| Abstract: | Novel modified cellulosic polymers with amphoteric character were prepared by grafting 2-dimethylaminoethyl methacrylate (DM) and 4-vinylbenzene sulphonic acid sodium salt (VB) onto sodium carboxymethylcellulose (NaCMC), and characterized by IR and composition analyses. Their properties as drilling-fluid additives in oilfields were investigated with respect to shale inhibition, filtration control and viscosity enhancement. It is found that the grafting of DM enhances the shale-inhibition effectiveness and that the grafting of VB increases the tolerances to salt and temperature. Different from commonly used anionic and cationic polymeric additives, the modified cellulosic polymer with suitable structural parameters has both good shale-inhibition and mud properties. © 1999 Society of Chemical Industry |
