Effect of GGBS and curing conditions on strength and microstructure properties of oil well cement slurry

Abstract

The addition of any supplementary cementitious materials has a significant influence on cement paste properties and its microstructure. In this paper, the effects of micro-fine Ground Granulated Blast Furnace Slag (GGBS) on the properties Oil Well Cement (OWC) slurry are investigated. The class G cement is replaced in a varying percentage (30–70%) with GGBS at intervals of 10%. Further, the influence of different curing conditions (i.e., dry curing, moist curing, curing at 60 °C, curing at 110 °C) on the compressive strength of blended cement with GGBS are also studied. The microstructure analysis of blended cement with GGBS is investigated using isothermal calorimetry, X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Thermogravimetric Analysis (TGA), and Mercury Intrusion Porosity (MIP). The results show that the compressive strength of blended cement with 40 % GGBS have significantly increased and more than that of unblended cement. Further, micro-fine GGBS has influence on the emission of hydration heat due to pozzolanic reaction. The heat of hydration of blended cement is decreased significantly with partial replacement of cement with GGBS. The most significant finding in this study is that the permeability of blended cement paste with 40 % GGBS is decreased by 51 % of that of unblended cement, which is very important because it is one of the main factors affecting the gas migration in the wellbore.