Method of producing viscous materials from subterranean formations

Abstract

A method of producing viscous materials from subterranean formation comprises a plurality of steps. At least two wells are drilled and completed into the subterranean formation that contains the viscous material. At least one of the wells is completed as an injection well and one of the wells is completed as a production well. A plurality of electrode wells are drilled into the subterranean formation with the plurality of electrode wells being generally arranged in a pattern to define at least one path between the production well and the injection well with the length of the path being substantially greater than the distance between the production well and the injection well. The electrode wells are spaced apart along the path at distances that are substantially less than the distance between the production well and the injection well. Thereafter, a voltage is applied across the adjacent pairs of electrode wells to thereby cause an electrical current to pass through the subterranean formation between each adjacent pair of the electrode wells. As the electrical current passes through the subterranean formation, the viscous material is heated to thereby lower the viscosity of such material. Following the heating of the subterranean formation in the vicinity of the path formed by the electrode wells, a driving fluid is injected through the injection wells to thereby migrate along the path and force the material having a reduced viscosity toward the production well. The material is produced through the production well and by continuing to inject a heated fluid through the injection wells, substantially all of the viscous material in the subterranean formation can be heated to lower its viscosity and be produced from the production well.