TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Method: The controlling of formation conditions comprises maintaining a temperature within the selected section within a pyrolysis temperature range. The controlling a pressure and a temperature within at least a majority of the selected section of the formation. The pressure is controlled as a function of temperature, or the temperature is controlled as a function of pressure. The pressure within the selected section of the formation is controlled with a valve coupled to heat sources (803) or coupled to a production well (825) located in the formation. Heat is controlled such as average heating rate of the selected section is less than about 1 degreesC per day during pyrolysis. The allowing of the heat to transfer comprises increasing a permeability of a majority of selected section to greater than about 100 millidarcy. The heat is controlled to yield greater than 60 wt.% condensable hydrocarbons, as measured by the Fischer Assay. The method further comprises separating the produced mixture into a gas stream and a liquid stream. A portion of the hydrogen sulfide is separated from non-condensable hydrocarbons. The heating is controlled such that the mixture can be produced from the formation as a vapor. The mixture is produced from a production well, the method further comprising heating a wellbore of the production well to inhibit condensation of the mixture within the wellbore.Preferred Parameters: The thermal conductivity of selected section is greater than 0.5 W/(mdegreesC). The produced mixture comprises condensable hydrocarbons having an API gravity of at least25degrees. The minimum pyrolysis temperature is about 270 degreesC. The method further comprises maintaining the pressure within the formation above about 2.0 bar absolute to inhibit production of fluids having carbon numbers above 25.Preferred Products: The produced mixture comprises non-condensable hydrocarbons containing ethene to ethane in molar ratio of 0.001-0.15, and condensable hydrocarbons. The non-condensable hydrocarbons contain 0.1-15 wt.% olefins, and 10-80 vol.% hydrogen. The condensable hydrocarbons contain less than 1 wt.% by weight nitrogen, less than 1 wt.% oxygen, 5-30 wt.% oxygen containing compounds such as phenols, less than 1 wt.% sulfur, greater than 20 wt.% aromatic compounds, less than 5 wt.% multi-ring aromatics with more than two rings, less than 0.3 wt.% asphaltenes, and 5-30 wt.% cycloalkanes. The produced mixture comprises 0.05 wt.% ammonia. The pressure within the selected section of the formation is controlled at 2 bar absolute to 100 bar. The produced mixture comprises a partial pressure of hydrogen within the mixture greater than about 0.5 bar. The produced mixture comprises hydrogen sulfide, carbon monoxide, and carbon dioxide.    TECHNOLOGY FOCUS - MECHANICAL ENGINEERING - Preferred Device: The heat sources comprise electrical heaters, surface burners, flameless distributed combustors, or natural distributed combustors.