Patent Number: 6,253,847

Title: Downhole power generation

Abstract: There is provided downhole power generation apparatus with a first electrode, a second electrode and an electrolyte, wherein the first electrode comprises a casing within a borehole. The first electrode and the second electrode are formed from dissimilar metals and by appropriate selection of the two dissimilar metals, the casing functions as the cathode. Typically the first electrode is formed from a steel casing and the second electrode is of zinc. The second electrode is provided on an insulated connector joining at least two sections of casing. Power is extracted in an electrical load connected between the casing and the second electrode. Where a cement holds the casing in place within the borehole, it serves as the electrolyte. The cement is provided with additives to improve its conductivity. The first electrode is provided with oxide coatings, such as iron (III) oxide, to mediate the electrolytic reaction at the cathode. A method of generating electrical power down a borehole is also provided, the method comprising positioning at least one hollow cylinder made from a first material within a borehole, placing a dissimilar second material within the borehole, the first and second materials both communicating with a common electrolytic medium, thereby to form an electrolytic cell, and connecting an electrical load to the first and second materials to complete an electrical circuit and allow a current to flow through the load.

Inventors: Stephenson; Kenneth E. (Newtown, CT)

Assignee: Schlumberger Technology Corporation

International Classification: C23F 13/00 (20060101); C23F 13/16 (20060101); H01M 6/04 (20060101); H01M 6/26 (20060101); H01M 4/52 (20060101); H01M 2/16 (20060101); H01M 6/18 (20060101); E21B 043/00 (); C25F 007/00 ()

Expiration Date: 07/03/2018