Layered negative pressure flowback plug removal tubular column

Abstract

The utility model discloses a layered negative pressure flowback plug removal tubular column which comprises an oil tube, a top packer, an interlayer packer, a bottom packer and a backwashing valve are sequentially arranged on the oil tube from top to bottom, and the layered negative pressure flowback plug removal tubular column further comprises a squeezing injection and suction conversion device and a flow channel dividing device. The squeezing, injecting and sucking conversion device is arranged between the interlayer packer and the bottom packer; the flow channel dividing device is arranged in the oil pipe, the upper end of the flow channel dividing device is connected with the top packer, and the lower end of the flow channel dividing device is connected with the squeezing and sucking conversion device. According to the utility model, layered negative-pressure flowback can be realized, differential negative-pressure plug removal tubular column design is carried out according to heterogeneity such as the blockage degree of each layer of a stratum, the tubular column is dragged from bottom to top, negative-pressure plug removal is carried out layer by layer, each layer is completely independent, different plug removal negative pressures are selected according to each layer, and the negative-pressure plug removal pressure is increased for well sections with serious blockage; and the highest unblocking pressure is the rated working pressure of the sleeve.

Description

Technical Field

[0001] The utility model relates to the technical field of oil well unblocking, in particular to a layered negative pressure backflow unblocking pipe column. Background Art

[0002] The development of the unconsolidated sandstone reservoirs in Shengli Oilfield has entered the middle and late stages. Often, one well exploits multiple different strata with many layers, long well sections and large interlayers. For example, a single well offshore Shengli encountered as many as 12 small layers, the span of the oil-bearing well section reached more than 300 meters, and the length of the interlayer reached more than 100 meters. There are large differences in interlayer permeability, porosity, mud content, blockage type, median particle size, sand production, etc. among the various strata.

[0003] For this type of reservoir, if the negative pressure unblocking measures are adopted in general, the layers with high permeability, high porosity and low mud content will return more blockages through negative pressure backflow, while the layers with low permeability, low porosity and high mud content will return less blockages through negative pressure backflow. The general negative pressure unblocking measures are not perfect, and the balanced utilization of each layer cannot be achieved in the later production, so that the layers with more liquid production still produce more liquid and oil, and the layers with less liquid production still produce less liquid and oil. This greatly affects the overall efficient development of loose sandstone reservoirs. After adopting reasonable stratified negative pressure flowback, differentiated negative pressure flowback measures can be carried out according to the specific reservoir characteristics of each layer. Differentiated negative pressure unblocking tubing strings can be designed according to the heterogeneity of each layer's physical properties, oil, gas and water content, mud content, blockage type, blockage degree, etc. In one trip of the tubing string, stratified negative pressure unblocking is carried out. From bottom to top, the tubing string is dragged to carry out negative pressure unblocking layer by layer. Different unblocking negative pressure pressures are selected for each layer, which is of great significance for the refined and efficient development of loose sandstone reservoirs.

[0004] Publication (Announcement) No.: CN116517506B, discloses a reciprocating rotary jet unblocking device and a method of using the device. The technical solution is: the lower end of the central tube is connected to a reciprocating motion conduit, the outer wall is provided with a first spiral track and a second spiral track, and the pitch of the second spiral track is greater than the pitch of the first spiral track, and the lower end of the reciprocating motion conduit is connected to a lower connecting seat; a rotating cylinder is installed on the outer wall, and the rotating cylinder is connected and matched with the first spiral track and the second spiral track through a crescent guide pin; the upper end of the rotating cylinder is movably connected to the upper rotating outer tube, and the lower end is movably connected to the lower rotating outer tube; the beneficial effects are: on the one hand, it reciprocates up and down while rotating to unblock the corresponding wellbore wall section with a rotary jet, and on the other hand, it generates a wellbore liquid water hammer impact effect, forms an impact vibration on the casing wall and the perforation blasthole, enhances the unblocking and dredging effect on the perforation blasthole, further improves the seepage capacity of the near-wellbore formation, and achieves the purpose of better reservoir transformation.

[0005] This prior art can only generally remove blockages, and cannot perform stratified negative pressure backflow and blockage removal construction.

