Gas lift valve having ratcheting orifice
A gas lift valve is opened and closed by subjecting a pressure-sensitive piston to pressure differentials between annulus and tubing pressures. The piston can be held in (and released from) a closed position by rotatably indexing an indexing assembly in incremental rotations on the piston when in the closed position. The indexing assembly is rotated when the piston is alternatingly moved in opposing axial directions when the pressure differential is alternated. In response to those incremental rotations, an outer ratchet on the piston can be alternately expanded and contracted. When expanded, the outer ratchet engages a ratchet profile in the gas lift valve to prevent the piston from moving open. When the outer ratchet is contracted, however, the piston can be moved open.
1 . A gas lift valve comprising:
a housing defining an internal passage having a first port, a second port, and a third port, the first port being exposed to an annulus pressure, the second port being exposed to a tubing pressure, the third port being configured to at least communicate outside the housing, a portion of the internal passage defining a catch profile disposed thereabout;
a piston disposed in the internal passage, the piston being movable in first and second axial directions with axial movement between first and second positions in the internal passage at least in response to a pressure differential between the first and second ports, the piston in the first and second positions being configured to at least control fluid communication between the first port and the third port; and
an indexing assembly having first and second cams, the first cam disposed on the piston, the second cam disposed relative to the first cam, the first cam and the piston in the second position being rotatably indexed in incremental rotations relative to the second cam in response to the axial movement alternatingly in the first and second axial directions, the second cam being configured to alternatingly engage and disengage with the catch profile in response to the incremental rotations of the first cam, the second cam engaged with the catch profile being configured to prevent the axial movement of the piston in the first axial direction, the second cam disengaged with the catch profile being configured to permit the axial movement of the piston in the first axial direction.
2 . The gas lift valve of claim 1 , wherein the first port is disposed in communication with the annulus pressure on a first sealed side of the piston; wherein the second port is disposed in communication with the tubing pressure on a second sealed side of the piston opposite to the first seal side; and wherein the third port is disposed in communication with the tubing pressure on the first sealed side of the piston.
3 . The gas lift valve of claim 2 , wherein the first port comprises a side port defined in a side of the housing; wherein the second port defines a tail port defined in a tail of the housing; and wherein the third port defines an end port defined in an end of the housing.
4 . The gas lift valve of claim 1 , comprising a check valve disposed in the internal passage, the check valve permitting fluid communication from the internal passage to the third port and preventing fluid communication from the third port to the internal passage.
5 . The gas lift valve of claim 1 , wherein the piston in the first position opens communication between the first port and the third port; and wherein the piston in the second position closes communication between the first port and the third port.
6 . The gas lift valve of claim 1 , wherein the second cam is configured to alternatingly expand and contract in an expanded state and a contracted state in response to the incremental rotations of the first cam, the second cam in the expanded state on the piston in the second position being configured to engage with the catch profile and being configured to prevent the axial movement of the piston in the first axial direction, the second cam in the contracted state on the piston in the second position being configured to be disengaged with the catch profile and being configured to permit the axial movement of the piston in the first axial direction.
7 . The gas lift valve of claim 6 , wherein the first cam comprises an intermediate outer surface disposed on the piston and having outer longitudinal ridges disposed therebout, the intermediate outer surface and the piston being rotatably indexed in the incremental rotations in response to the axial movement of the piston alternatingly in the first and second axial directions; and wherein the second cam comprises an outer collar disposed about the intermediate outer surface and being expandable and contractable, the outer collar having an inner surface and an outer surface, the inner surface having inner longitudinal ridges disposed thereabout, the outer surface having an outer circumferential catch disposed thereabout.
8 . The gas lift valve of claim 7 , wherein the incremental rotations of the intermediate outer surface are configured to alternately expand and contract the outer collar in the expanded and contracted states in response to the outer longitudinal ridges of the intermediate outer surface being alternately engaged and disengaged with the inner longitudinal ridges of the outer collar.
9 . The gas lift valve of claim 8 , wherein the outer circumferential catch on the outer collar in the expanded state is configured to engage with the catch profile and is configured to prevent the axial movement of the piston in the second axial direction; and wherein the outer circumferential catch on the outer collar in the contracted state is configured to disengage with the catch profile and is configured to allow the axial movement of the piston in the second axial direction.
10 . The gas lift valve of claim 7 ,
wherein the second cam comprises:
a first ring disposed on the piston and having a first cam surface; and
a second ring disposed on the piston and having a second cam surface, the first and second cam surfaces having an offset from one another, the outer collar disposed between the first and second rings, the first ring, the second ring, and the outer collar are axially aligned with each other and are isolated from the incremental rotations of the piston; and
wherein the first cam comprises an inner collar attached to the piston and disposed inside the outer collar, the inner collar having the intermediate outer surface and having first and second intermediate cam surfaces, the first and second intermediate cam surfaces spaced between the first and second rings, the intermediate outer surface having the outer longitudinal ridges disposed therebout, the first and second intermediate cam surfaces being configured to alternately engage the first and second cam surfaces, the offset of the first and second cam surfaces being configured to rotate the piston and the inner collar in the incremental rotations in response to the first and second intermediate cam surfaces alternatingly engaged with the first and second cam surfaces.
