an ungrounded two terminal source or from two terminals of a three terminal source where one terminal is positive phased with respect to ground and the other terminal is negative phased cable 40 within the well 30 may also have a metallic armor the upper parts of the well 30 include a surface casing 44 a flow line 45 connection to a product gathering system not shown a wellhead chamber 46 a pump rod lubricator or bushing 47 a pump rod 48 a production tubing 49 a pump 50 and a tubing anchor 51 the pump 50 may be located below the liquid level 59 at any depth the casing string in well 30 is grouted as at 52 down to and beyond the packer hanger 53 that attaches the upper casing to the more horizontal portions of the casing blank spacers 54 and a screen electrode assembly 38 the outermost portions of the screen electrode assembly 38 in the horizontal borehole 37 includes the blank steel spacer section 54 fiber reinforced plastic frp or other electrical insulator pipe sections 55a 55b and 55c a positive electrode 56a and a negative electrode 56b these electrodes are formed from sections of steel pipe the polarity designates the positive or negative phased a c terminals or connections direct current is not used both the.