Structure and inhibition properties of a new amine‐terminated hyperbranched oligomer shale inhibitor

Abstract

ABSTRACTTo inhibit the hydration and dispersion of shale in drilling, a new amine‐terminated hyperbranched oligomer (HBO‐NH2) shale inhibitor was synthesized. Compared with linear polymer inhibitors and inorganic salts, HBO‐NH2 possessed a unique hyperbranched structure and plenty of amine groups. The characterization of HBO‐NH2 was done through the aid of Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance hydrogen spectroscopy, and time of flight mass spectrum. Upon thermogravimetric analysis, HBO‐NH2 demonstrated favorable thermal stability below 180 °C. As a shale inhibitor, the interlayer spacing of wet bentonite treated with HBO‐NH2 was significantly reduced from 1.9070 to 1.3422 nm in X‐ray diffraction analysis. The recovery rate of shale cuttings reached the highest (76.85%) at 120 °C, when the concentration of HBO‐NH2 was 3 wt %. Due to the adsorption of protonated primary amine groups on bentonite particles, the zeta potential absolute value of bentonite base slurry was maintained in a relatively low range of 5–10 mV after HBO‐NH2 treatment. Also, FTIR analysis suggested that hydrogen bonds existed between bentonite and HBO‐NH2. In scanning electron microscope analysis, the inhibition of HBO‐NH2 was observed by the curl degree of bentonite. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47573.