New Chemical EOR Methods to Efficiently Extract Oil From the Subsurface

Abstract: With the increase in population, there is a need for constant supply of oil for decades to come until other energy sources reach a mature level. However, the recovery of oil from subsurface reservoirs is an extremely challenging process. The idea is to extract a fluid that is confined in tiny pores, thousands of feet underground, based on sparse information related to the geology, petrophysics and fluid phase behavior. The standard method of oil extraction, waterflooding, consists of injecting water to overcome the forces that trap oil in the pores. However, capillary forces, viscous instabilities and reservoir-scale heterogeneity make this process ineffective, with 60% of the initial oil remains unrecovered. There should be a better way. In this talk, we describe two new chemical processes developed in our group aimed at addressing some of the typical challenges faced by waterflooding, while keeping in mind often neglected economics constraints. The first relates to the use of compositionally-tuned surfactant solutions to form viscous microemulsions inside thief layers in reservoirs with conformance problems. The second relates to the use of compositionally-tuned polymer solutions to form high viscosity solutions deep into the reservoir to improve sweep efficiency in reservoirs with an unfavorable mobility ratio to water. We developed both processes by keeping the following guiding philosophies in mind: 

* The injection fluids are defined such that their viscosities are low. This translates into high injectivity, which is critical for a project to meet economics constraints. 

 * After mixing in situ, the viscosity of the injected fluid increases. This improves sweep efficiency at the reservoir scale, increasing oil recovery compared to the reference waterflooding.

Bio: Victor Torrealba has been a postdoctoral fellow at the Ali I. Al Naimi Petroleum Engineering Research Center at King Abdullah University of Science and Technology since October 2017. His research revolves around the practical aspects of chemical enhanced oil recovery, using both numerical and experimental tools. Prior to joining KAUST, he was a PhD student at The Pennsylvania State University, where he learned about the fundamentals of surfactant.