Gas lift nozzle valve

Abstract

The present invention relates to the design of a nozzle valve (GL) for gas lifting that can be used in place of conventional orifice valves (VO). The gas lift nozzle valve (GL) according to the present invention has a body (1) with admission orifices (2), and, immediately below these, a slight recess (3) in the internal diameter of the body where a convergent nozzle (4) is fitted to regulate the gas flow passing through the inside of the nozzle valve (GL) towards the outlet (5) of the latter.

Claims

1. A nozzle valve for gas lifting, comprising: a body (1) with admission orifices (2); a recess (3) provided below the admission orifices in an inside of the body, and a convergent nozzle (4) configured to regulate a gas flow passing through the inside of the body towards a valve outlet (5), wherein the nozzle comprises a perforated cylindrical block (40) provided on the recess with a large opening (41) provided at a first end of the block and with a small opening (43) provided at a second end of the block opposite to the first end, wherein an internal diameter of the large opening (41) is larger than an internal diameter of the small opening (43), wherein the small opening (43) corresponds to the minimum passage area for the gas flow through the inside of the body, wherein the nozzle between the first and second ends of the block is non-divergent, wherein the perforated cylindrical block (40) comprises a portion of a surface of a torus extending from the large opening to the small opening, and wherein the nozzle (4) further comprises a charged-bellows gas-lift valve, above the admission orifices (2), with a rod (6) connected to an actuating bellows (7), which acts inside the perforated cylindrical block (40).

2. The nozzle valve for gas lifting according to claim 1, wherein the nozzle (4) comprises the perforated cylindrical block (40), in toroidal form, with the large opening (41) in an upper face (42) of the block (40) and the small opening (43) in a lower face (44) of the block (40).

3. The nozzle valve for gas lifting according to claim 2, wherein the nozzle (4) further comprises a charged-bellows gas-lift valve, above the admission orifices (2), with a rod (6) connecting to an actuating bellows (7) which acts over a conventional seat, and forms a choke with the larger opening of the cylindrical block (40), and the smaller opening having a diameter less than or equal to the diameter of the opening of the conventional seat.

4. The nozzle valve for gas lifting according to claim 2, wherein the nozzle (4) further comprises an extension provided by the addition of a cylindrical throat (46) having the same internal diameter as the small opening (43) in the lower face (44) of the block (40).

5. The nozzle valve for gas lifting according to claim 4, wherein the nozzle (4) further comprises a charged-bellows gas-lift valve, above the admission orifices (2), with a rod (6) connecting to an actuating bellows (7) which acts over a conventional seat, and forms a choke with the larger opening of the cylindrical block (40), and the smaller opening having a diameter less than or equal to the diameter of the opening of the conventional seat.

6. The nozzle valve for gas lifting according to claim 1, wherein the nozzle (4) further comprises a charged-bellows gas-lift valve, above the admission orifices (2), with a rod (6) connecting to an actuating bellows (7), which acts over a conventional seat, and forms a choke with the larger opening of the cylindrical block (40), and the smaller opening having a diameter less than or equal to the diameter of the opening of the conventional seat.

7. The nozzle valve for gas lifting according to claim 1, wherein the nozzle (4) has a circular, conical, elliptical, parabolic or hyperbolic geometric cross section.

8. The nozzle valve for gas lifting according to claim 1, wherein a check valve (45) is positioned externally, internally or in a combination of both in relation to the nozzle valve.

9. The nozzle valve for gas lifting according to claim 1, wherein the nozzle (4) comprises the perforated cylindrical block (40), in toroidal form, with the large opening (41) on an upper-most face (42) of the block (40) and the small opening (43) on a lower-most face (44) of the block (40).

10. The nozzle valve for gas lifting according to claim 9, wherein the nozzle (4) further comprises a cylindrical throat (46) extending from the small opening (43) toward the outlet (5) and having an internal diameter same as the small opening (43) in the lower-most face (44) of the block (40) throughout an entire length of the cylindrical throat (46).

11. The nozzle valve for gas lifting according to claim 1, wherein a length of the convergent nozzle in an axial direction is equal to a distance between the large opening (41) and the small opening (43).

