Venturi pump-controlled discharge valve for gas lifting system.

Description

1 / 12 Venturi pump-controlled discharge valve for gas lifting system. FIELD OF THE INVENTION

[0001] This invention relates generally to the field of oil and gas production and, more particularly, to a gas lift system incorporating an optimized discharge valve. BACKGROUND

[0002] Gas lift is a technique in which pressurized gaseous fluids are injected into the production tubing string from the surrounding annular space to reduce the density of the produced fluids, allowing formation pressure to push the less dense mixture to the surface. The gaseous fluids can be injected into the annular space from the surface. A series of gas lift valves allows access from the annular space into the production tubing. The gas lift valves can be configured to open automatically when the pressure gradient between the annulus and the production tubing exceeds the closing force that keeps each gas lift valve in a closed position.

[0003] In most installations, gas lift valves are contained within side-chambered mandrels which provide a laterally offset valve compartment that secures the gas lift valve while providing access to lower components in the equipment string. Each of the gas lift mandrels within the gas lift system may be deployed above a plug or other zone isolation device to ensure that liquids and fluids from an oil well do not interfere with the operation of the gas lift valve. Side-chambered mandrels may include discharge valves designed to evacuate annular liquids or operating valves that conduct pressurized gas into the pipe string.

[0004] Before standard operating valves can be used to recover petroleum fluids from the well, it may be necessary to use a series of Petition 870250092232, dated 09 / 10 / 2025, page 12 / 72 2 / 12 Discharge valves are used to remove completion or oil well fluids from the annular space to expose the gas lift operating valves. Discharge valves are particularly useful in installations where the gas lift compressor is unable to supply sufficient gas pressures or volumes to actuate the operating valves located at the bottom of the well. Since the discharge valves are no longer submerged within a column of fluid in the annular space, the discharge valves are designed to close so that the injected gas is forced deeper into the well towards the operating valves. By sequentially actuating a series of discharge valves in the upper portions of the well, the compressor can then apply sufficient pressure to the remaining fluid column in the annular space to actuate the operating valves.

[0005] Conventional discharge valves are sometimes called injection operating pressure or IPO (injection operating pressure) valves. These IPO valves include an internal valve mechanism in which a compressible bellows filled with nitrogen presses a valve element against a valve seat within the discharge valve. As the bellows compresses under pressure from the annular space, the valve element lifts the valve seat to allow the flow of annular fluids through the discharge valve. While generally effective, bellows mechanisms are reliable only under a limited range of pressures. Increasingly, there is a need for a discharge valve that can operate under pressures exceeding the limits of conventional bellows-based discharge valves. The present disclosure is directed to these and other deficiencies in the prior art. SUMMARY OF THE INVENTION

[0006] In one aspect, the embodiments disclosed in this document include a discharge valve for use in evacuating fluids from an annular space of an oil well. The discharge valve may include a valve body, an inlet to the valve body, a valve body discharge, and an induced differential pressure valve control system. Petition 870250092232, dated 09 / 10 / 2025, page 13 / 72 3 / 12 configured to automatically shut off the inflow to the valve body in response to a change in the density of fluids passing through the discharge valve.

[0007] In another aspect, the present disclosure is directed to a discharge valve for use in evacuating fluids from an annular space of an oil well, wherein the discharge valve includes a valve body, an inlet to the valve body, a discharge from the valve body, and an induced differential pressure valve control system configured to automatically close the inflow to the valve body in response to a change in the density of fluids passing through the discharge valve. In these embodiments, the induced differential pressure valve control system includes a flow sleeve, a valve element, an extraction tube, and a bypass spring. The flow sleeve includes an inlet adjacent to the inflow, an outlet adjacent to the discharge, and a flow constriction in the flow sleeve that produces a pressure differential (ΔP) as fluids pass through the flow sleeve.The valve element is configured to move from an open position to a closed position, blocking the inlet. The extraction tube communicates the pressure differential (ΔP) to the valve element. The deflection spring is attached to the first end of the valve element and configured to push the valve element to the closed position against a force resulting from the pressure differential (ΔP). BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a side view of a gas lift system installed in a conventional well.

[0009] Figure 2 is a side view of a mandrel with a side chamber constructed according to an embodiment of the invention.

[0010] Figure 3 is a side cross-sectional view of the mandrel with side chamber of Figure 2 with a venturi pump-controlled discharge valve.

[0011] Figure 4 is a cross-sectional view of the discharge valve of Figure 3 in a first state. Petition 870250092232, dated 09 / 10 / 2025, page 14 / 72 4 / 12

[0012] Figure 5 is a cross-sectional view of the discharge valve in a second state.

