CO2-EOR IN MULTILAYERED MATURE OIL FIELDS

Among various enhanced oil recovery (EOR) methods the CO2 injection has proven to be an effective way to boost the oil production from mature fields. The Jaszczew field presented under this study approached the economic limits of production using conventional recovery methods. Considered field is multilayered with oil and gas horizons. Each hydrocarbon region is sealed by faults and is a hydrodynamically independent unit. Since the start of production in 1908 this field has been developed only in a conventional way (only production wells with no secondary and tertiary recovery methods). In this paper authors considered a possibility of CO2 injection into the oil horizon which may allow to combine increasing recovery factor with CO2 sequestration. Due to relative small pore volume and heterogeneity of considered field, injected CO2 can be observed in production wells. To solve that problem of gas circulation, CO2 separated from produced stream will be reinjected into the gas horizon. Proposed methodology can bring synergistic results in a form of increased oil recovery factor and environmental effect of carbon storage. The paper framework includes reservoir history matching and production forecasts based on calibrated numerical model. Results of numerical simulation are subsequently subjected to economic analysis which allows to choose the best way of further exploitation of the Jaszczew field.