CO_(2)埋存条件下SO_(4)^(2-)对油井水泥石腐蚀的影响  

Effect of sulfate ion on corrosion of oilwell set-cement under CO_(2) storage

作　　者：郭辛阳 吴广军[3] 步玉环 郭胜来 张锐[1,2] 王成文 GUO Xinyang;WU Guangjun;BU Yuhuan;GUO Shenglai;ZHANG Rui;WANG Chengwen(Key Laboratory of Unconventional Oil&Gas Development(China University of Petroleum(East China)),Ministry of Education,Qingdao 266580,China;School of Petroleum Engineering in China University of Petroleum(East China),Qingdao 266580,China;Drilling and Completion Technology Research Institute of Petroleum Engineering Technology Research Institute,SINOPEC Zhongyuan Oilfield Company,Puyang 457001,China)

机构地区：[1]非常规油气开发教育部重点实验室(中国石油大学(华东)),山东青岛266580 [2]中国石油大学(华东)石油工程学院,山东青岛266580 [3]中国石化中原油田分公司石油工程技术研究院钻完井技术研究所,河南濮阳457001

出　　处：《中国石油大学学报（自然科学版）》2022年第4期72-78,共7页Journal of China University of Petroleum(Edition of Natural Science)

基　　金：国家自然科学基金项目(51704325);中央高校基本科研业务费专项(18CX02103A)。

摘　　要：为探究CO_(2)埋存条件下SO_(4)^(2-)对油井水泥石腐蚀的影响,利用水泥柱表观及断面分析、X射线衍射(XRD)、扫描电子显微镜-背散射电子成像(SEM-BSE)、扫描电子显微镜-mapping图(SEM-mapping)等手段,分析SO_(4)^(2-)存在时水泥石表观特征、腐蚀速率、矿物组成及微观结构等方面的变化,揭示SO_(4)^(2-)对CO_(2)腐蚀油井水泥石过程的影响。结果表明:CO_(2)-SO_(4)^(2-)与CO_(2)腐蚀水泥石的机制类似,腐蚀过程中水泥石由外向内都出现淋滤脱钙层、碳化致密层、氢氧化钙溶解层和未腐蚀层等4个层位,不同之处在于CO_(2)-SO_(4)^(2-)腐蚀时淋滤脱钙溶出的Ca^(2+)在水泥石表面与SO_(4)^(2-)反应生成石膏;石膏起类似“保护层”的作用,降低了溶液中H^(+)和HCO_(3)^(-)等腐蚀性离子的侵入速率,使得水泥石的腐蚀深度和腐蚀速率较单独CO_(2)腐蚀情况要低。In order to explore the influence of sulfate ion on the corrosion of oilwell set-cement under CO_(2) storage,the changes of apparent characteristics,corrosion rate,mineral composition and microstructure with the existing of SO_(4)^(2-) were analyzed by the apparent and cross section analysis,X-ray diffraction(XRD),scanning electron microscope-back scattered electron imaging(SEM-BSE),and scanning electron miroscope-mapping diagram(SEM-mapping).The influence of SO_(4)^(2-) on the process of CO_(2) corrosion oilwell set-cement was revealed.The results show that the mechanism of CO_(2)-SO_(4)^(2-) corrosion is similar to that of CO_(2).During the corrosion process,there are 4 layers of cement from the outside to the inside,including leaching calcium layer,carbonized tight layer,dissolved layer of calcium hydroxide and uncorroded layer.The difference lies in that the Ca^(2+)dissolved by leaching of calcium during CO_(2)-SO_(4)^(2-) corrosion reacts with SO_(4)^(2-) on the surface of set-cement to form gypsum,which acts as a similar"protective layer"and reduces the invasion rate of corrosive ions such as H^(+) and HCO_(3)^(-) in the solution.Then,the corrosion depth and corrosion rate of set-cement are lower than that of CO_(2) alone.

关 键 词：CO_(2)埋存 硫酸根离子 油井水泥石 腐蚀 

分 类 号：TE256.5[石油与天然气工程—油气井工程]