Impact of Mud Contamination on Performance of Granite-Based Geopolymers
Doctoral thesis

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2024Metadata
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- PhD theses (TN-lEP) [33]
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Impact of Mud Contamination on Performance of Granite-Based Geopolymers by Pouya Khalili, Stavanger : University of Stavanger, 2024 (PhD thesis UiS, no. 782)Abstract
Ensuring zonal isolation and long-term integrity are fundamental in primary cementing in the well construction phase. Successful cementing can be compromised by various factors, including contamination with drilling fluid. Given that drilling fluid is present in the wellbore before cementitious material is pumped, it is possible that mixing between these fluids takes place downhole, affecting the properties of the barrier material. To mitigate this, spacer fluid is normally pumped in front of the cement slurry to minimize the commingling of drilling fluid and improve bonding. Geopolymer is seen as a potential replacement for Ordinary Portland Cement. Prior to its use in well construction and abandonment, the impact of drilling fluid contamination on geopolymer performance must be assessed.
In this study, the impact of drilling fluid contamination on the liquid-state and solid-state properties of granite-based geopolymer, developed at the University of Stavanger (UiS), was investigated at elevated temperatures (50 ℃ BHCT/70 ℃ BHST). Oil-based drilling fluid (OBDF) and water-based drilling fluid (WBDF) were formulated in the lab with representative mix designs for the contamination study. Additionally, a spacer fluid tailored for geopolymer was designed to minimize contamination by drilling fluid. The thesis presented here is the result of the SafeRock Project, a collaboration between UiS and operators aimed to meet industry standards with geopolymeric materials.
The PhD dissertation is structured into two primary sections: the first section outlines the research project, while the second section consists of appended papers comprising detailed scientific findings. The outcomes of this research have been published across five scientific papers: three in journals, one in a peer-reviewed conference, and one in an SPE conference. These papers are included as appendices and are labeled using Roman numerals. Throughout this thesis, the same numerals are utilized for the sake of referring.
Paper I: Geopolymer slurry was contaminated with different ratios of OBDF and WBDF, and its rheological behavior was analysed at 50°C. The flow curve, viscoelastic properties, gel strength, and rheological parameters of the geopolymer, post contamination, were investigated in the study. Experimental measurements were conducted using a scientific rheometer and a V-G meter, serving as industry-standard equipment, to ensure comparisons of the results.
Paper II: The effect of OBDF and WBDF contamination on the mechanical properties of geopolymer was investigated. The analysis targeted compressive strength, tensile strength, sonic strength development, and microstructure of the geopolymer.
Paper III: A hardening spacer was developed for the geopolymer. The design process consisted of tuning the viscosity profile with conventional rheology modifiers and optimizing the surfactant content to remove the drilling fluid layer from the casing and water-wet the surface. Finally, a compatibility study of the optimized spacer with geopolymer was performed.
Paper IV: The rheological compatibility of various mixtures of the spacer with OBDF was examined using a rheometer, and the resulting R-index, a measure of compatibility between downhole fluids, wasdetermined. Additionally, the influence of surfactant in the spacer designon rheological compatibility was investigated. A small-scale muddisplacement experiment was conducted to assess the effect of surfactanton drilling fluid displacement.
Paper V: A case study was conducted using 2D simulations to examine the process of drilling fluid displacement by spacer and geopolymer. The aim was to mitigate the risk associated with deploying new materials by quantitatively predicting optimal practices, including viscosity and density hierarchies while minimizing eccentricity to enhance displacement efficiency.
Appendix 6 presents a filed patent in Norway and Europe titled ‘LOW DENSE SETTABALE GEOPOLYMER SLURRY COMPRISING A SWELLABLE CLAY, AND SETTABLE TREATMENT FLUIDS OBTAINABLE FROM THE SLURRY’.
Has parts
Paper 1: P. Khalili, M. Khalifeh, and A. Saasen, "The Effect of FluidContamination on Rheological Properties of GeopolymerMaterials," presented at the ASME 2022 41st InternationalConference on Ocean, Offshore and Arctic Engineering,2022. https://doi.org/10.1115/OMAE2022-78994. This paper is not included in the repository due to copyright restrictions.Paper 2: P. Khalili, M. Khalifeh, and A. Saasen, "The Effect ofDrilling Fluid Contamination on the Properties of Granite-Based Geopolymers at Elevated Temperature," Paperpresented at the IADC/SPE International Drilling Conferenceand Exhibition, Galveston, Texas, USA, March 2024. doi:https://doi.org/10.2118/217942-MS. This paper is not included in the repository due to copyright restrictions.
Paper 3: P. Khalili, M. Khalifeh, A. Saasen, J. Djuve, and L. Delabroy" Experimental Evaluation of Hardening Spacer for Rock-Based Geopolymer," (submitted to a scientific journal 2024). This paper is not included in the repository because it's still under review.
Paper 4: P. Khalili, M. Khalifeh, A. Saasen, and M. Naccache,"Rheological Compatibility of a Hardening Spacer Fluid andOil-Based Drilling Fluid," SPE Journal, pp. 1-16, 2023, doi:10.2118/217446-pa.
Paper 5: A. Renteria, P. Khalili, I. Frigaard, and M. Khalifeh, "A casestudy for tailored formulation of geopolymers aided byannular displacement simulations," Geoenergy Science andEngineering, vol. 229, p. 212110, 2023/10/01/ 2023, https://doi.org/10.1016/j.geoen.2023.212110.