Sustainable cement blends with quartz-aluminum waste and silica-rich pozzolan for high-temperature oil well cementing

High-temperature oil well cementing requires silica-based additives to mitigate strength retrogression, yet conventional systems rely on high clinker contents and silica flour, resulting in significant environmental impacts. This study evaluated quartz-aluminum-rich residue (QARR) and silica-rich pozzolan (SRP) as sustainable supplementary materials in Class G oil well cement systems designed for high-temperature applications. A reference slurry (65 wt% Class G cement and 35 wt% silica flour) was compared with ternary blends containing 50 wt% replacement by the QARR and SRP. The samples were cured at 180 °C and 3,000 psi for up to 28 days and characterized by compressive strength, XRD, TGA, and SEM‒EDS. The optimal formulation (50 wt% cement, 32.5 wt% SRP, and 17.5 wt% QARR) exhibited compressive strength increases of 150% and 120% at 7 and 14 days, respectively, and achieved 87% of the reference strength at 28 days despite a 26% reduction in cement consumption. The XRD results revealed predominant tobermorite formation in the ternary systems, whereas the reference favored xonotlite. The combined mineralogical, thermal, and microstructural results suggest that the incorporation of QARR and SRP promotes the development of thermally stable hydration products capable of maintaining mechanical performance under HPHT conditions. These findings demonstrate the potential of the QARR and SRP to reduce cement consumption and clinker demand while providing technically viable cement systems for high-temperature oil well cementing applications.