Synthesis Techniques for Polymers Applied to Enhanced Oil Recovery

Abstract

A considerable portion of the total oil in place (OIP) present in mature reservoirscannot be extracted by conventional methods. Therefore, there is an enormousmotivation in the development of different techniques to increase the oil recovery.Enhanced Oil Recovery (EOR) is the implementation of several techniques toincrease the amount of oil extracted from reservoirs. Its purpose is to mobilizeand recover the capillary trapped oil in the reservoirs, and to improve oil sweepefficiency. Dilute aqueous polymer solutions are used, as flooding agents, toimprove the mobility index of regular water flooding. Polymers increase waterphaseviscosity and reduce the difference between the permeability of the oil andthe water phases. Polymers can significantly increase the viscosity of the injectedbrine by factors up to 20 at very low concentrations. The most used polymerin EOR applications is partially hydrolyzed polyacrylamide (HPAM), a linearcopolymer of acrylamide and acrylic acid. Numerous chemical modificationswere proposed to HPAM. In this short review, different chemical modificationsto the conventional HPAM are summarized and discussed. Furthermore, differentsynthesis strategies for these water-soluble polymers are analyzed and reviewed