摘要
超深井钻井过程中井下高温高压、管柱超长超重载,管柱受自重、水力循环等诸多因素的综合影响易产生纵向形变量,不同作业工况下管柱伸长量主控因素不同,造成作业现场井深校核、尾管作业中送放钻杆的预排、卡点计算等关键作业参数判断存在较大误差。为了精确计算不同工况下管柱伸长量,考虑重力、浮力、钻压、管内外压差、动力钻具及钻头水力截流产生的附加轴向载荷,推导不同工况下管柱综合拉伸量的实用计算方法,区别于分段计算,采用有限差分的方法求解,有助于提高计算精度。研究结果表明:①计算实例条件下,钻进和探底校核井深时,除弹性形变外水力因素影响占主导,管柱内外受力差与工具截流等水力因素造成的附加轴向力对管柱的伸长量变化影响可达2.5m,影响较大且不可忽略;②考虑重力、浮力、钻压、管内外受力差及工具水力截流产生的附加轴向载荷,所建立的不同工况下综合拉伸量的实用计算方法现场验证平均误差仅0.526‱,能够满足工程实际使用的需要。结论认为,该计算方法能够有效支撑超深井井深校核、钻具组合优化及作业安全控制,后续需集成温压效应以进一步提升该方法的适用性。
During ultra-deep well drilling operations,the downhole high temperature and high pressure,coupled with the overlength and overloaded pipe string,make the string prone to longitudinal deformation under the combined influence of factors including its own weight and hydraulic circulation.The dominant factors controlling pipe string elongation vary under different operating conditions,resulting in significant errors in determining the key operation parameters such as on-site well depth verification,prearrangement of drill pipe delivery for liner operation,and stuck point calculation.To accurately calculate the pipe string elongation,a practical method is derived with consideration of gravity,buoyancy,weight on bit(WOB),inner-outer pipe pressure difference,and additional axial loads generated by hydraulic interception of downhole motors and bits.Unlike segmented calculation approaches,a finite difference method is adopted to improve the accuracy.The following results are obtained.(i)Under the conditions of calculation cases,elastic deformation and hydraulic factors have dominant influence during drilling and bottom-probing depth verification.The inner-outer pipe pressure difference and the additional axial force generated by hydraulic factors such as tool interception induce a change in pipe string elongation up to 2.5 m,which means their influences are great and shall not be neglected.(ii)The proposed calculation method,considering gravity,buoyancy,WOB,inner-outer pipe pressure difference,and the additional axial loads induced by hydraulic interception of tools,has been field-validated with an average error of only 0.526‱,meeting practical engineering requirements.The conclusion indicates that this calculation method can effectively supports depth verification,bottom hole assembly(BHA)optimization,and operation safety control of ultra-deep wells.It is recommended to integrate the temperature and pressure effect to further improve the adaptability of this method.
作者
李昱垚
贺明敏
王泽东
廖志成
王稳
蔡明杰
LI Yuyao;HE Mingmin;WANG Zedong;LIAO Zhicheng;WANG Wen;CAI Mingjie(Chuanxi Drilling Company,CNPC Chuanqing Drilling Engineering Company Limited,Chengdu,Sichuan 610051,China)
出处
《天然气勘探与开发》
2025年第5期123-131,共9页
Natural Gas Exploration and Development
基金
中国石油集团川庆钻探工程有限公司川西钻探公司科研项目“基于川庆一体化数据的钻井工程实用计算分析及软件开发”(编号:CQ2024B-40-16-5-F)。
关键词
超深井
管柱拉伸量
计算方法
管内外压差
水力截流
重力
不同工况
Ultra-deep well
Pipe string elongation
Calculation method
Inner-outer pipe pressure difference
Hydraulic interception
Gravity
Various operating conditions
