For many years, Ordinary Portland Cement (OPC) is used in oil well cementing operation. But the OPC gets degraded in the acidic environment because of having poor mechanical characteristics. A new technology called geopolymeric cement system is developed from the secondary byproducts of the industry to replace the conventional cement slurry in oil well cementing operation. This study focus on the preparation of cement slurry with new formulation using fly ash and alkali binders at two sodium hydroxide treatment methods with various concentrations of NaOH solution and analyzing the prepared cement slurry for compressive strength, defiance to acid and fluid loss amount. Different cement slurry compositions made of 70:30 fly ash to alkaline activator ratios with 10, 12, 14 Molar NaOH solution with two sodium hydroxide treatment methods of direct addition and mixing after one day soaking of NaOH were prepared and cured for 24 hours at a temperature of 80°C and pressure 3000 psi. The obtained cement specimens were tested for compressive strength, resistance towards acid and density. Then based on the results, geopolymer can be considered as alternative for Class G cement in oil well cementing operation due to its high compressive strength and high acid resistance. © 2016 Trans Tech Publications, Switzerland.