Abstract
The performance of the EOR methods, particularly those involving gas injection schemes, is governed significantly by the reservoir fluid properties and the reservoir temperature and pressure. Other factors like reservoir rock properties and drive energy also control the ultimate success of the EOR technique. However, in this work, we concentrate on the influence of the properties of the reservoir fluids only.
We have also focused our attention on the following four questions:
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What is the minimum reservoir pressure at which the reservoir fluid will be miscible with CO₂? (miscible CO₂ flood).
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What is the minimum pressure at which field gas will become miscible with the reservoir fluid? (vaporizing hydrocarbon miscible gas flood).
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If the reservoir cannot be operated at or above the pressure required for achieving multiple contact miscibility with CO₂, could injection of CO₂ still be beneficial? (immiscible CO₂ flood).
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What rich fluid stock - like LPG condensate - and how much of it has to be added to field gas to make it miscible with the reservoir fluid at the existing pressure and temperature? (condensing hydrocarbon miscible gas flood).
Depending on the information available, several techniques can be used to answer the questions raised above. Naturally, the more information we have at hand, the less will be the degree of uncertainty in the answers we provide. In this work, we have utilized the empirical correlations available in the literature to answer the questions. We have also compared the answers we obtained by the application of these correlations with some experimental data already generated in the laboratories. Based on these, we plan to recommend the best way to carry out the screening process.