1. Field of the Invention
The invention relates generally to valve assemblies useful in well completions wherein it is desired to cement in a portion of a production liner and, thereafter, utilize gas lift technology to assist production of fluids from a well.
2. Description of the Related Art
After a well is drilled, cased, and perforated, it is necessary to anchor a production liner into the wellbore and, thereafter, to begin production of hydrocarbons. Oftentimes, it is desired to anchor the production liner into place using cement. Unfortunately, cementing a production liner into place within a wellbore has been seen as foreclosing the possibility of using gas lift technology to increase or extend production from the well in a later stage. In addition, cementing is of the production liner may make it difficult to produce hydrocarbons in a standard manner, without artificial lift. Excess cement may clog portions of the flowbore of the production system. Cementing the production liner into place prevents the production liner from being withdrawn from the well. Because a completion becomes permanent when the production liner is cemented, any gas lift mandrels that are to be used will have to be run in with the production string originally. This is problematic, though, since the operation of cementing the production liner into the wellbore tends to leave the gas inlets of a gas lift mandrel clogged with cement and thereafter unusable. Additionally, the annulus above the cemented portion may contain excess cement that would hamper the ability to transmit gas down to the gas lift valves via the annulus. To date, there is no satisfactory method known for cleaning cement from the annulus surrounding the production assembly.
The present invention addresses the problems of the prior art.