[0006] Publication (Announcement) No.: CN202970575U, discloses a high-pressure jet and negative pressure suction unblocking device, including a negative pressure suction backflow unblocking device, an oil drain, a check valve, a rotating connection device, and a self-rotating ejector connected in sequence from top to bottom. The self-rotating ejector of the device is equipped with an oblique nozzle. After the high-pressure water flow ejected from the oblique nozzle reaches the unblocking part, it will produce a tangential force for stripping the blockage. At the same time, the self-rotating ejector can also rotate when spraying water, so that the water flow produces impact fatigue on the unblocking part, making the blockage easier to loosen and detach. The device not only has a good unblocking effect, but also has high work efficiency. In addition, after the high-pressure water jet unblocks, the impurities are discharged from the ground by the negative pressure suction method, which can better solve the pollution blockage problem in the oil layer.

[0007] This prior art can only generally remove blockages, and cannot perform stratified negative pressure backflow and blockage removal construction.

[0008] Publication (Announcement) No.: CN105672976A, discloses an integrated device for acidizing and negative pressure backflow, including an oil pipe extending into the casing, on which a converter, a high-pressure packer, and a negative pressure unblocker are arranged in sequence from top to bottom, and the central tube of the converter is connected to a small oil pipe and connected to the diffusion tube inside the negative pressure unblocker through the sealing cannula of the unblocker. A downhole flow pressure gauge is arranged below the negative pressure unblocker and at the bottom of the oil pipe. A conversion hole is arranged on the converter, and the annulus between the oil pipe and the casing above the high-pressure packer is connected to the negative pressure unblocker through the conversion hole and the central tube. A suction port connected to the diffusion tube is arranged inside the negative pressure unblocker, and a nozzle connected to the suction port and at a certain distance from the inlet of the diffusion tube is arranged inside. The invention realizes the function of combining acidizing and acid removal and unblocking in one, and completes acidizing and unblocking the pollutants in the near-well zone to the ground in one trip of the tubing string, has the characteristics of strong suction energy and timely backflow, and effectively improves the acidizing and unblocking effect of oil and water wells.

[0009] This prior art can only generally remove blockages by acidification, and cannot perform stratified negative pressure backflow and blockage removal construction.

[0010] In short, the technical solutions of the above-disclosed technologies, the technical problems to be solved and the beneficial effects produced are all different from the present utility model. Regarding more technical features, technical problems to be solved and the beneficial effects of the present utility model, there is no technical inspiration in the above-disclosed technical documents. Utility Model Content

[0011] In view of the above-mentioned defects in the prior art, the purpose of the utility model is to provide a layered negative pressure backflow unblocking string, to carry out a differentiated negative pressure unblocking string design, to drag the string from bottom to top, to carry out negative pressure unblocking layer by layer, each layer is completely independent, and a different unblocking negative pressure pressure is selected for each layer, and the negative pressure unblocking pressure is increased in severely blocked well sections, and the maximum unblocking pressure is the rated working pressure of the casing.

[0012] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0013] A layered negative pressure backflow unblocking string comprises an oil pipe, on which a top packer, an interlayer packer, a bottom packer and a backwash valve are arranged in sequence from top to bottom, and the oil pipe also comprises an injection-injection conversion device and a flow channel dividing device; the injection-injection conversion device is arranged between the interlayer packer and the bottom packer; the flow channel dividing device is arranged in the oil pipe, with the upper end connected to the top packer and the lower end connected to the injection-injection conversion device.

[0014] Furthermore, the extrusion-injection-intake conversion device is a negative pressure return pump, and the flow channel dividing device is an extrusion-injection-discharge integrated discharge flushing pipe;

[0015] Specifically, the negative pressure flowback pump is arranged between the interlayer packer and the bottom packer, the upper end of the integrated squeezing and drainage flushing pipe is connected to the inside of the top packer, and the lower end is connected to the upper end of the negative pressure flowback pump.

[0016] Furthermore, the negative pressure return pump comprises a negative pressure return pump upper joint, an external sealing pipe, a negative pressure conversion device, a negative pressure return pump base pipe, and a negative pressure return pump lower joint;

[0017] Specifically, the upper joint of the negative pressure return pump is arranged at the upper end of the negative pressure return pump base pipe, the lower joint of the negative pressure return pump is arranged at the lower end of the negative pressure return pump base pipe, and the negative pressure conversion device is arranged in the negative pressure return pump base pipe and connected to the negative pressure return pump base pipe.

[0018] Furthermore, the negative pressure conversion device is provided with an axial central through hole, an axial flow hole, and a side wall is provided with an extrusion and suction conversion port connected to the axial central through hole;

[0019] Specifically, the axial center through hole is divided into an upper axial center through hole and a lower axial center through hole by the extrusion and suction conversion port, and a high-pressure nozzle is arranged at the upper end of the lower axial center through hole;

[0020] Specifically, the lower end of the outer sealed tube is connected to the upper end of the negative pressure conversion device, and a negative pressure chamber is provided at the lower end inside the outer sealed tube.

