本文選題：孔蝕 + 亞穩(wěn)孔�。� 參考：《西南石油大學(xué)》2015年碩士論文

【摘要】：P110鋼是川西氣田油套管使用的主要材料,局部腐蝕穿孔是川西氣田P110油套管腐蝕破壞的主要形式。油套管的腐蝕穿孔,給氣田生產(chǎn)帶來了安全隱患,川西氣田的正常生產(chǎn)與持續(xù)開發(fā)受到了嚴(yán)重的影響。因此,研究P110鋼在川西氣田腐蝕環(huán)境下的孔蝕行為及其影響因素,理解其孔蝕機(jī)理,總結(jié)各因素對(duì)P110鋼孔蝕行為的影響規(guī)律,為川西氣田P110油套管的合理使用及腐蝕防護(hù)提供了理論基礎(chǔ),具有重要的理論意義和實(shí)用價(jià)值。 本文結(jié)合川西氣田現(xiàn)場(chǎng)實(shí)際腐蝕背景資料,綜合應(yīng)用電化學(xué)測(cè)試方法、掃描電子顯微鏡觀察、統(tǒng)計(jì)學(xué)等多學(xué)科方法,研究了P110鋼在川西氣田腐蝕環(huán)境下孔蝕早期即亞穩(wěn)態(tài)孔蝕期間的電流波動(dòng)現(xiàn)象及其電化學(xué)特征；分析了溫度、Cl-濃度、HCO3-濃度及SO24-濃度對(duì)P110鋼孔蝕行為的影響規(guī)律；研究了緩蝕劑作用下P110鋼的孔蝕行為。主要結(jié)論如下： (1)在發(fā)生穩(wěn)定孔蝕前,P110鋼的電流波動(dòng)曲線上會(huì)出現(xiàn)小幅度的有規(guī)律的電流波動(dòng),每一個(gè)電流波動(dòng)峰是亞穩(wěn)態(tài)小孔形核、生長(zhǎng)及再鈍化的過程。亞穩(wěn)態(tài)孔蝕的萌生雖然具有很大的隨機(jī)性,但亞穩(wěn)孔出現(xiàn)電位Em的大小具有一定規(guī)律,實(shí)驗(yàn)結(jié)果表明,亞穩(wěn)孔出現(xiàn)電位Em服從正態(tài)分布。 (2)動(dòng)電位下,電位的增加將造成P110鋼亞穩(wěn)孔的形核數(shù)目增多,亞穩(wěn)孔的平均生長(zhǎng)速度加快,亞穩(wěn)孔平均峰值電流增大,亞穩(wěn)孔壽命也會(huì)變長(zhǎng)。P110鋼在亞穩(wěn)態(tài)孔蝕期間,表面蝕孔活性點(diǎn)溶解較慢,亞穩(wěn)孔生長(zhǎng)較慢,而亞穩(wěn)孔的再鈍化過程則比較迅速。當(dāng)腐蝕產(chǎn)物覆蓋在小孔表面,在小孔內(nèi)形成閉塞電池后,亞穩(wěn)態(tài)小孔逐步轉(zhuǎn)變?yōu)榉�(wěn)定孔。 (3)溫度、C1-濃度、HCO3-濃度和SO24-濃度這4個(gè)因素中,溫度對(duì)P110鋼孔蝕行為的影響高度顯著,Cl-濃度和SO24-濃度對(duì)P110鋼孔蝕行為的影響顯著,HCO3-濃度對(duì)P110鋼孔蝕行為的影響有顯著,這4個(gè)因素對(duì)P110鋼孔蝕行為影響大小排序?yàn)椋簻囟菴l-濃度SO24-濃度HCO3濃度。 (4)添加緩蝕劑H后,P110鋼的點(diǎn)蝕電位大大正移,其容抗弧半徑也大大增加,緩蝕劑H能有效抑制P110鋼孔蝕的發(fā)生,且緩蝕劑濃度達(dá)到100mg/L時(shí)達(dá)到了最佳緩蝕效果,緩蝕率高達(dá)91.23%,緩蝕效果能夠滿足現(xiàn)場(chǎng)的要求。
[Abstract]:P110 steel is the main material used in oil casing in western Sichuan gas field, and local corrosion perforation is the main form of corrosion failure of oil casing in western Sichuan gas field. The corrosion and perforation of oil casing has brought safety hidden trouble to gas field production, and the normal production and sustainable development of western Sichuan gas field have been seriously affected. Therefore, the pitting behavior of P110 steel in the corrosion environment of western Sichuan gas field and its influencing factors are studied, the pitting mechanism of P110 steel is understood, and the influence law of various factors on pitting corrosion behavior of P110 steel is summarized. It provides a theoretical basis for the rational use and corrosion prevention of P110 oil casing in western Sichuan gas field, and has important theoretical significance and practical value. In this paper, based on the actual corrosion background data in western Sichuan gas field, the methods of electrochemical measurement, scanning electron microscope observation, statistics and other multidisciplinary methods are comprehensively applied. The current fluctuation and electrochemical characteristics of P110 steel in the early stage of pitting corrosion, i.e. during metastable pitting, were studied, and the influence of temperature and concentration of Cl-HCO3- and SO24- on pitting corrosion behavior of P110 steel was analyzed. The pitting corrosion behavior of P110 steel under the action of corrosion inhibitor was studied. The main conclusions are as follows: (1) the current fluctuation curve of P110 steel before the stable pitting corrosion occurs a small amplitude of regular current fluctuation, each current fluctuation peak is the process of metastable pore nucleation, growth and repassivation. Although the initiation of metastable pitting corrosion is very random, the magnitude of the metastable pore occurrence potential E _ m has a certain regularity. The experimental results show that the metastable pore potential E _ m appears from the normal distribution. 2) under dynamic potential, the number of metastable pore nucleation will increase, the average growth rate of metastable pore will accelerate, the mean peak current of metastable pore will increase, and the life of metastable pore will also become longer during metastable pitting corrosion of P110 steel. The active point of surface etching is slower to dissolve, the metastable pore grows slowly, and the metastable pore is repassivated rapidly. When the corrosion product is covered on the surface of the pore and the occluded cell is formed in the pore, the metastable pore is gradually transformed into a stable pore. Among the four factors, the influence of temperature on pitting corrosion behavior of P110 steel is highly significant. The effect of Cl- concentration and so _ 24- concentration on pitting corrosion behavior of P110 steel is significant. The effect of HCO3- concentration on pitting corrosion behavior of P110 steel is significant. The order of influence of these four factors on pitting corrosion behavior of P110 steel is as follows: temperature Cl-concentration SO24- concentration HCO3 concentration. (4) the pitting potential of P110 steel after adding inhibitor H is greatly positive, and its arc resistance radius is also greatly increased. The corrosion inhibitor H can effectively inhibit the pitting corrosion of P110 steel, and the best corrosion inhibition effect is achieved when the concentration of inhibitor reaches 100mg/L. Corrosion inhibition rate up to 91.23, corrosion inhibition effect can meet the requirements of the site.
【學(xué)位授予單位】：西南石油大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TE983

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本文編號(hào)：1799577