Synthesis of decyl methyl carbonate and a comparative assessment of its performance as the continuous phase of synthetic-based drilling fluids

Abstract

Ester-based drilling fluids have been explored as an alternative to the mineral oil and diesel-based fluids for their low toxicity and high biodegradability. In this work, decyl methyl carbonate (DeMeC) was synthesized and assessed as a novel continuous phase for synthetic-based drilling fluids (SBF), since it is equally biodegradable, presents higher chemical stability and elastomer compatibility when compared to fatty ester bases. Babassu oil methyl esters (BME) were synthesized and tested for comparison. Fourier transform infrared spectroscopy (FTIR), gas chromatography coupled to a mass spectrometer (GC/MS) or a flame ionization (GC/FID) detector, thermogravimetry (TG/DTG/DSC) and proton nuclear magnetic resonance (1H NMR) techniques were applied for characterizing the obtained products and confirmed the synthesis of DeMeC and BME. The low pour point of DeMeC and BME may allow the application to approach the blowout preventer region in ultra-deepwater drilling, while the low viscosity of both compounds make them suitable for drilling operations. In addition, the high flash point value for both bases is considered safe for its use, transportation and storage. The drilling fluid produced with DeMeC (DeMeC-DF) presented high efficiency, with satisfactory results of plastic viscosity, initial and 10-min gel strengths, yield point and filtrate, thus standing out as a real alternative for application in synthetic-based drilling fluids.