化学组分和温度对水化硅铝酸钙凝胶结构及力学性能影响的分子动力学研究  

Influence of chemical composition and temperature on structural and mechanical properties of C-A-S-H with molecular dynamics

作　　者：刘慧婷 李妍[2] 于永金 张弛 夏修建 张佳滢 张汉其 杜涛 LIU Huiting;LI Yan;YU Yongjin;ZHANG Chi;XIA Xiujian;ZHANG Jiaying;ZHANG Hanqi;DU Tao(CNPC Engineering Technology R&D Company Limited,Beijing 102200,China;School of Petroleum Engineering,China University of Petroleum(Beijing),Beijing 102249,China;College of Geoscience And Surveying Engineering,China University of Mining&Technology(Beijing),Beijing 102206,China;School of Mechanics and Civil Engineering,China University of Mining and Technology,Xuzhou 221116,China)

机构地区：[1]中国石油集团工程技术研究院有限公司,北京102200 [2]中国石油大学(北京)石油工程学院,北京102249 [3]中国矿业大学(北京)地球科学与测绘工程学院,北京102206 [4]中国矿业大学力学与土木工程学院,江苏徐州221116

出　　处：《中国石油大学学报(自然科学版)》2025年第1期211-219,共9页Journal of China University of Petroleum(Edition of Natural Science)

基　　金：中国石油天然气股份有限公司科技项目(2023DQ0529)。

摘　　要：通过分子动力学方法研究化学组分和温度对水化硅铝酸钙(C-A-S-H)凝胶结构和力学性能的影响规律,结合强度试验为超高温固井水泥砂铝配比提供试验指导。构建C-A-S-H凝胶模型,研究温度、Ca/Si、Al/Si对硅氧四面体结构Q n分布、平均链长的影响规律。通过C-A-S-H凝胶断裂过程的应力应变关系,结合Al、Si原子平均受力特征,揭示富铝相C-A-S-H的增强机制。结果表明:Al的加入能够有效填补硅氧链桥位缺陷,增加平均链长,增强桥联层间硅氧结构,促进形成聚合度更高的硅氧四面体,进而提升强度;超高温220~260℃时,Ca、Si、Al物质的量比为0.9∶1∶0.15~0.2,对应加砂55%、铝质材料7%~10%BWOC,可满足固井水泥强度要求。The influence of chemical composition and temperature on the structure and mechanical properties of calcium aluminosilicate hydrate(C-A-S-H)gel was studied by molecular dynamics method.Integrated into the compression experiments,the experimental guidance for the ratio of sand and aluminum in well cement at ultra-high temperature was provided.The C-A-S-H gel model was constructed to study the influence of temperature,Ca/Si,Al/Si on the Q n distribution and the mean chain length of the silica tetrahedron structure.Subsequently,by analyzing the stress-strain curves during the fracture process of the C-A-S-H gel,along with the evolution of atomic stresses of Al and Si atoms,the mechanism behind the enhancement of mechanical properties in the aluminum-rich C-A-S-H phase was revealed.It is found that the incorporation of Al can effectively fill the defects at the bridging sites of silicon-oxygen dreierketten chains,increase the mean chain length,enhance the bridged interlayer silicon-oxygen structure,and promote the formation of higher polymerized silicon-oxygen tetrahedra,thereby improve the strength of cement.When the ultra-high temperature is 220-260℃,molar ratio of Ca,Si and Al is 0.9∶1∶0.15-0.2,corresponding to 55% sand and 7%-10%BWOC of aluminum material,can meet the strength requirements of well cement.

关 键 词：超高温 硅铝酸钙凝胶 固井水泥设计 力学性能 分子动力学 

分 类 号：TQ172[化学工程—水泥工业]