Selection of the EOR Methods for the Russkoe High-viscosity Oil Field Based on Laboratory and Field Experiments

The paper presents an approach and the results of laboratory tests of the EOR methods on core samples of Russkoe gas and oil field, and the results of pilot works to the implementation of the recommended method. The field is unique in terms of both its huge hydrocarbon reserves and problems associated with its development. It is located above the Polar Circle and is characterized with a complex geological structure of highly permeable poorly cemented reservoirs saturated with high-viscosity oil. Significant factors making field development difficult include presence of tectonic faults, extensive gas cap, and underlying water. At the first stage of the research the following main EOR methods have been analyzed: injection of hot water, steam injection, injection of polymer solutions and thermo-alkali flooding. Experimental studies have been conducted on natural cores and bulk models. The complexity of the preparation and conduct of experiments was attributed to work with weakly consolidated core. At the initial stage of the pilot project one of the most effective methods, which performance has been proven by both experiments and simulations, has been recommended for implementation, - the displacement of viscous oil with hot water. Test injection of hot water in one of the pilot areas commenced in August 2010 and, in general, confirms the effectiveness of oil displacement observed in laboratory experiments. The results of field tests of EOR methods in the Russkoe field by injecting hot water are described in detail in the report. In the next stage of the pilot project, which is aimed at finding appropriate technologies for the development of this extremely complicated field, the continuation of laboratory testing of the EOR methods is planned using new core samples. Along with this, further laboratory testing of WAG and surfactants applicability is envisaged. To achieve this objective, a special program of laboratory and analytical studies is planned.