12. A nozzle valve for gas lifting, comprising: a body (1) with admission orifices (2); a recess (3) provided below the admission orifices in an inside of the body, a convergent nozzle (4) configured to regulate a gas flow passing through the inside of the body towards a valve outlet (5); and a check valve (45) positioned externally, internally or in a combination of both, wherein the nozzle comprises a perforated cylindrical block (40) provided on the recess with a large opening (41) provided at a first end of the block and with a small opening (43) provided at a second end of the block opposite to the first end, wherein an internal diameter of the large opening (41) is larger than an internal diameter of the small opening (43), wherein the small opening (43) corresponds to the minimum passage area for the gas flow through the inside of the body (1) when the check valve (45) is in the open position, wherein the nozzle between the first and second ends of the block is non-divergent, wherein the perforated cylindrical block (40) comprises a portion of a surface of a torus extending from the large opening to the small opening, and wherein the nozzle (4) further comprises a charged-bellows gas-lift valve, above the admission orifices (2), with a rod (6) connected to an actuating bellows (7), which acts inside the perforated cylindrical block (40).

Description

SUMMARY OF FIGURES

(1) FIG. 1 shows a graph comparing performance curves for an orifice valve and a venturi valve of the prior art.

(2) FIG. 2 shows an orifice valve of the prior art.

(3) FIG. 3 shows a charged-bellows valve of the prior art.

(4) FIG. 4 shows a venturi valve of the prior art.

(5) FIG. 5 shows a center-body venturi valve of the prior art.

(6) FIG. 6 shows a first embodiment of the nozzle according to the present invention.

(7) FIG. 7 shows a second embodiment of the nozzle according to the present invention.

(8) FIG. 8 shows a third embodiment of the nozzle according to the present invention.

(9) FIG. 9 shows a fourth embodiment of the nozzle according to the present invention.

(10) FIG. 10 shows a fifth embodiment of the nozzle according to the present invention.

(11) FIG. 11 shows a sixth embodiment of the nozzle according to the present invention.

(12) FIG. 12 shows a graph comparing performance curves for an orifice valve, a valve with nozzle and a conventional venturi valve.

SUMMARY OF THE INVENTION

(13) The object of the present invention is to design a nozzle valve for gas lifting that can be used in place of conventional orifice valves.

(14) The object of this invention is achieved by building convergent nozzles fitted internally to a valve body. These nozzles, on account of their geometric arrangement, provide the valve with the desired characteristics present in orifice valves, with the advantage of providing a discharge coefficient close to one and a real critical ratio close to the theoretical critical ratio. These modified characteristics considerably reduce uncertainty when calculating the gas flow injected into the tubing and make a more efficient contribution to the dimensioning, operation and automation of the well.

(15) The build characteristics of the nozzle valve according to the present invention also provide greater resistance against erosion and, consequently, facilitate a quicker unloading of the wells.

(16) A preferred embodiment generically comprises a cylindrical block to be fitted into a valve body, with an upper circular face and a lower circular face, and, aligned with the generator of the cylindrical block, a toroidal opening that starts wide in the upper face of the cylindrical block and ends in an orifice in the lower face of the cylindrical block.

(17) The nozzle and the valve according to the present invention are not limited to use in artificial gas lifting in oil wells, this valve being able to be used in gas wells, in water-, gas- or steam-injection wells and in other applications, replacing the orifice valves originally used.

DETAILED DESCRIPTION OF THE INVENTION

(18) The detailed description of the nozzle valve for gas lifting to which the present invention relates is provided using the identification of the component parts thereof and the aforementioned figures.

(19) The present invention relates to the design of a nozzle valve for gas lifting that can be used in place of conventional orifice valves.

(20) The objective of this invention is achieved by building convergent nozzles to be fitted internally to a valve body. These nozzles, on account of their geometric arrangement, provide the valve with the desired characteristics present in orifice valves, with the advantage of providing a discharge coefficient close to one and a real critical ratio close to the theoretical critical ratio. These modified characteristics considerably reduce uncertainty when calculating the gas flow injected into the tubing and help to facilitate the dimensioning, operation and automation of the well.

(21) The relationship between the gas flow passing through the valve and the pressure differential between admission and discharge of the valve is usually referred to as the behaviour or dynamic performance of a valve. FIG. 1 shows a graph comparing a performance curve of an orifice valve (VO) with a performance curve of a venturi valve (Vv).

(22) To determine the values generating the performance curves, tests were carried out on a specific test unit for gas-lift valves using natural gas under an upstream gauge pressure of 140 bar and the diameters of the orifice and the throat of the venturi were equal.

