Fixed-liquid-volume lifting device and fixed-liquid-volume lifting method

Abstract

The invention provides a fixed liquid amount lifting device and a fixed liquid amount lifting method. The fixed-liquid-volume lifting device comprises a main body part, a first piston and a second piston, the main body part is of a hollow structure, a first via hole and a second via hole which are through inside and outside are formed in the side face of the main body part, and the first via hole is located above the second via hole; the first piston is axially and movably arranged in the main body part in a penetrating manner and is provided with a first closing position and a first opening position, and when the height of a liquid column of a shaft reaches a preset height, wellhead pressure drives the first piston to move to the first closing position; the second piston is provided with a hollow flow channel, the second piston is arranged in the main body part in a penetrating mode in an axial moving mode and located below the first piston, the second piston is provided with a second closing position and a second opening position, and when the bottom hole pressure reaches the bottom hole preset pressure, the bottom hole pressure drives the second piston to move to the second opening position. The problem that in the prior art, the water drainage and gas recovery effect in the plunger gas lift process is poor is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas exploitation, and in particular to a constant liquid volume lifting device and a constant liquid volume lifting method. Background Art

[0002] As gas well production enters the middle and late stages, pressure and production capacity gradually decrease. Gas wells cannot meet the requirements of continuous liquid carrying and cannot discharge formation water from the wellbore in time, resulting in liquid accumulation in the wellbore, affecting the gas well's production capacity. The plunger gas lift process is an important means of water drainage and gas production at this stage of gas well production. This technology uses the plunger as the mechanical interface between gas and liquid, and uses the gas well's own energy to push the plunger to lift water out of the wellbore.

[0003] Conventional plungers are generally controlled by timing the opening and closing of wells through the wellhead control device to control the up and down operation of the plunger. However, this method has many problems. First, when the well is opened for production, a lot of liquid is produced during the gas well stage, and a lot of liquid enters the wellbore at one time. For example, when a large amount of liquid accumulates in the horizontal section of a horizontal well and enters the wellbore, a high liquid column will be generated in the wellbore. At this time, the well is closed, and the plunger reaches the bottom of the well. When the well is opened again, the position of the upper liquid column is high, which may cause the plunger to be unable to move upward or the plunger to be unable to reach the wellhead, and it is impossible to efficiently drain water and produce gas. Second, when the well is opened at a scheduled time, the amount of liquid accumulated in the wellbore is small, resulting in the plunger running empty, affecting the implementation effect of the plunger gas well process.

[0004] From the above, it can be seen that the current plunger gas lift process has problems such as poor water drainage and gas production effect, that is, it is impossible to efficiently drain water and produce gas, and the plunger runs empty. Summary of the invention

[0005] The main purpose of the present invention is to provide a constant liquid volume lifting device and a constant liquid volume lifting method to solve the problem of poor water drainage and gas recovery effect in the plunger gas lift process in the prior art.

[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a fixed liquid volume lifting device is provided, including: a main body, a first piston, and a second piston. The main body has a hollow structure, and the side of the main body is provided with a first through hole and a second through hole penetrating inside and outside, and the first through hole is located above the second through hole; the first piston is axially movably arranged in the main body, and has a first closed position and a first open position. When the height of the liquid column in the wellbore reaches a preset height, the wellhead pressure drives the first piston to move to the first closed position; the second piston has a hollow flow channel, the second piston is axially movably arranged in the main body, and is located below the first piston. The second piston has a second closed position and a second open position. When the bottom hole pressure reaches the preset bottom hole pressure, the bottom hole pressure drives the second piston to move to the second open position.

[0007] Furthermore, a connecting hole is provided on the side of the second piston. When the second piston is located at the second open position, the connecting hole is aligned with the second through hole, and the hollow flow channel is connected with the gap between the fixed liquid volume lifting device and the wellbore through the connecting hole and the second through hole.

[0008] Furthermore, the fixed liquid volume lifting device also includes a first restoring member, which abuts against the first piston and drives the first piston to move toward the first open position.

[0009] Furthermore, the fixed liquid volume lifting device also includes a second reset member, which abuts against the second piston and drives the second piston to move toward the second closed position.

[0010] Furthermore, the first piston is located above the second piston, and the first piston and the second piston are spaced apart from each other.

[0011] Furthermore, there are multiple first through holes and / or second through holes, and the first through holes and / or second through holes are arranged at intervals along the circumference of the fixed liquid volume lifting device.

[0012] Furthermore, the main body includes an axially arranged upper segment and a lower segment, the first through hole and the second through hole are both located in the upper segment, and the constant liquid volume lifting device also includes a sealing assembly, the sealing assembly includes a radially expandable expansion member, the expansion member is arranged between the upper segment and the lower segment, and when the lower segment moves relative to the upper segment, the expansion member is squeezed to expand radially to seal the gap between the constant liquid volume lifting device and the wellbore.

[0013] Furthermore, the sealing assembly also includes a connecting section and a first shear nail. The connecting section is located in the main body and is inserted between the upper segment and the lower segment. The top end of the connecting section abuts against the upper segment, and there is an expansion space between the bottom end of the connecting section and the lower segment. The first shear nail is inserted between the connecting section and the lower segment. During sealing, the first shear nail breaks, and the lower segment moves upward under the action of the bottom hole pressure and squeezes the expansion piece to expand radially.

[0014] Furthermore, the fixed liquid volume lifting device also includes an anchoring assembly, which includes a cone portion, a retaining ring, a delivery head, a salvage neck, and multiple slips. The cone portion is connected to the top of the main body; the retaining ring is arranged on the top side of the cone portion; the delivery head is located at the top of the cone portion and is connected to the retaining ring through a second shear nail; the salvage neck sleeve is arranged on the outer ear of the cone portion and is located below the retaining ring; the slip is located at the conical surface of the cone portion and is connected to the bottom end of the salvage neck, and when the slip and the cone portion move axially relative to each other, the conical surface of the cone portion squeezes the slip and drives the slip to expand radially to abut against the inner wall of the wellbore.

