国海油 深圳分公司 研究院, 深圳 518000

1. National Key Laboratory of Petroleum Resources and Engineering, China University of Petroleum (Beijing), Beijing 102249, China; 2. College of Geoscience, China University of Petroleum (Beijing), Beijing 102249, China; 3. College of Science, China University of Petroleum (Beijing), Beijing 102249, China; 4. Tarim Oilfield Branch Company, CNPC, Korla, Xinjiang 841000, China; 5. SINOPEC Northwest Oil Field Company, Urumqi, Xinjiang 830011, China; 6. Shenzhen Branch of CNOOC Ltd., Shenzhen 518000, China

天然裂缝是影响塔里木盆地库车坳陷克深超深层致密砂岩气藏气井高产和水侵的重要因素，裂缝研究对明确气藏水侵规律及防控水政策的制定意义重大。通过岩心、铸体薄片、常规测井、成像测井、生产数据、试井等资料，研究了有效裂缝发育特征、分布规律及气藏水侵特征，探讨了不同缝网系统水侵的影响。高角度和近直立的剪切裂缝为该区最主要的裂缝类型。垂向上，巴什基奇克组一段多为全充填裂缝，为无效裂缝；巴二段和巴三段多为半—无充填裂缝，为有效裂缝。平面上，NNW—SSE向有效裂缝富集在气藏西部，且平均开度大；东部相对发育近E—W向、NWW—SEE向的有效裂缝，平均开度较小。有效裂缝越发育，开度越大，气井初期封存水的产出越低，多产出凝析水。从投产到见水，地层水呈封存水、凝析水、可动水、纯地层水等赋存形式产出。有效裂缝的发育程度，开度及走向是影响非均质水侵的重要因素。与水侵方向近平行的、密集的、高有效性的缝网系统会加快水侵速度，导致气井大量产水，严重降低气井产能。综合有效裂缝的发育特征和单井水侵特征，气藏呈现出边底水沿断裂/密集裂缝快速水窜型、边水沿稀疏裂缝缓慢锥进型、边底水缓慢抬升侵入型3种水侵模式。

Natural fractures are crucial factors influencing productivity and water invasion in the ultra-deep tight sandstone gas wells of the Keshen gas reservoir in the Kuqa Depression, Tarim Basin. Research on fractures is significant for understanding water invasion patterns and formulating effective water control strategies. This study investigated the development characteristics, distribution patterns, and water invasion characteristics of effective fractures using core samples, thin sections, conventional logging, imaging logging, production data, and well testing, as well as the influence of different fracture networks on water invasion. High-angle and nearly vertical shear fractures are the main fracture types. Vertically, the first member of Bashijiqike Formation (K1bs1) is predo-minantly characterized by completely filled fractures, which are ineffective fractures. Conversely, the second and third members of Bashijiqike Formation (K1bs2 and K1bs3) are mostly characterized by partially filled and unfilled fractures, which are effective fractures. Horizontally, the NNW-SSE striking effective fractures are concentrated in the western part of the gas reservoir and have larger average apertures. The eastern part has relatively deve-loped nearly E-W and NWW-SEE striking effective fractures with smaller average apertures. The more deve-loped and the larger the aperture of the effective fractures, the lower the initial water production from gas wells, with more production of condensate water. From production onset to water breakthrough, formation water is produced in various forms: sealed water, condensate water, movable water and pure formation water. The development stage, aperture and orientation of effective fractures are important factors affecting heterogeneous water invasion. Dense, highly effective fracture networks that are nearly parallel to the orientation of water invasion will accelerate the water invasion speed, resulting in significant water production and severely reducing gas well productivity. Integrating the development characteristics of effective fractures with individual well water invasion dynamics reveals three types of water invasion: rapid channeling along faults or dense fractures, slow coning along sparse fractures and slow uplift and invasion of edge-bottom water.

国家自然科学基金项目(U21B2062)资助。

https://doi.org/10.11781/sysydz202404812