复合纤维增强高温油井水泥石的力学性能研究

Mechanical Properties of Inorganic Fiber Reinforced Oil Well Cement

针对油井水泥石在高温下强度降低的问题,研究可耐高温的复合硅灰石纤维对其高温力学性能的增强效果。结果表明,不同长径比的硅灰石纤维对水泥石力学性能的影响不同,超长硅灰石纤维与超细硅灰石纤维按2:1比例复配而成的DRZ-1S效果较好,能够显著提高水泥石的抗压强度、抗拉强度和单轴应力—应变。加入质量分数为5%的DRZ-1S后,水泥石的力学性能得到明显提升;DRZ-1S加量5%时,水泥石在200℃下的3 d抗压强度、抗拉强度较空白水泥石分别提高52.9%和51.5%。通过X射线衍射仪和扫描电子显微镜对加入DRZ-1S前后的水泥石微观形貌进行对比分析后,得出结论,复合纤维DRZ-1S的加入改善了水泥石的孔隙分布,阻挡了裂纹发育,在受到外力荷载时,能有效使水泥石增强增韧。

This paper studies the modification of oil well cement by using compound wollastonite fiber at high temperature. The research shows that different length to diameter ratios of wollastonite have different effects on cement. Therefore, the compressive strength, tensile strength and uniaxial stress-strain of cement can be improved by adding the composite material DRZ-1S, which is made by laboratory and homogeneity mixed with ultra-long wollastonite fiber GHA(Length to diameter ratio 16:1) and ultra-fine wollastonite fiber GHB(length to diameter ratio 13 : 1) in the proportion of 2 : 1. It is found that the mechanical properties of cement can be greatly improved by adding 5% DRZ-1S. At 200 ℃ with 5% DRZ-1S, after hydration for 3 days, the compressive strength and tensile strength of cement increased by 52.9% and 51.5%, respectively, compared with blank cement. After comparing and analyzing the microstructure of cement before and after DRZ-1S by X-ray diffraction and scanning electron microscopy, we can get that the addition of composite fiber DRZ-1S can improve the pore distribution of cement and prevent the development of cracks.Under the external load, it can effectively strengthen and toughen the cement.