Layered sand control and polymer injection integrated pipe column and construction method

Abstract

The application discloses a layered sand prevention and polymer injection integrated pipe column and a construction method, relates to the technical field of oil exploitation, and the pipe column comprises a downhole pipe column and a control pipe column. The downhole pipe column comprises a layered sand prevention and polymer injection unit. The layered sand prevention and polymer injection unit comprises a positioning cylinder, an adjustable sand prevention and injection device, a blockage removal injection device and layered packers. The control pipe column comprises a positioning tool and a repeatedly switchable tool. The positioning tool can be positioned with the positioning cylinder, and the repeatedly switchable tool can control and regulate the adjustable sand prevention and injection device and the blockage removal injection device. The application realizes sand prevention and polymer injection integration through the adjustable sand prevention and injection device. The application realizes downhole efficient regulation through the positioning tool and the repeatedly switchable tool.

Description

Technical Field

[0001] This invention relates to the field of oil extraction technology, specifically to a layered sand control and polymer injection integrated tubing string and its construction method. Background Technology

[0002] Currently, the "3+2" chemical flooding projects in oilfields are mainly sand-producing reservoirs, all of which require sand control construction. However, due to the 5-1 / 2 wellbore size limitation, traditional mechanical filter installation cannot be used. Injection wells often use chemical sand control, followed by secondary well completion in the wellbore, i.e., running a single-tube polymer injection string. This process is cumbersome, takes a long time to occupy the well, and when the chemical sand control fails, the layered polymer injection string must also be retrieved, resulting in high operating costs.

[0003] Announcement No. CN114482943B discloses a layered polyinjection tubing string and its usage method for layered sand control wells. The string includes a plug, an electro-hydraulic integrated polyinjector, a through-type sealing plug, a hydraulic control line, an armored cable, a sand control casing, a polyinjection tubing, a positioner, a sand control cable-controlled high-thrust intelligent packer, a filter pipe, and several pressure sensors. It employs a single-tube layered injection method, with all supporting tools designed for small diameters. The single-layer polyinjector uses a hybrid electro-hydraulic approach to control its opening. An electric control adjusts the hydraulic circuit to provide hydraulic pressure to the downhole tools. Finally, flow control for each oil and water layer is achieved through a surface hydraulic control line and a signal cable.

[0004] The existing technology involves separately installing the sand control tubing and the polymer injection tubing. The polymer injection tubing has a large outer diameter, which cannot meet the requirements of mechanical layered sand control for 5-1 / 2 wellbore tubing.

[0005] Publication No. CN115726748A discloses a hydraulic-electric composite layered polymer injection string, device, and construction method. The polymer injection device includes a track reversing mechanism and a flow regulation mechanism connected to each other; a piston control mechanism, which controls and guides the flow rate of each layer downhole by monitoring the flow rate at the wellhead and adopts a step-by-step decreasing method, eliminating the need to run a flow meter and saving cable costs.

[0006] The existing technology involves separately installing the sand control tubing and the polymer injection tubing. The polymer injection tubing has a large outer diameter, which cannot meet the requirements of mechanical layered sand control for 5-1 / 2 wellbore tubing.

[0007] Publication No. CN115680586A discloses a layered polymer injection cylinder with intelligent measurement and adjustment function, including a layered polymer injection tubing and a layered polymer injection working cylinder installed inside it. The present invention aims to propose a layered polymer injection cylinder with intelligent measurement and adjustment function so as to realize real-time monitoring of polymer injection flow rate and pressure during the layered polymer injection process.

[0008] The existing technology uses a throttling unit to regulate polymer flow rate. The viscosity retention rate is affected by machining accuracy. The sand control tubing and the polymer injection tubing are installed separately. The polymer injection tubing has a large outer diameter, which cannot meet the requirements of mechanical layered sand control for 5-1 / 2 wellbore tubing.

[0009] Announcement No. CN112709556B discloses a rapid completion string and construction method for water injection wells in offshore oilfields. The completion string includes a sand control string and a water injection string, with the water injection string installed inside the sand control string. It also includes a bridge plug string connected to the lower end of the sand control string. The sand control string includes at least two filter pipes, each corresponding to a different oil layer, spaced downwards on the casing. Y341 packers are installed between each pair of filter pipes, above the uppermost filter pipe, and below the lowermost filter pipe. The water injection string includes at least two adjustable water distributors, each corresponding to a different oil layer, spaced downwards on the tubing. A setting switch is connected to the bottom of each adjustable water distributor.

[0010] The existing technology uses a throttling unit to regulate polymer flow rate. The viscosity retention rate is affected by machining accuracy. The sand control tubing and the polymer injection tubing are installed separately. The polymer injection tubing has a large outer diameter, which cannot meet the requirements of mechanical layered sand control for 5-1 / 2 wellbore tubing.

[0011] Announcement No. CN109252834B discloses a concentric dual-channel long-term stratified water injection device and method. The device includes an unsealing controller, a first bridge-type self-locking expansion packer, a first bridge-type anti-backflow water distributor, a second bridge-type self-locking expansion packer, and a second bridge-type anti-backflow water distributor connected in sequence from top to bottom. The first bridge-type anti-backflow water distributor is located in the first water injection layer, and the second bridge-type anti-backflow water distributor is located in the second water injection layer.

[0012] The existing technology uses a throttling unit to regulate polymer flow rate. The viscosity retention rate is affected by machining accuracy. The sand control tubing and the polymer injection tubing are installed separately. The polymer injection tubing has a large outer diameter, which cannot meet the requirements of mechanical layered sand control for 5-1 / 2 wellbore tubing.

