连续管全寿命安全评定与管理策略研究

连续管是“万能作业机”的“神经线”，连续管的安全运行关乎整个施工过程，连续管服役寿命是安全运行的重要指标之一。目前对连续管作业时全寿命安全评定研究较少，探索性地利用生存分析方法研究了连续管6个影响因素，20组分变量，采用Kaplan-Meier分析方法对连续管疲劳寿命的单因素生存时间进行描述，并结合连续管服役有效时间采用Cox比例风险模型进行多因素分析，疲劳累积结果与Cox比例风险模型计算结果对比认为，该模型是可行的。研究结果表明，共线性检验和PH假定检验结果显示399个样本用于连续管生存分析是可行的；分类变量中直径、壁厚、腐蚀、焊接对连续管服役风险影响显著；大直径管（直径>50.80 mm）的风险率是小直径管（直径<50.80 mm）风险率的1.484倍；H₂S环境的腐蚀风险率是无腐蚀风险率的2.509倍；直焊缝的风险率是无焊缝风险率的5.595倍；研究结论与现场连续管失效统计结果相吻合。根据累积生存率和现场失效统计结果提出的四级评价准则对连续管在钻井、完井、气举等安全作业具有指导意义。

Safety Assessment and Management Strategy of Whole Life of Coiled Tubing

Coiled Tubing(CT)is the"neural line"of the"universal working machine".The safe operation of CT is related to the entire construction process.The service life of CT is one of the important indicators of the safe operation.At present,there is little study on the safety assessment of the whole life of CT operation.Survival analysis was used to study 6 influencing factors of CT and 20 component variables.The Kaplan-Meier analysis method was used to describe the single-factor survival time of CT fatigue life,and the Cox proportional hazard model was used to perform multi-factor analysis in combination with the effective time of CT service.The comparison between the cumulative fatigue results and the Cox proportional hazard model calculation results shows that the model is feasible.The research results show that col linearity test and PH hypothesis are feasible for 399 samples survival analysis;among the classification variables:OD,wall thickness,corrosion,and welding have significant effects on the risk of CT;the risk rate of large-diameter CT(diameter>50.80 mm)is 1.484 times that of smalldiameter CT(diameter<50.80 mm);the corrosion risk rate of H2S environment is 2.509 times that of no corrosion risk rate;The risk rate of straight welds is 5.595 times that of no welds;the conclusions of the study are consistent with the statistical results of field CT failure.The four-level evaluation criteria proposed based on the cumulative survival rate and field failure statistical results have guiding significance for the safe operation of the CT in drilling,completion and gas lift.