Patent ID: 6568473
Filing Date: 2003-05-27
Classification: E21B,Y10T

Abstract:
A gas lift valve for use in a gas lift mandrel of an oil well producing by means of gas lift, the gas lift valve comprising:a body; a gas lift valve internal chamber having a first, original cross-sectional area; at least one gas intake port for providing a passage for a flow of injection gas from an annulus between a casing and a tubing of said oil well to said gas lift valve internal chamber, said at least one gas intake port located in an upstream portion of said gas lift valve internal chamber; and a hollow tip, connected to said gas lift valve internal chamber, said hollow tip provided with at least one gas discharge port; a central body venturi installed in said gas lift valve internal chamber, said central body venturi comprising: a first divergent upstream segment, which provides, in said gas lift valve internal chamber, a progressive constriction in a cross sectional area from the original cross-sectional area for the passage of said flow of injection gas; a second intermediate segment, located downstream of said first divergent upstream segment, which defines a substantially constant cross sectional area for the passage of said flow of injection gas, such area being substantially smaller than the original cross sectional area of said gas lift valve internal chamber; a third convergent downstream segment, located downstream of said second intermediate segment, which defines a progressive widening in the cross section area for the passage of said flow of injection gas until such cross sectional area becomes equal to the original cross sectional area of said gas lift valve internal chamber; and a seat, located at said upstream portion of said gas lift valve internal chamber and downstream of said at least one gas intake port, said seat able to accommodate said first divergent upstream segment of said central body venturi against it, thereby blocking off said gas lift valve and therefore precluding a reverse flow from said gas lift mandrel to said annulus from occurring.