H_2S腐蚀油井水泥的热力学条件  

The thermodynamic conditions of corrosion between oil well cement and H_2S

作　　者：刘维俊[1] 姚晓[1] 诸华军[1] 张亮[1] 华苏东[1] 

机构地区：[1]南京工业大学材料科学与工程学院,江苏南京210009

出　　处：《石油化工应用》2011年第6期4-8,共5页Petrochemical Industry Application

基　　金：江苏省企业博士基金资助项目;项目编号:BK2009666

摘　　要：从水泥化学角度出发,应用热力学方法计算了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℃和150℃下与H_2S发生腐蚀反应的吉布斯自由能及所需H2S的最低分压,讨论了油井水泥熟料矿物及水泥水化产物与H_2S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H_2S分压下,H_2S才会对油井水泥石中的CH、C_3S、C_3S_2H_3、C_2S、C_3A、C_2S_3H_(25)AFt及AFm产生腐蚀;在潮湿地层中H_2S主要以HS^-和S^(2-)形式存在,通过不断消耗水泥石中Ca^(2+),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。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℃,and 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 HSand S^2-,will react with Ca^2＋,causing the decline of pH value of pore solution,which trig the continuous solution of hydration products.The whole cement stone will decay and loss strength as a result.

关 键 词：固井 油井水泥石 H_2S腐蚀 化学热力学 

分 类 号：TE983[石油与天然气工程—石油机械设备]