A downhole gas injection safety valve

Abstract

The application discloses a downhole gas injection safety valve, which comprises a valve shell, a sliding sleeve switch mechanism, a metal valve disc switch mechanism, a reset mechanism and a control mechanism. The sliding sleeve switch mechanism comprises an inner sliding sleeve and an outer sliding sleeve. The inner sliding sleeve is arranged in the outer sliding sleeve. The outer sliding sleeve is provided with an outer fluid passage. The inner sliding sleeve is provided with an inner fluid passage which is matched with the outer fluid passage. The inner fluid passage and the outer fluid passage respectively have an open position and a closed position. One end of the outer sliding sleeve is connected with the valve shell. The metal valve disc switch mechanism is installed at the other end of the valve shell and is connected with the sliding sleeve switch mechanism through a valve push cylinder. The valve push cylinder is located in the valve shell. The metal valve disc switch mechanism respectively has a valve disc open position and a valve disc closed position and is synchronously opened or closed with the sliding sleeve switch mechanism. The reset mechanism is arranged in the valve shell and corresponds to the metal valve disc switch mechanism. The control mechanism is connected with the sliding sleeve switch mechanism and is connected with a ground control panel through a hydraulic control pipeline.

Description

TECHNICAL FIELD

[0001] The present application relates to oil drilling equipment, in particular to a downhole gas injection safety valve for a well completion tool. BACKGROUND

[0002] Gas lift oil production has the advantages of wide range of production regulation and simple operation, and is suitable for high gas-oil ratio wells, directional wells and wells with corrosive media in the well fluid. In conventional gas lift production, multiple gas injection valves are connected in the pipe string, and then gas is injected from the casing annulus, and the gas is injected into the tubing from the gas injection valve, thereby reducing the fluid density and viscosity, and realizing artificial lift by gas injection.

[0003] In the prior art gas lift equipment, there is no packer at the upper end of the gas injection valve pipe string, and there is a gas injection well control problem on the gas injection pipe string, which increases the well control risk. The passage of the conventional cable through the packer gas valve is small, and it is difficult to meet the requirement of gas injection amount, and at the same time, the conventional gas valve does not have good gas sealing effect. Therefore, the conventional cable through the packer and the gas valve cannot meet the requirements of gas injection well control and large displacement gas injection. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a downhole gas injection safety valve to solve the above-mentioned defects of the prior art.

[0005] In order to achieve the above-mentioned purpose, the present application provides a downhole gas injection safety valve, which is installed on a packer and connected with a tubing, and comprises:

[0006] a valve housing;

[0007] a sliding sleeve switch mechanism, comprising an inner sliding sleeve and an outer sliding sleeve, the inner sliding sleeve being arranged in the outer sliding sleeve, the outer sliding sleeve being provided with an outer fluid passage, the inner sliding sleeve being provided with an inner fluid passage matched with the outer fluid passage, the inner fluid passage and the outer fluid passage respectively having an open position and a closed position, and one end of the outer sliding sleeve being connected with the valve housing;

[0008] a metal valve disc switch mechanism, which is installed at the other end of the valve housing and connected with the sliding sleeve switch mechanism through a valve push cylinder, the valve push cylinder being located in the valve housing, the metal valve disc switch mechanism respectively having a valve disc open position and a valve disc closed position, and being synchronously opened or closed with the sliding sleeve switch mechanism;

[0009] a reset mechanism, which is arranged in the valve housing corresponding to the metal valve disc switch mechanism; and

[0010] a control mechanism, which is connected with the sliding sleeve switch mechanism and connected with a ground control panel through a hydraulic control pipeline.

[0011] The downhole gas injection safety valve, wherein the control mechanism comprises:

[0012] An upper joint connected to the top end of the outer sleeve;

[0013] A pipeline joint mounted on the upper joint, and the other end of the pipeline joint is connected to the hydraulic control pipeline; and

[0014] A piston rod mounted in the upper joint, one end of the piston rod is arranged in the hydraulic passage in the upper joint, and the piston rod is pushed by the increased hydraulic pressure, and the other end of the piston rod is connected to the inner sleeve.

