ALCOHOL AS AN ADDITIVE TO INCREASE C02 AND CRUDE OIL MISCIBILITY

Alcohol as a solvent can reduce minimum miscibility pressure (MMP) of
C02 flooding for enhanced oil recovery (EOR). C02 is not feasible for high
temperature and waxy reservoir. The objective of this study is to solve the problem
by using alcohol in order to reduce minimum miscibility pressure between C02 and
crude oil. In this research, the author used benzyl alcohol, branched alcohol and
normal alcohol. Although alcohol is often used as a co-surfactant and only a small
amount is needed, but alcohol can be used as the main IFT reducing agent if it can
be produced cheaply. Alcohol enhances the solvating power and polarity of carbon
dioxide in crude oil. In this project, an attempt had been done by using four types of
alcohol which are phenol, 2-methyl-2-butanol, 2-methyl-1-butanol and 2-butanol.
The alcohols were tested on Dulang crude oil at 60 ·c in order to see the effect of
branching, cyclic and straight chain alcohol on solubility of C02 into crude oil.
Vanishing interfacial tension method is used to obtain MMP. All alcohols had been
tested and the results showed that branched alcohol is a very good MMP reduction
agent compared to benzyl and normal alcohol. The branched alcohol reduced MMP
up to 23%. Optimum concentration is being tested for branched alcohols. The
optimum concentration was 50% pore volume for pressure at 1500 psi. Branched
alcohol is efficient in lowering the MMP and should be considered in EOR.