Fifteen Years of Polymer Flooding in Marmul Field: Performance, Recovery, and Operational Insights

Abstract Over the past 15 years, an extensive polymer flooding program has been implemented in the Marmul field to enhance oil recovery. This paper reviews the long-term performance of polymer flooding relative to water flooding and evaluates the effects of returning to water flooding after polymer injection. It also examines early results from the infill drilling project designed to increase sweep in mature patterns, and addresses key operational challenges encountered throughout. Historical production and injection data, pattern-level performance metrics, and recent infill pilot data are analyzed. Incremental recovery factors are computed for polymer flood periods vs waterflood-only periods. Pattern performance is compared before polymer implementation and after polymer injection, including after rotating back to water injection. Operational aspects, including polymer formulation, chemical logistics, injectivity maintenance, monitoring of produced water, and surface-subsurface integration, are also examined to assess sustainability and cost effectiveness. The polymer flood has delivered significant incremental recovery over baseline water flooding across multiple patterns; measured incremental recovery factors depend on well pattern properties, amount of injected polymer, and time since polymer startup. After returning to water injection, some patterns have maintained boosted oil rates for much longer than expected, illustrating the polymer's lasting effects on mobility control and sweep efficiency. Early infill results point to additional recovery potential in under-swept zones. Operational lessons include the impact of polymer quality variation, injection facility reliability, and monitoring reservoir response to optimize polymer flood management. This work presents one of the longest publicly documented datasets for polymer flooding in a clastic field, showing both sustained incremental recovery and performance durability after switching back to waterflooding. The inclusion of infill performance and detailed operational lessons adds practical insights for future EOR deployments in similar mature fields.