[0021] Furthermore, the top packer is a mechanical pressurized packer, comprising a top packer base pipe, a conversion upper joint, a top packer setting device, and a top packer lower joint;

[0022] Specifically, the lower end of the conversion upper joint is externally threadedly connected to the top packer base pipe, the top packer setting device is sleeved on the top packer base pipe, and the upper end of the top packer lower joint is connected to the top packer base pipe;

[0023] Specifically, the sealing component of the top packer setting device is a first rubber cylinder, and the starting component is a top packer setting shear pin.

[0024] Furthermore, the upper end of the conversion upper joint is threadedly connected to the oil pipe, and the lower end is internally threadedly connected to the integrated drainage flushing pipe for squeezing and draining;

[0025] Specifically, the conversion upper joint is provided with a negative pressure unblocking liquid inlet channel, and the negative pressure unblocking liquid inlet channel connects the annulus between the top packer base pipe and the squeeze and drain integrated liquid flushing pipe with the oil casing annulus.

[0026] Furthermore, an inner sealing tube is provided at the lower end of the integrated drainage flushing tube;

[0027] Specifically, the inner sealing tube and the outer sealing tube cooperate to form a combined seal.

[0028] Furthermore, the interlayer packer is a variable track compression packer, comprising a central pipe, an upper joint of the interlayer packer, a setting device of the interlayer packer, and a lower joint of the interlayer packer;

[0029] Specifically, the upper joint of the interlayer packer is arranged at the upper end of the central pipe, and the lower joint of the interlayer packer is arranged at the lower end of the central pipe;

[0030] Specifically, the interlayer packer setting device is sleeved on the outer wall of the central pipe, and a second rubber cylinder, a track and slips are arranged in the interlayer packer setting device.

[0031] Furthermore, the bottom packer is an expansion packer, which is provided with a bottom packer pressure transmission hole and a third rubber cylinder.

[0032] Furthermore, the top packer and the interlayer packer are connected via a first transition oil pipe, and the interlayer packer and the negative pressure flowback pump are connected via a second transition oil pipe.

[0033] Compared with the prior art, the utility model has the following beneficial effects:

[0034] 1. It can perform negative pressure flowback in different layers. According to the heterogeneity of each layer of the formation, a differentiated negative pressure unblocking string is designed. From bottom to top, the string is dragged to carry out negative pressure unblocking layer by layer. Each layer is completely independent. Different unblocking negative pressure is selected for each layer. The negative pressure unblocking pressure is increased in the seriously blocked well section. The highest unblocking pressure is the rated working pressure of the casing.

[0035] 2. No nitrogen vehicle is required, and hydraulic negative pressure is used, so the construction cost is low.

[0036] 3. Reverse circulation layered negative pressure return, positive layered squeezing and injection of plugging agents, each layer is completely independent, and different types of plugging agents can be selected according to the blockage type, blockage radius and mud content of each layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a structural schematic diagram of a layered negative pressure backflow and plugging removal column of the utility model;

[0038] Figure 2 It is a cross-sectional schematic diagram of a negative pressure conversion device for layered negative pressure backflow and plugging removal of a pipe column according to the utility model;

[0039] Figure 3 It is the state of the pipe string when the layered negative pressure backflow unblocking pipe string is lowered into the utility model;

[0040] Figure 4 The utility model is a layered negative pressure backflow unblocking pipe string tool set, ready for bottom layer unblocking pipe string state;

[0041] Figure 5 The utility model is a pipe column state in which acid and unblocking agent are squeezed into the bottom layer of a layered negative pressure backflow unblocking pipe column in a positive direction;

[0042] Figure 6 The utility model is a pipe column state of reverse hydraulic negative pressure backflow and blockage removal in the bottom layer of a layered negative pressure backflow and blockage removal pipe column;

[0043] Figure 7 The utility model is a pipe string state of a layered negative pressure backflow unblocking pipe string with middle layer negative pressure backflow unblocking;

[0044] Figure 8 The utility model discloses a layered negative pressure backflow unblocking pipe string with upper layer negative pressure backflow unblocking pipe string;

