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The Effect of Oil-Wet Induction Mechanisms on Effectiveness of Diluted and Modified Brine Injection in Sandstone Surface
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 75th EAGE Conference & Exhibition incorporating SPE EUROPEC 2013, Jun 2013, cp-348-00308
- ISBN: 978-90-73834-48-4
Abstract
The benefits of diluted and modified brine have been proved by investigators. The main oil recovery mechanism is believed to be wettability alteration. However, these benefits can be achieved in certain conditions. For sandstone, the natural surface can be induced to oil-wet condition by several mechanisms. Polar interaction and ion binding mechanisms are chosen in this study. Displacement-by-water ratio and residual oil saturation are measured for each sandstone sample experimented by several brine formulations to determine the effectiveness of study parameter From the experiments, calcium ion is the most sensitive to effectiveness of diluted and modified brine injection. It is also observed that oil-wet induced surface prepared from polar interaction generates strongly oil-wet condition and this does not allow cations exchange mechanism to occur. Hence, oil is hardly displaced by brine, remaining captured on surface. For oil-wet induced surface from divalent ion binding, the presence of divalent concentration contrast in aqueous phase results in instability of adsorbed material layer, causing the rupture of divalent bridge and eventually more oil is displaced by brine. Therefore, the bigger the contrast of divalent concentration, the higher the oil recovery from brine can be obtained.