[0013] Publication No. CN116104461A discloses a high-efficiency working string and construction method for layered flowback and layered acidizing, including a plug, tubing, anchor packer, several layered packers, and several integrated flowback and acidizing devices located inside the casing; the plug is located at the bottom of the tubing; an integrated flowback and acidizing device is installed at each oil layer on the tubing, and layered packers are installed above and below each oil layer on the tubing; the anchor packer is located above the uppermost layered packer on the tubing.

[0014] The existing technology uses a throttling unit to regulate polymer flow rate. The viscosity retention rate is affected by machining accuracy. The sand control tubing and the polymer injection tubing are installed separately. The polymer injection tubing has a large outer diameter, which cannot meet the requirements of mechanical layered sand control for 5-1 / 2 wellbore tubing.

[0015] In summary, the technical solutions, technical problems to be solved, and beneficial effects of the above-disclosed technologies are all different from those of the present invention. Regarding the more technical features, technical problems to be solved, and beneficial effects of the present invention, the above-disclosed technical documents do not provide any technical inspiration. Summary of the Invention

[0016] In view of the above-mentioned defects in the existing technology, the purpose of this invention is to provide a layered sand-proof and polymer-injection integrated pipe column and its construction method.

[0017] To achieve the above objectives, the present invention adopts the following technical solution:

[0018] On one hand, the present invention provides a layered sand control and polymer injection integrated tubing string, including a downhole tubing string, wherein the downhole tubing string includes a layered sand control and polymer injection unit; the layered sand control and polymer injection unit includes a positioning cylinder, an adjustable sand control injection device, and a layered packer.

[0019] Furthermore, the adjustable sand-control injection device includes a first outer jacket, inside which a bridge-type pipe section and a water distribution head are installed;

[0020] Specifically, the bridge-type pipe section is tubular, and the pipe wall of the bridge-type pipe section is provided with an axially through bridge-type channel. The upper end of the bridge-type pipe section is connected to the water distribution head, and the lower end of the bridge-type pipe section is connected to the sand-prevention and throttling pipe section.

[0021] Specifically, the water distribution head is provided with a first injection port, a water distribution control mechanism covering the first injection port is provided inside the water distribution head, and an anti-backflow mechanism covering the first injection port is provided between the water distribution head and the first outer jacket.

[0022] Furthermore, the water distribution control mechanism includes an upper inner pipe, a first switch sleeve, and a locking control mechanism;

[0023] Specifically, the outer wall of the upper inner tube is connected to the upper inner wall of the first outer sleeve, and the lower end of the upper inner tube is connected to the water distribution head; the first switch sleeve is fitted inside the upper inner tube, the inner wall of the first switch sleeve is provided with a first switch groove, and the first switch sleeve is connected to the upper inner tube through a locking control mechanism.

[0024] Specifically, the inner wall of the water distribution head is provided with a first convex ring, the water distribution head is provided with a radially penetrating first injection port on the first convex ring, the outer diameter of the first switch sleeve is the same as the inner diameter of the first convex ring of the water distribution head, and the first switch sleeve is provided with a radially penetrating second injection port.

[0025] Specifically, when the first switch sleeve and the upper inner tube are in the closed state, the second injection port is located above the first injection port; when the first switch sleeve and the upper inner tube are in the open state, the first injection port and the second injection port coincide.

[0026] Furthermore, the locking control mechanism includes a locking ball and a locking spring;

[0027] Specifically, the outer wall of the first switch sleeve is provided with a first countersunk hole, the inner wall of the upper inner tube is provided with a locking groove corresponding to the first countersunk hole, and the locking ball and locking spring are disposed in the first countersunk hole;

[0028] Specifically, the locking spring pushes the locking ball into the locking groove to lock the first switch sleeve;

[0029] Specifically, the locking groove includes an upper locking groove and a lower locking groove. The upper locking groove is used for locking the first switch sleeve in the closed state, and the lower locking groove is used for locking the first switch sleeve in the open state.

[0030] Furthermore, the anti-backflow mechanism includes an anti-backflow spring and an anti-backflow sleeve;

[0031] Specifically, the upper end of the first outer sleeve is provided with a second convex ring, the inner wall of the second convex ring is connected to the outer wall of the upper inner tube, the anti-backflow spring and the anti-backflow sleeve are provided in the annular space between the first outer sleeve and the upper inner tube, and the anti-backflow spring is located above the water distribution head;

[0032] Specifically, the anti-backflow sleeve is provided with a limiting part and a sealing part, and the lower outer wall of the upper inner tube is connected to the upper inner wall of the water distribution head;

[0033] Specifically, under the action of the anti-backflow spring, the limiting part of the anti-backflow sleeve contacts the upper surface of the water distribution head, and under the action of the anti-backflow spring, the sealing part of the anti-backflow sleeve covers the first injection port.

[0034] Furthermore, the sand-control throttling pipe section includes a lower inner pipe, a polymer injection sleeve, and anti-adsorption filling gravel;

[0035] Specifically, the lower end of the inner wall of the bridge-type pipe section is connected to the outer wall of the upper end of the lower inner pipe;

[0036] Specifically, the inner wall of the upper end of the injection sleeve is provided with a third convex ring, the inner wall of the third convex ring is connected to the outer wall of the lower inner tube, and the third convex ring is provided with an axial through hole;

[0037] Specifically, the upper outer wall of the polymer injection sleeve is connected to the lower end of the first outer sleeve, the lower end of the polymer injection sleeve is connected to the inner tube through a lower protective sleeve, the polymer injection sleeve is provided with a third injection port, and the annular space between the polymer injection sleeve and the lower inner tube is filled with anti-adsorption gravel.

