Many wells which primarily produce gas are also prone to produce liquid in varying quantities with the produced gas. As the gas is produced, the liquid accumulates in the well to a height such that it may well cover the perforations through the well casing into the gas-bearing formation, thereby slowing the production of gas from the well due to the increased hydrostatic head over the outlet from the gas-bearing formation. In some instances the liquid may reach sufficient depths that it substantially stops the production of gas. Such is clearly an undesirable situation. The liquid may be water, oil or mixtures thereof and is referred to herein as “water” or “liquid”.
In many instances it has been necessary to position pumps in the well powered by an external source at the surface to remove water from the gas well. This procedure requires additional expense for the installation of the pump and pump motor as well as expense for the electricity required to power the pump and additionally possible expensive maintenance for the pumping equipment. Many such gas wells may be prematurely abandoned due to such expenses when compared to the value of the produced gas.
U.S. Pat. No. 4,531,593 issued Jul. 30, 1985 to Guy R. Elliott, et al (Elliott) and entitled “Substantially Self-Powered Fluid Turbines” discloses a system for a self-powered turbine powered by mixtures of gas and liquid with turbines to produce hydrocarbon gases, water vapor, carbon dioxide, other gases and petroleum from watered out wells and from deep or hot wells. This system uses coaxially shaft-coupled turbines which do not provide the capability to run a pump at a necessary and controlled variable speed.
It would be highly desirable if a system could be developed to pump the water from the gas well with the pumping being powered by a downhole source which does not reply upon imported electricity but relies instead on power produced within the well to drive the pump. A continuing search has been directed to the development of such equipment.