[0013] Figure 6 is a cross-sectional view of the discharge valve in a third state.

[0014] Figure 7 is a cross-sectional view of the discharge valve in a fourth state.

[0015] Figure 8 is a cross-sectional view of the discharge valve with a reciprocating valve element. WRITTEN DESCRIPTION

[0016] As used in this document, the term petroleum refers broadly to all mineral hydrocarbons, such as crude oil, gas, and oil-gas combinations. The term fluid refers generically to gases and liquids, and two-phase or multiphase refers to a fluid that includes a mixture of gases and liquids. Upstream and downstream can be used as positional references based on the movement of a fluid flow from an upstream position in the well to a downstream position at the surface. Although embodiments of the present invention can be described in connection with a conventional well that is substantially vertically oriented, it will be recognized that the embodiments may also find utility in horizontal, deviated, or unconventional wells.

[0017] With respect to Figure 1, a gas lift system 100 is shown in a well 102. Well 102 includes a casing 104 and a series of boreholes 106 that admit oil well fluids from a production geological formation 108 through the casing 104 into the well 102. An annular space or circular crown 110 is formed between the gas lift system 100 and the casing 104. The gas lift system 100 is connected to the tubing 112 (also called the production tubing) which carries oil well fluids from the formation 108, through the gas lift system 100, to the wellhead 114 at the surface. Petition 870250092232, dated 09 / 10 / 2025, page 15 / 72 5 / 12

[0018] The gas lift system 100 includes one or more gas lift modules 116 (four are shown in Figure 1). The gas lift modules 116 each include a side-chambered mandrel 118, which can be connected to a short pipe 120. An inlet pipe 122 extends through one or more packers 124 into a lower wellbore zone 102 nearest to the boreholes 106. In this way, the produced fluids are transported through the inlet pipe 122 to the lower (upstream) gas lift module 116. The produced fluids are transported through the gas lift system 100 and the production pipe 112, which carries the produced fluids through the wellhead 114 to surface storage or processing facilities.

[0019] The gas lift modules 116 may include an operating valve 126 or a discharge valve 128. In the illustrative embodiment shown in Figure 1, each of the upper gas lift modules 116a includes a discharge valve 128 and each of the lower gas lift modules 116b includes an operating valve 126. It will be recognized that the gas lift system 100 may include fewer or more gas lift modules 116, with each gas lift module 116 including an operating valve 126, a discharge valve 128 or a combination of operating and discharge valves 126, 128.

[0020] The upper gas lift modules 116a are well positioned to discharge fluid into the annular space 110 above the lower gas lift modules 116b to allow efficient operation of the operating valves 126. According to well-established gas lift principles, pressurized fluids or gases are injected from the surface into the annular space 110 surrounding the gas lift system 100. During an initial discharge stage, the pressure applied from the surface forces the annular fluid through the open discharge valves 128 in the upper gas lift modules 116a to evacuate excess fluid into the annular space 110. Petition 870250092232, dated 09 / 10 / 2025, page 16 / 72 6 / 12

[0021] Once a sufficient volume of fluid in the annular space 110 has been removed and the discharge valves 128 have returned to a closed state, the lower gas lift modules 116b can be actuated by modulating the pressure gradient between the annular space 110 (Pa) and the pipe string 112 (Pt) to open the operating valves 126 to admit pressurized gases into the pipe string 112 through the side-chamber mandrels 118 of the lower gas lift modules 116b. The pressurized gases combine with the fluids produced in the gas lift modules 116 to reduce the total fluid density, which facilitates the recovery of the produced fluids from the well 102. The gas lift system 100 can be useful in recovering liquid and multiphase hydrocarbons, as well as recovering brine and other water-based fluids from the well 102.

[0022] With reference to Figures 2 and 3, side and cross-sectional views of the gas lift module 116 with a discharge valve 128 are shown. As best illustrated in the cross-sectional view in Figure 3, the side-chambered mandrel 118 includes a central body 130 and a valve compartment 132 within the side-chambered mandrel 118. The central body 130 includes a central hole 134. The valve compartment 132 is offset laterally and partially separated from the central hole 134. The discharge valve 128 is reversibly retained by a locking mechanism 136 within the valve seat 132. In some embodiments, the discharge valve 128 can be installed and reversed using a wire rope-supported kickover tool. The 128 discharge valve is designed to allow the efficient evacuation of denser liquids and multiphase fluids through the upper gas lift module 116b.

