水灰比对油井水泥石微观性能影响的试验研究  

Experimental Research on the Impact of Water-Cement Ratio on Microscopic Properties of Oil Well Cement Slurry

作　　者：张震 庞学玉 马朝阳 秦建鲲 李海龙 Zhang Zhen;Pang Xueyu;Ma Zhaoyang;Qin Jiankun;Li Hailong(School of Petroleum Engineering,China University of Petroleum(East China),Qingdao,Shandong 266580,P.R.China;Key Laboratory of Unconventional Oil&Gas Development,Ministry of Education,China University of Petroleum(East China),Qingdao,Shandong 266580,P.R.China;Deep Earth Energy Laboratory,Monash University,Melbourne 3800,Australia)

机构地区：[1]中国石油大学(华东)石油工程学院,山东青岛266580 [2]中国石油大学(华东)非常规油气开发教育部重点实验室,山东青岛266580 [3]蒙纳士大学深地能源实验室,澳大利亚墨尔本3800

出　　处：《地下空间与工程学报》2023年第2期521-532,共12页Chinese Journal of Underground Space and Engineering

基　　金：国家自然科学基金(51974352)。

摘　　要：为研究水灰比对油井水泥石微观结构和微观力学性能的影响,采用压汞、热重和X射线衍射表征油井水泥石内部孔隙结构、水化进程和物相含量变化,通过统计纳米压痕技术表征油井水泥石的微观力学性能,其中最小平方差和最大似然估计算法用于油井水泥石固相弹性模量、硬度和体积分数的解卷积计算。针对最小平方差算法在拟合频率分布时受面元尺寸的影响,采用BSI模型对面元尺寸进行合理评估和选取。结果表明:水灰比影响油井水泥石孔隙度、孔径分布及孔隙特征,较高的水灰比促进了水泥水化;水化产物的弹性模量随水灰比增加略有降低,在低水灰比下,水化硅酸钙凝胶更多为高密度型,而在高水灰比下则相反;尽管两种解卷积算法基于不同准则,但均适用于胶凝材料的解卷积计算。In order to investigate the effect of water-cement ratios on the microstructure and micromechanical properties of oil well cement slurry,mercury intrusion,thermogravimetric and X-ray diffraction techniques were used to characterize the internal pore structure,hydration process and phase content of oil well cement slurry.The statistical nanoindentation technique was utilized to probe the micromechanical properties of oil well cement slurry,in the meanwhile,both least squares estimation and maximum likelihood estimation methods were adopted for the deconvolution calculations,through which,elastic modulus,hardness,and volume fraction of solid phase in oil well cement slurry were gained.The BSI model is chosen to evaluate and select the most appropriate bin size because the bin size plays a significant role on the accuracy of the least squares estimation algorithm.The results of this study indicate that the water-cement ratio affects the porosity,pore size distribution,and pore properties of oil well cement slurry.A higher water-cement ratio favors the formation of hydration products.In addition,the elastic modulus of the hydration product decreases significantly with the increasement of water-cement ratio.The hydrated calcium silicate gel has a higher density under the low water-cement ratio condition and vice versa.Although the two deconvolution algorithms are based on distinct criteria,both of them are suitable for deconvolution calculations of cementitious materials.

关 键 词：油井水泥石 纳米压痕技术 解卷积算法 微观性能表征 

分 类 号：TU528[建筑科学—建筑技术科学]