[0038] Furthermore, the water distribution head is connected to the bridge-type pipe section via a connecting assembly, which includes a pressure ring and a connector;

[0039] Specifically, the lower end of the connector is connected to the inner wall of the bridge-type pipe section, the inner wall of the lower end of the pressure ring is connected to the outer wall of the upper end of the connector, the pressure ring is located below the first convex ring, the outer wall of the pressure ring is connected to the inner wall of the lower end of the water distribution head, and a third sealing ring is provided between the pressure ring and the first convex ring;

[0040] Specifically, a fourth sealing ring is provided between the upper inner tube and the first convex ring. The second injection port is above the fourth sealing ring in the closed state, and the lower end of the first switch sleeve is below the third sealing ring. When the lower end face of the first switch sleeve contacts the upper end face of the connector, the second injection port and the first injection port coincide.

[0041] Furthermore, at least two of the layered sand-prevention and polymer injection units are provided;

[0042] Specifically, the layered sand-prevention and polymer injection unit also includes a de-blocking injection device;

[0043] Specifically, the positioning cylinder, adjustable sand injection device, unblocking injection device, and layered packer are connected through the first oil pipe;

[0044] Specifically, the layered packer is located above the adjustable sand-proof injection device and the unblocking injection device, and the positioning cylinder is located below the adjustable sand-proof injection device and the unblocking injection device;

[0045] Specifically, one layered sand control and polymer injection unit corresponds to one oil layer;

[0046] Specifically, it also includes a control column, which includes a positioning tool and a repeatedly switchable tool. The positioning tool can be positioned with the positioning cylinder, and the repeatedly switchable tool can adjust the adjustable sand-proof injection device and the unblocking injection device.

[0047] Specifically, the positioning tool and the repeatedly switchable tool are connected via a second oil pipe.

[0048] Furthermore, the unblocking injection device includes a second outer sleeve, the lower end of which is connected to an injection sleeve. A fourth protruding ring is provided on the inner wall of the injection sleeve, and a fourth injection port is provided on the fourth protruding ring of the injection sleeve.

[0049] Specifically, the second outer sleeve is connected to the second switch sleeve through a two-way locking mechanism, the lower end of the second switch sleeve covers and seals the fourth injection port, the second switch sleeve is provided with a fifth injection port, and the inner wall of the second switch sleeve is provided with a second switch groove;

[0050] Specifically, when the second switch sleeve and the second outer sleeve are in the first locked state, the fourth injection port is sealed by the second switch sleeve, and when the second switch sleeve and the second outer sleeve are in the second locked state, the fifth injection port coincides with the fourth injection port.

[0051] Furthermore, the bidirectional locking mechanism includes an upper retaining ring, a lower retaining ring, a support sleeve, an upper locking claw, and a lower locking claw, and the outer wall of the second switch sleeve is provided with a fifth protruding ring;

[0052] Specifically, the upper stop ring and the lower stop ring are fixedly connected to the inner wall of the second outer sleeve, and the inner wall of the second outer sleeve is fixedly connected to the upper stop ring and the lower stop ring. There is an upper locking space between the upper stop ring and the support sleeve, and there is a lower locking space between the lower stop ring and the support sleeve.

[0053] Specifically, the upper end of the fifth protruding ring of the second switch sleeve is connected to the upper locking claw, and the lower end of the fifth protruding ring is connected to the lower locking claw. The upper and lower locking claws are elastic plates, and the ends of the upper and lower locking claws are provided with pawls. The pawls can extend into the upper locking space and the lower locking space under the action of elastic force to lock the second switch sleeve.

[0054] Specifically, when the upper locking claw engages with the upper locking space, the fourth injection port is in a sealed state; when the lower locking claw engages with the lower locking space, the fifth injection port coincides with the fourth injection port.

[0055] Furthermore, the positioning tool includes a tube body, a positioning sleeve is fixedly connected to the outer wall of the tube body, a sixth protruding ring is provided on the outer wall of the positioning sleeve, the upper and lower end faces of the sixth protruding ring are both guide surfaces, and the positioning sleeve is made of a soluble material;

[0056] Specifically, the inner wall of the positioning cylinder is provided with a seventh convex ring, the upper and lower end faces of the seventh convex ring are both guide surfaces, the inner diameter of the seventh convex ring of the positioning cylinder decreases from top to bottom, and the positioning sleeve can be positioned with a positioning cylinder.

[0057] Furthermore, the reusable switchable tool includes a body, which is tubular, and a second countersunk hole is provided on the side wall of the body, with a switch valve provided at the bottom of the second countersunk hole;

[0058] Specifically, a cover plate is provided on the side wall of the main body at the second countersunk hole, a return spring is provided between the cover plate and the switch valve, and a switch block is provided on the end face of the switch valve near the cover plate. When the switch valve compresses the return spring, the switch block can extend out of the second countersunk hole and the cover plate.

[0059] Specifically, a pressure hole is provided on the inner wall of the body, and the pressure hole is connected to the bottom of the second countersunk hole.

[0060] Secondly, the present invention provides a construction method for a layered sand-control and polymer-injection integrated pipe, comprising the following steps:

[0061] Prepare a layered sand control and polymer injection unit with the same number of oil layers. Set the anti-adsorption filling gravel filling amount of the sand control throttling pipe section according to the oil layer condition. Assemble the downhole tubing string, run the downhole tubing string into the well, and set it.

[0062] The layered sand control and polymer injection unit or the unblocking injection device is opened, the control column is lowered, and the positioning tool and positioning cylinder are positioned so that the repeatedly switchable tool corresponds to the first or second switch slot. The repeatedly switchable tool is then lowered to open the layered sand control and polymer injection unit or the unblocking injection device.

[0063] When the layered sand control and polymer injection unit or unblocking injection device is closed, the control column is lowered and positioned with the positioning tool and positioning cylinder so that the reversible tool corresponds to the first or second switch slot. The reversible tool is then lifted to close the layered sand control and polymer injection unit or unblocking injection device.

[0064] The injection and unblocking operations are achieved by controlling the layered sand-prevention and agglomeration unit and the unblocking injection device.

