The present disclosure is directed to an apparatus and method for extracting and communicating natural gas from gas wells, for example those operating under vacuum conditions, to a natural gas-fired piece of oil field equipment.
A pump jack (also known as a nodding donkey, pump unit, horsehead pump, beam pump, sucker rod pump, grasshopper pump, thirsty bird and jack pump) is often used to assist in the production of natural gas from low pressure wells by pumping liquid from the wellbore so that natural gas is able to flow from the well. Pump jacks are commonly driven by motors, or engines, which are commonly referred to as prime movers and may run on electricity, diesel, propane or natural gas. Due to their proximity to the well and the inherent difficulty in servicing many well sites, a large number of prime movers operate on natural gas supplied directly from the well. Unfortunately, natural gas-fired prime movers cease to operate when the pressure in a well, or gas supply line, develops a negative pressure or drops to such a low pressure level that it cannot supply natural gas to the prime mover.
As reservoir pressure drops, natural gas production from wells accessing the reservoir decreases. Liquid build up in natural gas wells also causes gas production to drop. When there is not a sufficient level of natural gas provided to a natural gas-fired prime mover due to low pressure in the well, the prime mover and pump jack cease to operate. This situation requires a manual restart of the prime mover, if possible, which may take days or weeks. The resulting fluid build up in the well frequently kills all production of natural gas from the well.
In a large field of natural gas wells, many wells are put under a vacuum to assist in the extraction of gas to be supplied to a gas supply line. When a well, or a field of wells, cease to produce gas without assistance, a compressor may be used to create a vacuum on the well to supply gas to a gas supply line. Whenever a vacuum is drawn on the well, there is usually an insufficient level of gas pressure available to provide fuel for the natural gas-fired prime mover. The vacuum on the well makes the use of a natural gas prime mover impractical or impossible without providing another fuel source.
The foregoing issues show there is a need for an apparatus to provide a consistent supply of natural gas to a prime mover for uninterrupted operations.