[0045] In the figure: 1. conversion upper joint; 2. negative pressure unblocking liquid inlet channel; 3. top packer; 4. first rubber cylinder; 5. top packer setting device; 6. top packer setting shear pin; 7. top packer lower joint; 8. squeeze and discharge integrated flushing pipe; 9. transition oil pipe; 10. interlayer packer upper joint; 11. second rubber cylinder; 12. interlayer packer; 13. slips; 14. track; 15. interlayer packer setting device ; 16. Lower joint of interlayer packer; 17. Upper joint of negative pressure return pump; 18. Negative pressure return pump; 19. Inner sealing tube; 20. Outer sealing tube; 21. Negative pressure chamber; 22. Negative pressure conversion device; 23. Base pipe of negative pressure return pump; 24. Conversion port for injection and suction; 25. High-pressure nozzle; 26. Lower joint of negative pressure return pump; 27. Bottom packer; 28. Pressure transmission hole of bottom packer; 29. ​​Third rubber cylinder; 30. Backwash valve. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0047] It should be noted that the contents of the drawings are not directly spliced ​​from the cut ends. The connection relationship between the two parts in a figure can be seen through the numbers.

[0048] Embodiment 1:

[0049] See also Figure 1 The utility model provides a layered negative pressure backflow unblocking pipe string, including a top packer 3, an interlayer packer 12, a negative pressure backflow pump 18, a bottom packer 27, and a backwash valve 30 connected in sequence from top to bottom; the top packer 3 and the interlayer packer 12 are connected by a transition oil pipe 9, and the top packer 3 is internally connected with an integrated drainage and flushing pipe 8 for squeezing and draining, and the lower end of the integrated drainage and flushing pipe 8 for squeezing and draining is connected to the negative pressure backflow pump 18.

[0050] The top packer 3 is a mechanically pressurized packer, including a top packer base pipe, a conversion upper joint 1, a top packer sealing device 5, and a top packer lower joint 7; the lower end of the conversion upper joint 1 is externally threadedly connected to the top packer base pipe, the top packer sealing device 5 is sleeved on the top packer base pipe, and the upper end of the top packer lower joint 7 is connected to the top packer base pipe; the sealing part of the top packer sealing device 5 is a first rubber cylinder 4, and the starting part is a top packer sealing shear pin 6; the top packer 3 is a prior art, and its structural composition is clear to those skilled in the art, so it will not be repeated.

[0051] The upper end of the conversion upper joint 1 is threadedly connected to the oil pipe, and the lower end is internally threadedly connected to the integrated drainage and flushing pipe 8 for squeezing and draining; the conversion upper joint 1 is provided with a negative pressure unblocking liquid inlet channel 2, and the negative pressure unblocking liquid inlet channel 2 connects the annulus between the top packer base pipe and the integrated drainage and flushing pipe 8 for squeezing and draining with the annulus of the oil casing.

[0052] The method of using the top packer 3 is as follows: after the pipe string is lowered to the designed depth, after the interlayer packer 12 is set, the oil pipe is continuously pressurized by 50 kN, the hanging weight of the oil pipe acts on the top packer setting device 5, the top packer setting shear pin 6 is cut off, and the first rubber cylinder 4 is set;

[0053] The interlayer packer 12 is a variable track compression packer, including a central tube, an interlayer packer upper joint 10, an interlayer packer sealing device 15, and an interlayer packer lower joint 16. The interlayer packer upper joint 10 is arranged at the upper end of the central tube, the interlayer packer lower joint 16 is arranged at the lower end of the central tube, the interlayer packer sealing device 15 is sleeved on the outer wall of the central tube, and the interlayer packer sealing device 15 is provided with a second rubber cylinder 11, a track 14, and a slip 13. The interlayer packer 12 is a prior art, and its structure and composition are clear to those skilled in the art, so it will not be described in detail.

[0054] The interlayer packer 12 is connected to the negative pressure flowback pump 18 through a transition oil pipe 9 .

[0055] The method of using the interlayer packer 12 is to lower the pipe string to the target depth, lift the pipe string to set the depth, and the interlayer packer sealing device 15 is changed to a long track through the track 14, push the slip 13 to anchor, and push the second rubber cylinder 11 to seal.

