In situ thermal processing of a hydrocarbon containing formation with a selected hydrogen to carbon ratio

A method of treating a hydrocarbon containing formation in situ, comprising:

• assessing an atomic hydrogen to carbon ratio of at least some hydrocarbons in the formation;
• selecting a part of the formation for heating, wherein at least some hydrocarbons in the part have an initial atomic hydrogen to carbon ratio greater than about 0.70 and less than about 1.65;
• providing heat from one or more heaters to the part of the formation;
• allowing the heat to transfer from the one or more heaters to the part of the formation to pyrolyze hydrocarbons in the part of the formation;
• controlling the heat such that an average heating rate of the part of the formation is less than about 1° C. per day during pyrolysis;
• and
• producing a mixture from the formation.

A method of treating a hydrocarbon containing formation in situ, comprising:

• assessing an atomic hydrogen to carbon ratio of at least some hydrocarbons in the formation;
• selecting a part of the formation for heating, wherein at least some hydrocarbons in the part have an initial atomic hydrogen to carbon ratio greater than about 0.70 and less than about 1.65;
• providing heat from one or more heat sources to the part of the formation, wherein the heated part of the formation is proximate the heat sources;
• allowing the heat to transfer from the one or more heat sources in the part to a pyrolysis zone to pyrolyze hydrocarbons in the pyrolysis zone;
• providing hydrogen (H2) to the heated part of the formation to hydrogenate hydrocarbons in the part of the formation;
• heating a portion of the part of the formation with heat from hydrogenation;
• and
• producing a mixture from the formation.