NOVELTY - In situ treatment of hydrocarbon containing formation involves supplying portion(s) of formation with heat from heat source(s), allowing heat to transfer from heat source(s) to selected section of formation, controlling heat from source(s) such that average temperature within at least a majority of selected section of the formation is less than 375 degreesC, and producing a mixture from formation.    USE - For in situ thermal processing of hydrocarbon containing formation such as formation containing coal, oil shale and/or heavy hydrocarbons to produce CH e.g. asphaltene, paraffins, cycloalkanes, aromatics, nitrogen containing compound, e.g. urea used as fertilizer, compounds containing oxygen, compounds containing sulfur; hydrogen; and synthesis gas. The paraffin may be used to produce diesel, jet fuel and naphtha products. Synthesis gas is used in catalytic methanation process to produce methane, and for production of methanol, gasoline, diesel fuel, ammonia and middle distillates and for synthesizing organic and inorganic compounds, for generating electricity in molten carbonate fuel cell, solid oxide fuel cell and as fuel in down hole gas heaters.    ADVANTAGE - A mixture of high quality hydrocarbon products, hydrogen and other products are produced. The heat generated during pyrolysis can be used for heating another portion of formation, for generating synthesis gas, electricity and/or as a stream flood in oil reservoir. By arranging heat sources with selected spacing, optimized heating of section is enabled. Hence hydrocarbons may be pyrolyzed within a large area of portion and economic viability of the process can be increased and high recovery efficiency of synthesis gas is enabled. Energy input cost is reduced by heating a portion of hydrocarbon by oxidation. The system for heating hydrocarbon has longer life time and is inexpensive. Formation of less desirable products are inhibited and qualities of produced mixture are improved. Pyrolysis of portion produced a high, uniform permeability throughout portion and allows generation of synthesis gas at low pressure. Hence equilibrium conditions during synthesis gas generation is maintained.    DETAILED DESCRIPTION - In situ treatment of hydrocarbon containing formation, involves supplying portion(s) of formation with heat from heat source(s), allowing heat to transfer from heat source(s) to selected section of formation, controlling heat from source(s) such that average temperature within at least a majority of selected section of formation is less than 375 degreesC, and producing a mixture from formation, inside production well. A well bore of production well is heated to inhibit condensate of mixture within wellbore. The wellbore comprises a heater element configured to heat formation adjacent to well bore. The formation is heated with heater element to produce mixture comprising a large non-CH gas and hydrogen.    INDEPENDENT CLAIMS are included for the following:    (1) an in situ method for heating hydrocarbon containing formation;    (2) an in situ method for producing hydrogen from hydrocarbon containing formation;    (3) a method for forming or installing heater wells in hydrocarbon containing formation;    (4) a system configured to heat a hydrocarbon containing formation;    (5) a mixture such as condensable mixture produced from a portion of hydrocarbon containing formation;    (6) a method for in situ production of synthetic gas from hydrocarbon containing formation;    (7) a method for forming spent portion of formation within hydrocarbon containing formation;    (8) a method of sequestering carbon dioxide within hydrocarbon containing formation;    (9) a method for in situ production of energy from hydrocarbon containing formation; and    (10) a method for producing ammonia using a carbon containing formation.