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用矿渣将泥浆转化成水泥浆（MTC）固井技术不仅能降低固井成本，而且能将钻井工程的污染物－泥浆填入地下。减少了对环境的污染也节约了废弃泥浆的处理费用。此外矿渣MTC技术还具有提高顶替效率及固井质量等优点。但矿渣结物高温脆裂是限制矿渣泥浆转化成水泥浆（MTC）技术在高温深井条件下应用的重要原因。文章在分析了现有的各种关于矿渣高温脆裂原因的观点后，在实验观测的基础上，提出了矿渣高温脆裂原因的新观点，即矿渣高温脆裂是由于C－S－H无定型凝胶高温脱水后发生体积膨胀造成的。文章设计了验证这一新观点的实验方法及装置，并用大量实验验证了这一新观点。最后根据这一新观点提出了预防矿渣胶结物高温脆裂的措施。

Embrittlement of Slag Cement at High Temperatures and Its Preventive Measures

Well cementing technique of mud to cement (MTC) by slag can not only reduce the cost of cementing but also make the mud-the pollutant of drilling engineering be directly buried underground,which avoids environmental contamination and economizes on waste mud disposal cost.Moreover slag MTC technique is also possessed of the advantages as raising displacement efficiency and cement job quality,etc.,the embrittlement of slag cement,however,at high temperature is an important reason of limiting the application of the slag MTC technique at high temperatures (in deep wells).After having analyzed existing viewpoints about various reasons causing the embrittlement of slag cement at high temperatures and on the basis of experiment and observation,a new viewpoint is proposed in the paper,i.e the embrittlement is caused by volumetric expansion because of the dehydration of C-S-H amorphous gels at high temperatures.For verifying such a new viewpoint,the experimental method and device are put forward and designed in the paper and a great number of experiments have been done.Finally,some measures for preventing slag cement from embrittling at high temperatures are proposed in the article.