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In order to produce crude oil three recovery techniques are used: primary, second and tertiary also known as Enhanced Oil Recovery (EOR). Oil production in the Carpatian region is difficult due to the long-term production and significant depletion of reservoir energy. One of the methods that are considered to increase oil recovery factor is CO2-EOR. This method is based on carbon dioxide injection into oil reservoir in order to maintain reservoir pressure and modify physicochemical oil properties. Combination of this method with geological sequestration of carbon dioxide (CCS) relying on its storage in geological structures implemented after the end of production stage brings additional benefits in terms of environmental protection and extends the reservoir life, which translates into a positive economic effect. In this paper an analysis of the possibilities of the CCS-EOR method application on one of the Carpathian oil fields is carried out. Suitable location of injection wells and proper selection of carbon dioxide injection parameters allow a significant increase in the cumulative oil production from the analyzed reservoir what enhances oil recovery factor by 3 percentage points over the 20 years of the forecast. [ABSTRACT FROM AUTHOR]

The application of enhanced oil recovery processes (EOR -- Enhanced Oil Recovery) on oil fields increases the recovery efficiency. This is especially important in depleted and mature fields. This should result in production increase by raising the recovery factor. Depending on the technology used and techniques applied in the field, the methods can be divided into thermal, gas injection or chemical methods. The CO2 injection method is very popular in the U.S.A. The production of cheap gas from natural sources and availability of pipelines connecting gas sources make this process economically attractive. There are 84 documented oil fields in Poland. Most of them have been exploited for many years with a relatively low recovery factor. This implies a considerable potential of production increase, even if no new bigger fields were to be found. At present advanced recovery methods are not used in Poland; only secondary methods are employed in several fields. This means that much can still be done in this area. Application of CO2-EOR method requires adequate wells preparation. EOR injection wells may be either drilled as new wells or, as is quite common in existing fields, re-completed by converting an existing producing well or a water injection well to a specific fluid injector. CO2 sequestration wells require detailed consideration of the well integrity in every aspect of the well design, construction, operation, monitoring, condition evaluation, workover, suspension and abandonment. New application may be based on international experience with miscible flood and WAG injection with CO2 and polish experience with acid gas injection and underground gas storage. [ABSTRACT FROM AUTHOR]