Gas-lift valve and method of use

Abstract

A gas-lift valve comprising an elongated vertically orientated tubular body with inlet ports positioned for communication with the inlet ports of a gas-lift valve mandrel, a valve seat and valve port at the upper end of the valve body, a movable gas charged dome positioned within the body below the valve seat, a valve ball assembly attached to the dome, and a collapsible bellows positioned to move the dome and manipulate the valve ball assembly downward onto and off of the valve seat in response to pressure from said inlet ports of the valve body and pressure on the seat and thereby allow injection gas to flow upward through the valve port to exit at the upper end of the valve body. A tubular latch is provided with a removable plug to provide for pressure testing and completion of the well with only one wireline trip.

What is claimed is: 
     
         1 . A check valve assembly for controlling fluid flow in retrievable gas-lift valve apparatus, comprising:
 a check valve housing, wherein the check valve housing has a vertically extending through-bore;   a substantially spherical body slideably disposed within the vertically extending through-bore of the check valve housing; and   a seat disposed in a lower portion of the vertically extending through-bore and permitting the fluid flow therethrough.   
     
     
         2 . The check valve assembly of  claim 1 , wherein the substantially spherical body is capable of substantially free-floating vertical movement within the check valve housing. 
     
     
         3 . The check valve assembly of  claim 1 , where in the substantially spherical body is a ball. 
     
     
         4 . The check valve assembly of  claim 1 , where in the substantially spherical body is a carbide ball. 
     
     
         5 . The check valve assembly of  claim 1 , wherein the through-bore of the check valve housing comprises clover-leaf-shaped orifices. 
     
     
         6 . The check valve assembly of  claim 1 , wherein the through-bore of the check valve housing comprises clover-leaf-shaped orifices. 
     
     
         7 . The check valve assembly of  claim 6 , wherein the clover-leaf-shaped orifices are located in its upper portion of the through-bore of the check valve housing. 
     
     
         8 . The check valve assembly of  claim 6 , wherein the clover-leaf-shaped orifices are located above the substantially spherical body. 
     
     
         9 . A retrievable gas-lift valve apparatus, the apparatus comprising:
 an upper portion, comprising:
 a check valve housing, wherein the check valve housing has a vertically extending through-bore; 
 a substantially spherical body located within the vertically extending through-bore of the check valve housing; 
   a lower portion comprising:
 valve seat housing, 
 a bellows housing, and 
 a valve core housing. 
   
     
     
         10 . The retrievable gas-lift valve apparatus of  claim 9 , wherein the substantially spherical body is a ball. 
     
     
         11 . The retrievable gas-lift valve apparatus of  claim 9 , wherein the substantially spherical body is a carbide ball. 
     
     
         12 . The retrievable gas-lift valve apparatus of  claim 9 , wherein the through-bore of the check valve housing has clover-leaf-shaped orifices. 
     
     
         13 . The retrievable gas-lift valve apparatus of  claim 9 , wherein the wherein the through-bore of the check valve housing has clover-leaf-shaped orifices in its upper portion. 
     
     
         14 . The retrievable gas-lift valve apparatus of  claim 9 , wherein the lower portion comprises a gas valve ball, wherein the gas valve ball comprises an upper substantially round portion, wherein the upper substantially round portion comprises a flat top. 
     
     
         15 . A method of injecting a gas into a production conduit of an oil well, the method comprising:
 a) installing a gas-lift valve assembly;   b) collapsing a bellows of the gas-lift valve assembly when the hydrostatic pressures in the tubing string are greater than the pressure inside and the bellows;   c) moving a bellows dome of the bellows and a gas valve ball of the gas-lift valve assembly downward and away from a valve seat to open a valve port of a valve assembly of the gas-life assembly;   d) moving a substantially spherical body vertically through a through-bore within a check valve housing of the gas-lift valve assembly; and   d) injecting gas from the gas valve assembly into the fluid column of the production tubing string.   
     
     
         16 . The method of  claim 15 , wherein the substantially spherical body is a ball. 
     
     
         17 . The method of  claim 15 , wherein the substantially spherical body is a carbide ball. 
     
     
         18 . The method of  claim 15 , wherein the through-bore of the check valve housing has clover-leaf-shaped orifices. 
     
     
         19 . The method of  claim 15 , wherein the gas flows through the clover-leaf-shaped orifices. 
     
     
         20 . The method of  claim 15 , wherein the gas valve ball comprises an upper substantially round portion, wherein the upper substantially round portion comprises a flat top.