Novel Environmentally Friendly Nano-Additives for Drilling Fluids

International audienceABSTRACT: The potential for environmentally friendly nano-additives based drilling fluids is extended here in the context of the ongoing EU project ‘ORCHYD’ where a hybrid drilling technology is developed by combining High Pressure Water Jet (HPWJ) and Percussive Drilling to improve the efficiency of deep geothermal drilling. In this work, different types of nanomaterials such as graphene oxide, hybrid nano silica and their composite nanomaterials are used as additives in a water-based drilling fluid. The influence of additives on the rheological properties and the friction of the drilling fluid has been investigated. The laboratory results showed that an increase in the concentration of additives will increase the viscosity of fluids. A significant reduction in the coefficient of friction (during wear testing of steel material) was also revealed with the addition of GO and chemical functionalization. The need for further characterizing and the perspective to upscale the enhanced nano-additives based fluids for HPWJ and percussive drilling application, in deep geothermal conditions, are discussed. 1. INTRODUCTION This study is performed in the context of the EU project ORCHYD, https://www.orchyd.eu/proiect/, where an innovative drilling tool combining (high pressure water jetting and percussive drilling) will be developed to increase hard rock drilling rates, in deep geothermal wells. The potential of new green additives to the drilling fluids is thus investigated to account for the best compromise for efficient jetting, cutting and transport of the rock particles, and the lifetime extension the drilling tools. Deep geothermal reservoirs are being targeted for renewable energy supply worldwide (Huttrer, 2021), however the high pressures and high temperatures in deep geothermal wells impose significant challenges for desiring drilling fluids. Over the past decade, various additives such as polyacrylamide, organic modified clays, poly carboxylic acids, asphaltic compounds, treated lignite have been used in the drilling fluid to optimize the rheological properties, filtration control and reduce the fluid loss, shale inhibitors and thereby improving wellbore stability (Boyou et al., 2019; Vryzas et al. 2017). However, most of the polymer-based materials degraded thermally and chemically at relative low temperature, which lowers their effectiveness