[0056] The negative pressure return pump 18 includes a negative pressure return pump upper connector 17, an external sealing tube 20, a negative pressure conversion device 22, a negative pressure return pump base pipe 23, and a negative pressure return pump lower connector 26;

[0057] The negative pressure return pump upper joint 17 is arranged at the upper end of the negative pressure return pump base pipe 23, the negative pressure return pump lower joint 26 is arranged at the lower end of the negative pressure return pump base pipe 23, the negative pressure conversion device 22 is arranged in the negative pressure return pump base pipe 23 and connected to the negative pressure return pump base pipe 23, the negative pressure conversion device 22 is provided with an axial center through hole, an axial flow hole, and a side wall is provided with an extrusion and suction conversion port 24 connected to the axial center through hole, the axial center through hole is divided into an upper axial center through hole and a lower axial center through hole by the extrusion and suction conversion port 24, the upper end of the lower axial center through hole is provided with a high-pressure nozzle 25, the lower end of the outer sealing tube 20 is connected to the upper end of the negative pressure conversion device 22, and the lower end of the inner part of the outer sealing tube 20 is provided with a negative pressure chamber 21.

[0058] An inner sealing tube 19 is disposed at the lower end of the integrated drainage flushing tube 8; the inner sealing tube 19 and the outer sealing tube 20 cooperate to form a combined seal to form two annular sealed spaces.

[0059] When squeezing and injecting the plugging-removing liquid, the plugging-removing liquid enters the squeezing and injection integrated flushing pipe 8 through the oil pipe, passes through the inner sealing pipe 19, passes through the negative pressure chamber 21, and under the obstruction of the high-pressure nozzle 25, passes through the squeezing and suction conversion port 24 to reach the formation;

[0060] During negative pressure backflow, clean produced water passes through the oil pipe and casing annulus to reach the negative pressure unblocking liquid inlet channel 2, enters the annular space of the top packer 3 and the integrated squeezing and drainage flushing pipe 8, passes through the interlayer packer 12 and the integrated squeezing and drainage flushing pipe 8 annular space, passes through the outer sealing pipe 20 and the negative pressure backflow pump base pipe 23 annular space, passes through the flow hole of the negative pressure conversion device 22, and reaches the high-pressure nozzle 25. The high-speed liquid flows through the negative pressure chamber 21 to generate negative pressure. The negative pressure attracts the formation mud and sand and the unblocking reaction products into the negative pressure chamber 21 through the squeezing and suction conversion port 24. The high-pressure clean produced water mixed with the negative pressure backflow reactants passes through the inner sealing pipe 19, enters the integrated squeezing and drainage flushing pipe 8, and finally reaches the ground recovery pool through the oil pipe.

[0061] By changing the high pressure nozzle 25, the negative pressure chamber 21 and the displacement of the ground pump, the negative pressure unblocking pressure can be changed.

[0062] The negative pressure return pump 18 is connected to the bottom packer 27 through the negative pressure return pump lower joint 26. The bottom packer 27 is an expansion packer, which is provided with a bottom packer pressure transmission hole 28 and a third rubber cylinder 29 inside. The bottom packer 27 is a prior art, and its structural composition is clear to those skilled in the art, so it will not be repeated.

[0063] Working process: In the forward direction, the unblocking liquid passes through the inner sealing tube 19, through the negative pressure chamber 21, and enters the bottom packer pressure transmission hole 28, and the third rubber cylinder 29 expands and seals. In the reverse direction, the clean produced water enters the bottom packer pressure transmission hole 28 through the outer sealing tube 20 and the annular space of the negative pressure return pump base pipe 23, and the third rubber cylinder 29 expands and seals. The bottom packer 27 can be sealed in both forward and reverse construction. After stopping the pump, the pressure diffuses and the third rubber cylinder 29 automatically retracts.

[0064] The backwash valve 30 is connected to the lower end of the bottom packer 27 by threads, and the backwash valve 30 can be backwashed at any time to prevent blockages from being deposited in the annular space between the tool and the casing, thereby improving construction safety. The backwash valve 30 is a prior art, and its structure and composition are clear to those skilled in the art, so it will not be described in detail.

[0065] The transition oil pipe 9 is divided into a first transition oil pipe 9 and a second transition oil pipe 9; the top packer lower joint 7 is connected to the upper end of the first transition oil pipe, and the interlayer packer upper joint 10 is connected to the lower end of the first transition oil pipe; the interlayer packer lower joint 16 is connected to the upper end of the second transition oil pipe, and the negative pressure return pump upper joint 17 is connected to the lower end of the second transition oil pipe; the first transition oil pipe and the second transition oil pipe are adjusted in length according to the thickness of the oil layer and the barrier layer.

