本文選題：火燒驅(qū)油 + CO_2腐蝕��； 參考：《西安石油大學(xué)》2015年碩士論文

【摘要】：本文利用鹽霧試驗機(jī)、高溫高壓腐蝕試驗設(shè)備并輔以SEM、EDS及XRD等分析技術(shù),研究了油套管用鋼N80、BG90H、BG90H-3Cr和BG90H-9Cr在模擬火燒驅(qū)油注氣井和生產(chǎn)井環(huán)境下的腐蝕行為,并通過電化學(xué)測試的方法研究了四種油套管用鋼的腐蝕機(jī)理。注氣井腐蝕試驗結(jié)果表明:不同腐蝕條件下,N80、BG90H、BG90H-3Cr、BG90H-9Cr的氧均勻腐蝕速率依次減小,濕空氣條件下,四種材料均出現(xiàn)不同程度的局部腐蝕(點蝕),N80的最大點蝕速率高達(dá)5.3655mm/a。生產(chǎn)井腐蝕試驗結(jié)果表明:在模擬不同腐蝕條件下,四種油套管用鋼的腐蝕速率大小總體表現(xiàn)為:N80BG90HBG90H-3CrBG90H-9Cr。在CO_2+H_2S腐蝕條件下,四種材料的腐蝕速率在120℃時出現(xiàn)峰值,并在該溫度下局部腐蝕較為嚴(yán)重;在CO_2+H_2S+O_2腐蝕條件下,四種材料的腐蝕速率隨溫度升高呈上升趨勢,在150℃左右局部腐蝕嚴(yán)重,溶解氧的存在不僅增大了油套管用鋼的腐蝕速率,同時也使其最大腐蝕速率峰值對應(yīng)的溫度有所上升;在CO_2+H_2S+砂腐蝕條件下,四種油套管用鋼的腐蝕規(guī)律與CO_2+H_2S腐蝕條件下相同,流體中砂粒的存在對腐蝕產(chǎn)物膜和鈍化膜存在沖刷作用,致使油套管材質(zhì)的腐蝕速度總體上呈增大趨勢,同時也促進(jìn)了油套管材料發(fā)生局部腐蝕的嚴(yán)重程度,在高溫下尤為明顯。極化曲線測試結(jié)果表明:在所模擬溫度范圍內(nèi)(30℃、60℃、90℃),N80、BG90H和BG90H-3Cr三種材料的陰陽極Tafel區(qū)較明顯,反應(yīng)機(jī)理沒有發(fā)生變化,均為活化控制,并且三種材料的陰極Tafel斜率明顯大于陽極,腐蝕反應(yīng)為陰極控制;而BG90H-9Cr的陽極極化曲線出現(xiàn)明顯鈍化現(xiàn)象,腐蝕反應(yīng)為陽極反應(yīng)控制。交流阻抗譜(EIS)測試分析結(jié)果表明,四種材料在所有溫度點均具有兩個時間常數(shù),即由高頻容抗弧和低頻容抗弧組成;隨溫度升高,N80、BG90H、BG90H-3Cr在60℃極化電阻最小,腐蝕速率最大,由于BG90H-3Cr含有較高的合金元素Cr,極化電阻相對較高,腐蝕速率較低;BG90H-9Cr的Cr含量高達(dá)9%wt,可在材料表面形成更加致密的富Cr腐蝕產(chǎn)物膜,其極化電阻遠(yuǎn)大于其他三種材料,并且隨溫度升高,極化電阻減小,腐蝕速率增大。EIS與極化曲線的測試分析結(jié)果一致,即N80、BG90H、BG90H-3Cr在60℃自腐蝕電流密度出現(xiàn)極大值,而BG90H-9Cr的自腐蝕電流密度要遠(yuǎn)低于N80、BG90H、BG90H-3Cr,并且隨溫度升高,自腐蝕電流密度增大。
[Abstract]:In this paper, the corrosion behavior of oil casing steel N80 BG90HU BG90H-3Cr and BG90H-9Cr under simulated combustion flooding gas injection well and production well environment was studied by using salt spray tester, high temperature and high pressure corrosion test equipment and SEMMO-EDS and XRD. The corrosion mechanism of four kinds of oil casing steels was studied by electrochemical measurement. The results of gas injection well corrosion test show that the oxygen uniform corrosion rate of BG90H-3CrG90H-9Cr decreases in turn under different corrosion conditions, and the maximum pitting rate of N80 is up to 5.3655mm / a under wet air conditions. The corrosion test results of production wells show that the corrosion rate of four kinds of oil casing steels is as follows: N80BG90HBG90H-3CrBG90H-9Crunder simulated different corrosion conditions. Under the condition of CO2H2S corrosion, the corrosion rate of the four materials peaked at 120 鈩，

本文編號：2083200