封堵井水泥石在CO_(2)湿相环境下的腐蚀规律研究  

Research on Effect of CO_(2)Wet Phase Environment on Corrosion of Cement Stone

作　　者：龚承萌 周念涛 梅宗斌 魏麟杰 李春月 黄耕 黎昌灵 林元华[1] GONG Chengmeng;ZHOU Niantao;MEI Zongbin;WEI Linjie;LI Chunyue;HUANG Geng;LI Changling;LIN Yuanhua(National Key Laboratory of Oil and Gas Reservoir Geology and Development Engineering,Southwest Petroleum University,Chengdu 610500,China;School of New Energy and Materials,Southwest Petroleum University,Chengdu 610500,China;Sichuan Huayu Drilling Equipment Co.,Ltd.,Luzhou 646000,China)

机构地区：[1]西南石油大学油气藏地质及开发工程国家重点实验室,四川成都610500 [2]西南石油大学新能源与材料学院,四川成都610500 [3]四川华宇钻采装备有限公司,四川泸州646000

出　　处：《新技术新工艺》2023年第5期60-66,共7页New Technology & New Process

基　　金：国家自然科学基金项目(52074232);四川省自然科学基金重点项目(2022NSFSC0028,2022NSFSC0994)。

摘　　要：为探讨不同湿相环境对油井水泥石在CO_(2)埋存条件下腐蚀的影响机理和规律,采用了试样表观分析、扫描电镜(SEM)、能谱仪(EDS)和物理分析等方法,测定了两种不同配比的水泥石在超临界CO_(2)气相和液相环境下的表观特征、腐蚀深度、抗压强度、渗透性、微观形貌等变化,并对比分析了气相CO_(2)和液相CO_(2)两种暴露条件下对水泥石腐蚀过程的影响。结果发现,水泥石在腐蚀过程中由外向内出现了淋滤脱钙层、碳化层、氢氧化钙溶解层和未腐蚀层等4个区域;两种水泥石在处于超临界CO_(2)的两相状态下,随着暴露时间的延长,其抗压强度显著下降,腐蚀深度、渗透率、孔隙结构都有不同程度的增加,且在液相CO_(2)环境下水泥石试样腐蚀更为严重;液相CO_(2)环境下高矿化度地层水的协同作用会增加CaCO_(3)的溶解度,增强浸出效果,加剧了CO_(2)对水泥的侵蚀。从而揭示了湿相环境对油井水泥石在二氧化碳埋存条件下耐久性能影响机理和规律,并为油井水泥腐蚀提供了参考依据。In order to explore the influence mechanism and law of different wet-phase environments on the corrosion of oil well cement under CO_(2)storage conditions,it was used that methods such as sample surface analysis,scanning electron microscopy(SEM),energy spectrometer(EDS),and physical analysis to determine the changes of the apparent characteristics,corrosion depth,compressive strength,permeability,and micro-morphology of two different proportions of cement stone under supercritical CO_(2)gas phase and liquid phase environments,and we compared and analyzed the effects of gas phase CO_(2)and liquid phase CO_(2)on the corrosion process of cement stone under two exposure conditions.The results showed that cement under corrosion appeared leached decalcification layer,carbonization zone,calcium hydroxide dissolved layer,and uncorroded layer outside to inside.Two cements under condition of supercritical CO_(2)two-phase,with the time extension of exposure,its compressive strength reduced significantly,the etch depth,permeability,and pore structure increased to varying degrees,and the cement sample corroded even more serious under liquid phase CO_(2)environment.The synergistic effect of formation water with high salinity under liquid phase CO_(2)environment would increase CaCO_(3)solubility,enhanced extraction effects,and intensified CO_(2)corrosion to cement.It revealed influence mechanism and rule of lasting quality of wet phase environment to oil well cement under CO_(2)storage conditions,which provided reference frame for oil well cement corrosion.

关 键 词：CO_(2) 油井水泥石 微观结构 SEM 腐蚀机理 

分 类 号：TE256[石油与天然气工程—油气井工程]