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井下天然气中H2S腐蚀油井水泥石的热力学条件

发表时间:2012-05-15  浏览量:1144  下载量:534
全部作者: 刘维俊,姚晓,诸华军,张亮,华苏东
作者单位: 南京工业大学材料科学与工程学院
摘 要: 从水泥化学角度出发,应用热力学方法计算干地层和潮湿地层中油井水泥熟料矿物及水化产物在50,80,150℃下与H2S发生腐蚀反应的吉布斯自由能及所需H2S的最低分压,讨论油井水泥熟料矿物及水泥水化产物与H2S发生腐蚀反应的条件及难易程度。结果表明:在干地层中只在特定的温度和H2S分压下,H2S才会对油井水泥石中的Ca(OH)2,3CaO·SiO2,3CaO·2SiO2·3H2O,2CaO·SiO2, 3CaO·Al2O3·6H2O,2CaO·3SiO2·2.5H2O,3CaO·Al2O3·3CaSO4·31H2O和3CaO·Al2O3·CaSO4·12H2O产生腐蚀;在潮湿地层中H2S主要以HS-和S2-形式存在,通过不断消耗水泥石中Ca2+,降低水泥石孔隙液的pH值,破坏水泥的水化产物,从而腐蚀油井水泥石基体。
关 键 词: 材料物理与化学;固井;油井水泥石;H2S腐蚀;化学热力学
Title: Thermodynamic conditions of corrosion between oil well cement and H2S
Author: LIU Weijun, YAO Xiao, ZHU Huajun, ZHANG Liang, HUA Sudong
Organization: College of Materials Science and Engineering, Nanjing University of Technology
Abstract: The thermodynamic method was applied from the perspective of cement chemistry to calculate the Gibbs free energy and the lowest partial pressure necessary for the corrosion reaction occurring between H2S and oil well cement clinker as well as its hydration products in dry stratum and wet stratum at 50, 80, 150℃. The corrosion conditions and its level of difficulty were studied according to above calculation results. It is found that the corrosion reaction between H2S and oil well cement and its hydration products Ca(OH)2, 3CaO·SiO2, 3CaO·2SiO2·3H2O, 2CaO·SiO2, 3CaO·Al2O3·6H2O, 2CaO·3SiO2·2.5H2O, 3CaO·Al2O3·3CaSO4·31H2O and 3CaO·Al2O3·CaSO4·12H2O only occurs at special temperature and pressure in dry stratum. While in wet stratum, the H2S, in forms of HS- and S2-, will react with Ca2+, causing the decline of pH value of pore solution, which trig the continuous solution of hydration products. The whole cement stone will decay and lose strength as a result.
Key words: materials physics and chemistry;cementing; oil well cement; H2S corrosion; chemical thermodynamics
发表期数: 2012年5月第9期
引用格式: 刘维俊,姚晓,诸华军,等. 井下天然气中H2S腐蚀油井水泥石的热力学条件[J]. 中国科技论文在线精品论文,2012,5(9):835-840.
 
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