NOVELTY - Heat is provided from heat source(s) to portion(s) of a hydrocarbon containing formation. The heat is transferred from the heat source(s) to a selected section of the formation. Then heat from heat source(s) is controlled, such that average temperature within majority of the selected section of formation is less than 375 degreesC, and a mixture having hydrocarbons is produced from the formation.    USE - For treatment of hydrocarbon containing formation in situ, for production of hydrocarbon, hydrogen and/or other products from various hydrocarbon containing formations such as formation containing coal, oil shale and/or heavy hydrocarbon, for in situ conversion of hydrocarbons to produce hydrocarbons, hydrogen and/or novel product streams from underground hydrocarbon containing formations, for production of synthesis gas used as fuel, for synthesizing wide range of organic and/or inorganic compounds such as hydrocarbons and ammonia, for generating electricity and/or steam flood in oil reservoir by reducing pressure of synthesis gas in turbines and/or using temperature of synthesis gas to form steam, used in energy generation units such as molten carbonate fuel cell, solid oxide fuel cell or other type of fuel cell, for production of branched and unbranched paraffins, for catalytic methanation to produce methane, for production of methanol, gasoline and diesel fuel, ammonia and middle distillates and for upgrading oils, and for production of carbon dioxide.    ADVANTAGE - The hydrocarbon treatment method yields relatively high quality hydrocarbon products, hydrogen and other products, inexpensively. Sequestering fluid formed within the formation significantly reduces or eliminates fluid which is released to the environment due to operation of the in situ conversion process. Superposition of heat varies depending on spacing between heat sources, and tends to increase the uniformity of distribution in the section of formation selected for treatment. The spacing is selected to increase the effectiveness of the heat sources, thereby increasing the economic viability of a selected in situ conversion process for hydrocarbons. Carbon deposition is effectively inhibited by utilizing an oxidizing fluid. Energy input cost is reduced by heating a portion of formation by oxidation in combination with heating the portion of formation by electric heater. The oxidation reaction is propagated slowly through a greater portion of formation, so that fuel heat sources are required to heat greater portion of formation. Controlling pressure, heat and/or heating rates of selected section in the formation increases production of selected formation fluids.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (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 heater wells in hydrocarbon containing formation;    (4) a method for installing a heater well into hydrocarbon containing formation;    (5) a system configured to heat hydrocarbon containing formation;    (6) a mixture produced from a portion of hydrocarbon containing formation;    (7) an in situ production of synthesis gas from hydrocarbon containing formation;    (8) a method of forming a spent portion of formation within hydrocarbon containing formation;    (9) a method of sequestering carbon dioxide within hydrocarbon containing formation;    (10) an in situ production of energy from hydrocarbon containing formation; and    (11) production of ammonia using a carbon containing formation.