A packoff gas lift water removal device and associated process method

Abstract

The application discloses a packoff type gas lift drainage device and a related process method. The device comprises a tool body, a variable-diameter blade type leakproof assembly, a cylinder sleeve, a return spring and an energy storage sleeve which are sleeved on the tool body; the cylinder sleeve, the return spring and the energy storage sleeve are axially movable along the tool body; the variable-diameter blade type leakproof assembly is arranged in the cylinder sleeve; the return spring is arranged in the energy storage sleeve; the variable-diameter blade type leakproof assembly comprises a plurality of blades, the roots of the blades are fixedly connected with the tool body, the blades are umbrella-shaped and are retractable relative to the cylinder sleeve, so that when the gas inflow into the well is greater than a preset threshold, the liquid in the well pushes the cylinder sleeve to compress the return spring, and the blades extend out of the cylinder sleeve to form a liquid blocking surface; after the liquid in the well is discharged, the blades retract into the cylinder sleeve. The application can repeatedly realize gas lift drainage, discharge the accumulated liquid in the reservoir space and the wellbore, change the water-sealed gas into movable gas and be produced, and improve the overall gas production efficiency.

Description

Technical Field

[0001] This invention relates to the field of oil and gas production technology, and in particular to a sealed gas lift drainage device and related process methods. Background Technology

[0002] Gas lift is used in the mid-to-late stages of gas field development when the energy of the gas well itself is insufficient to achieve continuous self-flowing liquid discharge. By using an external high-pressure gas source and through a gas lift valve, high-pressure natural gas is injected from the surface into the shut-in well. This increases the gas-liquid ratio above the injection point and reduces the pressure gradient, thereby establishing a larger production pressure differential. Gas and liquid continuously flow from the formation to the bottom of the well and flow to the wellhead in a self-flowing manner to restore the self-flowing production of water-flooded wells, or as an energy supplement method for self-flowing production to help achieve self-flowing.

[0003] When water-bearing gas reservoirs are under development, water intrusion may affect certain gas wells, certain blocks, or even the entire gas reservoir. Through the "drainage gas production" process, artificial lifting, assisted drainage, and self-flowing water-bearing gas production are used to drain the intruding reservoir space and the liquid accumulated in the wellbore, so that the water-sealed gas becomes movable gas and can be produced. At the same time, it prevents well leakage caused by the liquid column pressure and circulation pressure acting on the bottom of the well during the drainage process, which could lead to water flooding of the gas layer.

[0004] Therefore, there is an urgent need to develop a suitable lifting tool for the "drainage gas extraction" process. Summary of the Invention

[0005] In view of the above problems, the present invention is proposed to provide a sealed airlift drainage device and related process method that overcomes or at least partially solves the above problems.

[0006] In a first aspect, embodiments of the present invention provide a sealed airlift drainage device, comprising: a tool body, a variable diameter vane leak-proof assembly, a cylinder liner, a return spring, and an energy storage sleeve; wherein:

[0007] The variable diameter vane leak-proof assembly, the cylinder liner, the return spring, and the energy storage sleeve are sequentially sleeved on the outer surface of the tool body; the cylinder liner, the return spring, and the energy storage sleeve are movable along the axial direction of the tool body; the variable diameter vane leak-proof assembly is disposed inside the cylinder liner; the return spring is disposed inside the energy storage sleeve;

[0008] The variable diameter blade leak-proof assembly includes several blades, and the roots of the several blades are fixedly connected to the tool body.

[0009] The plurality of blades are umbrella-shaped and retractable relative to the cylinder liner, so that when the gas flow rate into the well exceeds a preset threshold, the cylinder liner compresses the return spring under the push of the liquid in the well, and the plurality of blades extend out of the cylinder liner to form a liquid barrier surface; and after the liquid in the well is discharged, the plurality of blades retract into the cylinder liner.

[0010] In one embodiment, the variable diameter blade leak-proof assembly further includes: a base;

[0011] The blades are arranged in an alternating stacked manner, and the root parts of the blades are riveted to the base by rivets.

