二氧化碳及硫化氢腐蚀水泥环机理研究

单位代码 10615 西南石油大学

硕士学位论文

论文题目：二氧化碳及硫化氢腐蚀水泥环机理研究

研究生姓名：牟春国

导师姓名：杨远光（副教授）

施太和（教授）

学科专业：油气井工程

研究方向：油气井固井

2008 年 04月

摘要

摘要

CO2和H2S作为石油和天然气的伴生气或地层水的组分存在于油气层或地层水中，在一定的湿度及压力条件下会对固井水泥环产生腐蚀作用，从而降低水泥环的碱性，使水泥环强度下降，渗透率增大，并诱发流体窜流、塑性地层井壁跨塌等事故，从而缩短油气井的生产寿命，造成巨大的经济损失。因此，如何提高水泥环抗CO2和H2S的腐蚀能力，日益引起人们的高度重视，并成为含CO2和H2S地层油气田开发中急待解决的问题。

本文对水泥环CO2腐蚀的机理和影响因素进行了研究，提出了常温和高温条件下CO2腐蚀水泥环的机理。通过实验方法研究了水泥环腐蚀影响因素腐蚀时间、温度及CO2分压对水泥环CO2腐蚀的影响规律，得出了水泥环抗压强度、渗透率、腐蚀深度随腐蚀时间、温度和CO2分压的变化规律。在对水泥环抗CO2腐蚀的机理和抗腐蚀方法研究的基础上，优选出了抗腐蚀添加剂，提出了抗腐蚀水泥浆体系，在水泥中添加抗腐蚀材料，可以提高水泥环的抗腐蚀能力。

在分析H2S的基本物化性质和酸性腐蚀性的基础上，对水泥环H2S腐蚀的机理和腐蚀影响因素进行了分析和研究，提出了水泥环抗H2S腐蚀的方法和抗H2S腐蚀的水泥浆体系。

本文的研究对于油气田开发和油气井生产作业中进一步研究CO2和H2S对水泥环的腐蚀机理、影响因素及腐蚀规律具有重要的理论意义；对于延长油气井的生产寿命、提高含硫气田的开发效益等都具有非常重要的实际应用价值。

关键词：水泥环；二氧化碳；硫化氢；腐蚀机理；抗腐蚀水泥；

西南石油大学2008届硕士学位论文

ABSTRACT

CO2 and H2S exist in the hydrocarbon zone and foramtion water，as the accompany gases of petroleum and nature gaso or components of formation water，which will cause corrostion to the cement sheath under certain conditions of humidity and pressure。It will decrease the cement sheath’s alkalinity，which results in the decrease of cement sheath’s strength，permeability increase，and places a premium on fluid channeling and borehole wall sloughs accident in plastic formation，shortening the oil- gas well’s production lifetime and giving rise to tremendous ecomonic losses。Wherefore，how to improve cement sheath’ proof-corresion competence to CO2 and H2S increasely comes to the perople’s field of vision，which also becomes the urgent-solving problem in the process of oil-gas field development。

This text studied the mechanism and impact factors of CO2 corrosion to cement sheath，and put forward the meachniam of CO2 corrosion under nomal temperature and high temperature condition。Studied the influence regulations which corrosion time、temperature、and CO2 differential pressure to cement sheath，get the regulations of compressive strength、permeability、corrosion depth with corrosion time、temperature、and CO2 differential pressure。Based on studied the anti-corrosion mechanism and anti-corrosion methods to the cement sheath，optimized anti-corrosion additives，put forward anti-corrosion cement slurrys，add the anti-corrosion materials to the cement slurry，can impoved the ability of anti-corrosion to the cement sheath。

Based on analysed the physical and chemical characters of H2S，analysed and studied the meachnism and impact factors of H2S corrosion to cement sheath，and put forword the anti-corrosion methods and anti-corrosion cement slurry of H2S corrosion。

The studies in this thesis are theoretical significance to oil/gas field development，further studies of sheath corrosion mechanism of CO2 and H2S in the production operation of oil/gas wells，contributing factors and corrosion discplines。It also has the all-important application value for extending oil/gas well production lifetime，improving production efficiency of the sulfurous gas field。

Key words：cement sheath；carbon dioxide；hydrogen sulfide；corrosive mechanism；anti-corrosive cement slurry