[0015] According to another aspect of the present invention, a fixed liquid volume lifting method is provided, which adopts the fixed liquid volume lifting device mentioned above, and the fixed liquid volume lifting method comprises: when the height of the liquid column in the wellbore reaches a preset height, the first piston moves to a first closed position under the action of the wellhead pressure, and the first through hole is closed. When the wellhead pressure reaches the preset wellhead pressure, the gas well is opened. At this time, the bottom hole pressure reaches the preset bottom hole pressure, and the second piston moves to a second open position under the action of the bottom hole pressure, and the second through hole is opened. The gas and liquid at the bottom of the well are transported to the top of the fixed liquid volume lifting device through the hollow flow channel of the second piston, the second through hole, and the gap between the wellbore and the fixed liquid volume lifting device. At the same time, the liquid in the wellbore is lifted and discharged, the height of the liquid column in the wellbore decreases, and both the wellhead pressure and the bottom hole pressure decrease. As the wellhead pressure decreases, the first piston moves to the first open position, the first through hole is opened, and at the same time, as the bottom hole pressure decreases, the second piston moves to In the second closed position, the second through hole is closed, and the gas and liquid at the bottom of the well are transported to the top of the fixed liquid volume lifting device through the hollow flow channel of the second piston, the first through hole, the gap between the wellbore and the fixed liquid volume lifting device, and the height of the liquid column in the wellbore gradually increases, and the wellhead pressure gradually increases; when the height of the liquid column in the wellbore reaches the preset height, the first piston moves to the first closed position under the action of the wellhead pressure, the first through hole is closed, the bottom of the well and the wellhead are disconnected, the wellhead flow rate is 0, and the gas well is shut in; after the well is shut in, the bottom hole pressure increases, and when the bottom hole pressure reaches the preset bottom hole pressure, the second piston moves to the second open position, the second through hole is opened, and the gas and liquid at the bottom of the well are transported to the top of the fixed liquid volume lifting device through the hollow flow channel, the second through hole, the gap between the wellbore and the fixed liquid volume lifting device, so that the wellhead pressure gradually increases, the first through hole remains closed, and when the wellhead pressure reaches the preset wellhead pressure, the gas well is opened, and the above process is repeated.

[0016] Furthermore, the fixed liquid volume lifting method also includes: when the height of the liquid column in the wellbore does not reach a preset height, the first piston is maintained in a first open position under the action of a first reset member; when the bottom hole pressure does not reach the preset bottom hole pressure, the second piston is maintained in a second closed position under the action of a second reset member.

[0017] Furthermore, the fixed liquid volume lifting method also includes a sealing process, which includes: after the fixed liquid volume lifting method is placed at a predetermined position in the wellbore, the first shear nail is cut off, and the lower segment of the main body moves upward relative to the upper segment and the connecting segment under the action of the bottom hole pressure. During the upward movement of the lower segment, the lower segment squeezes the expansion piece, and the expansion piece expands radially and contacts and seals with the inner wall of the wellbore.

[0018] Furthermore, the fixed liquid volume lifting method also includes an anchoring process, which includes: when launching, the fixed liquid volume lifting device is lowered into the wellbore through the launching head by connecting an external tool to the launching head, and the diameter of the cava is smaller than the diameter of the wellbore; when reaching the predetermined position, the launching head is lifted so that the cava moves downward relative to the cone part, and the cava expands radially under the action of the cone surface of the cone part and contacts and anchors with the inner wall of the wellbore; the second shear nail is cut off, and the launching head is recovered, and the launching and anchoring of the fixed liquid volume lifting device is completed.

[0019] By applying the technical solution of the present invention, the movement relationship between the first piston and the second piston under different pressure conditions is adopted to realize quantitative lifting and discharge of the bottom hole liquid. Specifically, when the height of the liquid column is higher than the preset height, the wellhead pressure exceeds the preset wellhead pressure, the first piston moves downward to the first closed position, blocks the first through hole to close it, and the gas well is opened; at this time, the bottom hole pressure also reaches the preset bottom hole pressure, the second piston moves upward to the second open position, the second through hole is connected with the connecting hole, and the gas and liquid at the bottom of the well are transported upward through the second through hole, while the liquid in the wellbore is lifted and discharged, the height of the liquid column in the wellbore decreases, and the wellhead pressure decreases; after the wellhead pressure decreases, the first piston moves to the first open position to avoid the first through hole to open it, and at the same time, the bottom hole pressure When the force decreases, the second piston moves to the second closed position, the second through hole is blocked and closed, the gas and liquid at the bottom of the well are transported upward through the first through hole, the height of the wellbore liquid column gradually increases, and the wellhead pressure gradually increases; when the height of the wellbore liquid column reaches the preset height, the wellhead pressure reaches the corresponding wellhead preset pressure, the first piston moves to the first closed position under the action of the wellhead pressure, the first through hole is blocked and closed, the wellhead and the bottom of the well are no longer connected, the wellhead flow is 0, and the gas well is shut in; after shutting in, the bottom hole pressure increases, when the bottom hole pressure reaches the bottom hole preset pressure, the second piston moves to the second open position, the second through hole is connected to the connecting hole and opened, the gas and liquid at the bottom of the well are transported upward through the second through hole, the first through hole remains closed, the gas well is opened, and the above process is repeated. This setting makes the liquid lifted by the plunger controlled by the fixed liquid volume lifting device a fixed amount, avoids the plunger running empty or unable to reach the wellhead, and improves the efficiency of the plunger operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0021] Figure 1 The structural schematic diagram of the fixed liquid volume lifting device of the present invention is shown;

[0022] Figure 2 Shows Figure 1 A schematic diagram of the structure of the fixed liquid volume lifting device when anchored;

[0023] Figure 3 Shows Figure 1 A schematic diagram of the structure of the fixed liquid volume lifting device when sealed;

[0024] Figure 4 Shows Figure 1 A partial schematic diagram of the fixed liquid volume lifting device when opening the well;

[0025] Figure 5 Shows Figure 1 A partial schematic diagram of the fixed liquid volume lifting device in the state where the liquid is discharged;

[0026] Figure 6 Shows Figure 1 A partial schematic diagram of the fixed liquid volume lifting device in the gas well during continuous flow production;

[0027] Figure 7 Shows Figure 1 A partial schematic diagram of the constant liquid volume lifting device when the well is shut in.

