An electro-osmotic method for the production of hydrocarbons utilizes in situ heating of earth formations having substantial electrical... Show moreAn electro-osmotic method for the production of hydrocarbons utilizes in situ heating of earth formations having substantial electrical conductivity. A particular volume of an earth formation is bounded with a waveguide structure formed of respective rows of discrete elongated electrodes in a dense array wherein the active electrode area and the row separation are chosen in reference to the deposit thickness to avoid heating barren layers. Electrical power is applied at no more than a relatively low frequency between respective rows of electrodes to deliver power to the formation while producing relatively uniform heating thereof and limiting the relative loss of heat to adjacent regions to less than a predetermined amount. At the same time the temperature of the electrodes is controlled near the vaporization point of water to maintain an electrically conductive path between the electrodes and the formation. A heat sink is provided by supplying aqueous liquid electrolyte to space between the electrodes and the adjacent formation, thereby maintaining the temperature thereat no greater than about the boiling point of water and maintaining a conductive path between said formation. A d.c. polarized potential is applied to enhance flow of reservoir fluid into a preselected row of electrodes, and collected reservoir fluids are removed from the electrodes in the preselected row. Sponsorship: IIT Research Institute United States Patent Show less
Improved methods and apparatus are disclosed for confining ohmic heating currents to a subsurface formation in the use of in situ ohmic... Show moreImproved methods and apparatus are disclosed for confining ohmic heating currents to a subsurface formation in the use of in situ ohmic heating for recovery of volatile and semi-volatile materials, such as hazardous waste, hydrocarbon-like materials, and valuable minerals having thermally responsive properties. Spacing between emplaced electrodes and the number of electrodes employed are controlled to cause coupling between electrodes for more uniform and higher temperature heating. Electrode designs are disclosed which suppress spurious earth currents which would heat other formations not of interest. Suppression of electrode end currents is accomplished by the use of distinct rings of insulation, control of the applied potential along the electrode, and injection or withdrawal of fluids at distinct locations along the electrode. Sponsorship: IIT Research Institute United States Patent Show less
