基于化学热力学的耐二氧化碳腐蚀水泥水化产物控制  

Control of Hydration Products of CO_(2) Resistant Cements Based on Chemical Thermodynamics

作　　者：田辉[1,2] 郭辛阳 宋雨媛[1] 步玉环 王成文[1] TIAN Hui;GUO Xinyang;SONG Yuyuan;BU Yuhuan;WANG Chengwen(College of Petroleum Engineering,China University of Petroleum,Qingdao,Shandong 266580,China;Technical Development Office,Sinopec Shengli Oilfield Service Corporation,Dongying,Shandong 257000,China)

机构地区：[1]中国石油大学(华东)石油工程学院 [2]中国石化胜利石油工程有限公司技术发展部

出　　处：《钻采工艺》2021年第2期86-89,共4页Drilling & Production Technology

基　　金：国家自然科学基金项目“CCS咸水层封存中二氧化碳—硫酸盐—镁盐协同作用下油井水泥石的腐蚀机理”(编号:51704325);中央高校基本科研业务费专项资金项目“井下温压复杂变化条件下水泥环完整性失效的机制及评价研究”(编号:18CX02103A)。

摘　　要：油井水泥石的二氧化碳腐蚀问题严重威胁着井眼寿命。文章介绍了油井硅酸盐、铝酸盐、硫铝酸盐、铁铝酸盐和改性磷铝酸盐等五种水泥水化产物,利用化学热力学理论建立了含二氧化碳地层水—水化产物体系热力学模型,计算了水化产物与H^(+)和HCO_(3)^(-)反应的热力学平衡关系,优选出耐腐蚀性能较优的水化产物。结果表明,温度升高会促进羟基磷灰石腐蚀反应,抑制其它水化产物腐蚀反应。水化产物耐腐蚀性能优劣次序为羟基磷灰石、Tobermorite型水化硅酸钙、单硫型硫铝酸钙、Jennite型水化硅酸钙、水化铝酸钙和钙矾石相近、羟钙石。改性磷铝酸盐水泥的耐腐蚀性能最优,建议以其为基础开发耐腐蚀水泥浆体系,并优化产物组成,进一步改善水泥石耐腐蚀性能。研究结果对于解决油井水泥石二氧化碳腐蚀问题具有重要的指导意义。The CO_(2) corrosion of oil well cement is a serious threat to the life of the well.The hydration products of oil well Portland cement,aluminate cement,sulphoaluminate cement,ferric aluminate cement and modified phosphoaluminate cement are summarized.The thermodynamic model of formation water dissolved by CO_(2) and hydrate products is developed and then the thermodynamic equilibrium relations of reactions that hydration products react with H^(+)and HCO_(3)^(-)are calculated by the model.The hydration product which has better CO_(2)-resistant property is selected among hydration products.The result shows that the increase of temperature will promote the corrosion reaction of hydroxyapatite and inhibit the corrosion reaction of other hydration products,and the increase of pressure will inhibit the corrosion reaction.The effect of temperature on thermodynamic equilibrium is more serious than that of pressure.The CO_(2)-resistant order of hydration products is hydroxyapatite,Tobermorite,monosulfoaluminate hydrate,Jennite-type calcium silicate hydrate,calcium aluminate hydrate and ettringite,portlandite.The modifid phosphoaluminate cement has the best CO_(2)-resistance.It is suggested to develop a CO_(2)-resistant cement slurry system based on the modified phosphoaluminate cement,and optimize the product composition to further improve the corrosion resistance of cement.The research results have important guiding significance for solving CO_(2) corrosion problem of cement in oil wells.

关 键 词：化学热力学 水泥 水化产物 耐二氧化碳腐蚀性能 

分 类 号：TE98[石油与天然气工程—石油机械设备]