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Abstract

Among the emerging technologies in the petroleum industry is the application of electro-kinetic phenomena to enhance oil recovery from tight heavy sandstone reservoir, which has been reported to yield technical and commercial success in some of the North American oil fields. The basic theory behind the stimulation effect is predicted to be the colloidal movement of pore lining clays that results in widening of pore throats and/or opening new flow tunnels. Nevertheless, few works have been performed on its applicability to water injection wells. This paper investigates the effect of electrokinetics on improving water injectivity in tight sandstone reservoirs. Two sets of experiments were conducted. In the first set, the DC potential is varied and optimized during the water injection. In the second set, the DC potential is kept constant and the injection rate is varied to determine the hydrodynamic effect on clay movement. The core plugs and liberated clays were characterized through size exclusion micro-filtration and ICP-MS analysis. The Joule heating phenomena associated with electrokinetics is also studied during the entire injection period. Results showed that several folds (up to 152%) apparent increase of core permeability could be achieved. Some of the experiments were more efficient in terms of dislodgement of clays and enhanced stimulation which is supported by produced brines analysis with higher concentration of clay elements. The results also showed larger quantity of clay elements in the produced brines in the initial periods of water injection, prior to the stabilization of differential pressure and electrical current, implying that the stimulation effect stops when the voltage gradient and flow rate values are no more able to remove additional clays. Additionally, fluid flow temperature measurements showed an increasing trend with the injection time and direct proportionality with applied voltages.

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/content/papers/10.3997/2214-4609-pdb.395.IPTC-17536-MS
2014-01-19
2024-06-14
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/content/papers/10.3997/2214-4609-pdb.395.IPTC-17536-MS
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