关键词: 膨润土, 阳离子钻井液, 表面活性剂, 胶体稳定性, 钻井

Abstract: A method for modifying bentonite by using surfactants is proposed.When the physical and chemical reaction of the bentonite with nonionic surfactants is made under certain conditions,the ion property on the surface of the bentonite is changed.The ZETA potential of the bentonite colloidal can be changed nearly to zero,and the uppgraded bentonite can be adequate for the cationic drilling fluid.While using the modified bentonite to make up the drilling fluid,the modified bentonite can match to cationic polymer with a large molecular weight or compound with a small molecular weight,without adding amphoteric or negative ionic guard colloidal.So the problem that anionic and cantion polymer can not match in the cationic drilling fluid could be completely solved,which makes the application of cationic drilling fluid becomes more simple and easy in oilfield.

Key words: bentonite, cationic drilling fluid, surfactants, colloidal stability, drilling