[0023] With reference to Figure 4, a simplified cross-sectional view of the discharge valve 128 is shown. The discharge valve 128 includes a discharge valve body 138, a central channel 140 within the valve body 138, an induced differential pressure valve control system 142, an inlet 144, and a discharge 146. The inlet 144 extends through the valve body 138 and is aligned with an external port. Petition 870250092232, dated 09 / 10 / 2025, p. 17 / 72 7 / 12 148 in the mandrel with side chamber 118 (shown in Figures 2 and 3) to place the discharge valve 128 in fluid communication with the annular space 110.

[0024] The induced differential pressure valve control system 142 includes a flow sleeve 150 within the central channel 140, a valve element 152, a diverter spring 154, and an extraction tube 156. The flow sleeve 150 includes a first end 158, a second end 160, an internal section 162 between the first end 158 and the second end 160, an inlet 164, an outlet 166, and a flow constriction 168. In the embodiment shown in Figure 4, the inlet 164 for the flow sleeve 150 is adjacent to the inlet 144 of the discharge valve 128. The flow sleeve 150 may be integrated into the central channel 140 or presented as a separate component that is fixed by welding or other means within the central channel 140.

[0025] In some embodiments, the valve element 152 is a substantially cylindrical piston with a first end 176 and a second end 178. The valve element 152 may include seals 170 that provide a tight clearance within the flow sleeve 150, while allowing the valve element 152 to reciprocate within the inner portion 162 of the flow sleeve 150. The first end 176 of the valve element 152 is attached to the deflection spring 154, which in turn is captured near the first end 158 of the flow sleeve 150. The deflection spring 154 is sized and configured to exert a spring force against the valve element 152 to impel the valve element 152 into an occluded position relative to the inlet 144 and inlet 164 to prevent fluid from entering the discharge valve 128 (as depicted in Figure 7).

[0026] The valve element 152 can be held in an initial installation position by a releasable locking pin or shear pin 172. When the pin 172 is sheared, released or removed, the valve element 152 is allowed to move in an alternate linear manner within the flow sleeve 150. Petition 870250092232, dated 09 / 10 / 2025, page 18 / 72 8 / 12

[0027] The flow constriction 168 has a smaller cross-sectional area than the adjacent portions of the flow sleeve 150. The flow constriction 168 thus forms a throat within the flow sleeve 150. When the fluid passes into the flow sleeve 150, the fluid has an inlet pressure (Po) at the inlet 164. As the fluid accelerates through the flow constriction 168, the pressure decreases according to the principles of conservation of energy, which are sometimes called the venturi effect. The flow constriction 168 therefore produces a reduced constriction pressure (Pi) which is lower than the initial pressure (Po). The pressure differential (P0-P1 or ΔP) increases with the fluid density and flow rate through the discharge valve 128.

[0028] The constriction pressure (Pi) within the flow constriction 168 is communicated to the extraction tube 156 through a suction communication port 174. The extraction tube 156 is displaced laterally from the flow sleeve 150 and extends from the flow constriction 168 to the first end 158 of the flow sleeve 150. The extraction tube 156 thus communicates the constriction pressure (Pi) from the flow constriction 168 to the first end 158 of the flow sleeve 150 and the first lateral end of the valve element 152. As illustrated in Figure 4, the second end 178 of the valve element 152 is exposed to the inlet pressure (Po). This creates a pressure differential (ΔP) across the valve element 152 between the higher inlet pressure (Po) and the lower constriction pressure (Pi) with a resulting force varying based in part on the density of the fluid passing through the flow constriction 168.The pressure differential (ΔP) generally decreases with a corresponding decrease in the density of the fluid passing through the discharge valve 128. Thus, as the well 102 is discharged and the denser liquids passing through the discharge valve 128 are replaced by lighter gases, the pressure differential (ΔP) created by the flow constriction and applied to the valve element 152 decreases until it is overcome by the closing force applied by the diverting spring 154.

[0029] The diverting spring 154 can be calibrated to push the valve element 152 into a closed state when the pressure differential (ΔP) Petition 870250092232, dated 09 / 10 / 2025, page 19 / 72 9 / 12 created by fluids passing through the discharge valve 128 falls below a closing pressure differential (ΔP1) at which the closing force applied by the diverting spring 154 exceeds the closing pressure differential (ΔP1). Until the closing pressure differential (ΔP1) is reached, the force applied by the diverting spring 154 must be insufficient to overcome a discharge pressure differential (ΔP1) generated by the evacuation of liquids through the discharge valve 128 that exceeds the limit densities and flow rates. As explained above, the discharge pressure differential (ΔP1) will decrease as the well 102 is discharged because the denser liquids initially present in the annular space 110 are gradually replaced by lighter gases injected from the surface.