[0066] Embodiment 2:

[0067] Please refer to Figure 1-8 This embodiment provides a method for using the column:

[0068] S1, running tool: the oil pipe is connected to the top packer 3, the top packer 3 is threadedly connected to the first transition oil pipe, the length of the first transition oil pipe is adjusted according to the thickness of the oil layer and the barrier layer, the first transition oil pipe is threadedly connected to the interlayer packer 12, the interlayer packer 12 is connected to the second transition oil pipe through the lower joint 16 of the interlayer packer, the length of the second transition oil pipe is adjusted according to the thickness of the oil layer and the barrier layer, the second transition oil pipe is threadedly connected to the negative pressure return pump 18, the lower joint 26 of the negative pressure return pump is threadedly connected to the bottom packer 27, and the bottom packer 27 is threadedly connected to the backwash valve 30;

[0069] S2, tool setting, prepare for bottom blockage removal: after reaching the designed depth, first set the interlayer packer 12, which is a variable track compression packer. After reaching the designed depth, lift the pipe string and rotate it forward. The interlayer packer setting device 15 is changed to a long track through the track 14, and the oil pipe is pressed down. The slip 13 is first pushed to anchor, and then the second rubber cylinder 11 is pushed to set and seal the annulus of the oil casing, so that when the bottom blockage is removed, the blockage removal fluid cannot enter the upper oil layer, and the return fluid cannot enter the bottom from the upper part during negative pressure return.

[0070] Continue to pressurize the tubing to 50kN, the tubing hanging weight acts on the top packer setting device 5, the top packer setting shear pin 6 is cut off, the first rubber cylinder 4 is set, and the top packer 3 seals the top casing annulus, so that during flowback, the clean produced water passes through the negative pressure unblocking liquid inlet channel 2, enters the top packer 3 and the annular space of the squeezing and drainage integrated flushing pipe 8, does not pass through the top and middle oil layers, and directly reaches the bottom oil layer, and only performs negative pressure unblocking on the bottom oil layer;

[0071] The bottom packer 27 is an expansion packer. When the plugging liquid is squeezed out in the forward direction, the plugging liquid passes through the inner sealing tube 19, passes through the negative pressure chamber 21, and enters the pressure transmission hole of the bottom packer. The third rubber cylinder 29 expands and seals. When the negative pressure is returned in the reverse direction, the clean produced water enters the pressure transmission hole 28 of the bottom packer through the outer sealing tube 20 and the annular space of the negative pressure return pump base pipe 23. The third rubber cylinder 29 expands and seals. The bottom packer 27 can be set in both forward and reverse construction. After the pump is stopped, the pressure is diffused and the third rubber cylinder 29 retracts.

[0072] S3, positively squeeze acid and unblocking agent into the bottom layer: when squeezing unblocking liquid, the ground is connected in a positive circulation mode, the unblocking liquid enters the squeezing and drainage integrated flushing pipe 8 through the oil pipe, passes through the inner sealing pipe 19, passes through the negative pressure chamber 21, and reaches the bottom oil layer through the squeezing and suction conversion port 24. The interlayer packer 12 and the third rubber cylinder 29 have been set to seal the oil casing annulus, and the unblocking liquid will not enter other oil layers;

[0073] S4, reverse hydraulic negative pressure backflow and unblocking in the bottom layer: during negative pressure backflow, clean produced water passes through the oil pipe and casing annulus to reach the negative pressure unblocking liquid inlet channel 2, enters the annular space of the top packer 3 and the integrated squeezing and drainage flushing pipe 8, passes through the interlayer packer 12 and the annular space of the integrated squeezing and drainage flushing pipe 8, passes through the outer sealing pipe 20 and the annular space of the negative pressure backflow pump base pipe 23, and passes through the flow hole of the negative pressure conversion device 22 to reach the high-pressure nozzle 25. The high-speed liquid flows through the negative pressure chamber 21 to generate negative pressure. The negative pressure attracts the formation mud and sand and the unblocking reaction products to enter the negative pressure chamber 21 through the squeezing and suction conversion port 24. The high-pressure clean produced water mixed with the negative pressure backflow reactants passes through the inner sealing pipe 19, enters the integrated squeezing and drainage flushing pipe 8, and finally reaches the ground recovery pool through the oil pipe; the interlayer packer 12 and the third rubber cylinder 29 have been sealed to isolate the oil casing annulus, and the unblocking liquid will not enter other oil layers;

[0074] S5. Lift the tool to the middle layer, seal the tool, squeeze acid in the middle layer, and use reverse hydraulic negative pressure to unblock: lift the tool to the designed depth of the middle layer, seal it according to the relevant operations of the bottom layer tool sealing, and when squeezing and injecting the unblocking liquid, the ground is connected in a positive circulation mode. The unblocking liquid enters the integrated flushing pipe 8 for squeezing and draining through the oil pipe, passes through the inner sealing pipe 19, passes through the negative pressure chamber 21, and reaches the bottom oil layer through the squeezing and suction conversion port 24. The interlayer packer 12 and the third rubber cylinder 29 have been sealed to seal the annulus of the oil casing, and the unblocking liquid will not enter the upper and lower oil layers.