[0028] The above drawings include the following reference numerals:

[0029] 11. First through hole; 12. Second through hole; 13. Upper segment; 14. Lower segment; 141. Outer tube; 142. Outer sleeve; 20. First piston; 30. Second piston; 31. Connecting hole; 40. First reset member; 50. Second reset member; 60. Sealing assembly; 61. Expansion member; 62. Connecting section; 63. First shear pin; 64. Expansion space; 70. Anchor assembly; 71. Conical part; 72. Retaining ring; 73. Launching head; 74. Salvage neck; 75. Slip; 76. Second shear pin; 80. Plug. DETAILED DESCRIPTION

[0030] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0031] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0032] In the present invention, unless otherwise specified, the directional words used, such as "up, down, top, bottom", usually refer to the directions shown in the drawings, or to the components themselves in the vertical, perpendicular or gravity directions; similarly, for ease of understanding and description, "inside and outside" refer to the inside and outside relative to the outline of each component itself, but the above-mentioned directional words are not used to limit the present invention.

[0033] In order to solve the problem of poor water drainage and gas recovery effect in the plunger gas lift process in the prior art, the present invention provides a constant liquid volume lifting device and a constant liquid volume lifting method.

[0034] like Figures 1 to 7 A fixed liquid volume lifting device shown in the figure includes: a main body, a first piston 20 and a second piston 30. The main body has a hollow structure, and the side of the main body is provided with a first through hole 11 and a second through hole 12 that penetrate inside and outside, and the first through hole 11 is located above the second through hole 12; the first piston 20 can be axially movably arranged in the main body, and has a first closed position that blocks the first through hole 11 and a first open position that avoids the first through hole 11. When the height of the liquid column in the wellbore reaches a preset height, the wellhead pressure drives the first piston 20 to move to the first closed position; the second piston 30 has a hollow flow channel, and the second piston 30 can be axially movably arranged in the main body, and is located below the first piston 20. The second piston 30 has a second closed position that blocks the second through hole 12 and a second open position that avoids the second through hole 12. When the bottom hole pressure reaches the preset bottom hole pressure, the bottom hole pressure drives the second piston 30 to move to the second open position.

[0035] In this embodiment, quantitative lifting and discharge of bottom hole accumulated liquid is achieved by adopting the movement relationship between the first piston 20 and the second piston 30 under different pressure conditions. Specifically, when the wellhead pressure exceeds the preset wellhead pressure, the first piston 20 moves downward to the first closed position, blocking the first through hole 11 to close it, and the gas well is opened; when the bottom hole pressure reaches the preset bottom hole pressure, the second piston 30 moves upward to the second open position, the second through hole 12 is opened, and the gas and liquid at the bottom of the well are transported upward through the second through hole 12 while the liquid in the wellbore is lifted and discharged, the height of the wellbore liquid column decreases, and the wellhead pressure decreases; after the wellhead pressure decreases, the first piston 20 moves to the first open position, avoiding the first through hole 11 to open it, and at the same time, the bottom hole pressure decreases, and the second piston 30 moves upward to the second open position, avoiding the first through hole 11 to open it, and at the same time, the bottom hole pressure decreases, and the second piston 30 moves upward to the second open position, and the second through hole 12 is opened. The plug 30 moves to the second closed position, and the second through hole 12 is blocked and closed. At this time, it is in the continuous flow section, and the gas and liquid at the bottom of the well are transported upward through the first through hole 11, the height of the wellbore liquid column gradually increases, and the wellhead pressure gradually increases; when the height of the wellbore liquid column reaches the preset height, the wellhead pressure reaches the corresponding wellhead preset pressure, and the first piston 20 moves to the first closed position under the action of the wellhead pressure, the first through hole 11 is blocked and closed, the wellhead flow is 0, and the gas well is shut in; after the well is shut in, the bottom hole pressure increases, and when the bottom hole pressure reaches the bottom hole preset pressure, the second piston 30 moves to the second open position, the second through hole 12 is opened, and the gas and liquid at the bottom of the well are transported upward through the second through hole 12, the first through hole 11 remains closed, the gas well is opened, and the above process is repeated. This arrangement ensures that the liquid lifted by the plunger controlled by the fixed liquid volume lifting device is a fixed amount, which not only avoids the situation where the plunger cannot move upward or cannot reach the wellhead due to the high position of the upper liquid column, resulting in inefficient water drainage and gas production, but also avoids the situation where the plunger runs empty due to the small amount of liquid accumulation in the wellbore, affecting the implementation effect of the plunger gas well process, thereby improving the efficiency of the plunger operation.

[0036] In this embodiment, the main body is roughly a cylinder with a hollow structure inside. When using the fixed liquid volume lifting device for fixed liquid volume lifting, the central axis of the main body is consistent with the central axis of the wellbore. Since the wellbore mentioned here is a vertically opened segment, the main body is used in a vertical manner, that is, the fixed liquid volume lifting device is hoisted vertically downward into the wellbore for use. The first piston 20 and the second piston 30 are arranged in the cavity of the main body and can move up and down in a direction parallel to the central axis of the main body, that is, in the longitudinal direction. And because the first through hole 11 is located above the second through hole 12, the first piston 20 is arranged above the second piston 30 in this embodiment, which is more convenient for coordination.

[0037] The first piston 20 and the second piston 30 of this embodiment both have one end that bears the strong pressure of gas and liquid and the other end that plays the role of shielding and avoiding the through hole. The top end of the first piston 20 is the end that bears the strong pressure of gas and liquid, and this end is affected by the pressure of the wellbore liquid column to realize the up and down movement of the first piston 20, while the bottom end of the first piston 20 is the end that plays the role of shielding and avoiding the first through hole 11. In contrast to the first piston 20, the bottom end of the second piston 30 is the end that bears the strong pressure of gas and liquid, and this end is affected by the bottom hole pressure to realize the up and down movement of the second piston 30, while the top end of the second piston 30 is the end that plays the role of shielding and avoiding the second through hole 12. In this way, when the first piston 20 moves upward as a whole, it can avoid the first through hole 11, that is, it is located in the first open position, and when the first piston 20 moves downward as a whole, it can shield the first through hole 11, that is, it is located in the first closed position; similarly, when the second piston 30 moves downward as a whole, it can avoid the second through hole 12, that is, it is located in the second open position, and when the second piston 30 moves upward as a whole, it can shield the second through hole 12, that is, it is located in the second closed position. Of course, based on the different specific configurations of the first piston 20 and the second piston 30 , the specific movement modes and the positional relationship between the corresponding through holes may also change accordingly.

