Abstract: A method of electrically enhancing oil-recovery from an underground rock formation comprising an oil-bearing reservoir is herein detailed. According to the method a controlled electrical charging potential between two or more electrically conductive elements is imposed for a charging time sufficient to cause a capacitive charging of the rock formation, the charging being followed by lowering or maintaining the charging potential below 40 mV per running meter between the conductive elements; during oil withdrawal. Further, a capacitor charging pump having feedback means for use with the method is detailed.

Abstract: A method of electrically enhancing oil-recovery from an underground oil-bearing reservoir (3), comprising: (a) selecting an underground rock formation (2) comprising an oil-bearing reservoir (3); (b) positioning two or more electrically conductive elements (4, 5) at two or more spaced apart locations in proximity to said formation (2, 3), at least one of said conductive elements (4, 5) being disposed in or adjacent to a bore hole affording fluid communication between the interior of said bore hole and said formation; (c) imposing a controlled electrical charging potential between said two or more electrically conductive elements (4, 5) for a charging time sufficient to cause a capacitive charging of said formation to an operating charging potential; (d) lowering or maintaining said charging potential below 40 mV per miming meter between said two or more electrically conductive elements (4, 5); and (e) withdrawing oil from at least one of said bore holes.