Synthesis of Crystalline-Phase Silica-Based Calcium Phosphonate Nanomaterials and Their Transport in Carbonate and Sandstone Porous Media

Phosphonates are widely used scale inhibitors in,oilfields for kale control. In this study, crystalline-phase, calcium phosphonate nanomaterials were prepared from amorphous silica-templated calcium phosphonate precipitates that were matured into crystalline phases by a simple diafiltration process. The crystalline solids were further dispersed into a surfactant solution to form a nanomaterial suspension (nanofluid) by ultrasonic treatment to expand their use in the delivery of phosphonate inhibitors into formation core materials for scale control. The physical and chemical properties of the synthesized crystalline nanomaterials were characterized by chemical analysis, electron microscopy, X-ray diffraction, infrared microscopy, and thermogravimetric analysis. The transport of the synthesized nanofluids through calcite and sandstone media was investigated using laboratory column breakthrough experiments. The nanofluids were transported through these media at different breakthrough levels. The experimental transport data were correlated using an advection diffusion equation, as well as colloid filtration theory, with emphasis on the effect of flow velocity on the particle transport The maximum transport distance of the nanomaterials in porous media was estimated based on the flow velocity and the particle attachment efficiency.