An oil shale formation may be treated using an in situ thermal process. Heat
may
be provided to a formation from one or more heat sources in the formation. Hydrocarbons
within the formation may be pyrolyzed. Hydrocarbons, H2, and/or other
formation fluids may be produced from the formation. In some embodiments, the formation
may include a relatively impermeable portion and/or a relatively permeable portion.