[0012] In one embodiment, the above-described device further includes: a locking cap;

[0013] The base of the variable diameter blade leak-proof assembly is threadedly connected to one end face of the locking cap;

[0014] The inner wall of the locking cap is fitted onto the outer surface of the tool body and is threadedly connected to the tool body.

[0015] In one embodiment, the tool body has an internal cavity, and the sidewall of the cavity has a hole communicating with the outside of the tool body.

[0016] In one embodiment, a main circulation hole is provided on the side wall of the cavity on one side of the direction to which several blades of the variable diameter blade leak-proof assembly face.

[0017] On one side of the variable diameter blade leak-proof assembly, several blades are facing away from each other, and a connecting hole for connecting to the cylinder liner is opened on the side wall of the cavity.

[0018] In one embodiment, the cylinder liner is sealed to the tool body by a sealing ring.

[0019] In one embodiment, the tool body has a variable diameter section to form a step, and the cylinder liner is disposed at the step formed by the variable diameter section and is limited by the step.

[0020] In one embodiment, a thrust bearing is further provided inside the energy storage sleeve, and the thrust bearing is sleeved on the outer surface of the tool body;

[0021] One end of the return spring abuts against the cylinder liner, and the other end abuts against the thrust bearing.

[0022] In one embodiment, the device further includes: a coupling;

[0023] One end of the coupling is connected to the tool body, and the other end is used to connect to an external oil pipe.

[0024] Secondly, embodiments of the present invention provide a process method for air-lift drainage, comprising:

[0025] Connect the aforementioned enclosed gas lift drainage device to the tubing and place it at the beginning of the horizontal section of the wellbore through the tubing.

[0026] Nitrogen gas is injected into the wellbore annulus to open the variable diameter blade leak-proof assembly in the sealed air-lift drainage device;

[0027] The liquid in the wellbore is drained until the pressure difference in the cylinder liner of the sealed air-lift drainage device disappears, and the variable diameter blade leak-proof assembly in the sealed air-lift drainage device is closed.

[0028] The beneficial effects of the above-described technical solutions provided in the embodiments of the present invention include at least the following:

[0029] The aforementioned sealed gas lift drainage device and related process provided in this invention embodiment include a variable-diameter blade-type leak-proof assembly. During operation, the pressure difference is generated by using the liquid discharged during reverse circulation as power. The cylinder liner compresses the return spring, causing the variable-diameter blade-type leak-proof assembly to open, forming a liquid barrier surface and sealing the wellbore, preventing liquid from entering the easily leaking formation. At this time, the liquid in the well can be lifted out by gas lift. This invention embodiment has a simple structure and a straightforward implementation process. It can repeatedly perform gas lift drainage, discharging intrusive liquid from the storage space and wellbore, transforming water-sealed gas into movable gas that can be extracted. Simultaneously, it prevents well leakage caused by liquid column pressure and circulation pressure acting on the bottom of the well during drainage, thus preventing water flooding of the gas layer. This invention embodiment can improve overall gas production efficiency.

[0030] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0031] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0032] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0033] Figure 1 This is a schematic diagram of the enclosed airlift drainage device in an embodiment of the present invention;

[0034] Figure 2 is a schematic diagram of the variable diameter blade leak-proof assembly in an embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram showing the placement of the enclosed air-lift drainage device in actual application according to an embodiment of the present invention;

[0036] Figure 4 is a schematic diagram of the state changes during the operation of the sealed airlift drainage device in an embodiment of the present invention.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1. Coupling 2. Tool body 3. Variable diameter blade leak-proof assembly 4. Lock cap 5. Cylinder liner 6. Sealing ring 7. Return spring 8. Thrust bearing 9. Energy storage sleeve 10. Main circulation hole 11. Connecting hole 31. Blade 32. Base 33. Rivet. Detailed Implementation

[0039] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0040] This invention provides a sealed air-lift drainage device, referring to... Figure 1 As shown, it includes: tool body 2, variable diameter vane leak-proof assembly 3, cylinder liner 5, return spring 7, and accumulator sleeve 9; wherein:

[0041] The variable diameter blade leak-proof assembly 3, the cylinder liner 5, the return spring 7, and the energy storage sleeve 9 are sequentially sleeved on the outer surface of the tool body 2;

[0042] The cylinder liner 5, the return spring 7, and the energy storage sleeve 9 are axially movable along the tool body 2; the variable diameter blade leak-proof assembly 3 is disposed inside the cylinder liner 5; the return spring 7 is disposed inside the energy storage sleeve 9;

[0043] The variable diameter blade leak-proof assembly 3 includes a plurality of blades 31, the roots of which are fixedly connected to the tool body 2.

