Effect of Shale Inhibitors on the Particle Size Distribution of Bentonite in Aqueous Suspensions

Shale inhibitor has been widely used as a cure of shale dispersion and swelling when drilling in shale formation. To make clear the effect of the interaction time, type and adding order of inhibitors on the hydration of bentonite, the particle size distribution (PSD) measurements of bentonite have been performed in this investigation. The results show that the hydration time of bentonite is quite short and the aging time has a little effect on the static hydration dispersion of bentonite. Moreover, the adding order of the different type of inhibitors has clearly effect on the hydration of bentonite. The observed results show that all the inhibitor solutions investigated, including organic salt, inorganic salt and polymeric inhibitor solutions, show obvious inhibiting ability on the hydration dispersion of bentonite. In contrast, after adding into bentonite suspensions, organic salt and inorganic salt inhibitors have little effect on the dispersion of bentonite, while the polymeric inhibitors can inhibit the hydration dispersion of bentonite effectively. It supports the idea that the salt inhibitor plays a preventive role rather than corrective role in inhibiting the bentonite dispersion.