The application of enhanced oil recovery processes (EOR – Enhanced Oil Recovery) on oil fields increases recovery efficiency. This is especially important in depleted and mature fields. This should result in an increase in production by raising the recovery factor (the ratio of oil produced to total geological reserves). This review presents the growing trend of gas injection (particularly carbon dioxide). In Polish oil fields, conventional methods are currently used. This means that much can still be done in this area. The selection of the optimum method for a given field is a complex procedure consisting of many stages, from collecting data about the field, through more advanced data interpretation, to working out a detailed proposal for the most efficient method of extraction. The pre-selection stage involves excluding methods which, owing to their specific mechanisms, cannot be used for a particular field – e.g. thermal methods in light oil fields or nitrogen injection into shallow reservoirs. This paper analyzes the potential for the application of EOR methods in Poland using a binary technical screening method. Forty-nine, mature Polish oil fields were analyzed. Apart from the rock type, other parameters were also taken into account in the analysis as follows: oil density and viscosity, average porosity, permeability and thickness of the reservoir, and also depth of deposit. In regard to the criteria for the EOR methods applied, the subjects of analysis are oil fields with medium density and viscosity and low permeability (double porosity in carbonate rocks), which are at a relatively shallow or medium depth of deposit. The results of analysis show that gas injection methods, especially carbon dioxide or nitrogen, have the highest potential. Application of this method must be preceded by detailed research and field pilot tests. International experience cannot be applied directly to Poland because of different field characteristics as well as technological and economic conditions.

The results of investigations in the field of CO2 storage in water-bearing horizons in the area of the Upper Silesian Coal Basin were presented. It has been stated that the CO2 injection process will appear in the area of the storage site and beyond its boundaries. The determination of protective zones for underground CO2 storage and other structural elements, e.g. big tectonic zones, was proposed. These zones will constitute a safety buffer between the underground storage site and utilitarian undertakings conducted in its neighbourhood. In the work the proposal of CO2 injection intensification through controlled fracturing of formations of the future storage site was presented. This action should increase the CO2 injection effectiveness, especially in rock series characterised by average values of reservoir parameters.