Conformance Improvement Using Polymer Gels: A Case Study Approach

Abstract Poor conformance is a problem that has plagued most operators of water and enhanced oil recovery (EOR) floods. Conformance improvement has been shown to significantly improve oil recovery; however, effectively selecting and implementing the correct conformance improvement technique still remains a complicated proposition. The selection of the correct technique is only becoming even more important as the industry advances EOR floods where it is critical in these capital intensive projects to effectively sweep the reservoir. Traditionally many operators have relied on mechanical or cement solutions to deal with poor conformance. Although these methods certainly have their place in conformance engineering they deal more with wellbore issues rather than reservoir flow dominated situations. The latter situation can be characterized as flow through highly conductive reservoir features such as fractures or highly permeable thief zones. In such situations it is advantageous to use a technology that can penetrate into the offending feature providing sustainable results. In water or EOR floods, the treatment of injection wells with polymer gels has been shown to be an effective technology in addressing such reservoir conformance issues. Extensive research has gone into characterizing polymer gels and numerous field case studies have been published. However, few references aid in understanding when polymer gels should be used and the critical aspects of designing and implementing such treatments. This paper will focus on diagnosing those conformance issues where it is most appropriate to use polymer gels. Further, it will explain how reservoir characterization should drive the design and implementation of this technology. Four injection well case studies will be used to develop a Polymer Gel Conformance Improvement Matrix that will provide heuristics for designing a polymer gel treatment. Finally, lessons learned from the case studies will be presented to give guidance on diagnosing conformance issue along with the design and implementation of conformance improvement polymer gel treatments.