Synthesis and Development of One-part Rock-based Geopolymers for Well Cementing Applications

Abstract

A one-part or Just Add Water (JAW) geopolymer system is an environmental- and user-friendly alternative to Ordinary Portland Cement (OPC) and conventional geopolymers. It helps with producing lower CO2 emissions avoiding OPC processing and eliminating the need for unnecessary liquid transportation for conventional geopolymers. A one-part geopolymer is ideal for large-scale deployment of geopolymers in well-cementing applications. It can help with quality control processes and reduce the need for extensive end-user knowledge of the chemistry involved. Accordingly, this study is to design a successful one-part naturally occurring (i.e., unprocessed nor pre-processed) granite-based geopolymer formulation. It aims to understand all possible impacts on the performance of these geopolymers of the utilized components including precursors, activators, water content and chemical admixtures. It is also to take into account petroleum engineering standards. This research is part of the SafeRock Project which is in collaboration between the University of Stavanger and operator and service companies. Additionally, it is done with a tight collaboration with academic institutes including Delft University of Technology (TU Delft, Netherlands), Universidade Federal do Rio de Janeiro (UFRJ, Brazil) and University of Oklahoma (OU, United States). The outcomes of this thesis have been published in seven scientific articles: four journal papers, two peer-reviewed conferences, one SPE conference, and a filed patent application in Norway and PCT application in Europe. This section is composed of a brief description of the published articles and their scientific findings. The outcomes of this research can be summarized as the following: Paper I shows the normalization of a Norwegian grounded granite in the solid phase by slag, microsilica, potassium silicates and alkali-metal hydroxides. It illustrates the synthesis of a one-part granite-based geopolymer for well-cementing applications (JAW). It reveals the chemical composition of granite needs normalization. Fluid-state properties at 50 ℃ and solid-state properties at 70 ℃ are investigated. These investigations include pumpability, strength development, mineralogy, and morphology. Papers II and III present monitoring and screening of the modified JAW mixes after the utilisation of various chemical admixtures to improve the early-age strength development at 70 ℃ of bottom-hole static temperature. Mechanical, chemical and mineralogical properties of the one-part geopolymers are investigated. Papers IV and V study the influence of different superplasticizers on the rheology of these granite-based geopolymers at 20 and 50 ℃ of bottom-hole circulating temperatures. Papers VI and VII illustrate various early-age characteristics of the screened and developed samples including their chemical, physical, mechanical, mineralogical, and morphological properties at 20 and 50 ℃ at bottom-hole circulating temperatures. Additionally, Paper VII further investigates and characterizes the aged JAW properties at 20 and 50 ℃ at bottom-hole circulating temperatures for up to two months of curing. Appendix 10 is a filed patent in Norway and Europe titled ONE-PART GEOPOLYMER COMPOSITION – ref. P31562NO – June 2022.