(247g) Understanding the Role of Cellulose Nanocrystals As Novel Shale Hydration Inhibitors for Water-Based Drilling Fluids

During oil well drilling operations, water-based drilling fluids (WDFs) are used to lubricate and cool down equipment, carry rock cuttings to the surface, and prevent excessive uptake of water by the clay minerals in the shale formation. Shale hydration issues can lead to reservoir instability problems and wellbore damage, which are responsible for important economic losses (>$500M/year) during drilling operations. Therefore, the development of effective and environmentally friendly hydration inhibitors for WDFs is a very important issue in the petroleum field [1,2]. Recent studies by our collaborator Qinglin Wu (LSU) suggests that biodegradable cellulose nanocrystals (CNCs) can be used as additives to WDFs to inhibit clay hydration and enhance WDF filtration and rheology [3-5]; however, the physics behind this observations remains uncertain. As an initial step, here we probe the interactions between CNCs and clays (Wyoming-type montmorillonites with potassium ions) in the presence of water, using all-atom classical molecular dynamics simulations. We will present and discuss our results for the potential of mean force as a function of the distance between different facets of the CNCs and the montmorillonites.

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