Patent ID: 8752904
Filing Date: 2014-06-17
Classification: C10G,E21B

Abstract:
1. A system for treating a subsurface hydrocarbon containing formation, comprising: one or more shafts; a first substantially horizontal or inclined tunnel extending from one or more of the shafts; a second substantially horizontal or inclined tunnel extending from one or more of the shafts; two or more heat source wellbores extending from the first tunnel to the second tunnel; a closed circulation system comprising piping positioned in the heat source wellbores, wherein the closed circulation system allows heated fluid to circulate through the piping between the first tunnel and the second tunnel during use; and a production system coupled to the second tunnel, the production system being configured to remove the heated fluid from the piping to the surface of the formation, reheat the removed heated fluid at the surface, and recirculate the reheated fluid into the piping in at least one of the heat source wellbores.