海陆过渡相煤系页岩气多岩系水平井体积压裂及效果评价

Volume fracturing and effect evaluation of horizontal wells in multi-rock series of marine-continental transitional coal measures shale gas

中文关键词: 南华北盆地  海陆过渡相  煤系页岩气  多岩系  体积压裂

英文关键词: the Southern of North China basin  marine-continental transitional  coal measure shale gas  multi-rock series  volumetric fracturing

中文摘要:

      Z1HF井为南华北盆地第一口煤系页岩气水平井，目的层存在埋藏深、岩性组合复杂、物性条件差、强非均质性、大水平应力差等难点。本文基于岩心分析、测井、岩石力学、压裂模拟对太原组②～④号层开展岩石破坏及裂缝延伸室内模拟实验，明确了岩石破坏特征及人工裂缝扩展形态。在综合分析 Z1HF井压裂改造难点基础上，以扩大多岩系穿层改造覆盖率、提高裂缝复杂程度、增加改造体积为目标，提出了“短段多簇+限流压裂+差异化泵注+高强度加砂+高效双暂堵+复合压裂液体系”为主体的压裂改造思路，累计完成 20段 129簇压裂施工，注液 35505.7 m3，加砂强度达 2.40 t/m，用液强度 29.3 m3/m，实现了多簇均衡起裂与延伸、多岩系纵向穿透和多尺度裂缝有效铺砂，形成了复杂裂缝网络，达到体积改造效果，压后最高产气量达 19000 m3/d，稳产 9000 m3/d以上。Z1HF井的实施为南华北盆地海陆过渡相煤系页岩地层水平井分段压裂改造积累了丰富经验，可为地区同类气藏提供重要借鉴和指导。

英文摘要:

      The Z1HF well was the first coal shale gas horizontal well in the Southern of North China Basin,which had difficulties such as deep burial, complex lithological combination, poor physical conditions, strong non-homogeneity and large horizontal stress difference. Based on core analysis, logging, rock mechanics, fracture simula-tion and other means to carry out rock damage and fracture extension simulation experiments on the Taiyuan Forma-tion (②-④), the fracture damage characteristics and artificial fracture extension pattern were clarified.Therefore,based on a comprehensive analysis of the fracturing difficulties in Z1HF well, the fracturing transformation idea of"short multi-clusters、flow-limiting fracturing、differential pumping、high-strength proppant injection、high-efficiency double temporary plugging、composite fracturing fluid system" was proposed with the goal of improvingthe coverage of the multi-rock series through vertical layer transformation, increasing the complexity of the fractureand the volume of fracturing. A total of 129 clusters in 20 sections were completed. The liquid injection was35505.7 m3, the sanding strength was 2.40 t/m, and the liquid strength was 29.3 m3/m. The balanced initiation andextension of multiple clusters, the longitudinal penetration of composite layers and the effective proppant of multi-scale fractures were realized. A complex fracture network was formed to achieve the effect of volume transformation.The maximum gas production was 19000 m3/day, and the stable production was 9000 m3/day. The implementation ofthe Z1HF well had accumulated rich experience in segmental fracturing and reconstruction of horizontal wells incoal shale formations in the marine-continental transition phase, which could provide important reference and guid-ance for similar gas reservoirs.