Gas Lift Valve Having Variable Orifice

A gas lift valve comprising:

• a housing defining an interior passage, the interior passage having a first port and a second port, the first port being exposed to one of an annulus pressure and a tubing pressure, the second port being exposed to the other of the annulus pressure and the tubing pressure, the interior passage defining a first shoulder on one side of the first port and defining a second shoulder on an opposite side of the first port;
• a piston disposed in the housing, the piston being exposed to an internal pressure in a first portion of the interior passage and being biased by a dome pressure in a second portion of the interior passage the internal pressure being at least associated with the annulus pressure, the piston being movable with axial movement in first and second axial directions in the interior passage at least in response to a pressure differential between the dome pressure and the internal pressure in the interior passage;
• a collar disposed in the interior passage, the collar defining an internal profile and defining an orifice port therein;
• a collet disposed on a distal end of the piston, the collet being selectively engageable with the internal profile in the collar, the collet engaged with the internal profile of the collar being configured to move the collar with the axial movement at least in the first axial direction;
• and
• an indexing arrangement being configured to rotate the collar in rotational positions in the interior passage at least in response to the collar being moved in the first axial direction, alignment of the orifice port of the collar with the first port of the housing being variable with respect to the rotational positions of the collar, whereby the orifice port is configured to vary communication between the first port and the second port.

A gas lift valve comprising:

• a housing defining an interior passage having a first port and a second port, the first port being exposed to one of an annulus pressure and a tubing pressure, the second port being exposed to the other of the annulus pressure and the tubing pressure, the housing defining a dome chamber having a dome pressure;
• a piston disposed in the housing, the piston comprising a bellows connected between the piston and the interior passage, the bellows separating the dome chamber from the interior passage, the piston being biased by the dome pressure in the dome chamber of the housing, the piston being movable in first and second axial directions with axial movement in the interior passage at least in response to a pressure differential between the dome pressure and an internal pressure in the interior passage;
• and
• an indexing collar disposed in the interior passage and defining an orifice port therein, the indexing collar being rotatably indexed in rotational positions in the interior passage in response to the axial movement of the piston in at least one of the first and second axial directions, alignment of the orifice port with the first port being variable based on the rotational positions of the indexing collar.