[0065] Furthermore, during the injection construction, a positioning tool with an appropriate outer diameter is selected according to the required control level, and the control string is assembled.

[0066] When the control string is lowered into the well and the positioning tool is lowered to the corresponding positioning cylinder, the resistance between the positioning sleeve and the positioning tool indicates to the surface personnel that the position has been reached. At this time, the fixed distance is raised so that the switch valve corresponds to the first switch slot in the adjustable sand injection device that needs to be adjusted, and pressure is applied to the second tubing. The pressure acts on the switch valve through the pressure hole, the switch valve compresses the reset spring, moves outward, and the switch block is locked into the first switch slot.

[0067] The downward movement of the tool allows for repeated opening and closing, which in turn moves the first switch sleeve downward, causing the adjustable sand injection device to change from a closed state to an open state.

[0068] When the second oil pipe stops pressurizing, the switch valve moves inward under the action of the return spring, and the switch block retracts.

[0069] Based on the surface flow rate, when the required flow rate can be achieved, the adjustment is terminated; when further adjustment is needed, another adjustable sand injection device is activated.

[0070] Raise the reversible switch tool according to the position of the tubing string, so that the reversible switch tool corresponds to the first switch slot in the other stage of the adjustable sand control injection device. If the opening cannot be accurately positioned, remove the control tubing string, replace the positioning tool, and then lower the control tubing string to open the adjustable sand control injection device until the required flow rate is reached.

[0071] When it is necessary to shut down the adjustable sand control injection device, the control string is lowered into the well, and the first switch sleeve is lifted by the reversible tool to change the adjustable sand control injection device from the open state to the closed state.

[0072] Furthermore, during the unblocking operation, a positioning tool with a suitable outer diameter is selected, the control string is assembled, and the control string is lowered into the well. The positioning tool is used to align the switch valve with the second switch slot in the unblocking injection device that needs to be adjusted. Pressure is applied into the second tubing, and the switch block is inserted into the second switch slot.

[0073] The tool that can be repeatedly switched on and off is lowered to change the second switch sleeve from the first locked state to the second locked state, thereby opening the unblocking injection device.

[0074] Stop pressurizing, and repeatedly switch the tool up and down according to the position of the tubing string to activate another stage of the unblocking injection device. If the device cannot be accurately positioned and activated, remove the control tubing string, replace the positioning tool, and then lower the control tubing string to activate the unblocking injection device that needs to be activated.

[0075] After unblocking is completed, a control column is lowered, and the second switch sleeve is lifted using a reversible tool, changing the second switch sleeve from the second locked state to the first locked state, thereby closing the unblocking injection device.

[0076] Furthermore, during the control process, when the positioning tool gets stuck with the positioning cylinder, a soluble activating material is pumped into the well to dissolve the positioning sleeve, allowing the positioning tool to be retrieved normally.

[0077] Compared with the prior art, the present invention has the following advantages:

[0078] 1. It adopts a layered sand control and polymer injection integrated design, realizing a high degree of integration of the two functions of the tubing string. It has functions such as layered injection, downhole adjustment, and large-volume unblocking. It can be used for mechanical layered sand control and layered polymer injection of 5-1 / 2 well tubing strings.

[0079] 2. Abandoning the original approach of regulating polymer flow rate by throttling units, we innovatively adopt pre-filling technology with different filling coefficients to regulate flow rate. The viscosity retention rate is not affected by machining accuracy and has a relatively high viscosity retention rate.

[0080] 3. Employing a continuous reading tubing + positioning tool + repeatedly switchable tool enables efficient downhole adjustment;

[0081] 4. The diameter of the integral tubing is significantly larger than that of the original step tubing, which further improves the viscosity retention rate and reduces operating costs.

[0082] 5. A reusable unblocking injection device is used to achieve efficient unblocking after downhole blockage. Attached Figure Description

[0083] Figure 1 This is a schematic diagram of the structure of a layered sand-proof and polymer-injection integrated tubular column according to the present invention;

[0084] Figure 2 This is a schematic diagram of the adjustable sand-proof injection device in this invention;

[0085] Figure 3 This is a schematic diagram of the unblocking injection device in this invention;

[0086] Figure 4 This is a schematic diagram of the positioning tool in this invention;

[0087] Figure 5 yes Figure 4 Schematic diagram of the cross section at point AA;

[0088] Figure 6 This is a schematic diagram of the repeatedly switchable tool in this invention.

[0089] In the diagram: 1. Plug, 2. Backwash valve, 3. First oil pipe, 4. Positioning cylinder, 5. Adjustable sand injection device, 6. Unblocking injection device, 7. Layered packer, 8. Positioning tool, 9. Repeatable switching tool, 10. Second oil pipe, 11. Casing;

[0090] 501 First coupling, 502 Upper inner tube, 503 First outer sleeve, 504 Locking ball, 505 Locking spring, 506 First switch sleeve, 507 Anti-backflow spring, 508 First sealing ring, 509 Anti-backflow sleeve, 510 Water distribution head, 511 Second sealing ring, 512 Third sealing ring, 513 Fourth sealing ring, 514 Pressure ring, 515 Connector, 516 Bridge-type pipe section, 517 Fifth sealing ring, 518 Lower inner tube, 519 Polymer injection sleeve, 520 Anti-adsorption filling gravel, 521 Lower protective sleeve, 522 First countersunk hole, 523 Locking groove, 524 First switch groove, 525 Second injection port, 526 First injection port, 527 Bridge-type channel, 528 Third injection port;

[0091] 601 Second coupling, 602 Second upper connector, 603 Sixth sealing ring, 604 Claw, 605 Second outer sleeve, 606 Upper locking claw, 607 Support sleeve, 608 Second switch sleeve, 609 Lower locking claw, 610 Fifth injection port, 611 Seventh sealing ring, 612 Eighth sealing ring, 613 Fourth injection port, 614 Injection sleeve, 615 Second lower connector, 616 Second switch groove;

