Notoginsenoside as an environmentally friendly shale inhibitor in water-based drilling fluid

The demand for non-toxic and biodegradable shale inhibitors is growing in the drilling industry. In this paper, the effect of notoginsenoside (NS) as a new, environmentally friendly inhibitor of shale hydration is systematically studied for the first time. The inhibition performance of NS was evaluated via inhibition evaluation tests, including mud ball immersion tests, linear expansion tests, shale rolling recovery tests, and compressive strength tests. The inhibition mechanism of NS was analyzed using Fourier transform infrared spectroscopy (FTIR), contact angle measurements, particle size distribution determination, thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The experimental results demonstrate that NS is able to adhere to the clay surface, forming a hydrophobic film that prevents the entry of water molecules and inhibiting the hydration dispersion of the clay. Because of this, NS can maintain the original state of bentonite pellets in water, which can effectively reduce the swelling rate of bentonite, increase the recovery rate of shale drill cuttings, maintain the strength of the shale, and therefore maintain the stability of the borehole wall during drilling. In addition, NS is non-toxic, degradable, and compatible with water-based drilling fluids. The above advantages make NS a promising candidate for use as an environmentally friendly shale inhibitor. ?? 2021 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).