Paper: Operational Problems Associated with Polymer Applications In Oilfield EOR Projects

Water soluble polymers find three major applications in oilfield enhanced oil recovery projects. Two of these applications involve reservoir fluid mobility control while the third involves profile control via reservoir heterogeneity modification. All polymer applications in the oilfield require certain operational practices to ensure that the polymers can function as designed. Many of the design criteria involved in polymer applications include production and injection equipment modifications in conjunction with reservoir fluid chemistry considerations. Finally, the proper choice of specialty chemicals to support injection and production of oilfield polymers is essential to the ultimate success of the projects. Two types of polymers are used in oilfield applications, the hydrolyzed polyacrylamides and the xanthan polysaccharides. Although each have their own specific advantages and disadvantages, the injection water quality requirements are essentially identical for both polymer types. A combination of specialty chemicals and specialized equipment is often required to meet the strict water quality requirements. In any system compatibility of all components is essential. This paper will discuss the water quality requirements and the problems involved in designing a compatible system. On the production side of polymer applications, compatibility is again of paramount importance. Saleable oil can only be attained if emulsions that are stabilized by the interactions of polymer, surfactants, solids, water, oil and bacteria can be resolved. Obtaining disposable or reusable water while minimizing produced fluid corrosivity is also a major consideration. Once again, systems must be designed that can effectively employ specialty chemicals (e.g. demulsifiers, water clarifiers, corrosion inhibitors, scale inhibitors, biocides), and mechanical techniques that minimize operational problems.