An investigation of viscoelastic polymer flooding in high permeability sandstones

Julia Liu Jin, Austin, The University Of Texas At, Matthew T. Balhoff, Kishore Kumar Mohanty
Recovery of oil is the key consideration of oil production in underground reservoirs. The correlated decline in oil discoveries and increase in demand for oil have created a scenario in which enhanced oil recovery (EOR) technologies have become increasingly necessary to compensate for the growing energy demand. Polymer flooding has been used as one EOR technique to increase oil recovery. Several authors have observed reduction of residual oil in porous media using polymers that are
more » ... Five coreflood experiments were completed using aqueous hydrolyzed polyacrylamide (HPAM) and scleroglucan (EOR-grade) polymer solutions. HPAM polymers were solubilized in low salinity brine which created viscoelastic solutions. All experiments were completed in high-permeability (>1000mD) Bentheimer and Boise sandstones. Two Bentheimer cores were chemically treated to be considered oil-wet. Three other water-wet Boise cores were also used. All experiments were completed using light (4-6 cP) oil. The elastic polymer floods were formulated so that they would have high relaxation times, and therefore high Deborah numbers. Each elastic flood was followed by an inelastic polymer flood with a similar viscosity. The Deborah number for the inelastic polymer floods were less than or close to 1. Following the successful experiments using alternating elastic and inelastic polymer floods in Bentheimer sandstones, these experiments were conducted in different mediums to see if this phenomenon could be replicated under different circumstances. Experiment #1 replicated previous work completed using viscoelastic polymers and alternating elastic and inelastic floods. The results in coreflood #1 showed extremely promising results in the comparatively more heterogeneous Boise sandstone. After alternating between elastic and inelastic polymer floods, the residual oil saturation decreased to lower than 6%. The viscoelastic polymer floods following a waterflood decreased residual oil saturation. In four of the five experiments, the residual [...]
doi:10.26153/tsw/5690 fatcat:gljd6t7ztnbzzkcxqjx3ygmwme