NOVELTY - Treating a hydrocarbon-containing formation in situ involves providing heat from heater(s) to portion(s) of the formation; allowing the heat to transfer from the heater(s) to a selected section of the formation; controlling the heat from the heater(s), such that an average temperature within the section of formation is less than 375degreesC; and producing a mixture from the formation.    USE - For treating a hydrocarbon-containing formation to produce hydrocarbons, hydrogen and other products.    ADVANTAGE - The novel method treats hydrocarbon-containing formations to yield relatively high quality hydrocarbon products, hydrogen and other products.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (a) A method for forming heater wells (520) in a hydrocarbon-containing formation by forming a first wellbore in the formation; forming a second wellbore in the formation using magnetic tracking, such that the second wellbore is parallel to the first wellbore; and providing heater(s) within the first wellbore and heater(s) within the second wellbore, such that the heaters can provide heat to at least a portion of the formation;    (b) A system for heating a hydrocarbon-containing formation comprising a heater in an opening in the formation, where the heater provides heat to a portion of the formation during use; an oxidizing fluid source; and a conduit in the opening, where the conduit provides an oxidizing fluid from the oxidizing fluid source to a reaction zone in the formation during use and the oxidizing fluid is selected to oxidize at least some hydrocarbons at the reaction zone during use such that heat is generated at the reaction zone and where the system allows heat to transfer by conduction from the reaction zone to a pyrolysis zone of the formation during use;    (c) A mixture produced from a portion of a hydrocarbon-containing formation comprising an olefin content of less than 10 wt.% and an average carbon number less than 35;    (d) A method for in situ production of synthesis gas from a hydrocarbon-containing formation,    (e) A method of sequestering carbon dioxide within a hydrocarbon-containing formation;    (f) A method for producing ammonia gas using a hydrocarbon-containing formation by separating air to produce an oxygen (O2) rich stream and a nitrogen (N2) rich stream; heating a selected section of the formation to support reaction of hydrocarbon-containing material in the formation to form synthesis gas; providing synthesis gas generating fluid and a portion of the O2 rich stream to the selected section; allowing the synthesis gas generating fluid and O2 in the O2 rich stream to react with at least a portion of the hydrocarbon-containing material in the formation; producing synthesis gas from the formation, wherein the synthesis gas comprises hydrogen (H2) and carbon monoxide (CO); providing at least a portion of the H2 in the synthesis gas to an ammonia synthesis process; providing N2 to the ammonia synthesis process; and using the ammonia synthesis process to generate ammonia;    (g) A method of installing a conductor-in-conduit heater of a desired length in a hydrocarbon-containing formation;    (h) A heater comprising a conduit to be placed within an opening in the formation; and a conductor to be placed within the conduit;    (i) A method of using a computer system for modeling an in situ process for treating a hydrocarbon-containing formation;    (j) A computer system comprising a CPU; a data memory coupled to the CPU; and a system memory coupled to the CPU;    (k) A carrier medium comprising program instructions that are computer-executable to implement the modeling of the in situ process;    (l) A method of using a computer system for operating an in situ process for treating a hydrocarbon-containing formation;    (m) A method of separating olefins, benzene, toluene, ethylbenzene, and xylene (BTEX) compounds, phenols, naphthalenes, anthracene, ammonia, pyridines, pyrroles, or thiophenes from fluids produced from a hydrocarbon-containing formation;    (n) A method of recovering thermal energy from a heated hydrocarbon-containing formation;    (o) A method of utilizing heat of a heated formation;    (p) A method for storing fluids within a hydrocarbon-containing formation;    (q) A method of filtering water within a hydrocarbon-containing formation;    (r) A method of shutting-in an in situ treatment process in a hydrocarbon-containing formation;    (s) A method of mining coal from a coal formation by mining coal from at least a portion of the treated formation;    (t) A system for drilling openings in a hydrocarbon-containing formation comprising a drilling apparatus; a magnetic string comprising two or more magnetic segments positionable in a conduit; and a sensor configurable to detect a magnetic field in the formation.    DESCRIPTION OF DRAWING(S) - The figure shows a pattern of heater wells in a hydrocarbon-containing formation, as used in the above method.    Heater wells (520)    Hydrocarbon layer (522)