STUDY ON THE EFFECT OF SILICA FUME WITH LOW CALCIUM FLY ASH IN GEOPOLYMER PROPERTIES FOR OIL WELL CEMENTING

Increasing concern of greenhouse gas emission had been a chief highlight in inducing
global warming. Application of Ordinary Portland Cement (OPC) for oil well
cementing contributes a large portion for these gases, and therefore, geopolymeric
technology is proposed to help curb down CO2 emission by replacing OPC. However,
enough justification has to be shown to ensure the new technology is reliable enough to
replace OPC for oil well cementing. This study aims to study the effect of silica fume
addition to low calcium fly ash geopolymer cement by focusing on compressive
strength and other properties such as thickening time, fluid loss and acid resistance test.
Low calcium fly ash pose geopolymeric properties besides having a very low utilization
rate which justify fly ash as our base material. Five different composition of varying
silica fume (SF) content (0, 5, 10, 15 and 20%) was prepared and cured under wellbore
condition (3000 psi and 200 F) under two curing time;8 hour and 24 hours, before being
tested for compressive strength. Composition with 15% SF posed highest compressive
strength of 5.6MPa (8 hours time) and 11.6MPa (24 hours time). Acid resistance test
was conducted by immersing the 15% SF mould in 4 different HCl and 35% reduction
of strength was observed for both mould cured at different time.