Curing Time Impacts on the Mechanical and Petrophysical Properties of a Laponite-Based Oil Well Cement

Abstract

Throughout the life of a well, the cement sheath is exposed to several loadings, which can harm its key properties and impede its functions. These loadings become more significant at the early age of forming the cement sheath in which the properties of the cement are not completely developed. In this study, 10 cement samples with and without laponite particles were prepared and cured for five different periods (6, 12, 24, 48, and 72 h). The failure properties, petrophysical parameters, elastic properties, and density variation along the samples were examined. All of the samples were characterized by nuclear magnetic resonance and X-ray diffraction to understand the influence of the curing times on the cement properties. The results showed that the compressive and tensile strengths of both cement systems increased with the curing time and the incorporation of the laponite particle increased the strength of the cement. The permeability of both cement samples decreased with curing time, and the addition of laponite also decreased the permeability of the cement samples because of the presence of laponite-clay particles. The addition of laponite particles also increased the elasticity of the cement as indicated by the decrease in Young’s modulus and the increase in Poisson’s ratio. Logarithmic relationships were established to represent the changes in porosity, compressive strength, and tensile strength, while the changes in the other properties of permeability, Poisson’s ratio, Young’s modulus, and density variation were represented accurately with power-law equations.