Green Cement with Enhanced Mechanical Properties

In the midst of increasing awareness of global warming, geopolymer-based cement has been recognized as one of the feasible solutions in reducing the emission of contributed by oil well cementing. Nevertheless, it is important for the developed geopolymer cement to possess specific oil well requirement and durable in extreme condition in order to substitute the conventional Portland cement. The use of geopolymer in cement system was widely tested and claimed to be an ideal alternative. However, this new cement system needs comprehensive study to yield better advantages of it. In this research, the main objective was to evaluate the geopolymer cement performance in terms of mechanical properties under extreme wellbore condition, as well as rheological behaviour, density and filtration loss. This research utilized the combination of low calcium (ASTM class F) fly ash and silica fume as the main substitute materials varying in terms of mix proportion. The base case and five samples were cured at 120°C and at 4000 psi pressure to simulate wellbore condition. The results indicate a significant pattern in geopolymer cement strength development with increasing curing time ideally with 40% fly ash and 60% silica fume while standard cement degrades. The higher silica fume content provides early and greater strength attainment. Geopolymer cements lies in ideal plastic viscosity range with sample D (40% fly ash, 60% silica fume) exhibit comparable high yield point to standard G cement. The pattern in density measurement meanwhile shows that the incorporation of silica fume helps in producing lower density slurry. All geopolymer cements show better fluid loss properties. Overall, geopolymer cement exhibit significant strength development and better properties compared to conventional cement but special consideration must be made in elevated curing temperature.