低温环境下钻柱材料力学特性试验及强度设计

Mechanical Properties Test and Strength Design of Drill String Materials in Low-Temperature Environments

低温条件下的钻柱强度校核与设计研究,对解决极地等低温环境下钻柱的技术问题具有重要意义。在低温和常温条件下,进行了G105钻杆和S135钻杆的力学特性试验,获取了2种材料的抗拉强度、屈服强度及冲击性能等参数随温度的变化规律,在此基础上,提出了低温环境下钻柱的强度设计方法。试验发现,随着温度降低,G105钻杆和S135钻杆的抗拉强度和屈服强度均升高,断面收缩率基本不变。在低温环境下,为保证钻柱的服役安全,钻柱的强度设计方法应由常温下应力控制转换为应力与应变共同控制。低温服役环境下进行钻柱强度设计时,钻柱材料的屈服强度应依照宽温区的材料强度特性取值。该研究结果对确保低温环境下钻柱的工程设计及服役安全具有指导意义。

Strength checking and design of drill strings at low temperature are crucial to solving the technical problems of drill string in low-temperature environments such as the Arctic region.In this paper,tests were carried out at both low and normal temperatures on drill string materials G105 and S135,and their temperature-dependent parameters including tensile strength,yield strength,and impact performance,etc.were obtained.On the basis of these results,the strength design method of drill strings in low-temperature environments was proposed.The results show that both tensile and yield strength of G105 and S135 increase as the temperature decreases while the cross section reduction rate remains unchanged.In low-temperature environments,it is important to note that to ensure the safety of the drill strings,their strength design should be controlled by both stress and strain,instead of only by stress in normal temperature environments.Yield strength of drill string materials should be determined according to the strength characteristics of the materials in the wide-temperature range.The results show that this study has directive significance to guarantee the engineering design of drill strings and their safety in low-temperature environments.