Method and apparatus for removing liquid from a gas well

Abstract

A method of removing liquid from a gas well having a production tubing with a restriction therein run into the upper portion thereof and wherein a plunger lift system in arranged within the production tubing, the plunger lift system comprising an upper limiting means, a lower limiting means, a plunger that is capable of moving between the upper and lower limiting means, and a one-way valve situated at or above the upper limiting means that is capable of allowing fluid passage therethrough in an upward direction.

1 - 9 . (canceled) 
   
   
       10 . A method of removing liquid from a gas well having a production tubing with a restriction therein run into the upper portion thereof and wherein a plunger lift system is arranged within the production tubing, the plunger lift system comprising an upper limiting means, a lower limiting means, a plunger that is capable of moving between the upper and lower limiting means, and a one-way valve situated at or above the upper limiting means that is capable of allowing fluid passage therethrough in an upward direction but not in a downward direction; the method comprising the steps of:
 a) allowing liquid to accumulate in the gas well with the plunger held at the upper limiting means until a column of liquid forms in the production tubing above the lower limiting means;   b) releasing the plunger such that it falls towards the lower limiting means through the column of liquid until it engages with the lower limiting means;   c) allowing gas pressure to build up in the gas well below the plunger until the plunger and column of liquid are forced towards the upper limiting means such that the plunger engages with the upper limiting means and at least a portion of the column of liquid passes through the one-way valve; and   d) repeating steps a) to c).   
   
   
       11 . A method as claimed in  claim 10 , wherein the plunger comprises two parts, a first part which has a channel extending there-through and which is held at the upper limiting means in step a), and a second part which is separable from the first part so as to fall towards the lower limiting means during step a), the second part being adapted to close off the channel of the first part when the first and second parts are brought into contact. 
   
   
       12 . A method as claimed in  claim 10 , wherein the gas well has a casing and in step c) gas pressure builds up in the annulus formed between the casing and the production tubing. 
   
   
       13 . A method as claimed in any  claim 10  which further comprises the steps of: e) arranging a further plunger lift system within the production tubing above the restriction in the production tubing and above the one-way valve, the further plunger lift system comprising an upper limiting means situated at, immediately above or immediately below the wellhead, a lower limiting means situated at or above the restriction within the production tubing and at or above the one-way valve, and a plunger that is capable of moving between the upper and lower limiting means;
 f) allowing a further column of liquid to accumulate above the restriction within the production tubing and above the one way-valve with the plunger of the further plunger lift system held at the upper limiting means;   g) releasing the plunger of the further plunger lift system such that the plunger falls towards the lower limiting means of the further plunger lift system and through the further column of liquid until it engages with the lower limiting means of the further plunger lift system;   h) allowing gas pressure to build up below the plunger of the further plunger lift system until the plunger of the further plunger lift system and the further column of liquid are forced towards the upper limiting means of the further plunger lift system such that the plunger engages with the upper limiting means and removing at least a portion of the column of liquid at the wellhead; and i) repeating steps e) to h).   
   
   
       14 . A method according to  claim 13 , including the further step of timing the release of the plunger in step g) so that said plunger engages the lower limiting means of said further plunger lift system after said portion of the column of liquid passes through the one-way valve in step c). 
   
   
       15 . An apparatus for removing liquids from a gas well having a production tubing with a restriction therein run into the upper portion thereof, the apparatus comprising a plunger lift system arranged within the production tubing wherein the plunger lift system comprises: an upper limiting means, a lower limiting means, a plunger that is capable of moving between the upper and lower limiting means, and a one-way valve that is capable of allowing fluid passage therethrough in an upward direction but not in a downward direction, wherein the one-way valve is situated at or above the upper limiting means, the upper limiting means is situated at or below the restriction in the production tubing, and the lower limiting means is situated at a location where, during production of gas from the gas well, a column of liquid accumulates in the production tubing, the plunger lift system further comprising retaining means for releasably holding the plunger at or near the upper limiting means. 
   
   
       16 . The apparatus of  claim 15 , wherein the plunger comprises a first part which has a channel extending there-through and which is releasably engageable with the retaining means, and a second part which is separable from the first part and which is adapted to close off the channel of the first part when the first and second parts are brought into contact. 
   
   
       17 . The apparatus of  claim 15 , further comprising a further plunger lift system arranged within the production tubing above the first plunger lift system, the further plunger lift system comprising: an upper limiting means, a lower limiting means and a plunger that is capable of moving between the upper and lower limiting means, wherein the lower limiting means is situated at or above the restriction in the production tubing, the further plunger lift system additionally comprising retaining means for releasably holding the plunger at or near the upper limiting means. 
   
   
       18 . The apparatus of  claim 17 , further comprising a timer device for activating the retaining means of the further plunger lift system to release the plunger of the further plunger lift system.