TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Process: The heating is controlled such that, (1) average heating rate of selected section is less than 1degreesC per day during pyrolysis, (2) thermal conductivity of at least a portion of selected section is greater than 0.5 W/(mdegreesC) and (3) condensable hydrocarbon is obtained in yield of greater than 60 weight% as measured by Fischer method. The mixture is pyrolyzed at about 270C. The heating energy per day (Pwr), is calculated by the relation Pwr = hxVxCvxrhob, where V is the selected volume of hydrocarbon containing formation, Cv is the average heat capacity of the formation, h is the average heating rate of the formation (10degreesC per day), and rhob is the formation bulk density. The pressure of at least a majority of selected sections of the formation, is controlled to at least 2 bar absolute. The formation conditions (comprising recycle of a portion of hydrogen from mixture into formation) are controlled such that the product mixture has hydrogen partial pressure of greater than 0.5 bar. The pressure within formation is altered to inhibit production of hydrocarbon from the formation having carbon number greater than 25. The heat transfer uniformly increases permeability of selected section to greater than 100 millidarcy. The mixture is produced in a production well having at least 7 heat source disposed in triangular pattern.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The mixture produced after treatment of hydrocarbon containing formation, contains condensable hydrocarbon and non-condensable hydrocarbons each comprising 0.1-15 weight% (wt.%) of olefins. The non-condensable hydrocarbon contains ethene and ethane in molar ratio of 0.001-0.15. The condensable hydrocarbon contains 5-30 wt.% of oxygen containing compound such as phenol, less than 1 wt.% of sulfur compound, greater than 20 wt.% of aromatic compounds, less than 5 wt.% of multi-ring aromatics with more than 2 rings, less than 0.3 wt.% of asphaltenes and 5-30 wt.% of cyclo alkanes. The non-condensable component contains 10-80 volume% of hydrogen. The mixture produced contains 0.05 wt.% of ammonia, hydrogen, condensable hydrocarbons, hydrogen sulfide and carbondioxide. A portion of condensable hydrocarbons is hydrogenated by the produced hydrogen.