(23) The curves on the graph show that the behaviour of the two valves is quite distinct. The venturi valve (Vv) reaches a critical flow with a pressure difference (upstream-downstream) of less than 10% of the upstream pressure.

(24) The orifice valve (VO) requires a pressure differential of between 35% and 45%, depending on the exact geometry of the valve.

(25) As mentioned above, the venturi valve (Vv) is an important solution for some operational problems, because it is a valve that provides a near-constant gas flow and almost completely eliminates, for example, the phenomenon known as casing heading, which is an oscillatory instability that occurs in certain wells that can cause major operational difficulties, and the other known means for controlling it in gas lifting can result in significant production losses in a well or significantly increase operating costs and system complexity.

(26) However, it should be remembered that, in continuous gas lifting, the method most commonly used for adjusting injection flow in operation, regardless of whether or not there is any instability, is adjustment of the annulus pressure (also known as the casing pressure). The venturi valve (Vv), unlike the orifice valve (VO), has low sensitivity to casing pressure, i.e. the gas injection flow varies very little as the casing pressure increases or decreases, considering the practical ranges of variation of this pressure. Accordingly, designers of gas-lift installations often use orifice valves (VO) to benefit from the operational flexibility that they provide and, in the event of an unstable flow, they apply a corrective measure.

(27) Calculation of the flow rate of gas passing through a gas-lift valve is essential both for the design and for the operation and automation of wells that use this artificial lifting method.

(28) The mathematical models for a venturi valve (Vv) enable real performance to be extrapolated with a reasonable degree of precision. The flow through this type of valve is very similar to reversible adiabatic flow, i.e. isentropic flow, and even when the critical flow rate is established, the flow can be considered to be isentropic until the throat of the venturi. Since there is no practical need to model the flow in the diffuser once critical flow has been established through the valve, the calculation approach considering isentropic flow to the throat is quite reasonable. The shape of the nozzle ensures that the discharge coefficient is nearly equal to one. Thus, the isentropic model provides theoretical flow rate values that are quite close to the real values, requiring only minimal calibration with experimental data.

(29) In the case of orifice valves, modelling is much more difficult, because the geometry of the valves introduces a very wide range of irreversibilities into the flow. The pressure differentials through the orifice plate are high and the diameters of the orifices and internal diameters of the valve itself are very small. The vena contracta (region of the fluid flow following passage through the orifice characterised in that the fluid flow remains contracted, having a diameter equal to or less than the diameter of the same fluid flow immediately following passage through the orifice) is difficult to model in this case. The critical ratio is also highly variable, since pressure recovery following the orifice, which still exists, although it is small, is difficult to predict.

(30) The value of this critical ratio in venturi valves does not need to be known with any great precision in terms of modelling, because it only defines the minimum pressure differential required for operation in critical flow. In other words, it defines the minimum differential that the designer of the installation has to take into account to ensure that the venturi valve operates in the desired situation, i.e. in critical flow, never in sub-critical flow. In consideration of this, modelling is then only of interest for evaluating critical flow.

(31) With orifice valves, the precise pressure recovery value needs to be known, because in the vast majority of cases operation is undertaken at sub-critical flow rates. Obtaining estimates that are not particularly representative of a real situation in terms of pressure recovery and estimates of vena contracta introduce significant errors into flow rate estimates, because only the pressures upstream and downstream of the valve as a whole are known. A comprehensive experimental evaluation is required and the discharge coefficient is significantly less than one and is very unpredictable in practical models.

(32) In consideration of the foregoing, it is clear that designers are required to choose between two extremes: a valve with near-isentropic flow and critical ratio and discharge coefficient close to one that is easy to model but provides limited operational flexibility, or a valve with practically adiabatic flow, but with a high level of irreversibility, with operational flexibility, but that is difficult to model.

(33) The present invention addresses this issue with a nozzle valve for gas lifting where the shape of this gas flow adjustment nozzle provides advantages such as: in terms of modelling, maintaining predictable dynamic behaviour; maintaining gas-flow control flexibility similar to an orifice valve; and also having a smooth geometry that induces a gradual acceleration of the fluid while increasing tolerance to erosion and other mechanical damage.

(34) Purely by way of clarification, the components of the valves illustrated in FIGS. 2, 3 and 4 and described below are referenced alphabetically as they are valves that exist in the prior art.

(35) FIG. 2 is a schematic longitudinal cross section of an orifice gas-lift valve (VO) of the prior art for use with side-pocket mandrels.

