高温射流井底流场与参数影响分析  

Analysis of Downhole Flow Field and Parameter Effect in Hydrothermal Jet Drilling

作　　者：崔柳 汪海阁 纪国栋 吕泽昊 宋先知[2] Cui Liu Wang Haige Ji Guodong Lu Zehao Song Xianzhi(CNPC Drilling Research Institute State Key Laboratory of Petroleum Resources and Prospecting, China University of Petrole-um （Beijing)

机构地区：[1]中国石油集团钻井工程技术研究院 [2]中国石油大学(北京)油气资源与探测国家重点实验室

出　　处：《石油机械》2017年第5期1-9,共9页China Petroleum Machinery

基　　金：国家自然科学基金项目"高温射流冲击--热裂解耦合破岩机理与实验研究;高温射流井筒温度控制与携岩规律研究"(51504272;U1562212);中英牛顿联合基金地热项目"地热智能井钻完井关键技术与优化设计平台"(2016YFE0124600);中石油钻井新技术新方法"高围压下热力射流破岩效率实验研究"(2016A-3902);中石油创新基金项目"热力射流冲击--裂解耦合破岩机理研究"(2015D-5006-0308);教育部优秀博士论文作者专项基金项目"热力射流提高深井钻速可行性研究"(201352)

摘　　要：高温射流钻井过程中,高温流体在上返时易引起上部井壁岩石的裂解垮塌和钻柱持续高温,为实现安全高效钻井,提出了通过钻柱侧向注冷水的环空冷却方案,研究了射流速度、射流温度和冷水速度等参数对环空冷却效果的影响。研究结果表明:随着射流速度的增加,环空平均温度对射流速度的变化敏感性越来越弱,同时环空平均温度与射流温度呈线性关系。冷水速度存在某一临界值,该临界值与射流速度和井眼直径等因素有关,当冷水速度大于临界值时,既能够保证高温流体对井底的破岩效果,又可以对环空进行较好地冷却。研究中,临界值为射流速度的70%80%,高温射流与冷却水的临界流量比为0.91,且随井筒尺寸的增加而增大。高温射流破岩的能量利用率高,在深井硬地层中采用非接触式破岩可提高钻井速度。在实际较软地层钻井过程中,两侧冷却条件下的高温射流方案在需要进行扩眼钻进的地层具有一定的适用性。It is prone to encounter wellbore wall rock thermal spallation and collapse and drill string keeping in constant high temperature during hydrothermal jet drilling due to the returned high temperature fluid. To achieve safe and efficient drilling, the annular cooling scheme by side injecting cold water through drill pipe has been proposed. The effect of different jet velocities and temperatures and different cooling water velocities on annulus cooling perform-ance has been analyzed. Results indicate that, with the increase of the jet velocity, the average annular temperature is less sensitive to the change of the jet velocity, and has linear relation with the jet temperature. There exists a criti-cal cooling water velocity that makes the annular temperature distribution obviously different. The critical cooling wa-ter velocity is influenced by the jet velocity and the borehole diameter. When the cooling water velocity is higher than the critical value, it not only ensures the bottomhole rock breaking performance of the high temperature fluid, but also could effectively cool the annular. In the study,the critical value is 7 0 %？80% of the jet velocity,the critical flow ratio of the hydrothermal jet and the cooling water is 0. 91, and increases with the size of the wellbore. The en-ergy utilization rate of hydrothermal jet rock breaking is high, and the non-contact rock breaking in deep well hard layer can improve the drilling speed. In the soft formation drilling operation,the hydrothermal jet scheme under the cooling condition on both sides has certain applicability in the formation where reaming is needed.

关 键 词：高温射流 环空温度 冷却方案 井底流场 参数分析 

分 类 号：TE248[石油与天然气工程—油气井工程]