[0038] Considering that the up and down movements of the first piston 20 and the second piston 30 are relatively independent, the first piston 20 and the second piston 30 of this embodiment are arranged with an upper and lower interval. The interval between the two can ensure that when one of them moves, it will not abut against the other, and ensure that its own movement will not affect the other.

[0039] Since the first piston 20 moves downward to block the first through hole 11, the bottom side of the first piston 20 can directly cooperate with the first through hole 11 to achieve the effect of blocking and avoiding the through hole. However, since the second piston 30 cooperates with the second through hole 12 at the top, and avoids the second through hole 12 when the second piston 30 moves upward, the connecting hole 31 is provided on the side of the second piston 30 in this embodiment. When the second piston 30 moves upward to the second open position, the connecting hole 31 and the second through hole 12 are radially aligned. At this time, the hollow flow channel is connected to the gap between the fixed liquid volume lifting device and the wellbore through the connecting hole 31 and the second through hole 12; and when the second piston 30 moves downward to the second closed position, the connecting hole 31 moves downward to be offset from the second through hole 12, and the second through hole 12 is blocked by the top side of the second piston 30 and closed.

[0040] In this embodiment, an O-ring is used for sealing between the first piston 20 and the main body, and an O-ring may also be used between the second piston 30 and the main body. In addition, multiple O-rings may be provided to ensure the sealing effect and prevent air pressure from rising from the gap between the piston and the main body.

[0041] In this embodiment, the fixed liquid volume lifting device also includes a first reset member 40, which can be a spring, etc. The first reset member 40 is in contact with the first piston 20, always giving the first piston 20 a force to move to the first open position, and when the end face of the first piston 20 that bears the gas and hydraulic pressure is not subjected to sufficient pressure, that is, when the wellbore liquid column has not reached a preset height, the first piston 20 is driven to move to the first open position, and the first piston 20 is kept in the first open position under the action of the first reset member 40, and the first through hole 11 is not blocked by the first piston 20 and remains open. Only when the wellbore liquid column reaches a preset height will the first piston 20 close the first through hole 11 under the pressure of the wellbore liquid column. In this way, the first reset member 40 and the pressure of the wellbore liquid column work together to achieve the up and down movement of the first piston 20 according to the difference of the wellbore liquid column.

[0042] In this embodiment, the fixed liquid volume lifting device also includes a second reset member 50, which can be a spring or the like. The second reset member 50 abuts against the second piston 30, always giving the second piston 30 a force to move to the second closed position, and when the end face of the second piston 30 that is subjected to the gas and hydraulic pressure is not subjected to sufficient pressure, that is, when the bottom hole pressure does not reach the preset bottom hole pressure, the second piston 30 is driven to move to the second closed position, and the second piston 30 is kept in the second closed position under the action of the second reset member 50, and the second through hole 12 is blocked by the second piston 30, and the hollow flow channel of the second piston 30 is in a disconnected state with the second through hole 12. In this way, the second reset member 50 and the bottom hole pressure work together to realize the up and down movement of the second piston 30 according to the different wellbore liquid columns. Of course, the second reset member 50 may also not be set, and the gravity of the second piston 30 itself can be used to achieve the effect of automatic downward movement.

[0043] In actual use, the elastic force of the first reset member 40 and the second reset member 50 can be adjusted accordingly according to the required parameters such as the preset height of the wellbore liquid column, the preset wellhead pressure, the preset bottom hole pressure, etc., so that the elastic force matches the parameters, thereby achieving the required parameter effect.

[0044] In this embodiment, there are multiple first through holes 11 and / or second through holes 12. In this embodiment, both the first through holes 11 and the second through holes 12 are extended radially along the constant liquid volume lifting device, and multiple through holes are provided, so as to meet the gas production needs. The first through holes 11 and the second through holes 12 are arranged at circumferential intervals along the constant liquid volume lifting device to ensure the uniformity of the gas and avoid accumulation somewhere outside the wellbore.

[0045] like Figure 1 and Figure 3As shown, in this embodiment, the main body includes an upper segment 13 and a lower segment 14 which are arranged axially from top to bottom in sequence, and both the upper segment 13 and the lower segment 14 of the main body have a hollow cavity in which other accessories can be arranged, wherein the first through hole 11 and the second through hole 12 are both located on the side of the upper segment 13, the first piston 20 and the first reset member 40 are located in the upper segment 13, the second piston 30 and the second reset member 50 are located in the lower segment 14, and the top end of the second piston 30 extends upward into the upper segment 13, so as to cooperate with the second through hole 12. The upper segment 13 and the lower segment 14 of this embodiment are not fixedly arranged, but can be relatively moved up and down, more specifically, the lower segment 14 can move upward to approach the upper segment 13. At the same time, the fixed liquid volume lifting device also includes a sealing assembly 60, which includes a radially expandable expansion member 61. The expansion member 61 can be a rubber tube formed by a rubber member, etc., which is in a circular ring shape, and the middle part is for the second piston 30 and other components to pass through. The expansion member 61 is arranged between the upper segment 13 and the lower segment 14. In this way, when sealing is required, the lower segment 14 moves upward under the action of the bottom hole pressure. Since the upper segment 13 is anchored and immovable, the lower segment 14 will squeeze the expansion member 61 to cause the expansion member 61 to deform, and the expansion member 61 will expand radially, thereby contacting the inner wall of the wellbore, and the effect of blocking the gap between the fixed liquid volume lifting device and the wellbore is achieved.

