Comparison on the Inhibitive Properties of Different Inhibitorsin Water-Based Drilling Fluid
Xiaodong Bai, Yuqian Xu, Xuepeng Zhang, Xuemei Yong, Zhenyu Li
Abstract
The inhibitors for shale gas can be divided into two categories, including inorganic inhibitors and organic inhibitors. The inorganic inhibitors usually include sodium chloride and potassium chloride, while the organic inhibitors include potassium sorbate, polyethylene glycol, polyetheramine, and diethylenetriamine. The inhibitive properties of these inhibitors for shale gas have been comprehensively compared in detail. The results show that the inhibitive effect of potassium chloride is much better than the other inorganic inhibitor sodium chloride, and polyetheramine exhibits the best inhibitive performance to other organic inhibitors. From the analysis of the inhibition mechanism, it can be found that both inorganic salt inhibitors and potassium sorbate, polyethylene glycol can effectively squeeze out the water molecules, adsorbed within clay layers, through ion exchange. As for polyetheramine and diethylenetriamine, the protonated ammonium ions can be adsorbed onto clay surface through electrostatic interaction to exchange hydrated sodium ions, thereby reduce the hydration repulsion of the clay.