11 . The gas lift valve of claim 7 , wherein the intermediate outer surface has a slot profile having upper and lower positions offset from one another; and wherein the inner surface of the outer collar has at least one pin disposed in the slot profile, the at least one pin being configured to move in the slot profile alternating between the first and second positions.
12 . A gas lift valve comprising:
a housing defining an internal passage having a first port, a second port, and a third port, the first port exposed to an annulus pressure, the second port exposed to a tubing pressure, the third port being configured to at least communicate outside the housing, a portion of the internal passage defining a ratchet profile disposed thereabout;
a piston sealed in the internal passage, the piston being movable in first and second axial directions with axial movement between first and second positions in the internal passage at least in response to a pressure differential between the first and second ports, the piston in the first position permitting communication between the first port and the third port, the piston in the second position restricting communication between the first port and the third port; and
an indexing assembly disposed on the piston and comprising:
a first ring disposed on the piston and having a first cam surface;
a second ring disposed on the piston and having a second cam surface, the first and second cam surfaces having an offset from one another;
an inner collar attached to the piston, the inner collar having an intermediate outer surface and having first and second intermediate cam surfaces, the first and second intermediate cam surfaces spaced between the first and second rings, the intermediate outer surface having outer longitudinal ridges disposed therebout; and
an outer collar disposed about the inner collar and being expandable and contractable, the outer collar having an inner surface and an outer surface, the inner surface having inner longitudinal ridges disposed thereabout, the outer surface having an outer circumferential ratchet disposed thereabout,
the first and second intermediate cam surfaces being configured to alternately engage the first and second cam surfaces,
the offset of the first and second cam surfaces being configured to rotate the piston and the inner collar in incremental rotations in response to the first and second intermediate cam surfaces alternatingly engaged with the first and second cam surfaces,
the incremental rotations of the inner collar being configured to alternatingly expand and contract the outer collar in an expanded state and a contracted state in response to the outer longitudinal ridges of the inner collar engaged and disengaged with the inner longitudinal ridges of the outer collar,
the outer circumferential ratchet on the outer collar in the expanded state on the piston in the second position being configured to engage with the ratchet profile and being configured to prevent the axial movement of the piston in the first axial direction,
the outer circumferential ratchet on the outer collar in the contracted state on the piston in the second position being configured to disengage with the ratchet profile and being configured to allow the axial movement of the piston in the first axial direction.
13 . The gas lift valve of claim 12 , wherein the first cam surface and the first intermediate cam surface defines first complementary ramped teeth oriented in a first direction; and wherein the second cam surface and the second intermediate cam surface defines second complementary ramped teeth oriented in a second direction opposite to the first direction.
14 . The gas lift valve of claim 12 , wherein the piston defines a first shoulder and a second shoulder, the first and second rings being spaced between the first and second shoulders, the first and second rings and the outer collar being axially movable on the piston between the first and second shoulders.
15 . The gas lift valve of claim 12 , further comprising a biasing element biasing between a first surface in the internal passage and the first ring on the piston.
16 . The gas lift valve of claim 12 , wherein the outer circumferential ratchet is configured to ratchet past the ratchet profile in response to the axial movement of the piston in the second axial direction.
17 . The gas lift valve of claim 12 , wherein the outer collar comprises a sleeve defining a longitudinal split.
18 . The gas lift valve of claim 12 , wherein a distal end of the piston is movable relative to a throat in the internal passage between the first port and the third port, the distal end having an annular seal configured to seal in the throat.
19 . The gas lift valve of claim 12 , comprising pins engaged between the first ring and the outer collar.
20 . A method used for a gas lift completion in a wellbore, the method comprising:
at least controlling fluid communication through a gas lift valve by:
producing pressure differentials in an internal passage of the gas lift valve between an annulus pressure of the wellbore and a tubing pressure of the gas lift completion; and
alternatingly moving a pressure-sensitive piston in first and second axial directions with axial movement between first and second positions in the gas lift valve in response to the pressure differentials;
holding and releasing the pressure-sensitive piston at least in the second position by:
rotatably indexing an indexing assembly in incremental rotations in response to the axial movement of the pressure-sensitive piston in the second position alternatingly in the first and second axial directions; and
alternatingly expanding and contracting an outer circumferential ratchet in expanded and contracted states in response to the incremental rotations of the indexing assembly on the pressure-sensitive piston in the second position; and
alternatingly preventing and allowing the axial movement of the pressure-sensitive piston in the first axial direction from the second position by alternatingly engaging and disengaging the outer circumferential ratchet in response to the expanded and contracted states with a ratchet profile defined in the internal passage.