[0046] In this embodiment, the sealing assembly 60 further includes a connecting section 62 and a first shear nail 63. The connecting section 62 is located in the main body and is arranged between the upper segment 13 and the lower segment 14. The connecting section 62 and the first shear nail 63 only play the role of controlling the movement of the lower segment 14. Specifically, the top of the connecting section 62 abuts against the upper segment 13, and there is an expandable and compressible expansion space 64 between the bottom of the connecting section 62 and the lower segment 14. The first shear nail 63 radially penetrates between the connecting section 62 and the lower segment 14 and fixes the two. In this way, when the fixed liquid volume lifting device is lowered, since the connecting section 62 is fixed with the relative position between the upper segment 13 and the lower segment 14 at the same time, there is no relative movement adjustment between the upper segment 13 and the lower segment 14, so that the expansion member 61 remains contracted and does not come into contact with the inner wall of the wellbore, thereby ensuring smooth lowering. When the sealing assembly 60 needs to seal the space between the wellbore and the fixed liquid volume lifting device, the first shear nail 63 breaks, and the fixed relationship between the lower segment 14 and the connecting segment 62 is released. The lower segment 14 can move upward under the action of the bottom hole pressure. Due to the existence of the expansion space 64 between the connecting segment 62 and the lower segment 14, the lower segment 14 has space to rise. At the same time, the gas in the expansion space 64 can be transferred to the inside of the expansion member 61, so that the lower segment 14 squeezes the expansion member 61 to expand radially, and the expansion member 61 then contacts the inner wall of the wellbore to achieve blocking. In this embodiment, the first shear nail 63 is a soluble pin. After the fixed liquid volume lifting device is placed in the wellbore, the soluble pin dissolves, the fixed relationship between the connecting segment 62 and the lower segment 14 is released, and the lower segment 14 can rise and the expansion member 61 can expand, completing the corresponding sealing process.

[0047] The lower segment 14 of this embodiment includes an outer cylinder 141 and an outer sleeve 142, wherein the outer cylinder 141 is located directly below the expansion member 61 and is flush with the outer surface of the upper segment 13, and the top portion of the outer sleeve 142 is located on the inner side of the outer cylinder 141 and forms a space with the inner wall of the outer cylinder 141, the bottom end of the connecting segment 62 is located in the space, and the expansion space 64 is also located in the space, the bottom end of the outer sleeve 142 is located directly below the outer cylinder 141 and is flush with the outer surface of the outer cylinder 141, a step structure is formed between the top and bottom ends of the outer sleeve 142, and the bottom end of the outer cylinder 141 abuts against the step structure, and sealing members such as sealing rings are provided between the connecting segment 62 and the outer cylinder 141, and between the outer cylinder 141 and the outer sleeve 142 to seal the gap. At the same time, there is a space between the bottom end portion of the outer sleeve 142 and the second piston 30 inserted therein, and the second restoring member 50 is located in the space, so that a downward restoring force can be applied to the second piston 30 .

[0048] In this embodiment, the fixed liquid volume lifting device also includes a plug 80, which is located at the bottom end of the lower segment 14 and is connected to the lower segment 14 through structures such as threads. The plug 80 is annular, and its inner diameter is smaller than the outer diameter of the second piston 30, thereby sealing the second piston 30 in the lower segment 14 to prevent the second piston 30 from escaping from the lower segment 14.

[0049] like Figure 1 and Figure 2 As shown, in this embodiment, the fixed liquid volume lifting device also includes an anchoring assembly 70, which includes a cone portion 71, a retaining ring 72, a delivery head 73, a salvage neck 74, and a plurality of slips 75. The cone portion 71 can be connected to the top of the main body by various connection methods such as threaded connection. The cone portion 71 is divided into two parts. The shape of the cone portion 71 is roughly a combination of a truncated cone and a cylinder, wherein the cylinder is located on the top surface of the truncated cone with a smaller area, and the bottom surface of the truncated cone with a larger area is connected to the top of the upper segment 13 of the main body, that is, the truncated cone is a structural form with a small top and a large bottom. The retaining ring 72 is arranged on the top side of the cone portion 71, and can be connected to the cone portion 71 by various methods such as threaded connection. The retaining ring 72 protrudes from the outer side of the cylinder of the cone portion 71, so as to play a limiting role. The delivery head 73 is located at the top of the cone 71 and is connected to the retaining ring 72 and the cone 71 through the second shear nail 76. The delivery head 73 is mainly used to cooperate with the equipment connected to the fixed liquid volume lifting device externally, so that the fixed liquid volume lifting device can be easily lifted by the external equipment. When it is lowered to the predetermined position, the tip of the second shear nail 76 is separated between the delivery head 73 and the cone 71, and the delivery head 73 can be taken out, while the other parts of the fixed liquid volume lifting device are placed underground. The salvage neck 74 is sleeved on the outer ear of the cone 71 and is located below the retaining ring 72. The salvage neck 74 is mainly used to salvage the fixed liquid volume lifting device and take it out of the wellbore. Since the retaining ring 72 is located above the salvage neck 74, the salvage neck 74 is stopped between the retaining ring 72 when moving upward, thereby preventing the salvage neck 74 and the slip 75 from upwardly separating from the cone 71. The slip 75 is located at the conical surface of the conical portion 71 and is connected to the bottom end of the salvage neck 74. The slip 75 and the conical portion 71 are axially relatively movable. When the slip 75 is located on the outside of the cylinder, there is no extrusion fit relationship between the slip 75 and the conical surface of the conical portion 71. The slip 75 contracts radially, thereby reducing the diameter to be smaller than the inner diameter of the wellbore, which facilitates the lowering of the fixed liquid volume lifting device. When the fixed liquid volume lifting device is lowered to a predetermined position, it is necessary to anchor it. During anchoring, the slip 75 moves from the cylinder to the truncated cone. At this time, the slip 75 is squeezed between the conical surface, and the extrusion action of the conical surface drives the slip 75 to expand radially, so that the slip 75 abuts against the inner wall of the wellbore. The slip 75 cooperates with the inner wall of the wellbore through the toothed structure on the outside, thereby realizing the anchoring of the fixed liquid volume lifting device.

