硫化氢环境下G-105 和S-135 钻杆的低载多冲疲劳性能测试

针对钻杆材料在钻井工程中因承受小能量多次冲击载荷作用而出现的刺穿、断裂等失效情况，提出了对钻杆材料进行评价的一种低载多冲实验方法，应用该方法对G-105 和S-135 钻杆材料进行了测试。在没有腐蚀介质的环境中，改变单次冲击能量的测试结果表明，随着单次冲击能量的增大，G-105 和S-135 钻杆材料的低载多冲抗力下降到了原来的22.2% 和28.7%， 钻杆的低载多冲抗力下降显著。在硫化氢环境中，采用NACE TM 0177-96 标准A 溶液分别对G-105 和S-135 钻杆试片浸泡不同的时间，并在2.21 J 的单次冲击功作用下开展了低载多冲测试，结果表明两种钻杆材料的低载多冲抗力随着硫化氢腐蚀时间的延长分别下降到了原来的49.8% 和46.9%，且钢级更高的S-135 对腐蚀环境更为敏感。另外，选取典型的冲断断口进行了微观形貌观察与分析，发现了导致破断的脆化相。以上实验结果均表明这种低载多冲实验方法能够较明显地还原钻杆在工作过程中的实际失效情况，尤其是在含有硫化氢腐蚀介质中的失效规律。

Low-load repeated impact testing of G-105 and S-135 drill pipes in H2S environment

In view of drill pipe washout and fracture failures, etc. caused by multiple impact loads of small energy during drilling operations, this paper presents a kind of low-load repeated impact experiment method to assess the drill pipe materials. The G-105 and S-135 drill pipe materials were tested using this method. In an environment where there is no corrosion medium, test was conducted to the change of single-impact energy and test result indicates that, with the increase of single-impact energy, the low-load repeated impact resistance of G-105 and S-135 drill pipe materials reduced to 22.2% and 28.7% of the original values respectively, so the low-load repeated impact resistance of drill pipe decreases significally. In H2S environment, the test blocks of G-105 and S-135 were soaked in the A solution of NACE TM 0177-96 standard for different durations, and lowload repeated impact test was conducted under single-impact energy of 2.21 J. The test result shows that the low-load repeated impact resistances of the materials of two drill pipes reduced to 49.8% and 46.9% of their original values respectively with the extension of H2S corrosion time, and the higher grade S-135 is more sensitive to corrosion environment. Besides, typical fracture was selected to observe and analyze the microstructure and the embrittlement phase causing fracture was found. The above experiment results indicate that this low-load repeated impact experiment method can remarkably shows the actual failure of drill pipe in its working process, esp. the failure pattern in corrosion media containing H2S.