[0030] In Figure 4, the valve element 152 is held in the open state by the shear pin 172. When the discharge operation begins, the pressurized gases injected into the annular space 110 force the dense fluids in the annular space 110 to enter the discharge valve 128 through the outer port 148. The flow of dense fluids through the discharge valve 128 produces a significant initial pressure differential (ΔPο) across the valve element 152 which pulls the valve element 152 towards the first end 158 against the force exerted by the deflection spring 154. The movement of the valve element 152 breaks or releases the shear pin 172 to allow the valve element 152 to subsequently reciprocate in the flow sleeve 150.

[0031] As represented in Figure 5, the continuous flow of dense fluids through the discharge valve 128 and the resulting pressure differential (ΔPο) applied to the valve element 152 keeps the valve element 152 in the open state to allow the passage of fluids from the annular space 110 to the tube column 112 through the discharge valve 128. The fluids are discharged from the discharge valve 128 to the tube column 112 through the side chamber mandrel 118.

[0032] As well 102 is discharged, the fluid passing through discharge valve 128 transitions from primarily liquid Petition 870250092232, dated 09 / 10 / 2025, p. 20 / 72 10 / 12 for a multiphase fluid characterized by a mixture of gases and liquids. As the fluid density inside the discharge valve 128 decreases, the pressure differential (ΔP) applied to the valve element 152 also decreases, which allows the diverting spring 154 to propel the valve element 152 upwards towards the inner portion 162 of the flow sleeve 150. Figure 6 depicts the movement of the valve element 152 to a partially closed state in which the valve element 152 partially obstructs the inlet 164.

[0033] As the flow through the discharge valve 128 continues to transition to lighter, less dense gases injected from the surface, the pressure differential (ΔP) applied to the valve element 152 continues to decrease until it falls below the closing pressure differential (ΔPι) and is overcome by the force applied by the diverting spring 154 to the valve element 152. When the fluid passing through the discharge valve 128 produces a pressure differential that falls below the closing pressure differential (ΔPι), the diverting spring 154 forces the valve element 152 into a closed state in which the valve element 152 blocks the inlet 164 to prevent the passage of fluids to the discharge valve 128.

[0034] Thus, unlike prior art discharge valves which rely on a nitrogen-filled bellows to control the displacement of the internal valve element, the induced pressure differential valve control system 142 controls the passage of fluids through the discharge valve 128 in response to a variable pressure differential (ΔP) created by the passage of fluids from the annular space 110 through the flow constriction 168.

[0035] Once the closing pressure differential (ΔP-ι) has been reached, the diverting spring 154 will hold the valve element 152 in the closed position to prevent gases from entering the discharge valve 128. This allows the gases injected into the annular space 110 to reach the discharge valves 128 and the operating valves 126 located deeper in the well 102. Once the well 102 has been sufficiently Petition 870250092232, dated 09 / 10 / 2025, page 21 / 72 11 / 12 discharged, the injected gases can be admitted into the pipe column 112 through the operating valves 126 to assist in the recovery of petroleum products in accordance with established gas lift recovery techniques.

[0036] Returning to Figure 8, an alternative embodiment is shown in which the valve element 152 includes a bypass channel 180. The bypass channel 180 allows a portion of fluid to bypass the valve element 152 when it is in the closed state. This can be useful for reopening the discharge valve 128 in the event that the valve element 152 is placed in the closed position by a transient gas event, or if the annular space 110 is replenished with denser liquids or multiphase fluids. If sufficiently dense fluids enter the flow sleeve 150 through the bypass channel 180, the fluids will produce a pressure differential (ΔP) that can retract the valve element 152 against the force applied by the bypass spring 154 to return the discharge valve 128 back to an open state.

[0037] The induced differential pressure valve control system 142 of the discharge valve 128 represents a significant and important development that overcomes many of the shortcomings of standard opening valves that rely on nitrogen-filled bellows. In particular, because the induced differential pressure valve control system 142 automatically closes the discharge valve 128 in response to a change in the density of fluids passing through the discharge valve 128, the discharge valve 128 can be easily calibrated to close automatically after the successful evacuation of denser fluids in the annular space 110 near the applicable gas lift module 116.