[0015] The downhole gas injection safety valve, wherein the other end of the piston rod is connected to the inner sleeve through a connecting cover.

[0016] The downhole gas injection safety valve, wherein the metal valve flap switching mechanism comprises:

[0017] A valve seat mounted at the bottom end of the valve housing;

[0018] A self-balancing valve mounted at the bottom of the valve seat and corresponding to the opening and closing positions of the sleeve switching mechanism to open and close respectively;

[0019] A valve flap corresponding to the self-balancing valve mounted at the bottom end of the valve seat, the valve flap has a valve opening position and a valve closing position relative to the valve seat, and the valve opening position and the valve closing position are synchronized with the opening and closing of the self-balancing valve respectively; and

[0020] A reset member corresponding to the valve flap for resetting the valve flap.

[0021] The downhole gas injection safety valve, wherein the reset member is a leaf spring, one end of the leaf spring is mounted on the valve seat, and the other end of the leaf spring abuts against the fixed end of the valve flap.

[0022] The downhole gas injection safety valve, wherein the metal valve flap switching mechanism further comprises:

[0023] A lower joint connected to the bottom end of the valve housing, and the valve seat, the leaf spring, the self-balancing valve and the valve flap are all located in the cavity of the lower joint.

[0024] The downhole gas injection safety valve, wherein when the valve flap is in the valve closing position, the valve flap and the valve seat are in metal-to-metal sealing.

[0025] The aforementioned downhole gas injection safety valve includes a reset mechanism comprising an upper spring seat, a reset spring, and a lower spring seat. The upper spring seat is fitted outside the valve push cylinder and abuts against the bottom end of the outer sliding sleeve. The lower spring seat is fitted outside the valve push cylinder and abuts against the protrusion on the valve housing. The two ends of the reset spring abut against the upper spring seat and the lower spring seat, respectively.

[0026] In the aforementioned downhole gas injection safety valve, an upper sealing element and a lower sealing element are respectively provided between the outer sliding sleeve and the inner sliding sleeve.

[0027] The aforementioned downhole gas injection safety valve includes a protective cap at the top of the upper connector, and a pipeline crossing connector is provided on the protective cap.

[0028] The technical advantages of this invention are as follows:

[0029] The downhole gas injection safety valve of this invention is applicable to completions in conventional oil and gas reservoirs as well as high-pressure oil and gas reservoirs. This downhole gas injection safety valve, combined with a production packer and installed at the upper end of the injection tubing, can better achieve high-dose gas injection and controlled wellbore function with a controlled gas ring. The downhole gas injection safety valve adopts a combination of a sliding sleeve and a metal-to-metal sealing structure, preventing end-face flow throttling during the gas injection process and avoiding increased injection friction. After closing the injection valve, an effective seal is formed, ensuring airtightness and no leakage, reducing well control risks in gas lift wells. Furthermore, it has a simple and compact structure, is easy to operate, and is safe to use.

[0030] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of a structure according to an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the downhole gas injection safety valve in the closed state according to an embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of the open state of a downhole gas injection safety valve according to an embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram showing the installation position of the gas injection safety valve on the packer according to an embodiment of the present invention;

[0035] Figure 5 This is a schematic diagram illustrating the working principle of an embodiment of the present invention.

[0036] Among them, the attached reference numerals

[0037] 100 well downhole gas injection safety valve

[0038] 1. Pipeline crossing joint

[0039] 2 protective caps

[0040] 3 pipe joints

[0041] 4 piston rods

[0042] 5 Connector

[0043] 6 Connecting Covers

[0044] 7 Inner Sliding Sleeve

[0045] 8 outer sliding sleeve

[0046] 9. Upper seal

[0047] 10 Lower Seals

[0048] 11 Valve Push Cylinder

[0049] 12 upper spring seat

[0050] 13 Valve Housing

[0051] 14 return springs

[0052] 15 lower spring seat

[0053] 16 valve seats

[0054] 17 Reset Components

[0055] 18 Self-balancing valve

[0056] 19 valve discs

[0057] 20 lower connector

[0058] 21 Hydraulic control lines

[0059] 22 oil pipes

[0060] 23 packers

[0061] 24 sleeves Detailed Implementation

[0062] The structural and working principles of the present invention will be described in detail below with reference to the accompanying drawings:

[0063] See Figure 1 , Figure 1Figure 1 is a structural schematic diagram of an embodiment of the present application. The downhole gas injection safety valve 100 of the present application is installed on a packer 23 and connected with a tubing 22, the packer 23 is installed in a casing 24, the downhole gas injection safety valve 100 comprises: a valve housing 13; a sliding sleeve switch mechanism, comprising an inner sliding sleeve 7 and an outer sliding sleeve 8 which are adapted to each other, the inner sliding sleeve 7 is arranged in the outer sliding sleeve 8, the outer sliding sleeve 8 is provided with an outer fluid passage B, the inner sliding sleeve 7 is provided with an inner fluid passage A which is adapted to the outer fluid passage B, the inner fluid passage A and the outer fluid passage B have an open position and a closed position respectively; one end of the outer sliding sleeve 8 is connected with the valve housing 13, the outer sliding sleeve 8 and the inner sliding sleeve 7 are respectively provided with an upper sealing element 9 and a lower sealing element 10; a metal valve disc 19 switch mechanism is installed at the other end of the valve housing 13 and connected with the sliding sleeve switch mechanism through a valve push cylinder 11, the valve push cylinder 11 is located in the valve housing 13, the metal valve disc 19 switch mechanism has a valve disc 19 open position and a valve disc 19 closed position respectively and is synchronously opened or closed with the sliding sleeve switch mechanism; a reset mechanism is arranged in the valve housing 13 corresponding to the metal valve disc 19 switch mechanism; and a control mechanism is connected with the sliding sleeve switch mechanism and connected with a surface control panel through a hydraulic control pipeline 21.

[0064] In the embodiment, the control mechanism comprises: an upper joint 5 connected with the top end of the outer sliding sleeve 8, the upper joint 5 can be further provided with a protective cap 2 at the top end, the protective cap 2 is provided with a pipeline through joint 1; a pipeline joint 3 is installed at one end of the upper joint 5, the other end of the pipeline joint 3 is connected with the hydraulic control pipeline 21; and a piston rod 4 is installed in the upper joint 5, one end of the piston rod 4 is arranged in a hydraulic passage in the upper joint 5, the other end of the piston rod 4 is connected with the inner sliding sleeve 7. Preferably, the other end of the piston rod 4 is connected with the inner sliding sleeve 7 through a connecting cover 6.

[0065] The metal valve disc 19 switch mechanism of the embodiment comprises a valve seat 16 installed at the bottom end of the valve housing 13, a self-balancing valve 18 installed at the bottom of the valve seat 16 and corresponding to the open position and the closed position of the sliding sleeve switch mechanism to open and close respectively, a valve disc 19 corresponding to the self-balancing valve 18 installed at the bottom end of the valve seat 16, the valve disc 19 having a valve open position and a valve closed position relative to the valve seat 16, the valve open position and the valve closed position being synchronous with the opening and the closing of the self-balancing valve 18 respectively, and a reset member 17 corresponding to the valve disc 19 and used for resetting the valve disc 19. The reset member 17 is preferably a leaf spring, one end of the leaf spring is installed on the valve seat 16, and the other end of the leaf spring abuts against the fixed end of the valve disc 19. The metal valve disc 19 switch mechanism can further comprise a lower connector 20 connected with the bottom end of the valve housing 13, and the valve seat 16, the leaf spring, the self-balancing valve 18 and the valve disc 19 are all located in the cavity of the lower connector 20. When the valve disc 19 is located at the valve closed position, the valve disc 19 and the valve seat 16 are in metal-to-metal sealing.

[0066] The reset mechanism comprises an upper spring seat 12, a reset spring 14 and a lower spring seat 15. The upper spring seat 12 is sleeved on the valve push cylinder 11 and abuts against the bottom end of the outer sliding sleeve 8, the lower spring seat 15 is sleeved on the valve push cylinder 11 and abuts against the boss of the valve housing 13, and the two ends of the reset spring 14 abut against the upper spring seat 12 and the lower spring seat 15 respectively.

