NOVELTY - Treating vented or fugitive methane streams involves providing at least two thermal catalytic converters coupled to form a catalytic converter assembly, and pressure activated valves positioned between the thermal catalytic converters; providing at least one pilot heat source to initiate a catalytic reaction within the catalytic converter assembly; and channeling a vented or fugitive methane stream through the catalytic converter assembly.    USE - The method is used for treating vented or fugitive methane streams from well vents, field battery facilities, compressor station vents, or process buildings. It is used in oil and gas operations, as an alternative to raw gas venting, flaring, or incineration.    ADVANTAGE - The invention allows the conversion of highly variable, low volume, and/or dilute hydrocarbon containing streams. It utilizes low cost or even recycled thermal catalytic units to convert varying amounts of methane or other vented hydrocarbons into carbon dioxide to lower the net greenhouse gas emissions from a given site.    DETAILED DESCRIPTION - Treating vented or fugitive methane streams involves providing at least two thermal catalytic converters coupled to form a catalytic converter assembly, and pressure activated valves positioned between each of the thermal catalytic converters in the catalytic converter assembly; providing at least one pilot heat source to initiate a catalytic reaction within the catalytic converter assembly; and channeling a vented or fugitive methane stream through the catalytic converter assembly. The catalytic converters start up and shut down in sequence in response to variations in the supply of methane gas. The pressure activated valves open in response to increased supply of methane gas to bring an additional one of the thermal catalytic converters on line, and closes in response to decreased supply of methane gas to take the additional one of the thermal catalytic converters off line.    An INDEPENDENT CLAIM is also included for an apparatus for treating vented or fugitive methane streams, which comprises at least two catalytic converters coupled to form a catalytic converter assembly, pressure activated valves between each of the thermal catalytic converters in the catalytic converter assembly, and at least one pilot heat source to initiate a catalytic reaction within one of the catalytic converters within the catalytic converter assembly.    DESCRIPTION OF DRAWING(S) - The figure shows the basic equipment configuration to turn a highly variable methane casing vent stream from a conventional heavy oil well into a product stream consisting of carbon dioxide, water, and energy, resulting in a reduction of greenhouse gas emissions by 80-85%.