摘要
磷铝酸盐水泥(PAC)作为一种新兴的特种水泥,具有优异的耐腐蚀性能和力学性能,是CCUS井极具前景的固井材料之一。然而目前关于PAC的碳化腐蚀机理尚不明确。因此,模拟了8 MPa CO_(2)分压及20 MPa地层压力条件下,采用抗压强度测试、渗透率测试、扫描电子显微镜(SEM)、X射线衍射(XRD)等技术手段分析90℃和110℃下PAC腐蚀前后宏观性能和微观结构的变化。结果表明:PAC的碳化腐蚀过程按阶段划分为溶解过程、诱导过程、碳化过程、分解过程和溶蚀过程。PAC的碳化腐蚀机理为PAC水化产生的羟基磷灰石吸收CO_(2)生成CaCO_(3)、Ca_(10)(PO_(4))_(6)CO_(3)和可溶性Ca_(3)(PO_(4))_(2)等物质。Ca_(10)(PO_(4))_(6)CO_(3)具备的独特六方分子结构在水泥表面形成保护层,能防止进一步腐蚀。此外,CaCO_(3)与PAC水化生成的凝胶、C_(3)AH_(6)连在一起填充孔隙,增强微观结构,导致水泥力学性能提高。
As an emerging cementitious material with excellent corrosion resistance and mechanical properties,phosphoaluminate cement(PAC)is one of the most promising cementing materials for CCUS wells.However,the mechanism of carbonation corrosion of PAC is not clear at present.Therefore,this paper simulates the conditions of 8 MPa CO_(2)partial pressure and 20 MPa formation pressure and analyzes the macroscopic properties and microstructural changes of PAC before and after corrosion at 90℃and 110℃by using compressive strength test,permeability test,scanning electron microscope(SEM),X-ray diffraction(XRD),and other technological means.It shows that the carbonation corrosion process of PAC is divided into dissolution,induction,carbonation,decomposition,and solution corrosion processes according to the stages.The carbonation corrosion mechanism is that hydroxyapatite produced by the hydration of PAC absorbs CO_(2)to generate CaCO_(3),Ca_(10)(PO_(4))_(6)CO_(3),and soluble Ca_(3)(PO_(4))_(2),etc.Ca_(10)(PO_(4))_(6)CO_(3)has a unique hexagonal molecular structure that forms a protective layer on the surface of the cement,which can prevent further corrosion.In addition,CaCO_(3)is linked to the gel and C 3AH 6 generated by the hydration of PAC to fill the pores and enhance the microstructure,leading to the improvement of the mechanical properties of cement.
作者
崔策
冯颖韬
张浩
田进
马睿
张荥阳
袁彬
CUI Ce;FENG Yingtao;ZHANG Hao;TIAN Jin;MA Rui;ZHANG Xingyang;YUAN Bin(Research Institute of Oilfield Chemistry,China Oilfield Services Corporation,Yanjiao,065201,Hebei,China;National Key Laboratory of Reservoir Geology and Development Engineering,Southwest University of Petroleum,Chengdu 610500,China)
出处
《材料导报》
北大核心
2025年第S2期132-137,共6页
Materials Reports
基金
油气重大专项(2025ZD1403200)
国家自然科学基金青年科学基金(52204014)
四川省青年基金(2023NSFSC0926)。