[0044] The plurality of blades 31 are umbrella-shaped and retractable relative to the cylinder liner 5, so that when the gas flow rate into the well exceeds a preset threshold, the cylinder liner 5 compresses the return spring 7 under the push of the liquid in the well, and the plurality of blades 31 extend out of the cylinder liner 5 to form a liquid barrier surface; and after the liquid in the well is discharged, the plurality of blades 31 retract into the cylinder liner 5.

[0045] Reference Figure 1 As shown, the tool body 2 is cylindrical. The variable diameter blade leak-proof assembly 3, the cylinder liner 5, the return spring 7, and the energy storage sleeve 9 are sequentially fitted onto the tool body 2.

[0046] In one embodiment, refer to Figure 2A and Figure 2B As shown, the variable diameter blade leak-proof assembly 3 includes: a plurality of staggered blades 31 and a base 32;

[0047] The staggered arrangement of the blades 31 ensures that when the variable diameter blade leak-proof assembly 3 is opened, it can form a barrier surface to block liquid, and prevent liquid from leaking out from the gaps between the blades.

[0048] The root portion of the blade 31 is riveted to the base 32 by rivets 33.

[0049] In one embodiment, refer to Figure 1 As shown, the above-mentioned sealed airlift drainage device also includes: a locking cap 4; the locking cap 4 is used to lock the root of the blade 31 of the variable diameter blade leak-proof assembly 3 between the tool body 2.

[0050] The base 32 of the variable diameter blade leak-proof assembly 3 is threadedly connected to one end face of the locking cap 4;

[0051] The inner wall of the locking cap 4 is fitted onto the outer surface of the tool body 2 and is threadedly connected to the tool body 2.

[0052] In one embodiment, the tool body 2 has a cavity inside, and the side wall of the cavity has a hole that communicates with the outside of the tool body 2.

[0053] Furthermore, on one side of the cavity, a main circulation hole 10 is opened on the side wall of a cavity of several blades 31 of the variable diameter blade-type leak-proof assembly 3.

[0054] The variable diameter blade leak-proof assembly 3 has several blades 31 facing away from each other, and the cavity sidewall has a connecting hole 11 that connects to the cylinder liner 5.

[0055] The main functions of the main circulation port 10 include: overcoming the buoyancy of the well fluid when the packer-type air lift drainage device is placed downhole (the main circulation port 10 can guide the well fluid into the cavity inside the tool body 2), allowing the packer-type air lift drainage device connected to the tubing to be smoothly lowered to the preset position in the horizontal section. Another more important function is that when the variable diameter blade leak-proof assembly 3 is opened, it forms a liquid blocking surface, at which time the well fluid will enter the tool body 2 from the main circulation port 10 and be lifted to the surface through the tubing.

[0056] The main function of the connecting hole 11 is as follows: when the sealed air lift drainage device is placed in the designated position of the horizontal section, gas is introduced and the liquid in the well enters the cylinder liner 5 through the connecting hole 11, creating a pressure difference at both ends of the cylinder liner 5. Under the action of the pressure difference, the cylinder liner 5 is pushed open and the return spring 7 is compressed.

[0057] In one embodiment, the cylinder liner 5 and the tool body 2 are sealed by a sealing ring 6, for example, an O-ring seal 6 is used for sealing.

[0058] Reference Figure 1 As shown, the tool body 2 has a variable diameter section to form a step, and the cylinder liner 5 is disposed at the step formed by the variable diameter section and is limited by the step.

