A coal formation may be treated using an in situ thermal process. A mixture
of hydrocarbons, H.sub.2, 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 pyrolysis temperature.
After pyrolysis, the portion may be heated to a synthesis gas production
temperature. A synthesis gas producing fluid may be introduced into the
portion to generate synthesis gas. Synthesis gas may be produced from the
formation in a batch manner or in a substantially continuous manner.
