油套管钢在注气高压氧环境中的腐蚀规律研究

Study on the Corrosion Behavior of Casing and Tubing Steel in Gas Injection Environment With High Pressure of O

高压注气提高油田采收率过程中引入氧气,会对油井管造成很严重的氧腐蚀,因此有必要开展常用油井管材料在注气环境中的氧腐蚀行为研究。对比研究了N80、N80-3Cr、N80-13Cr、P110在高压注气环境的均匀腐蚀和局部腐蚀情况,利用XRD对腐蚀产物进行了分析。结果表明:4种材料在高压氧环境中会发生严重的均匀腐蚀和局部腐蚀,N80-13Cr的均匀腐蚀最低,但也高达42.53 mm·a^(-1),局部腐蚀速率高达53.18 mm·a^(-1);N80-3Cr的均匀腐蚀和局部腐蚀速率都是4种材料中最高的。N80、P110在气相中的均匀腐蚀和局部腐蚀速率远低于在液相中的。几种材质的腐蚀产物均以Fe O(OH)和Fe2O3为主。结合腐蚀产物的分析,对几种材质的局部腐蚀机理进行了探讨。

Oxygen is introduced into the oil well in the process of enhancing oil recovery by injection of high pressure gas,which can cause the severe corrosion of casing and tubing steel.Therefore,it is necessary to study the corrosion behavior of steel in gas injection environment.In this paper,the corrosion behavior of steel N80,N80-3Cr,N80-13Cr,P110 was studied in gas injection environment with high pressure of O2,and the formed corrosion products were analyzed by XRD.The results showed that severe general and local corrosion occurred on these four kinds of steel in environment with high pressure of oxygen.The corrosion rate of N80-13Cr was the lowest among these four steels,but its general and local corrosion rates were still up to 42.53 mm·a^(-1) and 53.18 mm·a^(-1).The general and local corrosion rate of N80-3Cr was the highest among these steels.The corrosion rates of N80 and P110 in gas phase were far below those in liquid phase.The corrosion products mainly compose of Fe O(OH) and Fe2O3.Finally,the local corrosion mechanism of these steels was discussed.