[0092] 801. Third upper connector; 802. Positioning sleeve; 803. Locking slot;

[0093] 901 Body, 902 Cover plate, 903 Fixing nail, 904 Switch valve, 905 Spring, 906 Pressure hole, 907 Rubber ring. Detailed Implementation

[0094] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0095] Please see Figures 1 to 6 This invention provides a layered sand control and polymer injection integrated tubing string, including a downhole tubing string and a control tubing string. The downhole tubing string includes at least two layered sand control and polymer injection units. Each layered sand control and polymer injection unit includes a positioning cylinder 4, an adjustable sand control injection device 5, a deblocking injection device 6, and a layered packer 7, all connected via a first tubing 3. The layered packer 7 is located at the top of the layered sand control and polymer injection unit, and a backwash valve 2 is installed at the lower end of the bottom layered sand control and polymer injection unit. A plug 1 is installed at the lower end of the backwash valve 2. One layered sand control and polymer injection unit corresponds to one oil layer. The control tubing string includes a second tubing 10, on which a positioning tool 8 and a repeatedly switchable tool 9 are installed. The positioning tool 8 can be positioned with the positioning cylinder 4, allowing the repeatedly switchable tool 9 to adjust the adjustable sand control injection device 5 and the deblocking injection device 6.

[0096] The layered packer 7 is used for oil layer sealing, and preferably, the layered packer 7 is a hydraulic packer.

[0097] The unblocking injection device 6 is located at the lower end of the layered packer 7 and is used to unblock the formation and adjust the sand control injection device 5.

[0098] The adjustable sand control injection device 5 is located at the lower end of the unblocking injection device 6. The adjustable sand control injection device 5 corresponds to the oil layer and is used for downhole polymer injection.

[0099] The positioning cylinder 4 is located at the lower end of the adjustable sand-proof injection device 5 and is used in conjunction with the positioning tool 8 to confirm the depth of the control column.

[0100] The positioning tool 8 is located at the lower end of the repeatedly switchable tool 9, and a plug is installed at the lower end of the positioning tool 8.

[0101] In use, the downhole tubing is run into the casing 11 using the existing well tubing and release device, then set and released. When it is necessary to adjust the adjustable sand control injection device 5, the control tubing is run in, and the positioning tool 8 is positioned with the positioning cylinder 4 in the layered sand control injection unit that needs to be adjusted. Two or more adjustable sand control injection devices 5 are set according to the flow rate adjustment needs. Each adjustable sand control injection device 5 has a different filling coefficient, resulting in different injection pressure differentials.

[0102] Example 1:

[0103] like Figure 2 As shown, this embodiment provides the specific structure of the adjustable sand-proof injection device 5.

[0104] The adjustable sand-control injection device 5 includes a first outer sleeve 503, within which a bridge-type pipe section 516 and a water distribution head 510 are provided. The bridge-type pipe section 516 is tubular, and its pipe wall is provided with an axially penetrating bridge-type channel 527. The upper end of the bridge-type pipe section 516 is connected to the water distribution head 510, which is provided with a first injection port 526. A water distribution control mechanism covering the first injection port 526 is provided inside the water distribution head 510. An anti-backflow mechanism covering the first injection port 526 is provided between the water distribution head 510 and the first outer sleeve 503. The lower end of the bridge-type pipe section 516 is connected to a sand-control throttling pipe section.

[0105] Furthermore, the water distribution control mechanism includes an upper inner tube 502, a first switch sleeve 506, and a locking control mechanism. The outer wall of the upper inner tube 502 is threadedly connected to the upper inner wall of the first outer sleeve 503. The lower end of the upper inner tube 502 is connected to the water distribution head 510. The first switch sleeve 506 is sleeved inside the upper inner tube 502, and the inner wall of the first switch sleeve 506 is provided with a first switch groove 524. The first switch sleeve 506 is connected to the upper inner tube 502 through the locking control mechanism. The inner wall of the water distribution head 510 is provided with a first convex ring. The water distribution head 510 has a radially penetrating first injection port 526 on the first convex ring. The outer diameter of the first switch sleeve 506 is the same as the inner diameter of the first convex ring of the water distribution head 510. The first switch sleeve 506 has a radially penetrating second injection port 525. When the first switch sleeve 506 and the upper inner tube 502 are in the closed state, the second injection port 525 is located above the first injection port. When the first switch sleeve 506 and the upper inner tube 502 are in the open state, the first injection port 526 and the second injection port 525 coincide.

[0106] The first switch slot 524 is used to cooperate with the repeatedly switchable tool 9.

[0107] The first injection port 526 and the second injection port 525 are each provided in at least two, evenly distributed around the water distribution head 510, and correspond one to one.

[0108] Specifically, the locking control mechanism includes a locking ball 504 and a locking spring 505. The outer wall of the first switch sleeve 506 is provided with a first countersunk hole 522, and the inner wall of the upper inner tube 502 is provided with a locking groove 523 corresponding to the first countersunk hole 522. The locking ball 504 and the locking spring 505 are disposed in the first countersunk hole 522. The locking spring 505 pushes the locking ball 504 into the locking groove 523 to lock the first switch sleeve 506. The locking groove 523 includes an upper locking groove and a lower locking groove. The upper locking groove is used for locking the first switch sleeve 506 in the closed state, and the lower locking groove is used for locking the first switch sleeve 506 in the open state.

[0109] Among them, the number of locking balls 504, locking springs 505 and first countersunk holes 522 are the same, and they are arranged in at least two rows axially and at least two columns evenly circumferentially.

[0110] The locking force of the locking ball 504 and the locking groove 523 can be set by the locking spring 505.

