Theoretical and Experimental Approach for Understanding the Interactions Among SiO2 Nanoparticles, CaCO3, and Xanthan Gum Components of Water- Based Mud

JV Clavijo and I Moncayo-Riascos and M Husein and SH Lopera and CA Franco and FB Cortes, ENERGY & FUELS, 35, 4803-4814 (2021).

DOI: 10.1021/acs.energyfuels.0c03898

This study aims to understand the interactions among SiO2 nanoparticles (NPs) and the main chemical constituents of bentonite-free water-based mud, including CaCO3 and xanthan gum. To this end, both theoretical and experimental protocols are developed coupling molecular dynamics simulations with filtration and rheological property measurements of mud systems having different NP contents. The resultant filter cakes are inspected to capture the role of interactions among the deposited components. Static filtration tests at high pressure-temperature are carried out on a standard filter paper as well as an in-house prepared sandstone disk. The filtrate volume and filter cake thickness and permeability were reduced by 56, 36, and 72%, respectively, at an optimum NP content of 0.1 wt %. Using the sandstone disk, the mud with the optimum NP content showed a 72 and 59% reduction in spurt loss and total filtrate volume, respectively. Scanning electron microscopy images showed that the NPs improved the morphology of the filter cake. The higher NP-sandstone interaction was successfully described by molecular dynamics simulations, which showed the highest interaction between sandstone and NPs followed by CaCO3 and then the system xanthan gum and water polymer solution. Moreover, the theoretical analysis showed that SiO2 NPs reduced the repulsion energy among the CaCO3 surfaces, promoting a tighter filter cake and subsequently less mud filtrate, as evident experimentally.

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