[0075] During negative pressure backflow, clean produced water passes through the oil pipe and casing annulus to reach the negative pressure unblocking liquid inlet channel 2, enters the annular space of the top packer 3 and the integrated squeezing and drainage flushing pipe 8, passes through the interlayer packer 12 and the annular space of the integrated squeezing and drainage flushing pipe 8, passes through the outer sealing pipe 20 and the annular space of the negative pressure backflow pump base pipe 23, and passes through the flow hole of the negative pressure conversion device 22 to reach the high-pressure nozzle 25. The high-speed liquid flows through the negative pressure chamber 21 to generate negative pressure. The negative pressure attracts the formation mud and sand and the unblocking reaction products to enter the negative pressure chamber 21 through the squeezing and suction conversion port 24. The high-pressure clean produced water mixed with the negative pressure backflow reactants passes through the inner sealing pipe 19, enters the integrated squeezing and drainage flushing pipe 8, and finally reaches the ground recovery pool through the oil pipe; the interlayer packer 12 and the third rubber cylinder 29 have been sealed to isolate the oil casing annulus, and the unblocking liquid will not enter the upper and lower oil layers;

[0076] S6, lift the tool to the upper layer, set the tool, squeeze acid in the upper layer, and reverse hydraulic negative pressure to unblock: lift the tool to the upper layer design depth, set the tool according to the bottom layer and middle layer tool setting related operations, squeeze and inject the unblocking liquid, the ground is connected in a positive circulation mode, the unblocking liquid enters the squeezing and drainage integrated flushing pipe 8 through the oil pipe, passes through the inner sealing pipe 19, passes through the negative pressure chamber 21, and reaches the bottom oil layer through the squeezing and suction conversion port 24. The interlayer packer 12 and the third rubber cylinder 29 have been set, the oil casing annulus is sealed, and the unblocking liquid will not enter the upper and lower oil layers;

[0077] During negative pressure backflow, clean produced water passes through the oil pipe and casing annulus to reach the negative pressure unblocking liquid inlet channel 2, enters the annular space of the top packer 3 and the integrated squeezing and drainage flushing pipe 8, passes through the interlayer packer 12 and the integrated squeezing and drainage flushing pipe 8 annular space, passes through the outer sealing pipe 20 and the annular space of the negative pressure backflow pump base pipe 23, and reaches the high-pressure nozzle 25 through the flow hole of the negative pressure conversion device 22. The high-speed liquid flows through the negative pressure chamber 21 to generate negative pressure. The negative pressure attracts the formation mud and sand and the unblocking reaction products into the negative pressure chamber 21 through the squeezing and suction conversion port 24. The high-pressure clean produced water mixed with the negative pressure backflow reactants passes through the inner sealing pipe 19, enters the integrated squeezing and drainage flushing pipe 8, and finally reaches the ground recovery pool through the oil pipe; the interlayer packer 12 and the third rubber cylinder 29 have been sealed to isolate the oil casing annulus, and the unblocking liquid will not enter the upper and lower oil layers.

[0078] Embodiment 3:

[0079] Please refer to Figure 1 This embodiment provides the simplest form of the pipe string, including an oil pipe, on which a top packer, an interlayer packer, a bottom packer, a backwash valve are sequentially arranged from top to bottom, and also includes a squeeze-injection suction conversion device and a flow channel dividing device;

[0080] The squeeze-injection-injection conversion device is arranged between the interlayer packer and the bottom packer; the flow channel dividing device is arranged in the oil pipe, the upper end of which is connected to the top packer, and the lower end of which is connected to the squeeze-injection-injection conversion device.

[0081] All components and connection methods of components not discussed in this application belong to the known technologies in this technical field and can be directly applied without further explanation.

[0082] In the present invention, the term "plurality" means two or more than two, unless otherwise clearly defined. The terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0083] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by terms such as "up", "down", "left", "right", "front" and "back" are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore, cannot be understood as a limitation on the present invention.