[0111] Furthermore, the anti-backflow mechanism includes an anti-backflow spring 507 and an anti-backflow sleeve 509. A second convex ring is provided at the upper end of the first outer sleeve 503, and the inner wall of the second convex ring is connected to the outer wall of the upper inner tube 2. The anti-backflow spring 507 and the anti-backflow sleeve 509 are disposed in the annular space between the first outer sleeve 503 and the upper inner tube 502. The anti-backflow spring 507 is located above the water distribution head 510. The anti-backflow sleeve 509 is provided with a limiting part and a sealing part. The lower outer wall of pipe 502 is connected to the upper inner wall of water distribution head 510. Under the action of anti-backflow spring 507, the limiting part of anti-backflow sleeve 509 contacts the upper end face of water distribution head 510. Under the action of anti-backflow spring 507, the sealing part of anti-backflow sleeve 509 covers the first injection port 526. When the injection pressure of the first injection port 526 pushes the anti-backflow sleeve 509 upward, the anti-backflow sleeve 509 compresses the anti-backflow spring 507, opening the first injection port 526.

[0112] Specifically, the limiting part contacts the inner wall of the first outer sleeve 503 and the outer wall of the upper inner tube 502, and is sealed by the first sealing ring 508.

[0113] Specifically, the sealing part contacts the inner wall of the first outer sleeve 503 and the outer wall of the water distribution head 510, and is sealed by the second sealing ring 511. The second sealing ring 511 is located below the first injection port 526, so that the first injection port 526 is sealed.

[0114] Furthermore, the sand-control and throttling pipe section includes a lower inner pipe 518, a polymer injection sleeve 519, and anti-adsorption filling gravel 520. The lower end of the inner wall of the bridge-type pipe section 516 is threadedly connected to the upper outer wall of the lower inner pipe 518. The upper inner wall of the polymer injection sleeve 519 is provided with a third convex ring, and the inner wall of the third convex ring is threadedly connected to the outer wall of the lower inner pipe 518. The third convex ring is provided with an axial through hole. The upper outer wall of the polymer injection sleeve 519 is welded to the lower end of the first outer sleeve 503. The lower end of the polymer injection sleeve 519 is connected to the inner pipe 518 through a lower protective sleeve 521. The polymer injection sleeve 519 is provided with a third injection port 528. The annular space between the polymer injection sleeve 519 and the lower inner pipe 518 is filled with anti-adsorption filling gravel 520.

[0115] Among them, the anti-adsorption filling gravel 520 plays a throttling role. The filling coefficient of the sand-preventing injection device 5 is adjusted by controlling the density of the anti-adsorption filling gravel 520. The anti-adsorption filling gravel 520 also plays a sand-preventing role.

[0116] Specifically, the inner wall of the lower sheath 521 is threaded to the outer wall of the lower end of the lower inner tube 518, and the outer wall of the lower sheath 521 is welded to the lower end of the injection sleeve 519.

[0117] Furthermore, the water distribution head 510 and the bridge pipe section 516 are connected by a connecting assembly, which includes a pressure ring 514 and a connector 515. The lower outer wall of the connector 515 is threaded to the upper inner wall of the bridge pipe section 516, and the lower inner wall of the pressure ring 514 is threaded to the upper outer wall of the connector 515. The pressure ring 514 is located below the first convex ring, and the outer wall of the pressure ring 514 is threaded to the lower inner wall of the water distribution head 510. A third sealing ring 512 is provided between the pressure ring 514 and the first convex ring, and a fourth sealing ring 513 is provided between the upper inner pipe 502 and the first convex ring. The second injection port 525 is above the fourth sealing ring 513 in the closed state, and the lower end of the first switch sleeve 506 is below the third sealing ring 512. When the lower end face of the first switch sleeve 506 contacts the upper end face of the connector 515, the second injection port 525 and the first injection port 526 coincide.

[0118] The third sealing ring 512 and the fourth sealing ring 513 cooperate with the first switch sleeve 506 to seal the first injection port 526.

[0119] Specifically, the bridge-type pipe section 516 is connected to the first outer sleeve 503 by threads, positioned by steps, and sealed by a fifth sealing ring.

[0120] Preferably, all sealing rings are irregularly shaped polytetrafluoroethylene (PTFE) sealing rings.

[0121] Specifically, if the sealing method is not specified, it can be a sealing ring seal, a threaded engagement seal, etc.

[0122] Specifically, the upper end of the upper inner tube 502 is provided with a first upper connector, and the upper end of the first upper connector is connected to a first coupling 501; the lower end of the lower inner tube is provided with a first lower connector.

[0123] Example 2:

[0124] like Figure 3 As shown, this embodiment provides the specific structure of the unblocking injection device 6.

[0125] The unblocking injection device 6 includes a second outer sleeve 605, the lower end of which is connected to an injection sleeve 614. The inner wall of the injection sleeve 614 is provided with a fourth protruding ring, and the injection sleeve 614 is provided with a fourth injection port 613 on the fourth protruding ring. The second outer sleeve 605 is connected to a second switch sleeve 608 through a bidirectional locking mechanism. The lower end of the second switch sleeve 608 covers and seals the fourth injection port 613. The second switch sleeve 608 is provided with a fifth injection port 610. The inner wall of the second switch sleeve 608 is provided with a second switch groove 616 for cooperating with a repeatedly switchable tool 9. When the second switch sleeve 608 and the second outer sleeve 605 are in a first locked state, the fourth injection port 613 is sealed by the second switch sleeve 608. When the second switch sleeve 608 and the second outer sleeve 605 are in a second locked state, the fifth injection port 610 coincides with the fourth injection port 613.

