Integrated Study and Application of Polymer Injection in Arctic Environment

This work presents the interpretation of a polymer injectivity test performed in a heavy-oil field (50-200 cP), located in a challenging arctic environment, during the first half of 2019 to assess the feasibility of the polymer injection process. Following the positive results achieved with the injectivity test, a polymer interwell pilot test started in the last months of 2019, but it was suspended in April 2020 due to Covid restrictions. Thanks to the acquired data during the pilot test, polymer model was tuned into a dedicated sector of the reservoir model, including one injector and two producers. Using internal company EOR-screening tools, polymer flooding was identified as the most suitable technology for the asset. An integrated study of 3D-modeling and in-house laboratory activities was performed to assess polymer injection potentialities and select the best chemical product for the asset. 3D dynamic analyses confirm the benefits of polymer injection with a significant oil production gain. Four representative horizontal wells were selected for the injectivity test in order to confirm the injection effectiveness. The selection of injectors was based on an extensive analyses of wells status and performance. The test strategy consisted of 2-weeks polymer injection per well, at constant injection rate and increasing polymer concentration steps. A detailed real-Time surveillance plan was realized to monitor injector pressures and polymer solution properties. The injectivity test was concluded successfully: Target viscosity, defined during the laboratory and modeling analyses, was achieved with a limited impact on injectivity. Pressure increase and stabilization during polymer injection confirmed the feasibility of the technique for the reservoir. Well test and temperature profile acquired before and after polymer injection were interpreted. Once assessed the feasibility of polymer injectivity, a 1-year inter-well pilot started in November 2019. Injection took place up to March 2020 and was suspended due to Covid restrictions. The re-start is planned for mid-2021. During the test several injection and production data were gathered, analyzed and interpreted. In addition to that, starting from the full reservoir model, a detailed sector model was set up in order to match pressures and water cut and forecast the performances of polymer injection. © IOR 2021 - 21st European Symposium on Improved Oil Recovery.