[0050] In this embodiment, when production and fixed liquid volume lifting are carried out, the fixed liquid volume lifting device needs to be deployed, anchored and sealed first. The specific process is to first use a wire tool to connect the deployment head 73 to lower the device into the wellbore. During the deployment process, under the action of gravity, the cava 75 is in a radially contracted state. When the device reaches the designed sealing position, the wire operation tool is slowly lifted, and the deployment head 73 and the cone part 71 move upward compared with the cava 75. The cava 75 is squeezed by the conical surface of the cone part 71, driving the cava 75 to expand radially to clamp with the inner wall of the wellbore, and then the second shear nail 76 is cut off, and the deployment head 73 is recovered to the wellhead under the action of the wire operation tool. The deployment and anchoring of the fixed liquid volume lifting device is completed. After the fixed liquid volume lifting device is deployed and anchored, the first shear nail 63, that is, the soluble pin in this embodiment is cut off, and the fixing state of the connecting section 62 and the lower segment 14 is released. The lower segment 14 moves upward under the action of the bottom hole pressure. Under the action of the high pressure in the well, the closed expansion space 64 formed by the connecting section 62 and the lower segment 14 transfers gas to the inside of the expansion member 61, so that the expansion member 61 is radially expanded under force, thereby achieving sealing of the wellbore. Figures 1 to 3 The status is shown.

[0051] In this embodiment, sealing rings and other sealing members may be provided at positions where sealing is required between the components to seal the gaps between the components. The specific sealing positions may be set as required and will not be described in detail in this embodiment.

[0052] In the present embodiment, a method for lifting with a fixed liquid volume is provided, which adopts the above-mentioned lifting device with a fixed liquid volume. The method for lifting with a fixed liquid volume comprises: when the height of the liquid column in the wellbore reaches a preset height, the first piston 20 moves to a first closed position under the action of the wellhead pressure, and the first through hole 11 is closed. When the wellhead pressure reaches the preset wellhead pressure, the gas well is opened. At this time, the bottom hole pressure reaches the preset bottom hole pressure, and the second piston 30 moves to a second open position under the action of the bottom hole pressure, and the second through hole 12 is opened. The gas and liquid at the bottom of the well are transported to the top of the fixed liquid volume lifting device through the hollow flow channel of the second piston 30, the second through hole 12, and the gap between the wellbore and the lifting device with a fixed liquid volume. At the same time, the liquid in the wellbore is lifted and discharged, the height of the liquid column in the wellbore decreases, and both the wellhead pressure and the bottom hole pressure decrease. As the wellhead pressure decreases, the first piston 20 moves to the first open position, and the first through hole 11 is opened. At the same time, as the bottom hole pressure decreases, the second piston 30 moves to the second open position. In the second closed position, the second through hole 12 is closed, and the gas and liquid at the bottom of the well are transported to the top of the fixed liquid volume lifting device through the hollow flow channel of the second piston 30, the first through hole 11, and the gap between the wellbore and the fixed liquid volume lifting device, so that the height of the liquid column in the wellbore gradually increases, and the wellhead pressure gradually increases; when the height of the liquid column in the wellbore reaches the preset height, the first piston 20 moves to the first closed position under the action of the wellhead pressure, the first through hole 11 is closed, the bottom of the well and the wellhead are disconnected, the wellhead flow rate is 0, and the gas well is shut in; after the well is shut in, the bottom hole pressure increases, and when the bottom hole pressure reaches the preset bottom hole pressure, the second piston 30 moves to the second open position, the second through hole 12 is opened, and the gas and liquid at the bottom of the well are transported to the top of the fixed liquid volume lifting device through the hollow flow channel, the second through hole 12, and the gap between the wellbore and the fixed liquid volume lifting device, so that the wellhead pressure gradually increases, the first through hole 11 remains closed, and when the wellhead pressure reaches the preset wellhead pressure, the gas well is opened, and the above process is repeated.

[0053] In this embodiment, a fixed liquid volume lifting device and a fixed liquid volume lifting method cooperate with each other, so that the liquid lifted by the plunger controlled by the fixed liquid volume lifting device is fixed, thereby avoiding situations such as the plunger running empty or failing to reach the wellhead, and improving the efficiency of the plunger operation.

[0054] This embodiment is specifically described using an example in which the preset liquid column height of the wellbore is 300m, the preset wellhead pressure is 5MPa, and the preset bottom hole pressure is 5MPa. When using the fixed liquid volume lifting device in this embodiment for fixed liquid volume lifting, the fixed liquid volume lifting device is also equipped with a wellhead remote controller for sensing parameters such as wellhead pressure and wellhead flow, as well as for controlling related operations of opening and closing the gas well.

[0055] In combination with the above-mentioned specific parameters, the fixed liquid volume lifting method of this embodiment is specifically as follows:

[0056] When the height of the wellbore liquid column is 300m, the wellhead pressure reaches 5MPa. At this time, the first piston 20 in the downhole fixed liquid volume lifting device overcomes the opposite direction force provided by the first reset member 40 under the action of the wellhead pressure and moves downward. The first piston 20 switches from the first open position to the first closed position, and the first through hole 11 is blocked and closed by the first piston 20. The wellhead remote controller senses the wellhead oil pressure of 5MPa. At this time, the bottom hole pressure is 8MPa, and the gas well is opened. Figure 4 At this time, since the bottom hole pressure has also reached the preset bottom hole pressure, under the action of the bottom hole pressure, the second piston 30 overcomes the opposite direction force provided by the second reset member 50 and moves upward, the second piston 30 is located at the second open position, the connecting hole 31 is connected with the second through hole 12, the second through hole 12 is opened, and the bottom hole gas and liquid are transported upward through the hollow flow channel of the second piston 30 and the second through hole 12, while the liquid in the wellbore is lifted and discharged by the plunger.

[0057] As the 300m liquid column is completely discharged, the wellhead pressure drops to 2MPa. At this time, the wellhead and the bottom of the well are connected. Ignoring the pressure gradient, the bottom hole pressure is also 2MPa. Under the reset force of the first reset member 40, the first piston 20 moves upward, and the first piston 20 switches from the first closed position to the first open position. The first through hole 11 is avoided and opened by the first piston 20; due to the reduction of the bottom hole pressure, the second piston 30 moves downward under the action of the second reset member 50, and the second piston 30 blocks the second through hole 12 to close the second through hole 12. The bottom hole gas and liquid are transported upward through the first through hole 11, as shown in FIG. Figure 5 shown.

