Electrode well method and apparatus

Claim 1

An electrode well adapted to form part of an electric circuit within a formation comprising: (a) a wellbore extending from the surface into such formation; (b) a casing within said wellbore, said casing having a conductive section situated at least partially within said formation, said section being insulated from adjacent sections of said casing; (c) a cement liner within said wellbore, said liner having a section of predetermined electrical conductivity surrounding said conductive casing section in contact with such formation; the electrical conductivity of said section being substantially higher than that of any sections of said liner adjacent thereto; (d) means for creating a hydraulic fracture within said formation extending outwardly from said electrode well in communication with said conductive liner section; (e) conductive means substantially filling the void within said fracture; and (f) means for interconnecting said conductive casing section with a source of electrical potential so as to establish multiple current paths between said conductive casing section and said fracture conductive means through said conductive liner section.

Claim 7

The method of forming an electrode well for heating a selected formation comprising the steps of: (a) drilling a borehole from the surface into said formation; (b) introducing a casing within said borehole extending into said formation, said casing having an electrical conductive section situated within said formation; (c) electrically isolating said conductive casing section from casing sections adjacent thereto; (d) introducing a first body of cement of lower electrical conductivity between the casing and the wellbore adapted to form an upper liner section; (e) introducing thereafter a second body of cement of higher electrical conductivity in said wellbore adapted to form a lower liner section abutting said upper liner section, said lower liner section surrounding said conductive casing section in contact with said formation; (f) creating a hydraulic fracture within said formation in communication with said lower liner section; (g) filling said hydraulic fracture with electrical conductive means and (h) interconnecting said conductive casing section with a source of electrical potential at the surface, thereby establishing multiple current paths through said lower liner section as part of an electric circuit extending between said fracture conductive means and said conductive casing section.

Claim 8

The method of forming an electrode well for heating a selected formation comprising the steps of: (a) drilling a borehole from the surface into said formation; (b) introducing a casing within said borehole extending into said formation, said casing having an electrical conductive section situated within said formation; (c) electrically isolating said conductive casing section from casing sections adjacent thereto; (d) introducing a first body of cement of lower electrical conductivity between the casing and the wellbore adapted to form an upper liner section; (e) introducing thereafter a second body of cement of higher electrical conductivity in said wellbore adapted to form a lower liner section abutting said upper liner section, said lower liner section surrounding said conductive casing section in contact with said formation; (f) creating a hydraulic fracture within said formation in communication with said lower liner section; (g) filling said hydraulic fracture with electrical conductive means and (h) interconnecting said conductive casing section with a source of electrical potential at the surface, thereby establishing multiple current paths through said lower liner section as part of an electric circuit extending between said fracture conductive means and said conductive casing section.