[0059] The diameter of the variable diameter section is smaller than that of other sections, which can form a step. When the fluid in the well is discharged, the pressure difference of cylinder liner 5 decreases, and cylinder liner 5 returns to its original position, it will be limited by this step.

[0060] Reference Figure 1 As shown, a thrust bearing 8 is also provided inside the energy storage sleeve 9, and the thrust bearing 8 is sleeved on the outer surface of the tool body 2.

[0061] One end of the return spring 7 abuts against the cylinder liner 5, and the other end abuts against the thrust bearing 8.

[0062] In one embodiment, the device further includes: a coupling;

[0063] One end of the coupling is connected to the tool body 2, and the other end is used to connect to an external oil pipe.

[0064] Both ends of the coupling have internal threads. One end is threaded to the tool body 2, and the other end is threaded to the external oil pipe.

[0065] The coupling and the tool body 2 are connected by API oil pipe thread, which has the functions of sealing, tensile (compression) resistance and torsion transmission.

[0066] The materials for couplings, tool bodies, variable diameter blade leak-proof assemblies, lock caps, cylinder liners, accumulator sleeves, and rivets can all be, for example, 17-4PH (martensitic precipitation hardening stainless steel). The sealing rings are made of fluororubber. The return springs can be made of, for example, 17-7PH (austenitic-martensitic precipitation hardening stainless steel). The thrust bearings can be made of, for example, DD400 steel. The main reason for choosing these materials is that they are corrosion resistant and can withstand the long-term erosion of large-volume fluids, thereby extending the working life of the equipment in the high-temperature and corrosive environment downhole.

[0067] The sealed air-lift drainage device provided in this embodiment of the invention, when in use, sends the oil pipe to such... Figure 3 At point A (the beginning of the horizontal section) shown, nitrogen gas is injected into the wellbore annulus to open the variable diameter blade leak-proof assembly 3 in the sealed gas lift drainage device;

[0068] The liquid in the wellbore is drained until the pressure difference between the left and right sides of the cylinder liner 5 in the sealed gas lift drainage device disappears. The variable diameter blade anti-leakage assembly 3 in the sealed gas lift drainage device is then closed, and normal gas extraction can proceed.

[0069] Reference Figure 4A and Figure 4B Before nitrogen is injected, the variable diameter blade leak-proof assembly 3 of the device is normally closed (see reference). Figure 4A It is normally open during operation (refer to...). Figure 4B Nitrogen injection lift utilizes the large volume of liquid discharged during reverse circulation (the direction of liquid flow can be referenced). Figure 4A and Figure 4B The arrow in the image points to the force and generates a pressure difference. Under the action of the pressure difference, the cylinder liner 5 compresses the return spring 7 and simultaneously moves downward. Figure 4B Compared to Figure 4A (The cylinder liner moves to the right), the variable diameter vane leak-proof assembly 3 opens and seals the wellbore, preventing liquid from entering the easily leaking formation. The liquid is then lifted out by gas lift. After completion, the pump stops, the aforementioned pressure difference disappears, and the cylinder liner 5 moves upward (to the left) under the action of the return spring 7, closing the variable diameter vane leak-proof assembly 3, thus connecting the inside and outside of the wellbore. Gas production then begins. If water intrusion continues in the wellbore after a certain period of gas production, the above nitrogen injection process can be repeated without raising the tubing string to complete the gas lift drainage.

[0070] Based on the same inventive concept, embodiments of the present invention also provide a process method for air-lift drainage, which includes the following steps:

[0071] 1. Connect the aforementioned sealed gas lift drainage device to the tubing and place it at the beginning of the horizontal section of the wellbore through the tubing;

[0072] 2. Inject nitrogen into the wellbore annulus to open the variable diameter blade leak-proof assembly in the sealed air-lift drainage device;

[0073] 3. Drain the liquid in the wellbore until the pressure difference of the cylinder liner in the sealed air lift drainage device disappears, and the variable diameter blade leak-proof assembly in the sealed air lift drainage device is closed.