[0058] The gas well enters the continuous flow stage. Figure 6 As shown, as the wellbore liquid column gradually rises, the wellhead and bottom hole pressures gradually increase, the first piston 20 gradually moves downward, the first piston 20 is in the process of switching from the first open position to the first closed position, and the first through hole 11 is gradually closed; when the liquid column reaches 300m, the wellhead pressure reaches 5MPa, the first piston 20 completes the switching process and is in the first closed position, the first through hole 11 is completely closed, and the wellhead flow is 0 at this time. When the wellhead remote controller detects that the gas well flow is 0, the well is shut in. Figure 7 shown.

[0059] During the gradual increase of bottom hole pressure, the second piston 30 overcomes the second reset member 50 and moves upward, and the second piston 30 is in the process of switching from the second closed position to the second open position, but the second through hole 12 is still not connected with the connecting hole 31; due to the well shut-in, the bottom hole pressure continues to increase, and the second piston 30 continues to move upward. Once the bottom hole pressure is greater than 5MPa, the second through hole 12 is connected with the connecting hole 31, the second through hole 12 is opened, and the bottom hole gas and liquid are transported upward through the hollow flow channel of the second piston 30 and the second through hole 12. As the height of the liquid column increases, the wellhead oil pressure starts to increase from 2MPa, the pressure at the first piston 20 increases, and the first through hole 11 is always in a closed state. When the height of the wellbore liquid column reaches 300m, the wellhead oil pressure reaches 5MPa, and the wellhead remote controller performs gas well opening, such as Figure 4 As shown, the next cycle begins.

[0060] In this embodiment, the fixed liquid volume lifting method also includes: when the wellhead pressure does not exceed the wellhead preset pressure, the first piston 20 is maintained in the first open position under the action of the first reset member 40; when the bottom hole pressure does not exceed the bottom hole preset pressure, the second piston 30 is maintained in the second closed position under the action of the second reset member 50.

[0061] In this embodiment, the fixed liquid volume lifting method also includes a sealing process and an anchoring process before normal use, that is, when the fixed liquid volume lifting device is lowered. The sealing process includes: after the fixed liquid volume lifting method is placed at a predetermined position in the wellbore, the first shear nail 63 is cut off, and the lower segment 14 of the main body moves upward relative to the upper segment 13 and the connecting segment 62 under the action of the bottom hole pressure. During the upward movement of the lower segment 14, the lower segment 14 squeezes the expansion piece 61, and the expansion piece 61 expands radially and contacts and seals with the inner wall of the wellbore. The anchoring process includes: when placing, the external tool is connected to the placing head 73, and the fixed liquid volume lifting device is lowered into the wellbore through the placing head 73, at which time the diameter of the slip 75 is smaller than the diameter of the wellbore; when reaching the predetermined position, the placing head 73 is lifted, so that the slip 75 moves downward relative to the cone 71, and the slip 75 expands radially under the action of the cone surface of the cone 71 and contacts and anchors with the inner wall of the wellbore; the second shear nail 76 is cut off, and the placing head 73 is recovered, and the fixed liquid volume lifting device is placed and anchored. The specific process of sealing and anchoring and the matching mode between the components have been described in the aforementioned fixed liquid volume lifting device, and will not be repeated here.

[0062] It should be noted that, the multiple in the above embodiments refers to at least two.

[0063] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0064] 1. The invention solves the problem in the prior art that the plunger cannot reach the wellhead or the plunger runs empty during plunger gas lift drainage due to excessive or insufficient wellbore liquid accumulation.

[0065] 2. Avoid the situation where the plunger cannot move upward or cannot reach the wellhead due to the high position of the upper liquid column, resulting in inefficient drainage and gas production;

[0066] 3. It avoids the situation where the amount of liquid accumulated in the wellbore is small, resulting in the plunger running empty, which affects the implementation effect of the plunger gas well process, and improves the efficiency of the plunger operation.

[0067] Obviously, the above-described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0068] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0069] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A constant liquid volume lifting device, characterized in that: include: A main body, the main body having a hollow structure, a side surface of the main body being provided with a first through hole (11) and a second through hole (12) penetrating inside and outside, the first through hole (11) being located above the second through hole (12); a first piston (20), the first piston (20) being axially movable and penetrating the main body, and having a first closed position for shielding the first through hole (11) and a first open position for avoiding the first through hole (11); when the height of the wellbore liquid column reaches a preset height, the wellhead pressure drives the first piston (20) to move to the first closed position; The second piston (30) has a hollow flow passage. The second piston (30) is axially movable and penetrates the main body and is located below the first piston (20). The second piston (30) has a second closed position for shielding the second through hole (12) and a second open position for avoiding the second through hole (12). When the bottom hole pressure reaches a preset bottom hole pressure, the bottom hole pressure drives the second piston (30) to move to the second open position.

2. The constant liquid volume lifting device according to claim 1, characterized in that: A connecting hole (31) is provided on the side of the second piston (30); when the second piston (30) is located at the second open position, the connecting hole (31) is aligned with the second through hole (12); and the hollow flow channel is connected to the gap between the fixed liquid volume lifting device and the wellbore through the connecting hole (31) and the second through hole (12).

3. The constant liquid volume lifting device according to claim 1, characterized in that: The fixed liquid volume lifting device also includes a first reset member (40), the first reset member (40) abuts against the first piston (20) and drives the first piston (20) to move toward the first open position.

4. The constant liquid volume lifting device according to claim 1, characterized in that: The fixed liquid volume lifting device further comprises a second reset member (50), wherein the second reset member (50) abuts against the second piston (30) and drives the second piston (30) to move toward the second closed position.

5. The constant liquid volume lifting device according to claim 1, characterized in that: The first piston (20) is located above the second piston (30), and the first piston (20) and the second piston (30) are spaced apart from each other.

6. The constant liquid volume lifting device according to claim 1, characterized in that: There are a plurality of the first through holes (11) and / or the second through holes (12), and the first through holes (11) and / or the second through holes (12) are arranged at intervals along the circumference of the fixed liquid volume lifting device.

