Polymer adsorption at the brine/rock interface: the role of electrostatic interactions and wettability

Injection of polymers that selectively reduce the water permeability can be used to control water production from oil or gas wells. Because this method relies on the adsorption of a polymer layer onto the rock surface, a deeper understanding of the relevant polymer/rock interactions is of primary importance in order to develop reliable chemical selection rules for field applications. In this paper we study the role of electrostatic interactions and wettability in the adsorption of water-soluble polymers (bearing differently charged groups) onto solid surfaces of siliceous nature. By means of static adsorption tests, we show that the adsorption is dominated by the electrostatic interactions between the polymer molecules and the solid surface. We also show that lithology, brine composition and wettability are critical parameters that can influence the adsorption behavior at a brine/rock interface.