Sensitivity analysis of fly ash geopolymer cement slurries: Implications for oil and gas wells cementing applications

Geopolymers are a new class of binder materials suitable for applications in civil industry and Oil and Gas well cementing. Although these materials are widely applied in civil industry applications, they still need more research and development before they can be fully applied for Oil and Gas well cementing. Specifically, these materials have potential to reduce wellbore isolation problems reported by use of ordinary Portland cement (OPC). The study here first presents a comprehensive literature study of geopolymers and results of laboratory testing of class Fly ash geopolymer mixtures under various experimental conditions. We conducted a sensitivity analysis of various factors on specimen's strength as well as selection of plasticizer type and dosage, the effect of Sodium Hydroxide molarity, the effect of shear mixing and rate, mixing time, and effects of solid to liquid ratio. Study results show a strong impact of temperature and curing time on geopolymer mixture's strength whereas mixing condition were not found as a significant factor. Finally, this paper investigates the effect of drilling fluid's contamination on the performance of geopolymers when compared with ordinary Portland cement. (C) 2016 Elsevier B.V. All rights reserved.