Methods of generating subsurface heat for treating a hydrocarbon containing formation are described herein. The methods include providing a stream that includes water to a plurality of wellbores. Fuel and oxidant is provided to one or more flameless distributed combustors positioned in at least one of the wellbores. The fuel and oxidant is mixed to form a fuel/oxidant mixture. At least a portion of the mixture is flamelessly combusted in at least one of the flameless distributed combustors to generate heat. The fuel includes at least 0.1% hydrogen sulfide by volume.