TP110TS和P110钢在CO2注入井环空环境中应力腐蚀行为比较

Comparison of Stress Corrosion Behavior of TP110TS and P110 Steel in a Simulated Annular Environment of CO2 Injection Well

利用U形弯试样浸泡实验和电化学测试技术研究了两种油套管钢在CO2注入井环空环境中的应力腐蚀开裂行为。结果表明,TP110TS钢和P110钢在注入井环空环境(大量CO2-微量H2S)下存在一定的应力腐蚀敏感性,其应力腐蚀机制为阳极溶解和氢脆协同作用机制。在CO2-H2S环境下,咪唑啉类缓蚀剂的浓度对TP110TS和P110油套管钢的应力腐蚀产生不同的影响,添加足量的缓蚀剂对P110钢的应力腐蚀行为产生较好的抑制效果;但当添加量不足时,缓蚀剂会增加P110钢发生应力腐蚀的倾向性。而TP110TS钢的应力腐蚀敏感性随着缓蚀剂浓度的增加而减小,相对更适用于添加缓蚀剂的CO2-H2S环境。

The stress corrosion cracking behavior of two oil casing steels TP110 TS and P110 in a simulated solution in the annulus space of CO2 injection wells was comparatively studied by U-bend specimen immersion test and electrochemical test.The results show that TP110 TS steel and P110 steel have certain degree of stress corrosion sensitivity in the solution(large amount of CO2 and micro H2S),and the stress corrosion mechanism is the synergistic mechanism of anodic dissolution(AD)and hydrogen embrittlement(HE).In the CO2-H2S environment,the concentration of imidazoline corrosion inhibitor has different effect on the stress corrosion of oil casing steels TP110 TS and P110.Adding sufficient corrosion inhibitor has a good inhibitory effect on the stress corrosion behavior of P110 steel.However,when the added amount is insufficient,the corrosion inhibitor increases the stress corrosion tendency of P110 steel.The stress corrosion sensitivity of TP110 TS steel decreases with the increase of corrosion inhibitor concentration.It follows that TP110 TS is more suitable for the CO2-H2S environment where corrosion inhibitors are added.