Injection of seawater into low permeable and high porous chalk reservoirs has received considerable interest as a method for enhanced oil recovery with a great challenge due to unfavorable wetting conditions, i.e. low water wetness in the matrix block.

The paper addresses two parts. The first part is related to flooding with water and CO2. The study revealed the efficiency of the CO2 flooding following water injection; however it is interesting to observe that the difference in the oil recovery is minimal at the start of CO2 injection after water injection. The oil recovery then showed vast increase in oil recovery with CO2 injection after the initial period.

The second part addresses the effect of the temperature on non-asphaltenic and asphaltenic oils showing the preferential water composition on enhancing asphaltenic oil recovery from matrix. The study demonstrates the effect of CO2 and the preferential water composition on recovery from the matrix, which concluded that the CO2 reversed the ranking of the water composition on oil recovery suggesting asphaltene/ionic interaction.

Keywords:
ssw, co 2, critical temperature, saturation, wettability, upstream oil & gas, reservoir, hamouda, spe 131190, asphaltene
Subjects:
Improved and Enhanced Recovery, Waterflooding
Copyright 2010, Society of Petroleum Engineers
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