The oil and gas sector extracts and processes hydrocarbon resources from deep below ground. Extracting these resources involves drilling a well into the production zone and then flowing the raw production up the well and into processing facilities. To prevent adverse conditions in the production network such as freezing and corrosion, several different chemicals are pumped into the production stream early in the production process. To overcome the downhole pressure in adding these chemicals, a special pump is used. Typically, these pumps run on pneumatic pressure supplied by a fuel gas line to actuate the pump, then the natural gas is vented to atmosphere. Instrument control devices on site such as level controllers, pressure controllers, positioners are typically also powered by freely available natural gas. With the installation of an instrument air system, compressed air may be generated on site which effectively removes the vented natural gas. The fuel gas used to drive pneumatic pumps is primarily composed of methane, which is a potent greenhouse gas with a global warming potential of 25. The quantity of natural gas that would have been vented in the absence of the project is estimated by measuring the volume of compressed air consumed by the instrument air system.