Oil Recovery by Polymer- Enriched Water: Influence of Modification Polyacrylamide as EOR Agent

Enhanced Oil Recovery (abbreviated EOR) is a generic term for techniques for increasing the amount of crude oil that can be extracted from an oil field. Using EOR, 30-60%, or more,of the reservoir s original oil can be extracted compared with 20-40% using primary and secondary recovery. EOR is basedon one or more of two principles: increasing the capillary number and/or lowering the mobility ratio, compared to their waterflood values. The injectant mobility may be reduced byincreasing water viscosity, reducing oil viscosity, reducing water permeability or all of the above several different typesof associating polymers have been studied. one include the hydrophobically modified polyacrylamide (HMPAM) [1].Hydrophobically associative polymers contain, in mostcases, a small number of hydrophobic groups,i.e. 8–18 carbon atoms moieties Distributed along the main backbone .Depending on the concentration, intra- or intermolecular associations are formed, which are schematically illustrated inFig 1. There are different methods of synthesizing HMPAM such as micellar, homogeneous and heterogeneous copolymerization. Polyacrylamides usually prepared via a freeradical polymerization in aqueous solution [2]. Polyacrylamide was the first polymer used as thickening agent for aqueous solutions. Partially hydrolyzed polyacrylamide (HPAM) HPAM (Fig 2), by far the most used polymer in EOR applications, In most cases the degree of hydrolysis of the acrylamide monomers is between 25 and 35% . The fact that a relevant fraction of the monomeric units needs to be hydrolyzed (lower limit of 25%) is probably related to the viscosity [3].