A coal formation may be treated using an in situ thermal process. A mixture of
hydrocarbons, H2, and/or other formation fluids may be produced from
the formation. Heat may be applied to the formation to raise a temperature of a
portion of the formation to a synthesis gas production temperature. A synthesis
gas producing fluid may be introduced into the formation to generate synthesis
gas. Synthesis gas may be produced from the formation in a batch manner or in a
substantially continuous manner.
