Cetyltrimethylammonium modified graphene as a clean swelling inhibitor in water-based oil-well drilling mud

The shale inhibition features of cetyltrimethylammonium modified graphene (CTAB-Gr) were demonstrated in the present work. The inhibition characteristics were evaluated by the dispersion test and inhibition durability test. The outcomes revealed that the addition of CTAB-Gr to the drilling mud clearly improves the shale inhibition features as compared to other shale inhibitors and enhances the rheological features to make it more suitable for the drilling. CTAB-Gr modified water-based drilling mud (CTAB-Gr-WBM) shows the highest shale dispersion recovery (88.5 %) as compared to unmodified drilling mud (74.6 %), KCl (50.3 %), and water (26.2 %). The swelling test indicates the stability of clay materials against the reactive action of water in the presence of CTAB-Gr. The clay shows 17 % swelling in CTAB-Gr while 22 % and 27 % in KCl and water respectively. The inhibition mechanism was investigated by Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and energy dispersive X-Ray spectroscopy. The positively charged amines of the CTAB support CTAB-Gr to bind the surface of clay through hydrogen bonding. The intercalation and adsorption of CTAB-Gr plug the pores rendering clay surface hydrophobicity. Consequently, due to less hydration, there is mitigation of clay swelling.