STUDY ON THE CHANGE OF ASPHALTENE CONTENT OF THE RECOVERED OIL DURING C02 INJECTION FOR LIGHT OIL

Gas injection is one of the oldest and widely known methods in the Enhanced
Oil Recovery (EOR) process. Injection of C02 resulted in the increasing of oil recovery
and created a permanent storage of C02 in geological formation when it was injected in
a particular reservoir conditions. Unfortunately, when the C02 was injected to the light
oil reservoir, it will cause severe asphaltene problems especially in light oil reservoir
which contained low percentage of asphaltene content. Asphaltene will precipitate and
deposited in the reservoir, well bore, tubing as well as surface facilities. Presence of
asphaltene may reduce the permeability of the reservoir, changing the wettability of
reservoir and plugging the well bore and tubing which cause of loss in production. This
project studied the changes of asphaltene content (weight %) in recovered oil during
C02 injection using Dulang crude oil at three (3) different injection pressures.
Recovered oil was collected every 4 cc of pore volume has been injected with C02
during core flooding at 3 different injection pressure which are 2000, 2300 and 2600
psig. Asphaltene content in the recovered oil was measured using ASTM (D3279-07)
standard test method. Results showed the decreasing trend of asphaltene content in the
recovered oil for all the three (3) injection pressures. As the injection pressure decreased,
the asphaltene precipitation in the porous media increased as well decrease the oil that
can be recovered during the C02 injection.