[0067] Referring to Figure 2 , Figure 2 Fig. 1 is a schematic view of the closed state of the downhole gas injection safety valve 100 according to an embodiment of the present application. The inner fluid passage A on the inner sliding sleeve 7 and the outer fluid passage B on the outer sliding sleeve 8 are not communicated with each other, the passage C of the self-balancing valve 18 is not opened, and the passage D of the valve disc 19 is not opened.

[0068] Referring to Figure 3 , Figure 3 Fig. 2 is a schematic view of the open state of the downhole gas injection safety valve 100 according to an embodiment of the present application. The passage C of the self-balancing valve 18 is opened, the inner fluid passage A on the inner sliding sleeve 7 and the outer fluid passage B on the outer sliding sleeve 8 are communicated with each other, the passage D of the valve disc 19 is opened, and the fluid passes through the passage D of the valve disc 19 and the inner fluid passage A / outer fluid passage B to flow out of the wellbore.

[0069] Referring to Figure 4 , Figure 4Figure 1 is a schematic diagram of the installation position of the gas injection safety valve according to an embodiment of the present application. The downhole gas injection safety valve 100 according to the present application is installed on the packer 23, connected with the tubing 22, and connected to the surface control panel through the hydraulic control line 21, which is connected with the top line joint 3 of the gas injection safety valve, and then lowered to the predetermined depth in the well, and the packer 23 is set, and the downhole gas injection safety valve 100 is in the closed state, and the seal between the valve disc 19 and the valve seat 16 is a metal-to-metal seal.

[0070] Referring to Figure 5 , Figure 5 Figure 2 is a schematic diagram of the working principle of the gas injection safety valve according to an embodiment of the present application. When gas injection is needed, the hydraulic control line 21 on the surface can be pressurized, the piston rod 4 pushes the connecting cover 6 and pushes the inner sleeve 7 and the valve push cylinder 11. At the beginning of the action, the valve push cylinder 11 will first open the self-balancing valve 18 to balance the pressure inside the gas injection safety valve and the lower end of the valve disc 19. The piston rod 4 continues to push, and through the force transmission, the valve disc 19 is finally opened, and the valve push cylinder 11 is pushed to the bottom of the lower joint 20 and forms a metal-to-metal seal with the lower joint 20. At this time, the inner sleeve 7 and the outer sleeve 8 are aligned, and the annulus at the upper end of the packer 23 and the annulus at the lower end of the packer 23 are connected with each other. Figure 3 Gas injection can be performed. During gas injection, gas is injected from the annulus, enters the annulus at the lower end of the packer 23 through the downhole gas injection safety valve 100, and then enters the tubing 22 through the downhole gas injection safety valve 100 to perform artificial gas lifting.

[0071] When gas injection is not needed, the line hydraulic pressure can be released, and the valve push cylinder 11, the inner sleeve 7, and the piston rod 4 are pushed back to the original position under the action of the spring force of the downhole gas injection safety valve 100. At this time, the valve disc 19 is also automatically closed, and the self-balancing valve 18 is automatically closed under the action of the spring force, and the pressure between the downhole gas injection safety valve 100 and the lower end of the packer 23 is isolated.

[0072] The present application is suitable for the reasonable combination of the gas injection safety valve and the production packer in the completion of conventional oil and gas reservoirs and high-pressure oil and gas reservoirs, and is installed on the upper end of the gas injection string, which can better realize the functions of large-dose gas injection and annular well shut-in. The metal-to-metal seal structure of the sliding sleeve and the safety valve is combined, no end face flow is formed during gas injection, no gas injection friction is increased, effective sealing can be formed after well shut-in, gas tightness is ensured, no leakage occurs, and the well control risk of gas lifting wells is reduced.

[0073] Of course, the present application can have other various embodiments, and those skilled in the art can make various corresponding changes and modifications according to the present application without departing from the spirit and essence of the present application. However, these corresponding changes and modifications should all belong to the protection scope of the claims attached to the present application.

