石油、天然气储存在地表以下数百至数千米，钻采过程中使用油井管柱作为采油

石油、天然气储存在地表以下数百至数千米，钻采过程中使用油井管柱作为采油、采气的密封通道，油井管柱是由专用连接接头将单根油井管连接而成，可达数千米长，数百吨重。
在使用过程中，整个油井管柱承受重力拉伸、压缩（水泥固井）、内压（采气）、外压（钻井液或地层）、弯曲力（水平井）等复合载荷作用。若管体或连接接头的性能不足则极易发生泄漏或破坏失效，损失巨大。
据统计，80%以上的油井管失效位置均在管柱连接接头处，油井管功能的正确实现取决于管体和螺纹接头机械结构的完整性。
本文对一种新型高气密封钢管连接接头的结构进行设计，并对其在复合极限载荷下密封性能的稳定性进行分析研究，使其适用较恶劣的油气井况。具体研究内容如下：
1、设计一种新型高气密封钢管连接接头，使其满足在复合极限载荷下的密封要求；
2、通过数值分析法计算出新型接头的极限复合载荷和接头的理论上扣扭矩值；
3、应用有限元分析软件ANSYS对接头的结构形状进行优化，并对新型接头在拉伸、拉伸+内压、内压、压缩+内压、压缩+外压、外压以及弯曲+拉伸+内压等极限复合载荷下的结构变化趋势进行分析，根据密封面接触压力的大小及分布，判断接头密封的完整性；
4、编制新型接头的加工工艺及检验方法。依据ISO 13679标准CAL IV级试验要求，模拟最苛刻的工况，试制八组极限公差配合的接头，在多次反复上卸扣后，对新型接头进行极限复合载荷循环密封试验评价，验证新型接头在各种极限复合工况条件下接头密封的完整性。

結果 (英文) 3:

Oil and gas reservoir exists below the surface of hundreds to thousands of meters, sealing channel drilling process using oil well pipe column as oil, gas production, oil well pipe column is by a special joint single oil well pipe connection and, up to several thousand meters long, hundreds of tons. In the course of use, the entire oil well pipe string is subjected to gravitational tension, compression (cement), internal pressure (gas), external pressure (drilling fluid or formation), bending force (horizontal well), etc.. If the performance of the pipe body or the connecting joint is very easy to leak or damage, the loss is huge. According to statistics, over 80% of the failure position of the oil well pipe is connected with the joint of the pipe string,The function of oil well pipe is realized by the integrity of the mechanical structure of the pipe body and the screw joint. In this paper, a new type of high gas seal steel pipe connection joint is designed, and the stability of the sealing performance of the composite ultimate load is studied. Specific research contents are as follows:
1, design a new type of high gas sealed steel pipe connection joints, so that it meets the requirements under the composite limit load,
2, through the numerical analysis method to calculate the new type of composite load and joint of the theory of the torque value;
3,Finite element analysis software ANSYS was used to optimize the structure of the joints, and the structural change trend of the new type of joint was analyzed under tensile, tensile, compression, compression, compression, external pressure and bending tension. According to the requirements of ISO 13679 standard cal IV test, simulate the harsh working conditions, joint trial eight sets of limit tolerance and fit, after repeatedly shackle.The new type of composite load cycling sealing test was carried out to verify the integrity of the new type of joint sealing under various extreme conditions.