7. The constant liquid volume lifting device according to any one of claims 1 to 6, characterized in that: The main body includes an axially arranged upper segment (13) and a lower segment (14), the first through hole (11) and the second through hole (12) are both located in the upper segment (13), the fixed liquid volume lifting device also includes a sealing assembly (60), the sealing assembly (60) includes a radially expandable expansion member (61), the expansion member (61) is arranged between the upper segment (13) and the lower segment (14), and when the lower segment (14) moves relative to the upper segment (13), it squeezes the expansion member (61) to expand radially, so as to seal the gap between the fixed liquid volume lifting device and the wellbore.

8. The constant liquid volume lifting device according to claim 7, characterized in that: The sealing assembly (60) further comprises a connecting section (62) and a first shear nail (63). The connecting section (62) is located in the main body and is arranged between the upper segment (13) and the lower segment (14). The top end of the connecting section (62) is in contact with the upper segment (13). An expansion space (64) is provided between the bottom end of the connecting section (62) and the lower segment (14). The first shear nail (63) is arranged between the connecting section (62) and the lower segment (14). When sealing, the first shear nail (63) breaks, and the lower segment (14) moves upward under the action of the bottom hole pressure and squeezes the expansion member (61) to expand radially.

9. The constant liquid volume lifting device according to any one of claims 1 to 6, characterized in that: The fixed liquid volume lifting device further comprises an anchoring assembly (70), wherein the anchoring assembly (70) comprises: A cone portion (71), wherein the cone portion (71) is connected to the top end of the main body portion; a retaining ring (72), the retaining ring (72) being arranged on the top side of the cone portion (71); A delivery head (73), the delivery head (73) is located at the top of the cone portion (71) and is connected to the retaining ring (72) via a second shear nail (76); A fishing neck (74), the fishing neck (74) being sleeved on the outer ear of the cone portion (71) and being located below the retaining ring (72); A plurality of slips (75) are provided, wherein the slips (75) are located at the conical surface of the conical portion (71) and are connected to the bottom end of the fishing neck (74); when the slips (75) and the conical portion (71) move axially relative to each other, the conical surface of the conical portion (71) squeezes the slips (75) and drives the slips (75) to expand radially so as to abut against the inner wall of the wellbore.

10. A method for lifting a fixed liquid volume, characterized in that: The fixed liquid volume lifting device according to any one of claims 1 to 9 is used, and the fixed liquid volume lifting method comprises: When the height of the liquid column in the wellbore reaches a preset height, the first piston (20) moves to a first closed position under the action of the wellhead pressure, and the first through hole (11) is closed. When the wellhead pressure reaches the preset wellhead pressure, the gas well is opened. At this time, the bottom hole pressure reaches the preset bottom hole pressure, and the second piston (30) moves to a second open position under the action of the bottom hole pressure, and the second through hole (12) is opened. The gas and liquid at the bottom of the well are transported to the top of the fixed liquid volume lifting device through the hollow flow channel of the second piston (30), the second through hole (12), and the gap between the wellbore and the fixed liquid volume lifting device. At the same time, the liquid in the wellbore is lifted and discharged, the height of the liquid column in the wellbore decreases, and both the wellhead pressure and the bottom hole pressure decrease. As the wellhead pressure decreases, the first piston (20) moves to the first open position, and the first through hole (11) opens. At the same time, as the bottom hole pressure decreases, the second piston (30) moves to the second closed position, and the second through hole (12) closes. The gas and liquid at the bottom of the well are transported to the top of the fixed liquid volume lifting device through the hollow flow channel of the second piston (30), the first through hole (11), and the gap between the wellbore and the fixed liquid volume lifting device. The height of the liquid column in the wellbore gradually increases, and the wellhead pressure gradually increases. When the height of the wellbore liquid column reaches a preset height, the first piston (20) moves to a first closed position under the action of the wellhead pressure, the first through hole (11) is closed, the well bottom and the wellhead are disconnected, the wellhead flow is 0, and the gas well is shut down; After the well is shut in, the bottom hole pressure increases. When the bottom hole pressure reaches the preset bottom hole pressure, the second piston (30) moves to the second open position, the second through hole (12) opens, and the gas and liquid at the bottom of the well are transported to the top of the fixed liquid volume lifting device through the hollow flow channel, the second through hole (12), and the gap between the wellbore and the fixed liquid volume lifting device, so that the wellhead pressure gradually increases. The first through hole (11) remains closed. When the wellhead pressure reaches the preset wellhead pressure, the gas well is opened and the above process is repeated.

11. The method for lifting a fixed liquid volume according to claim 10, characterized in that: The fixed liquid volume lifting method also includes: When the height of the wellbore liquid column does not reach a preset height, the first piston (20) is kept in the first open position under the action of the first reset member (40); When the bottom hole pressure does not reach the preset bottom hole pressure, the second piston (30) is kept in the second closed position under the action of the second reset member (50).

12. The method for lifting a fixed liquid volume according to claim 10, characterized in that: The fixed liquid volume lifting method also includes a sealing process, and the sealing process includes: After the fixed liquid volume lifting method is placed at a predetermined position in the wellbore, the first shear nail (63) is cut off, and the lower segment (14) of the main body moves upward relative to the upper segment (13) and the connecting segment (62) under the action of the bottom hole pressure. During the upward movement of the lower segment (14), the lower segment (14) squeezes the expansion member (61), and the expansion member (61) expands radially and contacts and seals with the inner wall of the wellbore.

13. The method for lifting a fixed liquid volume according to claim 10, characterized in that: The fixed liquid volume lifting method also includes an anchoring process, and the anchoring process includes: During placement, the external tool is connected to the placement head (73), and the fixed liquid volume lifting device is lowered into the wellbore through the placement head (73). At this time, the diameter of the slip (75) is smaller than the diameter of the wellbore; When the predetermined position is reached, the delivery head (73) is lifted up, so that the slip (75) moves downward relative to the cone (71), and the slip (75) expands radially under the action of the cone surface of the cone (71) and contacts and anchors with the inner wall of the wellbore; The second shear nail (76) is cut off, and the delivery head (73) is recovered, and the delivery and anchoring of the fixed liquid volume lifting device is completed.

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