(36) The orifice valve (VO) has a body (C) with admission orifices (OA) and a recess (R) in the internal diameter of the body where an orifice plate (PR) is fitted to regulate the gas flow. The gas coming from the annulus passes through the orifices of the mandrel (not shown), enters the orifice valve (VO) through admission orifices (OA), passes through an orifice (O), through the check valve (VR) and comes out through exit orifices (OS) of the nose of the orifice valve (VO), mixing thereafter with the fluids coming from the reservoir inside a tubing (CP).

(37) The check valve (VR) shown is an internal check valve and is shown in the open position, enabling the passage of gas from the annulus towards the tubing (CP). If gas injection stops and fluids from inside the tubing (CP) start to flow in reverse, a dart (D) of the check valve (VR) is drawn until there is contact between the top of the dart (D) and the sealing seat (SV), preventing the progression of this unwanted flow.

(38) FIG. 3 is a schematic longitudinal cross section of a charged-bellows gas-lift valve belonging to and known from the prior art, also known as a pressure valve.

(39) The charged-bellows valve (VF) is similar to the orifice valve (VO), but it also has a rod (H) with a tip (Ph), which is usually spherical and made of a very hard material, that in the position shown in FIG. 3 causes the sealing of the orifice (O), preventing the flow of fluid from the annulus to the tubing and vice versa. The rod (H) is connected to a bellows (F) the internal space of which communicates with a small chamber, known as the dome (Dv) of the valve. The dome (Dv) and, consequently, the bellows (F) contain a gas, usually nitrogen, at a given pressure. Thus, the tip (Ph) of the rod (H) remains pressed against the orifice (O). As a result of the forces acting on the rod (H), forces deriving essentially from the action of the pressures of the gas in the bellows (F), of the gas in the annulus and of the fluid in the tubing (CP), the rod (H) can be kept in the position in FIG. 3, in which the charged-bellows valve (VF) is closed, or be moved such as to compress the bellows (F), enabling the passage of the gas through the orifice (O), in which case the charged-bellows valve (VF) is described as being open. When the tip (Ph) of the rod (H) is sufficiently removed from the orifice (O) that it does not obstruct the gas flow, the charged-bellows valve (VF) exhibits a dynamic behaviour similar to that of the orifice valve (VO).

(40) FIG. 4 is a schematic longitudinal cross section of a venturi gas-lift valve (Vv) of the prior art for use with side-pocket mandrels. The venturi valve (Vv) has a body (C) with admission orifices (OA) and a recess (R) in the internal diameter of the body (C) where a compact venturi or venturi nozzle (Bv) is fitted to regulate the gas flow. The venturi orifice may be divided for instructional purposes into three parts: the nozzle (B), the throat (G) and the diffuser (Di). The throat (G) is the smallest passage area open to the fluid flowing through the venturi. It may have an infinitesimal length, being merely a straight transitional section between the nozzle and the diffuser, or it may have a finite length.

(41) The check valve (VR) shown is an external check valve and is shown in the closed position. The dart (D) is held in the position shown by a spring. If a pressure differential is applied between annulus and tubing (CP) that overcomes the resistance of the spring, the dart (D) is moved to a lower position, enabling the passage of gas from the annulus to the inside of the tubing (CP). If gas injection stops and fluids from inside the tubing (CP) start to flow in reverse, the dart (D) of the check valve (VR) returns to its original position, the top of this dart (D) pressing against the sealing seat (SV), preventing this unwanted flow.

(42) FIG. 5 is a schematic longitudinal cross section of a center-body venturi gas-lift valve (VCC) from the prior art for use with side-pocket mandrels.

(43) The only difference from the venturi valve (Vv) in FIG. 4 is the replacement of the conventional venturi (V) by a center-body venturi (Vc) which is an annular venturi with a nozzle (B), a throat (G) and a diffuser (Di) that perform the same functions as the corresponding parts in the conventional venturi (V). Equally, the throat (G) can have an infinitesimal length or a finite length.

(44) Although there may be variations, in general the geometry of the central body (Cc) is such that, when comparing a conventional venturi with a central-body venturi (Vc), with the same passage area in the throat (G), the area of the annulus between the housing and the central body (Cc) in a straight section at a given distance from the throat (G) is equal to the area of the straight section of the conventional venturi (V) for the same distance from the throat (G). Thus, the area variation profile of the conventional venturi (V) is maintained as the area becomes annular.