Claims

1. A downhole gas injection safety valve, characterized in that The downhole gas injection safety valve is installed on a packer and connected with a tubing. A valve housing; A sliding sleeve switch mechanism including an inner sliding sleeve and an outer sliding sleeve, the inner sliding sleeve being arranged in the outer sliding sleeve, the outer sliding sleeve being provided with an outer fluid passage, the inner sliding sleeve being provided with an inner fluid passage adapted to the outer fluid passage, the inner fluid passage and the outer fluid passage each having an open position and a closed position; one end of the outer sliding sleeve being connected with the valve housing; the outer sliding sleeve and the inner sliding sleeve being respectively provided with an upper sealing member and a lower sealing member; A metal valve disc switch mechanism being installed at the other end of the valve housing and connected with the sliding sleeve switch mechanism through a valve push cylinder, the valve push cylinder being located in the valve housing, the metal valve disc switch mechanism having a valve disc open position and a valve disc closed position and being synchronously opened or closed with the sliding sleeve switch mechanism; A reset mechanism being arranged in the valve housing corresponding to the metal valve disc switch mechanism; and A control mechanism being connected with the sliding sleeve switch mechanism and connected with a surface control panel through a hydraulic control pipeline; wherein the control mechanism includes: An upper joint being connected with the top end of the outer sliding sleeve; A pipeline joint being installed at one end of the upper joint, the other end of the pipeline joint being connected with the hydraulic control pipeline; and A piston rod being installed in the upper joint, one end of the piston rod being arranged in a hydraulic passage of the upper joint, the other end of the piston rod being connected with the inner sliding sleeve; the other end of the piston rod being connected with the inner sliding sleeve through a connecting cover; The metal valve disc switch mechanism includes: A valve seat being installed at the bottom end of the valve housing; A self-balancing valve being installed at the bottom of the valve seat and being opened and closed corresponding to the open position and the closed position of the sliding sleeve switch mechanism; A valve disc being installed at the bottom end of the valve seat corresponding to the self-balancing valve, the valve disc having a valve open position and a valve closed position relative to the valve seat, the valve open position and the valve closed position being synchronously opened and closed with the self-balancing valve; A reset member being arranged corresponding to the valve disc for resetting the valve disc; the reset member being a leaf spring, one end of the leaf spring being installed on the valve seat, the other end of the leaf spring being abutted with a fixed end of the valve disc; and A lower joint being connected with the bottom end of the valve housing, and the valve seat, the leaf spring, the self-balancing valve and the valve disc being located in a cavity of the lower joint; During gas injection, the piston rod pushes the connecting cover and pushes the inner sliding sleeve and the valve push cylinder, the valve push cylinder opens the self-balancing valve to balance the pressure between the inside of the gas injection safety valve and the lower end of the valve disc; the piston rod continues to push to open the valve disc and pushes the valve push cylinder to the bottom of the lower joint to form a metal-to-metal seal with the lower joint, the inner sliding sleeve and the outer sliding sleeve are aligned to form a communication between the annulus at the upper end of the packer and the annulus at the lower end of the packer, and the gas injection operation is performed. Without the need for gas injection, the ground hydraulic control pipeline is hydraulically released, the valve push cylinder, inner slide and the piston rod are pushed back to the original position under the force of the spring, the valve flap is automatically closed, the self-balancing valve is automatically closed under the force of the leaf spring, and the downhole gas injection safety valve is isolated from the pressure at the lower end of the packer.

2. The downhole gas injection safety valve of claim 1, wherein, The reset mechanism comprises an upper spring seat, a reset spring and a lower spring seat, the upper spring seat is sleeved outside the valve push cylinder and abuts against the bottom end of the outer slide, the lower spring seat is sleeved outside the valve push cylinder and abuts against the boss of the valve housing, and the two ends of the reset spring abut against the upper spring seat and the lower spring seat respectively.

3. A downhole gas injection safety valve according to claim 1 or 2, characterised in that The upper joint top end is further provided with a protective cap, and the protective cap is provided with a pipeline through joint.

Images