摘要：In this work, a series of ammonium-citric acid salts (ACS) was prepared with citric acid and amines as green small molecular shale swelling inhibitor. The inhibitors were screened by the linear expansion test of bentonite firstly, and the result shows that the inhibitor prepared by citric acid and triethanolamine with the mole ratio of 1:1 (ACS- 10) displays excellent inhibition effect on the hydration expansion of bentonite. The inhibition of ACS-10 to bentonite was fully evaluated by various methods in the following work, including clay linear swelling test, anti-swelling test and particle distribution measurement. The results showed that ACS-10 has superior performance to inhibit the hydration swelling and dispersion of bentonite, and the anti-swelling rate of 1.0% ACS-10 reaches up to 71.8%. In water water-based drilling fluid, ACS- 10 was compatible with the conventional additives, and behaved high ability of increasing viscosity and reducing fluid loss. Besides, it can control the particle size of bentonite in water as characterized by scanning electron microscope (SEM) and laser particle size analysis. At last, the inhibition mechanism of the ACS was discussed in detail through thermogravimetric analysis (TGA), FT-IR and cation exchange test.