[0126] Specifically, the bidirectional locking mechanism includes an upper retaining ring, a lower retaining ring, a support sleeve 607, an upper locking claw 606, and a lower locking claw 609. A fifth protruding ring is provided on the outer wall of the second switch sleeve 608. The upper and lower retaining rings are fixedly connected to the inner wall of the second outer sleeve 605. The support sleeve 607 is fixedly connected between the upper and lower retaining rings on the inner wall of the second outer sleeve 605. An upper locking space exists between the upper retaining ring and the support sleeve 607, and a lower locking space exists between the lower retaining ring and the support sleeve 607. The upper end of the fifth protruding ring of the second switch sleeve 608 is connected to... The upper locking claw 606 is connected to the lower locking claw 609 at the lower end of the fifth protruding ring. The upper locking claw 606 and the lower locking claw 609 are elastic plates. The ends of the upper locking claw 606 and the lower locking claw 609 are provided with claws 604. The claws can extend into the upper locking space and the lower locking space under the action of elastic force to lock the second switch sleeve 608. When the upper locking claw 606 is engaged with the upper locking space, the fourth injection port 613 is in a sealed state. When the lower locking claw 609 is engaged with the lower locking space, the fifth injection port 610 coincides with the fourth injection port 613.

[0127] Specifically, the upper retaining ring is the second upper connector 602, and the second outer sleeve 605 has a small diameter variable step on the support sleeve 607, with the lower retaining ring at the horizontal position of the step.

[0128] Specifically, the second upper connector 602 is threadedly connected to the second outer sleeve 605 and sealed by the sixth sealing ring 603, and the upper end of the second upper connector 602 is connected to the second coupling 601.

[0129] Specifically, the lower end of the second outer sleeve 605 is threadedly connected to the second lower connector 615.

[0130] Specifically, the lower outer wall of the small diameter of the second outer sleeve 605 is threadedly connected to the upper inner wall of the injection sleeve 614 and sealed by the seventh sealing ring 611. The upper end face of the fourth convex ring provides positioning for the second outer sleeve 605.

[0131] Specifically, an eighth sealing ring 612 is provided on the inner wall of the fourth convex ring above and below the fourth injection port 613. The eighth sealing ring 612 cooperates with the second switch sleeve 608 to seal the fourth injection port 613.

[0132] Specifically, the upper locking claw 606 and the lower locking claw 609 are connected to the fifth convex ring by threads, and the pawl 604 is an arc-shaped pawl 604, which ensures locking force and detachability.

[0133] Specifically, all the sealing rings are made of shaped polytetrafluoroethylene.

[0134] Preferably, all sealing rings are irregularly shaped polytetrafluoroethylene (PTFE) sealing rings.

[0135] Specifically, if the sealing method is not specified, it can be a sealing ring seal, a threaded engagement seal, etc.

[0136] Example 3:

[0137] like Figure 4 , Figure 5 , Figure 6 As shown in the figure, this embodiment provides the specific structure of the positioning tool 8 and the repeatedly switchable tool 9.

[0138] The positioning tool 8 includes a tube body, and a positioning sleeve 802 is fixedly connected to the outer wall of the tube body. A sixth protruding ring is provided on the outer wall of the positioning sleeve 802. The upper and lower end faces of the sixth protruding ring are both guide surfaces. A seventh protruding ring is provided on the inner wall of the positioning cylinder 4. The upper and lower end faces of the seventh protruding ring are both guide surfaces. The inner diameter of the seventh protruding ring of the positioning cylinder 4 decreases from top to bottom. The positioning sleeve 802 can be positioned with one positioning cylinder 4.

[0139] The guide surface is a conical surface, which facilitates the positioning sleeve 802 to pass through the non-fitting positioning cylinder 4.

[0140] One positioning method for positioning sleeve 802 and positioning cylinder 4 is that the outer wall of the sixth convex ring and the inner wall of the seventh convex ring can be interference-fitted, and the downhole position of positioning sleeve 802 is determined by the surge in resistance.

[0141] Another positioning method for positioning sleeve 802 and positioning cylinder 4 is that the lower end of the sixth convex ring can sit on the upper end of the seventh convex ring, and the inner diameter of the seventh convex ring of positioning cylinder 4 decreases from top to bottom.

[0142] Specifically, the positioning sleeve 802 is provided with at least two evenly distributed locking grooves 803 on its exterior, which can reduce the resistance during the lowering process of the positioning sleeve.

[0143] Preferably, the positioning sleeve 802 is made of a soluble material. If the positioning sleeve 802 gets stuck, since the positioning sleeve 802 is preferably made of a soluble material, an activating material of the soluble material, such as KCL, can be pumped into the well to enable the normal retrieval of the positioning tool 8.

[0144] Specifically, the upper end of the pipe body is threaded with a third upper connector 801, and the lower end of the pipe body is provided with a third lower connector.

[0145] The reusable switching tool 9 includes a body 901, which is tubular. At least two countersunk holes evenly distributed circumferentially are provided on the side wall of the body 901. A switching valve 904 is disposed at the bottom of each countersunk hole. A cover plate 902 is disposed on the side wall of the body 901 at each countersunk hole. A return spring 905 is disposed between the cover plate 902 and the switching valve 904. A switching block is disposed on the end face of the switching valve 904 near the cover plate 902. When the switching valve 904 compresses the return spring 905, the switching block extends out of the countersunk hole and the cover plate 902. A pressure hole 906 is provided on the inner wall of the body 901, which communicates with the bottom of the countersunk hole. By applying pressure, the switching valve 904 compresses the spring 907, causing the switching block to extend out of the countersunk hole and the cover plate 902, engaging with the switching groove.

[0146] Specifically, a rubber ring 907 is provided between the outer wall of the switching valve 904 and the wall of the second countersunk hole.

[0147] Specifically, the cover plate 902 is fixed to the body 901 by fixing nails 903.

[0148] Specifically, a third upper connector is provided at the upper end of the body 901, and a third lower connector is provided at the lower end of the body 901.

