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Polymer flooding is one of the most documented and commercially viable methods for enhanced oil recovery. In its basic form it consists of injecting polymer enhanced water that has higher viscosity than formation water into the reservoir, thus reducing the mobility ratio and increasing sweep efficiency resulting in higher oil recoveries. In order to design proper polymer flood it is necessary, after initial screening of potential oil field candidates (typically brown fields), to conduct laboratory measurements in order to validate, change or improve on the pre assumptions of the initial polymer screening. The best way to do so is to conduct polymer rheology and core flood experiments to find the most economically and technically viable polymer concentration for injection. Because there is an interest in INA Company for future pilot and later on full field scale polymer- flood project on Kozarica oil field it was necessary to prepare Rock and Fluid Analysis laboratory for polymer-flooding and other EOR experiments. This paper deals with the necessary experimental procedures, equipment and it’s setup for conducting such experiments along with the results and interpretation. All the experiments are done according to the reservoir pressure and temperature and are implemented in numerical simulator through developed Core flood simulation model in order to further validate the test data and improve input data for full-field reservoir simulation. Detailed rheology measurements were performed on HPAM polymer solutions of various concentrations and on different temperatures, extensive core flood measurements were conducted in order to determine adsorption, incremental recovery, resistance factor all on reservoir conditions using synthetic paraffinic oil. After laboratory tests all data were validated through core flood simulation for which core model was built. Results obtained showed repeatability and consistency through every test. Sensitivity analysis of parameters that affect polymer solution rheology, relative permeability and polymer adsorption index were performed both in laboratory and by simulation model to further understand polymer solution behavior on various conditions. Experiments show great agreement with the core flood simulation. Acquired data will greatly help in designing polymer flood. This Core-flooding setup and workflow is new for our Company and is included in application for 2017 MOL Group’s Golden Barrel award under CORES (Core Optimization for Reservoir Simulation) Project. Equipment setup has proven to be reliable and relatively easy to use thanks to the new method of real time logging of all important parameters during flooding. |
