低温下油井水泥石孔结构与抗压强度的关系

Mathematical model for structure and compressive strength of hardened class G oilwell cement paste at low temperature

根据Powers理论模型,通过引入相对水化程度及选定油井水泥石的本征强度参数,结合Balshin方程和Schiller方程,建立了低温条件下油井水泥石孔结构和抗压强度的数学模型。比较结果表明:Balshin方程的计算值与实验值有着良好的线性关系,在水泥浆体的水化龄期小于90d时结果比较吻合,而Schiller方程则不适用。

Structure of hardened oilwell cement paste is much more complicated than that of solid materials. It is a multiphase, porous structural system consisting of many components, which develops with the time and space of hydration, hardening and surrounding conditions. Based on the Powers classical theory and on both relative degree of hydration and intrinsic strength of oilwell cement paste together with Balshin equation, a mathematical model for calculating and predicting both the compressive strength and the porous structure of hardened oilwell cement paste at low temperature was elaborated. The calculated results shows a good linear relation compared with test findings, especially when hydration period of the cement is no more than 90 d.