(45) The nozzle valve (GL) for gas lifting according to the present invention has a body (1) with admission orifices (2), and, immediately below these, a slight recess (3) in the internal diameter of the body (1) where a convergent nozzle (4) is fitted to regulate the gas flow passing through the inside of the valve towards the outlet (5) of the latter.

(46) The preferred embodiments of the convergent nozzle (4), hereinafter referred to simply as the nozzle (4), are described below.

(47) In a first embodiment of the nozzle (4) according to the present invention to be fitted in a nozzle valve (GL) for gas lifting, shown in FIG. 6, it can be seen that it comprises a perforated toroidal (or torus) cylindrical block (40) with a larger opening (41) in the upper face (42) of the block (40) close to the admission orifices (2) of the valve and a smaller opening (43), or throat, in the lower face (44) of the block (40) oriented towards a check valve (VR) (45) located in the outlet (5) (or nose) of the valve.

(48) The gas coming from the annulus of the well passes through the orifices of a mandrel (not shown), enters the valve through the admission orifices (2), passes through the nozzle (4), passes through the check valve (45) and goes out through 15 the outlet (5) of the valve, mixing thereafter with the fluids coming from the reservoir inside the tubing (not shown).

(49) In a second embodiment of the nozzle (4) according to the present invention to be fitted in a nozzle valve (GL) for gas lifting, shown in FIG. 7, it can be seen that it comprises a perforated toroidal cylindrical block (40) with the larger opening (41) in the upper face (42) close to the admission orifices (2) of the valve and the smaller opening (43) with an extension provided by the addition of a small cylindrical throat (46) having the same diameter as this smaller opening (43) that terminates in the lower face (44) oriented towards a check valve (45) located in the outlet (5) (or nose) of the valve.

(50) In a third embodiment of the nozzle (4) according to the present invention to be fitted in a nozzle valve (GL) for gas lifting, shown in FIG. 8, it can be seen that it comprises a perforated cylindrical block (40) in the form of a center-body nozzle that in turn comprises an upper centring device (411), perforated with holes (412) followed by a central body (413) the diameter of which increases from the upper centring device (411) and forms an annulus (414) that gradually reduces the flow passage area from a larger opening oriented towards the gas admission orifices to a smaller opening that defines a smaller flow passage area, oriented towards the check valve (VR) (45) and towards the outlet (5) (or nose) of the valve.

(51) In a fourth embodiment of the nozzle (4) according to the present invention to be fitted in a nozzle valve (GL) for gas lifting, shown in FIG. 9, it can be seen that it comprises a perforated cylindrical block (40) in the form of a center-body nozzle that in turn comprises an upper centring device (411), perforated with holes (412) followed by a central body (413) the diameter of which increases from the upper centring device (411) and forms an annulus (414) that gradually reduces the flow passage area from a larger opening oriented towards the gas admission orifices to a smaller opening that defines a smaller flow passage area, supplemented by a small cylindrical throat (415) of finite length, that defines the smaller flow passage area, oriented towards the check valve (45) and towards the outlet (5) (or nose) of the valve.

(52) The charged-bellows nozzle valve (FC) for gas lifting according to the present invention has a body (1) with admission orifices (2), and, immediately below these admission orifices (2) there is a slight recess (3) in the internal diameter of the body (1) where a convergent nozzle (4) is fitted to regulate the gas flow passing through the inside of the valve (FC) towards the outlet of the latter and, above the admission orifices (2) a rod (6) connected to an actuating bellows (7).

(53) In a fifth embodiment of the nozzle (4) according to the present invention to be fitted in a charged-bellows nozzle valve (FC) for gas lifting, shown in FIG. 10, it can be seen that it comprises a perforated toroidal cylindrical block (40) with a larger opening (41) in the upper face (42) of the block (40) close to the admission orifices (2) of the valve and a smaller opening (43), or throat, in the lower face (44) of the block (40), inside which is actuated the rod (6) linked to the bellows (7) of the charged-bellows gas-lift valve (FC).

(54) In a sixth embodiment of the nozzle (4) according to the present invention to be fitted in a charged-bellows nozzle valve (FC) for gas lifting, shown in FIG. 11, it can be seen that it comprises a perforated toroidal cylindrical block (40) intended to replace a conventional orifice plate known in the prior art as a choke, with a larger opening (41) in the upper face (42) of the block (40) and a smaller opening (43), or throat, having a diameter that may be less than or equal to the diameter of the opening of the conventional seat of the charged-bellows gas-lift valve (FC).