[0084] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0085] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A layered negative pressure backflow unblocking string, comprising an oil pipe, on which a top packer, an interlayer packer, a bottom packer, and a backwash valve are arranged in sequence from top to bottom. It is characterized in that It also includes an extrusion-injection-intake conversion device and a flow channel dividing device; The squeeze-injection-intake conversion device is arranged between the interlayer packer and the bottom packer; The flow channel dividing device is arranged in the oil pipe, the upper end of which is connected to the top packer, and the lower end of which is connected to the squeeze-injection suction conversion device.

2. A layered negative pressure drainage and plugging removal column according to claim 1, characterized in that: The extrusion and suction conversion device is a negative pressure return pump, and the flow channel dividing device is an extrusion and drainage integrated drainage flushing pipe; The negative pressure flowback pump is arranged between the interlayer packer and the bottom packer, the upper end of the integrated squeezing and drainage flushing pipe is connected to the inside of the top packer, and the lower end is connected to the upper end of the negative pressure flowback pump.

3. A layered negative pressure drainage and plugging removal column according to claim 2, characterized in that: The negative pressure return pump comprises a negative pressure return pump upper joint, an external sealing pipe, a negative pressure conversion device, a negative pressure return pump base pipe, and a negative pressure return pump lower joint; The upper connector of the negative pressure return pump is arranged at the upper end of the base pipe of the negative pressure return pump, the lower connector of the negative pressure return pump is arranged at the lower end of the base pipe of the negative pressure return pump, and the negative pressure conversion device is arranged in the base pipe of the negative pressure return pump and connected to the base pipe of the negative pressure return pump.

4. A layered negative pressure drainage and plugging removal column according to claim 3, characterized in that: The negative pressure conversion device is provided with an axial central through hole, an axial flow hole, and a side wall is provided with an extrusion and suction conversion port connected to the axial central through hole; The axial center through hole is divided into an upper axial center through hole and a lower axial center through hole by the extrusion and suction conversion port, and a high-pressure nozzle is arranged at the upper end of the lower axial center through hole; The lower end of the outer sealed tube is connected to the upper end of the negative pressure conversion device, and a negative pressure chamber is arranged at the lower end inside the outer sealed tube.

5. A layered negative pressure drainage and plugging removal column according to claim 4, characterized in that: The top packer is a mechanical pressurized packer, comprising a top packer base pipe, a conversion upper joint, a top packer setting device, and a top packer lower joint; The lower end of the conversion upper joint is externally threadedly connected to the top packer base pipe, the top packer setting device is sleeved on the top packer base pipe, and the upper end of the top packer lower joint is connected to the top packer base pipe; The sealing part of the top packer setting device is a first rubber cylinder, and the starting part is a top packer setting shear pin.

6. A layered negative pressure drainage and plugging removal column according to claim 5, characterized in that: The upper end of the conversion upper joint is threadedly connected to the oil pipe, and the lower end is internally threadedly connected to the integrated drainage flushing pipe for squeezing and drainage; The conversion upper joint is provided with a negative pressure unblocking liquid inlet channel, and the negative pressure unblocking liquid inlet channel connects the annulus between the top packer base pipe and the squeeze and drain integrated liquid flushing pipe with the oil casing annulus.

7. The layered negative pressure drainage and plugging removal column according to claim 6, characterized in that: An inner sealing tube is provided at the lower end of the integrated drainage flushing pipe; The inner sealing tube and the outer sealing tube cooperate to form a combined seal.

8. The layered negative pressure drainage and plugging removal column according to claim 1, characterized in that: The interlayer packer is a variable track compression packer, comprising a central pipe, an upper joint of the interlayer packer, a setting device of the interlayer packer, and a lower joint of the interlayer packer; The upper joint of the interlayer packer is arranged at the upper end of the central pipe, and the lower joint of the interlayer packer is arranged at the lower end of the central pipe; The interlayer packer setting device is sleeved on the outer wall of the central pipe, and a second rubber cylinder, a track and slips are arranged in the interlayer packer setting device.

9. The layered negative pressure drainage and plugging removal column according to claim 1, characterized in that: The bottom packer is an expansion packer, and is internally provided with a bottom packer pressure transmission hole and a third rubber cylinder.

10. A layered negative pressure drainage and plugging removal column according to any one of claims 2 to 9, characterized in that: The top packer and the interlayer packer are connected via a first transition oil pipe, and the interlayer packer and the negative pressure flowback pump are connected via a second transition oil pipe.

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