EXPERIMENTAL AND THEORETICAL DETERMINATION OF PHYSICAL PROPERTIES OF CO2 / HYDROCARBON MIXTURES FOR ENHANCED OIL RECOVERY

Abstract

C02 flooding is considered to have multi-contact miscibility displacement mechanisms. It changes the reservoir fluid in a complex manner. This type of Enhanced Oil Recovery (EOR) technique is very economically viable, readily available, and environmentally acceptable. C02 flooding is one of the EOR techniques in the gas processes category.

In evaluating a field for possible C02 flooding certain data are required that can either be measured in the laboratory or, in the absence of measurements, be estimated from fundamental and theoretical considerations. The required data include the following: a) Minimum miscibility pressure (MMP), b) Swelling of crude oil, c) Viscosity reduction.

Miscibility is defined as physical condition between two or more fluids that will permit them to mix in all proportions without the existence of an interface. The minimum pressure required to achieve a multi-contact miscibility between injected fluid and oil, specifically, is called the minimum miscibility pressure (MMP).

. The C02 MMP is an important parameter for screening and selecting reservoirs for C02 injection project to simulate reservoir performance as a result of C02 injection.

The objectives of this study were separated into two parts. The first one was to predict the MMP using different correlations available in the literature i.e. Petroleum Recovery Inst., Yellig, Glas0, Alston, and Orr. The thermodynamic MMP was also evaluated using an EOS (Equation Of State).The simulator (PEPPER ) was used to obtain the bubble-points and dew-points, based on this data, the thermodynamic minimum miscibility pressures are determined using pseudo ternary diagram. This simulator uses 58

Soave-Redlich-Kwong (SRK) equation of state <

point, i.e. critical point.

l. The MMP coincides