A STUDY OF WAG AND FAWAG INJECTION INDUCED ASPHALTENE PRECIPITATION IN LIGHT OIL RESERVOIR

Petroleum is the backbone of world energy. We can’t live without it. From the
efforts put in primary to tertiary recovery (Enhanced Oil Recovery, EOR), the
ultimate objective is to maximize the recovery and to squeeze out the last drop of oil
from reservoir.
. Asphaltene is an aromatic hetero-compound with aliphatic substitutions and
asphaltene formed the most polar fraction of crude oil. The instability of asphaltene
precipitation can causes permeability and porosity reduction, alteration of formation
wettability, plugging of reservoir and fouling of surface facilities.
In this project, two EOR methods are being studied. The first objective is to
investigate and compare the amount of asphaltene precipitated during Wateralternating-
gas (WAG) injection and Foam-Assisted-Water-Alternating-Gas
(FAWAG) injection. Through this experimental research, dynamic core flooding
experiments is conducted to study the effect of WAG injection and FAWAG
injection in inducing asphaltene precipitation in light oil reservoir. WAG injection is
the mobility enhancement method of CO2 injection and it is believed that the
presence of water could reduce the asphaltene precipitation. The amount of
asphaltene precipitation in light oil will also be recorded for WAG and FAWAG
injection. It is proven that FAWAG injection is able to further reduce asphaltene
precipitation than WAG.
Core properties before and after displacement is being investigate to study the
effect of on porosity, permeability and wettability alteration. Through the studies, it
is found out that FAWAG has less effect on changing rock properties. FAWAG
injection gives less asphaltene precipitation, less formation damage, and higher oil
recovery compare to WAG injection.