Executive Secretary
XIV International Symposium on Structures, Geotechnics and Construction Materials
ESTRUCTURAS 2025
3rd International Workshop on Sustainable Production and Use of Cement and Concrete
Abstract
In the present study, a calcined kaolinitic clay was evaluated as an extender in cement slurries for primary cementing of oil wells, comparing it with a natural zeolite (clinoptilolite-mordenite), both of Cuban origin. Two series of slurries were prepared by substituting 5%, 10%, 20%, and 30% by mass of Class G Portland cement with calcined clay or zeolite. The free fluid percentage, rheological properties (yield point, plastic viscosity, and gel strength), and compressive strength at 8 h and 55°C were analyzed.
The results demonstrated that both additives reduced the free fluid percentage as substitution increased, with calcined clay showing greater effectiveness. The yield point and gel strength steadily increased with both materials, with calcined clay exhibiting higher values and lower plastic viscosities compared to equivalent zeolite substitutions. Mechanical strength showed a relative minimum at 10% substitution with calcined clay and an absolute maximum at 30%, demonstrating a positive correlation between substitution level and structural performance at high percentages.
These findings confirm the potential of calcined clay as a sustainable extender that simultaneously optimizes rheological stability in the fresh state (lower fluid loss and plastic viscosity) and final mechanical strength, particularly at substitutions ≥20%. Its superior performance over zeolite in rheological-strength balance positions it as a viable alternative for primary cementing in oil wells, with implications for cost reduction, reduced cement consumption, and adaptability to complex geological formations.
Resumen
En el presente estudio se evaluó una arcilla caolinítica calcinada como extensor en lechadas cementicias para cementación primaria de pozos petroleros, comparándola con una zeolita natural (clinoptilolita-mordenita), ambas de origen cubano. Se prepararon dos series de lechadas sustituyendo 5 %, 10 %, 20 % y 30 % en masa de cemento Portland clase G por arcilla calcinada o zeolita. Se analizaron el porcentaje de fluido libre, propiedades reológicas (punto de cedencia, viscosidad plástica y resistencia del gel) y resistencia a compresión a 8 h y 55 °C.
Los resultados demostraron que ambas adiciones redujeron el porcentaje de fluido libre al incrementarse la sustitución, con mayor eficacia por la arcilla calcinada. El punto de cedencia y resistencia del gel aumentaron sostenidamente con ambos materiales, destacando la arcilla calcinada por valores superiores en estas propiedades y viscosidades plásticas menores frente a sustituciones equivalentes de zeolita. La resistencia mecánica exhibió un mínimo relativo a 10 % de sustitución con arcilla calcinada, y máximo absoluto a 30 %, evidenciando una correlación positiva entre sustitución y desempeño estructural a altos porcentajes.
Estos hallazgos confirman el potencial de la arcilla calcinada como extensor sostenible que optimiza simultáneamente la estabilidad reológica en estado fresco (menor filtrado y viscosidad plástica) y la resistencia mecánica final, especialmente en sustituciones ≥20 %. Su desempeño superior a la zeolita en equilibrio reológico-resistencial la posiciona como alternativa viable para cementaciones primarias en pozos petroleros, con implicaciones en reducción de costos, menor consumo de cemento y adaptabilidad a formaciones geológicas complejas.
About The Speaker
MsC. Juan Alberto Ribalta Quesada
Discussion