富镁矿渣对油井水泥浆体膨胀性能的影响及水化机理

Effects of Magnesium-rich Slag on Expansive Property of Oil Well Cement Slurry and Its Hydration Mechanism

80℃水浴养护环境下,研究了不同掺量富镁矿渣对G级油井水泥浆体膨胀性能及其他基本性能的影响,考察了40%富镁矿渣掺量下水泥浆体的工程性能,同时研究了富镁矿渣的水化机理。实验结果表明,掺加富镁矿渣的水泥浆体具有微膨胀性能,其中掺40%富镁矿渣的水泥浆1d线膨胀率为0.0035%,28d线膨胀率为0.0255%;富镁矿渣掺量对水泥浆体凝结时间、流动度、密度影响不大;水化放热量和水泥石早期强度(3d前)均随富镁矿渣掺量的增加而降低,而后期强度(28d后)逐渐升高并高于净浆水泥石;硬化体中Ca(OH)2含量随富镁矿渣掺量增加和养护龄期的延长而降低;40%富镁矿渣掺量下,浆体各项工程性能基本满足固井施工基本技术要求。

At the water-bath curing temperature of 80 ℃,effects of magnesium-rich slag on expansive property and other basic properties of class G oil well cement slurry were studied,and the engineering properties of cement slurry with 40％ slag were determined,and its hydration mechanism were researched at the same time.The results show that the cement slurry with magnesium-rich slag has micro-expansive property.The linear expansivity of cement slurry with 40％ magnesium-rich slag is 0.0035％ on the first day and 0.0255％ on the 28th day.The mixing amount of magnesium-rich slag has no significant effect on setting time,fluidity and density of cement paste.The hydration heat and early strength （three days ago） of cement slurry decrease with increasing content of magnesium-rich slag,but the late strength （after 28 days） gradually increase even more than the strength of pure cement slurry.The contents of calcium hydroxide in the cement stone decrease with the increase of magnesium-rich slag and the intension of curing periods.The various engineering properties of cement slurry containing 40％ magnesium-rich slag meet the basic technology requirements of cementing operation.