Branched alcohols from renewable resources for reducing the MMP of C02-crude oil systems

Miscible displacement by carbon dioxide (C02) is a method to increase oil recovery.
This technique is a very economical method in enhanced oil recovery (EOR),
especially in C02-crude oil reservoir. It maintain reservoir pressure and also reduce
oil viscosity. One of the most important parameters that should be known to utilise
C02 miscible displacement is minimum miscibility pressure (MMP). MMP is the
pressure at which C02 will achieve miscibility with the oil. Alcohol is well known as
a co-surfactant in reducing interfacial tension (IFT) which is a direct parameter in
reducing MMP. There are intensive researches on branched alcohol surfactants such
as branched alcohol propoxylate sulphate. Branch alcohol may also reduce IFT better
compare to straight chain alcohol surfactants. Yet, alcohol can only be used as the
main IFT reducing agent if it can be produced cheaply. This paper focuses on
synthesis of branched alcohol from Jatropha oil. However, due to the unavailability
of reactant needed, final step of synthesizing branched alcohol cannot be done. But,
the research is still continued with alkoxyl FAME since it shows potential for use as
additives to reduce MMP due to alcohol branch attached. For the first step of
synthesizing, transesterification of jatropha oil, 87% fatty acid methyl ester (FAME)
yield was achieved. Next step of epoxidation FAME and alcohol addition to the
epoxide FAME is done and expected to have 83.5% (Campanella, et al. 2008) and
100% (Smith. et al. 2009) conversion respectively. The effect of products on C02-
crude oil MMP is then determined using Vanishing Interfacial Technique (VIT). The
result shows MMP reduced to 1990 psia from 2240 psia when alkoxyl FAME
Jatropha is mixed with Dulang crude oil at 60°C. Alkoxyl FAME Jatropha shows
greater effect in reducing MMP compare to alkoxyl FAME Palm, 11.6% reduction
compare to 4.46% reduction. Alkoxyl FAME Jatropha also shows better result
compare to 2-methyl butan-2-ol in reducing MMP, 11.6% and 5.8% reduction
respectively. This happened because alkoxyl FAME Jatropha mainly consists of
highly branched alcohol FAME structures (65.86%) which result to higher polarity.
This higher polarity affects the COz capacity to form interaction with the crude oil,
thus lower the MMP. Meanwhile for alkoxyl FAME Palm, it mainly consists of
FAME structures without alcohol branched (52.69%). And eventhough FAME
structures with alcohol branched (47.31%) are present, it only mainly made up of
single alcohol branched FAME. This make alkoxyl FAME Palm less in polarity.

Therefore, the ability of alkoxyl FAME Palm to reduce MMP is lower than alkoxyl
FAME Jatropha. For 2-methyl butan-2-ol, lower polarity compare to alkoxyl FAME
Jatropha is resulted from lesser branched alcohol. As conclusion, alkoxyl FAME
synthesized from Jatropha oil have the ability in reducing MMP for C02 - crude oil
systems, and gives better result compare to alkoxyl FAME from Palm oil and 2-
methyl butan-2-ol.