Fluids produced from wells often include multiple phases. For example, a conventional gas well can be used to produce hydrocarbon gases from a subterranean reservoir to a surface location. The reservoir where the gas is found may also contain liquids, such as water or hydrocarbon liquids. In a typical completion of a gas well, a tubular casing having one or more radial layers is disposed from the surface location to or through the reservoir. A production tube or tubing or string, typically a steel pipe, is disposed within the casing, typically with an annulus defined between the outside of the production tubing and the innermost well casing. At depth, in some embodiments, the outer surface of the production tubing is sealed to the inner surface of the casing by packers so that the production tubing provides a pathway from the reservoir to the surface location, and all produced fluid flowing through the well from the reservoir to the surface location flows through the production tubing. The casing is perforated to admit the produced fluid from the reservoir into the production tubing.
Gas and liquid that are present in the reservoir may enter the casing. During a typical operation of a gas well, the level of water or other liquids in the casing is below the inlet of the production tubing. Nevertheless, a phenomenon referred to as “liquid loading” of the produced gas may occur and the additional liquid may negatively impact production.
Even if the upper level of the liquid remains below the inlet of the production tubing, the gas may carry some liquid. In some cases, the liquid can be carried first in a gaseous phase, e.g., as water vapor, that liquefies as the produced fluid travels through the production tubing. As the vapor liquefies, it can form a mist, i.e., small droplets suspended in the gas. Mist-like droplets of the liquid can also be present in the gas as it enters the production tubing. In either case, the droplets of liquid typically tend to combine and form larger drops of liquid in the produced fluid. Thus, as the produced fluid travels through the production tubing, the liquid content may increase and may become more difficult to lift, thereby reducing the flow rate of the well. The liquid content in the produced fluid may even stop the production of gas from the well until sufficient pressure builds.
A number of conventional methods exist for deliquefying a produced fluid during production or otherwise increasing the flow rate of a gas producing well. Artificial lift can be provided to the well, such as by injecting a lift gas at high pressure into the annulus of the well so that the lift gas enters the production tubing at a particular depth and helps lift the produced fluid with it through the production tubing. Alternatively, a plunger- or rod-type pump can be used to draw gas from a well. Another conventional method includes injecting a diluent material or other chemical into the well to facilitate gaseous production.
While such conventional methods can be successful in facilitating production in some gas wells, there exists a continued need for improvements in the area of deliquification of produced fluids being produced from wells.
USPTO Backgrounds
USPTO Backgrounds