Polymers for application in high temperature and high salinity reservoirs - critical review of properties and aspects to consider for laboratory screening

A significant amount of oil resides in deep reservoirs characterized by relatively high temperature and high salinity. In such reservoirs, most available chemicals fluids for EOR have limited applicability. Even though recent effort has been dedicated to the development of high temperature polymers, there is no clear understanding of what would work best in those harsh environments. In addition, the oil and gas community is also evaluating potential applications of chemical EOR to offshore assets where similar conditions are often found. Field applications in harsh reservoirs have shown limited success in the use of polymers for improved oil recovery. Detail analysis reveals that screening of the fluids was done under 'model' laboratory conditions, using non-reservoir core samples and non-representative fluids. These facts have motivated research and development work towards understanding the type of polymers that may be suitable for use in high temperature and high salinity reservoirs and to determine the type of tests to use to assess their performance in a field application for use as lab screening criteria. In this paper, we provide a critical review of the available polymers for application in high temperature and high salinity reservoirs and summarize best practices for their laboratory screening though a recommended workflow.