[0074] Experiments have shown that the enclosed air-lift drainage device and related air-lift drainage process provided in the embodiments of the present invention have the following advantages:

[0075] 1. The process is not limited by well inclination (the centralizer at the top of the refueling pipe during construction), well depth, hydrogen sulfide, or gas-liquid ratio;

[0076] 2. The drainage volume is relatively large, 350-400 m3 / d per day, and the production increase effect of a single well is significant;

[0077] 3. It can be started repeatedly, reducing the number of well workover operations;

[0078] 4. The equipment is simple to set up, easy to manage, and requires minimal investment;

[0079] 5. Easy to measure liquid level and pressure data, reliable design, and high economic benefits.

[0080] This device can achieve air lift drainage while preventing water from flooding the gas layer, improving operational efficiency by 5-8 days. The fixed cost per well is 30,000 yuan per day, resulting in savings of 150,000-240,000 yuan per well.

[0081] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A sealed-type air-lift drainage device, characterized in that, include: Tool body, variable diameter vane leak-proof assembly, cylinder liner, return spring and accumulator sleeve; wherein: The variable diameter vane leak-proof assembly, the cylinder liner, the return spring, and the energy storage sleeve are sequentially sleeved on the outer surface of the tool body; the cylinder liner, the return spring, and the energy storage sleeve are movable along the axial direction of the tool body; the variable diameter vane leak-proof assembly is disposed inside the cylinder liner; the return spring is disposed inside the energy storage sleeve; The variable diameter blade leak-proof assembly includes several blades, and the roots of the several blades are fixedly connected to the tool body. The plurality of blades are umbrella-shaped and retractable relative to the cylinder liner, so that when the gas flow rate into the well exceeds a preset threshold, the cylinder liner compresses the return spring under the push of the liquid in the well, and the plurality of blades extend out of the cylinder liner to form a liquid barrier surface; and after the liquid in the well is discharged, the plurality of blades retract into the cylinder liner.

2. The apparatus as claimed in claim 1, characterized in that, The variable diameter blade leak-proof assembly also includes: a base; The blades are arranged in an alternating stacked manner, and the root parts of the blades are riveted to the base by rivets.

3. The apparatus as described in claim 2, characterized in that, Also includes: locks cap; The base of the variable diameter blade leak-proof assembly is threadedly connected to one end face of the locking cap; The inner wall of the locking cap is fitted onto the outer surface of the tool body and is threadedly connected to the tool body.

4. The apparatus as claimed in claim 1, characterized in that, The tool body has an internal cavity, and the side wall of the cavity has a hole that communicates with the outside of the tool body.

5. The apparatus as described in claim 4, characterized in that, The variable diameter blade leak-proof assembly has several blades facing one side, and a main circulation hole is opened on the side wall of the cavity. On one side of the variable diameter blade leak-proof assembly, several blades are facing away from each other, and a connecting hole for connecting to the cylinder liner is opened on the side wall of the cavity.

6. The apparatus as claimed in claim 1, characterized in that, The cylinder liner is sealed to the tool body by a sealing ring.

7. The apparatus as claimed in claim 1, characterized in that, The tool body has a variable diameter section to form a step, and the cylinder liner is disposed at the step formed by the variable diameter section and is limited by the step.

8. The apparatus as claimed in claim 1, characterized in that, The energy storage sleeve is also provided with a thrust bearing, which is sleeved on the outer surface of the tool body; One end of the return spring abuts against the cylinder liner, and the other end abuts against the thrust bearing.

9. The apparatus according to any one of claims 1-8, characterized in that, The device also includes: a coupling; One end of the coupling is connected to the tool body, and the other end is used to connect to an external oil pipe.

10. A process for air-lift drainage, characterized in that, include: The sealed gas lift drainage device as described in any one of claims 1-9 is connected to the tubing and placed at the beginning of the horizontal section of the wellbore through the tubing; Nitrogen gas is injected into the wellbore annulus to open the variable diameter blade leak-proof assembly in the sealed air-lift drainage device; The liquid in the wellbore is drained until the pressure difference in the cylinder liner of the sealed air-lift drainage device disappears, and the variable diameter blade leak-proof assembly in the sealed air-lift drainage device is closed.

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