A hydrocarbon containing 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 pyrolysis temperature. Heat sources may be used
to heat the formation. The heat sources may be positioned within the formation
in a pattern. The pattern may be a repeating pattern of triangles.
