Water Soluble Polymers as Mobility Control Agents in Enhanced Oil Recovery (EOR): A Literature Review

Water soluble polymers as mobilitycontrol agents in the oil recovery process have attracted great attention in recent years. The use of polymers leads to an improved mobility in the oil reservoir by increasing the viscosity of the injected fluid (water) and by reducing the permeability through adsorption of the polymer chains on the surface of the rock which can improve sweep efficiency during enhanced oil recovery processes. Partially hydrolyzed polyacrylamide (HPAM) is the most widely used polymer to date for polymer flooding in EOR. The limitations of HPAM include, among others, the low resistance toward the presence of salts. Salts will lead to a significant reduction of solution viscosity and even the precipitation upon interaction with divalent ions. In addition to HPMA, biopolymers such as xanthan gum have been used for EOR. The drawbacks of biopolymers originate from high cost, high susceptibility to biodegradation and potential for injectivity problems due to cellular debris remaining from the manufacturing process. To address these problems, hydrophobically modified polymers (HMPs) have been widely studied as flooding agents in EOR over the past two decades.In this review, some examples of synthetic polymers, biopolymers and especially HMPs for enhanced oil recovery applications are discussed along with their limitations.