Two-Piece Plunger with Sleeve and Spear for Plunger Lift System

Abstract

A plunger lift system has a plunger with a sleeve and a spear that dispose in tubing. The sleeve and spear can move in the tubing between a bumper and a lubricator. The sleeve has a passage for fluid to pass therethrough, and the spear can insert partially into the sleeve's passage. The sleeve and spear fall independently of one another from the surface to the bumper. When disposed on the bumper, the sleeve and spear mate together. Building gas pressure downhole can then lift the mated sleeve and spear, which can sweep liquid along the tubing and push the liquid along with them to the surface.

What is claimed is: 
     
         1 . A plunger lift apparatus for tubing in a well, comprising:
 a sleeve for disposing in the tubing, the sleeve defining a passage therethrough from a first proximal end to a first distal end; and   a spear for disposing in the tubing downhole of the sleeve, the spear being elongated and extending from a second proximal end to a second distal end, the second distal end of the spear inserting in the passage of the sleeve, the second proximal end of the spear mating with the first proximal end of the sleeve, the spear at least partially closing fluid communication through the passage of the sleeve when mated therewith.   
     
     
         2 . The apparatus of  claim 1 , wherein the sleeve comprises means for producing a pressure differential across the sleeve. 
     
     
         3 . The apparatus of  claim 1 , wherein the sleeve and the spear mated together move uphole within the tubing by application of a pressure differential. 
     
     
         4 . The apparatus of  claim 1 , wherein the spear deploys at a faster rate downhole in the tubing than the sleeve. 
     
     
         5 . The apparatus of  claim 1 , wherein the spear comprises a first weight greater than a second weight than the sleeve. 
     
     
         6 . The apparatus of  claim 1 , wherein the spear comprises a first cross-sectional area that is greater than a second cross-sectional area of the sleeve. 
     
     
         7 . The apparatus of  claim 1 , wherein the spear comprises a first axial length greater than a second axial length of the sleeve. 
     
     
         8 . The apparatus of  claim 7 , wherein the second distal end of the spear extends beyond the first distal end of the sleeve and the second proximal end of the spear extends beyond the first proximal end of the sleeve when the spear is mated with the sleeve. 
     
     
         9 . The apparatus of  claim 1 , wherein the spear comprises a first ratio of cross-sectional area to weight that is less than a second ratio of cross-sectional area to weight of the sleeve. 
     
     
         10 . The apparatus of  claim 1 , wherein the sleeve defines a seat in the passage toward the first proximal end, the seat configured to engage a portion of the second proximal end of the spear. 
     
     
         11 . The apparatus of  claim 1 , wherein the second proximal end of the spear comprises a head, and wherein the second distal end of the spear comprises a stem extending from the head. 
     
     
         12 . The apparatus of  claim 11 , wherein the head defines a bullet tip, and wherein the stem defines a sharpened end. 
     
     
         13 . The apparatus of  claim 11 , wherein the head comprises one or more landers disposed thereon and stabilizing engagement of the spear downhole in the tubing. 
     
     
         14 . The apparatus of  claim 11 , wherein the head comprises a first outer dimension being greater than a second outer dimension of the stem, a portion of the first outer dimension of the head being configured to engage a portion of the passage of the sleeve toward the first proximal end. 
     
     
         15 . The apparatus of  claim 1 ,
 wherein the passage of the sleeve has a first proximal opening toward the first proximal end and has a first distal opening toward the first distal end;   wherein the second distal end of the spear installs through the first proximal opening; and   wherein the second proximal end of the spear at least partially mates at the first proximal opening of the passage.   
     
     
         16 . The apparatus of  claim 1 , further comprising a catcher disposed uphole of the tubing and operable to engage the sleeve. 
     
     
         17 . The apparatus of  claim 16 , further comprising a controller operably coupled to the catcher and controlling engagement of the catcher with the sleeve. 
     
     
         18 . The apparatus of  claim 1 , further comprising:
 a valve in fluid communication with the tubing; and   a controller operably coupled to the valve and controlling the valve in response to a condition in the tubing.   
     
     
         19 . The apparatus of  claim 1 , wherein the second distal end of the spear is longer than the second proximal end. 
     
     
         20 . A plunger lift apparatus for tubing in a well, comprising:
 a sleeve for disposing in the tubing, the sleeve defining a passage therethrough; and   a spear for disposing in the tubing downhole of the sleeve, the spear mating with the sleeve downhole and at least partially closing fluid communication through the passage of the sleeve when mated therewith, the spear deploying at a faster rate downhole in the tubing than the sleeve.   
     
     
         21 . A plunger lift apparatus for tubing in a well, comprising:
 a sleeve for disposing in the tubing, the sleeve defining a passage therethrough and having a first ratio of cross-sectional area to weight; and   a spear for disposing in the tubing downhole of the sleeve, the spear mating with the sleeve downhole and at least partially closing fluid communication through the passage of the sleeve when mated therewith, the spear having a second ratio of cross-sectional area to weight being less than the first ratio of the sleeve.   
     
     
         22 . The apparatus of  claim 21 , wherein the cross-sectional area comprises an effective area responsible for force generated under differential pressure. 
     
     
         23 . A plunger lift method for tubing in a well, comprising:
 deploying a spear with a first ratio of cross-sectional area to weight downhole in the tubing;   deploying a sleeve with a second ratio of cross-sectional area to weight downhole in the tubing separate to the spear by allowing fluid communication through a passage in the sleeve;   preventing fluid communication through the passage in the sleeve by inserting a distal end of the spear in the passage and mating a proximal end of the spear with the passage; and   lifting the mated sleeve and spear uphole in the tubing by application of a pressure differential.   
     
     
         24 . The method of  claim 23 , further comprising catching the sleeve lifted uphole in the tubing. 
     
     
         25 . The method of  claim 24 , further comprising redeploying the sleeve downhole in the tubing by releasing the sleeve manually or automatically. 
     
     
         26 . The method of  claim 23 , further comprising redeploying the spear downhole in the tubing by unmating the spear from the sleeve lifted uphole in the tubing. 
     
     
         27 . The method of  claim 26 , wherein redeploying the spear comprises permitting the spear to deploy downhole in the tubing before permitting the sleeve to deploy downhole. 
     
     
         28 . The method of  claim 23 , wherein deploying the spear downhole in the tubing comprises permitting the spear to deploy at a faster rate downhole than the sleeve. 
     
     
         29 . The apparatus of  claim 28 , wherein permitting the spear to deploy at the faster rate downhole than the sleeve comprises providing the spear with one or more of:
 a first weight greater than a second weight than the sleeve;   a first cross-sectional area that is greater than a second cross-sectional area of the sleeve;   a first axial length greater than a second axial length of the sleeve; and   the first ratio of cross-sectional area to weight that is less than the second ratio of cross-sectional area to weight of the sleeve.