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 ...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.展开更多
为了满足我国非常规油气井勘探开发对特殊螺纹套管的结构完整性及密封完整性需求,设计出适用于Φ177.8 mm油井管的特殊螺纹接头。采用有限元仿真分析方法对设计的Φ177.8 mm BJC-Ⅱ特殊螺纹接头进行模拟分析,并依据API RP 5C5:2017 CAL...为了满足我国非常规油气井勘探开发对特殊螺纹套管的结构完整性及密封完整性需求,设计出适用于Φ177.8 mm油井管的特殊螺纹接头。采用有限元仿真分析方法对设计的Φ177.8 mm BJC-Ⅱ特殊螺纹接头进行模拟分析,并依据API RP 5C5:2017 CALⅣ级试验标准对特殊螺纹接头进行了全尺寸实物性能评价。结果表明,设计的Φ177.8 mm BJC-Ⅱ特殊螺纹接头在拉伸/压缩、内压/外压、弯曲及180℃高温载荷作用下具有优异的气密封性能,接头的拉伸效率、内压效率、外压效率、压缩效率达到100%等管体性能,为我国非常规油气井的勘探开发提供了产品保障。展开更多
基金Supported by the National Natural Science Foundation of China(52174003,52374008).
文摘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.
文摘为了满足我国非常规油气井勘探开发对特殊螺纹套管的结构完整性及密封完整性需求,设计出适用于Φ177.8 mm油井管的特殊螺纹接头。采用有限元仿真分析方法对设计的Φ177.8 mm BJC-Ⅱ特殊螺纹接头进行模拟分析,并依据API RP 5C5:2017 CALⅣ级试验标准对特殊螺纹接头进行了全尺寸实物性能评价。结果表明,设计的Φ177.8 mm BJC-Ⅱ特殊螺纹接头在拉伸/压缩、内压/外压、弯曲及180℃高温载荷作用下具有优异的气密封性能,接头的拉伸效率、内压效率、外压效率、压缩效率达到100%等管体性能,为我国非常规油气井的勘探开发提供了产品保障。