[0038] It should be understood that, although numerous features and advantages of various embodiments of the present invention have been set forth in the preceding description, together with details of the structure and functions of various embodiments of the invention, this disclosure is illustrative only and changes may be made to certain details, especially regarding the structure and arrangement of parts, which are within the principles Petition 870250092232, dated 09 / 10 / 2025, page 22 / 72 12 / 12 of the present invention, to the extent indicated by the broad general meaning of the terms in which the appended claims are expressed. It will be recognized by those skilled in the art that the teachings of the present invention can be applied to other systems without departing from the scope and spirit of the present invention. Petition 870250092232, dated 09 / 10 / 2025, page 23 / 72

Claims

1 / 4 CLAIMS 1. Discharge valve for use in evacuating fluids from an annular space of an oil well, the discharge valve being characterized by comprising: a valve body; an inlet to the valve body; a discharge from the valve body; and an induced differential pressure valve control system configured to automatically close the inlet to the valve body in response to a change in the density of fluids passing through the discharge valve, the induced differential pressure valve control system comprising: a flow sleeve; a valve element configured for linearly reciprocating motion within the flow sleeve between an open and a closed position, wherein the valve element is substantially cylindrical with first and second ends; a flow constriction in the flow sleeve that produces a pressure differential (ΔP) as fluids pass through the flow sleeve;an extraction tube that communicates the pressure differential (ΔP) to the valve element; and a pin that secures the valve element in an initially open position.

2. Discharge valve, according to claim 1, characterized in that the diverter spring is configured to move the valve element to the closed position when the differential pressure (ΔP) across the valve element reaches a value lower than a closing differential pressure (ΔPι).

3. Discharge valve, according to claim 1, characterized in that the diverter spring is configured to hold the valve element in the open position when the differential pressure (ΔP) across the valve element exceeds a closing differential pressure (ΔPι).

4. Discharge valve for use in evacuating fluids from an annular space of an oil well, the discharge valve being characterized by comprising: a valve body; an inlet to the valve body; a discharge from the valve body; and an induced differential pressure valve control system configured to automatically close the inlet to the valve body in response to a change in the density of fluids passing through the discharge valve, the induced differential pressure valve control system comprising: a flow sleeve comprising: an inlet adjacent to the inflow; an outlet adjacent to the discharge; and a flow constriction in the flow sleeve that produces a pressure differential (ΔP) as fluids pass through the flow sleeve; a valve element configured to move from an open position to a closed position blocking the inlet;an extraction tube that communicates the pressure differential (ΔP) to the valve element; and a deflection spring fixed to the first end of the valve element and configured to push the valve element to the closed position against a resultant force of the pressure differential (ΔP); and a pin that secures the valve element in an initial open position.

5. Discharge valve, according to claim 4, characterized in that the diverting spring is configured to move the valve element to the closed position when the differential pressure (ΔP) across the valve element reaches a value lower than a closing differential pressure (ΔPι).

6. Discharge valve, according to claim 4, characterized in that the diverter spring is configured to maintain the valve element in the open position when the differential pressure (ΔP) across the valve element exceeds a closing differential pressure (ΔPι).

7. Discharge valve for use in evacuating fluids from an annular space of an oil well, the discharge valve being characterized by comprising: a valve body; an inlet to the valve body; a discharge from the valve body; and an induced differential pressure valve control system configured to automatically close the inlet to the valve body in response to a change in the density of fluids passing through the discharge valve, the induced differential pressure valve control system comprising: a flow sleeve; a valve element configured for linearly reciprocating motion within the flow sleeve between an open and a closed position, wherein the valve element is substantially cylindrical with first and second ends and wherein the valve element comprises a bypass channel;a flow constriction in the flow sleeve that produces a pressure differential (ΔP) as fluids pass through the flow sleeve; an extraction tube that communicates the pressure differential (ΔP) to the valve element; 8. Discharge valve for use in evacuating fluids from an annular space of an oil well, the discharge valve being characterized by comprising: a valve body; Petition 870250092805, dated 10 / 10 / 2025, page 11 / 12 4 / 4 an inlet to the valve body; a discharge from the valve body; and an induced differential pressure valve control system configured to automatically close the inlet to the valve body in response to a change in the density of fluids passing through the discharge valve, the induced differential pressure valve control system comprising: a flow sleeve comprising: an inlet adjacent to the inflow; an outlet adjacent to the discharge; and a flow constriction in the flow sleeve that produces a pressure differential (ΔP) as fluids pass through the flow sleeve;A valve element configured to move from an open position to a closed position blocking the inlet, wherein the valve element comprises a bypass channel; an extraction tube that communicates the pressure differential (ΔP) to the valve element; a bypass spring fixed to the first end of the valve element and configured to impel the valve element to the closed position against a resultant force of the pressure differential (ΔP). Petition 870250092805, dated 10 / 10 / 2025, page 12 / 12;

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