(55) The present invention is flexible in application in relation to conventional gas-lift valves, and it may replace one or more components required to restrict gas flow, including by combining the embodiments described above, for example: in a charged-bellows gas-lift valve (FC), the main seat and the choke may be replaced by the nozzle in the first embodiment.

(56) The check valves (45) shown in most of the figures are external check valves, which simply represents a preferential construction. There is no reason why an internal check valve, or even both types of check valves simultaneously, cannot be used. Other types of check valves other than those shown by way of example could be used in any of the embodiments.

(57) The embodiments of nozzles (4) shown have a preferential geometric profile in cross section formed by circular arcs, but there is no reason why other known geometric forms in which the passage area is progressively reduced cannot be used. The nozzles (4) may be conical, and the arcs may be elliptical, parabolic, hyperbolic or any other curve deemed suitable for structural or other practical or operational reasons.

(58) Tests with prototypes of the first embodiment and the second embodiment were carried out in a specific test unit for gas-lift valves using natural gas at an upstream gauge pressure of 140 bar.

(59) A performance test was carried out with a gas-lift valve fitted with a conventional orifice, this orifice having a diameter of 5.2 mm. The same test was repeated for a nozzle valve (GL) for gas lifting fitted with a toroidal nozzle as in the first embodiment, in which the smaller opening had a diameter of 5.2 mm, and a conventional venturi valve (Vv) in which the throat diameter was 5.2 mm was then tested. The values obtained during the test were plotted as performance curves, as follows: a performance curve for the orifice valve (VO), a performance curve for a nozzle valve (GL) and a performance curve for a venturi valve (Vv), which are shown in the comparative graph in FIG. 12.

(60) The discharge coefficients in relation to the flow rates calculated for a natural-gas isentropic-flow model had values such as 0.85 for the orifice valve (VO), 0.94 for the nozzle valve (GL) and 0.95 for the venturi valve (Vv).

(61) In consideration of the above values, it can be concluded that, in terms of discharge coefficient, the nozzle (4) behaves identically or near-identically to the venturi (V), with a much more isentropic flow up to the throat (G) than that established in an orifice plate (PR). What distinguishes the dynamic behaviour as a whole is that in the venturi (V) there is a diffuser that provides pressure recovery. Thus, when the pressure downstream of the venturi (V) is 120 bar, for example, the pressure in the throat (G) thereof is approximately 75 bar and the flow in the throat (G) is critical (sonic). In a nozzle (4) that has no pressure recovery in sudden expansion, the pressure at the smaller opening will be nearer to 120 bar and the flow is sub-critical.

(62) For the conditions of the test mentioned above, the theoretical isentropic gas flow model suggests a theoretical critical ratio of 0.53. The test demonstrated an experimental critical ratio of 0.64 for the nozzle, 0.56 for the orifice and 0.94 for the venturi (V). This demonstrates that the nozzle (4), even without a diffuser, provides greater pressure recovery downstream of the throat (G) than the orifice (O) (11% compared with 3% for the orifice). To adjust the critical ratio to bring it closer to the theoretical value, a cylindrical throat (G) of finite length may be used. Experiments carried out under the same conditions as the above test with a nozzle (4) fitted with a cylindrical throat (G) of a given length demonstrated the same discharge coefficient and a critical ratio equal to the theoretical ratio, which in this case is 0.53. Shorter lengths may be used to adjust the critical ratio to an intermediate value between the theoretical value and the value obtained with the nozzle (4) only without the finite-length throat (G). Greater lengths may be used to obtain a critical ratio lower than the theoretical ratio, increasing the size of the sub-critical region in the performance curve.

(63) Although the present invention has been described in its preferred embodiment, the principal concept that orients the present invention, which is a nozzle valve (GL) for gas lifting such that this valve can replace conventional orifice valves by building and coupling to the body of the latter convergent nozzles that, on account of their geometric shape, retain the existing desirable characteristics of orifice valves, with the advantage of providing a discharge coefficient close to one and a real critical ratio close to the theoretical critical ratio, retains its innovative nature, to which a person normally skilled in the art could conceive of and implement variations, modifications, alterations, adaptations and similar that are suitable and compatible with the working medium in question, without thereby moving outside the spirit and scope of the present invention, which are set out in the claims below.