天然气勘探与开发2025，Vol.48Issue(5)：123-131,9.DOI:10.12055/gaskk.issn.1673-3177.2025.05.012
超深井不同工况下钻具伸长量计算方法及其应用
A method for calculating drill string elongation under various operating conditions in ultra-deep wells and its application
摘要
Abstract
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.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Key words
Ultra-deep well/Pipe string elongation/Calculation method/Inner-outer pipe pressure difference/Hydraulic interception/Gravity/Various operating conditions分类
能源科技引用本文复制引用
李昱垚,贺明敏,王泽东,廖志成,王稳,蔡明杰..超深井不同工况下钻具伸长量计算方法及其应用[J].天然气勘探与开发,2025,48(5):123-131,9.基金项目
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). （编号:CQ2024B-40-16-5-F）
