Analysis of secondary makeup characteristics of drill collar joint and prediction of downhole equivalent impact torque of Well SDTK1  

作　　者：WANG Chunsheng MING Chuanzhong ZHANG Hao CHEN Jialei QU Hao WANG Wenchang DI Qinfeng 

机构地区：[1]PetroChina Tarim Oilfield Company,Korla 841000,China [2]Shanghai Institute of Applied Mathematics and Mechanics,Shanghai University,Shanghai 200072,China

出　　处：《Petroleum Exploration and Development》2024年第3期697-705,共9页石油勘探与开发（英文版）

基　　金：Supported by the National Natural Science Foundation of China(52174003,52374008).

摘　　要：Based on the three-dimensional elastic-plastic finite element analysis of the 8"(203.2 mm)drill collar joint,this paper studies the mechanical characteristics of the pin and box of NC56 drill collar joints under complex load conditions,as well as the downhole secondary makeup features,and calculates the downhole equivalent impact torque with the relative offset at the shoulder of internal and external threads.On the basis of verifying the correctness of the calculation results by using measured results in Well GT1,the prediction model of the downhole equivalent impact torque is formed and applied in the first extra-deep well with a depth over 10000 m in China(Well SDTK1).The results indicate that under complex loads,the stress distribution in drill collar joints is uneven,with relatively higher von Mises stress at the shoulder and the threads close to the shoulder.For 203.2 mm drill collar joints pre-tightened according to the make-up torque recommended by American Petroleum Institute standards,when the downhole equivalent impact torque exceeds 65 kN·m,the preload balance of the joint is disrupted,leading to secondary make-up of the joint.As the downhole equivalent impact torque increases,the relative offset at the shoulder of internal and external threads increases.The calculation results reveal that there exists significant downhole impact torque in Well SDTK1 with complex loading environment.It is necessary to use double shoulder collar joints to improve the impact torque resistance of the joint or optimize the operating parameters to reduce the downhole impact torque,and effectively prevent drilling tool failure.

关 键 词：Well SDTK1 drill tool threaded joint secondary makeup relative offset equivalent impact torque 

分 类 号：TE921[石油与天然气工程—石油机械设备]