Abstract: A rig for drilling a borehole from an underground tunnel includes a base assembly, a drilling assembly mounted to the base assembly, an upper frame assembly mounted to the drilling assembly above the base assembly, and a support hood coupled to the drilling assembly and positioned above the upper frame assembly. The support hood is configured to bear against a ceiling of the tunnel during drilling operations.

Abstract: A closed loop drilling fluids circulation system includes a first drilling fluid circulation system disposed at a first subterranean drill site. The first drilling fluid circulation system includes a supply tank for holding clean drilling fluid and a solids control device configured to separate solids from used drilling fluid. In addition, the system includes a central processing facility disposed at a location remote from the first drill site and configured to receive used drilling fluid from the solids control device and supply clean drilling fluid to the supply tank.

Abstract: A method for accessing a hydrocarbon reservoir in a subterranean formation from a subterranean tunnel system includes (a) drilling a first bore between an upper tunnel and a lower tunnel. In addition, the method includes (b) drilling a second bore downward from the lower tunnel.

Abstract: A system for recovering hydrocarbons from a subterranean formation includes an upper tunnel extending through the formation. In addition, the system includes a lower tunnel extending through the formation below a portion of the upper tunnel. Further, the system includes a plurality of conduits extending from the upper tunnel through the formation to the lower tunnel. Still further, the system includes a plurality of wellbores extending from the lower tunnel into a hydrocarbon-bearing portion of the formation.