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研究了硫酸对油井水泥石强度及微观结构的影响。结果表明:水泥石被硫酸腐蚀后,强度明显下降,硬化浆体中100 nm以上有害孔的数量显著增多,水化产物变得疏松多孔,硬化水泥浆体的物相组成发生变化,有新的腐蚀产物CaSO4 2H2O生成;水泥石抵抗酸性介质腐蚀的能力不仅与其致密程度有关,还与其硬化浆体的矿物组成密切相关;不同水化产物抵抗腐蚀的能力不同,Ca(OH)2比C-S-H凝胶更容易受到酸性介质的腐蚀;C-S-H凝胶被腐蚀后产生的孔隙主要是细小孔隙,而Ca(OH)2被腐蚀后产生的孔隙主要是100 nm以上有害孔,降低硬化浆体中Ca(OH)2的含量是提高水泥石抗腐蚀性能的关键。
The effect of sulfuric acid on the strength and microstructure of cement stone was studied. The results show that the strength of cement paste is obviously decreased after being corroded by sulfuric acid. The number of harmful holes with a size of more than 100 nm in the hardened paste increases significantly, the hydration products become loose and porous, and the phase composition of hardened cement paste changes. The corrosion resistance of cement stone against acidic medium is not only related to the degree of densification but also to the mineral composition of the hardened slurry. The ability of different hydration products to resist corrosion is different. Compared with CSH gel The corrosion of Ca (OH) 2 is mainly caused by the corrosion of the acid medium; the pores produced by the corrosion of CSH gel are mainly tiny pores, ) 2 content is to improve the corrosion resistance of cement stone key.