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

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 per -centage (30 - 70 %) with GGBS at intervals of 10 %. Further, the influence of different curing conditions (i.e., dry curing, moist curing, curing at 60 degrees C , curing at 11 0 degrees 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 ce-ment 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 un-blended cement, which is very important because it is one of the main factors affecting the gas migration in the wellbore.