Patent ID: 6830108
Filing Date: 2004-12-14
Classification: E21B

Abstract:
The method for operating a well installation having a casing extending within a geologic formation from a wellhead to a bottom region exhibiting a given liquid fluid induced down hole pressure, said casing having a perforation interval extending to an end location at a given depth, said installation including a collection facility and a source of gas under pressure having an injection output, comprising the steps of:(a) providing a tubing assembly within said casing including a plunger lift tube having a tube outlet at said wellhead and extending to a tubing input located in adjacency with or below said perforation interval end location communicable in fluid passage relationship with formation fluids and having an injection input; (b) providing an injection passage adjacent said plunger lift tube extending from said injection output at least to said plunger lift tube injection input, said injection passage defining with said casing, a casing passageway extending to said wellhead; (c) providing a plunger within said plunger lift tube movable between a bottom position located above said injection input and said wellhead; (d) providing a formation fluid receiving assembly defining a chamber with said injection passage in fluid communication with said tubing assembly, said chamber having a lower disposed check valve assembly with an open orientation admitting formation fluid within said chamber and responsive to injection fluid pressure to define a U-tube function with said injection passage and said tubing assembly; (e) providing a tubing valve between said tube outlet and said collection facility actuable between an open orientation permitting the flow of fluid to said collection facility and a closed orientation blocking said tube outlet; (f) providing an injection control assembly actuable between an open condition effecting application of gas under pressure from said pressurized gas output to said injection gas input and a closed condition; (g) providing a detector at said wellhead having a detector output in response to the arrival of said plunger at said wellhead; (h) accumulating formation liquid fluid into said chamber by passage thereof through said check valve assembly under equalizing pressure between said chamber and said casing passage; (i) moving liquid fluid from said chamber into said tubing assembly above said plunger; (j) actuating said injection control assembly to said open condition to apply gas under pressure to said defined U-tube from said injection input, to impart upward movement to said plunger; (k) actuating said tubing valve to said open orientation; (l) actuating said injection control assembly to said closed condition in response to said detector output; (m) then, actuating said tubing valve into said closed orientation for an off-time interval at least sufficient for the movement of said plunger from said wellhead to said bottom position; and (n) providing a casing gas fluid flow communication path between said casing passageway and said collection facility and producing gas fluid to said collection facility from said casing passageway.