Modification of waste persimmon peel and application in water-based drilling fluid

To develop a green drilling fluid additive, the modification and application of persimmon peel in a water-based drilling fluid was studied in this work. A natural product derivative, aluminium chloride–persimmon peel (ACPP), was prepared from aluminium chloride and persimmon peel and was assessed as a shale inhibitor. The clay-swelling ratio in 0.30% ACPP-3 solution was reduced to 28.10% from 69.50%. The rolling recovery tests and rheological evaluation of drilling fluids concluded that ACPP-3 has a high inhibition property to montmorillonite-hydrated expansion. ACPP-3 can adjust the particle size of montmorillonite to a large degree. ACPP-3 effectively reduces the apparent viscosity of carboxymethyl cellulose drilling fluids and the volume of filtration; furthermore, ACPP-3 can reduce the viscosity and the volume of filtration under high temperature, which means it can be used as an additive for deep drilling. The inhibition mechanism of ACPP-3 was investigated by thermogravimetric analysis and scanning electron microscopy. The results of this scientific research will be beneficial to the eco-friendly drilling fluid materials.