[0149] Example 4:

[0150] In conjunction with Examples 1-3, this embodiment provides a construction method for a layered sand-control and polymer-injection integrated tubular column, including the following steps:

[0151] S1. Prepare layered sand control and polymer injection units with the same number of oil layers. According to the water absorption of each oil well, fill different sand control and throttling pipe sections with anti-adsorption filling gravel 520 with different filling coefficients so that the injection pressure of the lowered adjustable sand control injection device 5 is within the adjustment range required by the formation.

[0152] Assemble the downhole tubing string and run it into the well. Adjust the sand control injection device 5 and the unblocking injection device 6 to be in the closed state. Pressurize from the wellhead into the first tubing 3 to pressurize and set the layered packer 7.

[0153] S2. Adjust the layered sand-prevention and agglomeration unit. When adjusting, select a positioning tool 8 with an appropriate outer diameter according to the required adjustment level and assemble the control string.

[0154] When the control string is lowered into the well and the positioning tool 8 is lowered to the corresponding positioning cylinder 4, the positioning sleeve 4 and the positioning tool 8 will generate a cooperation resistance, which can inform the surface personnel that the position has been reached. At this time, lifting it up a fixed distance will make the switch valve 904 correspond to the first switch groove 524 in the adjustable sand injection device 5 that needs to be adjusted, and pressurize the second oil pipe 10. The pressure acts on the switch valve 904 through the pressure hole 906. When a certain pressure is reached, the switch valve 904 compresses the return spring 905, the switch valve 904 moves outward, and the switch block is locked into the first switch groove 524.

[0155] By moving the repeatedly switchable tool 9 downwards, when the downward load exceeds the locking force of the locking ball 504, the repeatedly switchable tool 9 drives the first switch sleeve 506 to move downwards. The first switch sleeve 506 sits on the upper end face of the connector 515, and the locking ball 504 is inserted into the lower locking groove. At this time, the second injection port 525 and the first injection port 526 correspond, and the adjustable sand injection device 5 is opened.

[0156] When the second oil pipe 10 stops pressurizing, the switch valve 904 moves inward under the action of the return spring 905, and the switch block is retracted.

[0157] Based on the ground flow rate, when the required flow rate can be achieved, the adjustment is terminated; when further adjustment is needed, another adjustable sand injection device 5 is activated.

[0158] The reversible switch tool 9 is lifted according to the position of the tubing column, so that the reversible switch tool 9 corresponds to the first switch slot 524 in the other stage of the adjustable sand injection device 5. The positioning of a positioning cylinder 4 may cause deviations in the subsequent adjustment process. When the positioning cannot be accurately opened, the control tubing column is lifted, the positioning tool 8 is replaced, and the control tubing column is lowered again to open the adjustable sand injection device 5 until the required flow rate is reached.

[0159] S3. During the injection process, when the injected fluid reaches a certain pressure, the anti-backflow sleeve 509 moves upward and compresses the anti-backflow spring 507. At this time, the injected fluid passes through the bridge channel 527, enters the lower injection sleeve 519, passes through the anti-adsorption filling gravel 520, and flows into the formation.

[0160] After injection is stopped, the anti-backflow sleeve 9 moves down under the action of the anti-backflow spring 507, which can automatically close the injection channel and prevent foreign objects from the formation from being ejected into the tubing 3.

[0161] S4. When it is necessary to close the adjustable sand control injection device 5, select a positioning tool 8 with a suitable outer diameter, assemble the control string, and lower the control string into the well. Use the positioning tool 8 to make the switch valve 904 correspond to the first switch slot 524 in the adjustable sand control injection device 5 that needs to be adjusted, pressurize the second tubing 10, and the switch block will be inserted into the first switch slot 524.

[0162] By moving the repeatedly switchable tool 9 upward, when the lifting load exceeds the locking force of the locking ball 504, the repeatedly switchable tool 9 drives the first switch sleeve 506 to move upward, the first switch sleeve 506 becomes closed, the locking ball 504 cooperates with the upper locking groove, at this time, the second injection port 525 and the first injection port 526 are staggered, realizing the closure of the adjustable sand injection device 5;

[0163] Stop pressurizing, lift the repeatedly switchable tool 9 according to the position of the tubing string, and close the other stage adjustable sand injection device 5. If it cannot be accurately positioned and closed, remove the control tubing string, replace the positioning tool 8, and then lower the control tubing string to close the adjustable sand injection device 5 that needs to be closed.

[0164] S5. When it is necessary to open the unblocking injection device 6 for unblocking operation, select a positioning tool 8 with a suitable outer diameter, assemble the control string, and lower the control string into the well. Use the positioning tool 8 to make the switch valve 904 correspond to the second switch groove 616 in the unblocking injection device 6 that needs to be adjusted, pressurize the second tubing 10, and the switch block will be inserted into the second switch groove 616.

[0165] When the load on the lowered tool 9 exceeds the locking force of the upper locking claw 606, the second switch sleeve 608 moves down and the lower locking claw 609 engages with the lower locking space. At this time, the fifth injection port 610 and the fourth injection port 613 are aligned, thereby opening the unblocking injection device 6 and locking the second switch sleeve 608 with the lower locking claw 609.

[0166] Stop pressurizing, and lift the repeatedly switchable tool 9 according to the position of the tubing string to open the other stage unblocking injection device 6. If it is not possible to accurately position and open it, remove the control tubing string, replace the positioning tool 8, and then lower the control tubing string to open the unblocking injection device 6 that needs to be opened.

[0167] S6. Inject unblocking agent. After unblocking is completed, select a positioning tool 8 with a suitable outer diameter, assemble the control string, and lower the control string into the well. Use the positioning tool 8 to make the switch valve 904 correspond to the second switch groove 616 in the unblocking injection device 6 that needs to be adjusted, and pressurize the second tubing 10. The switch block is then inserted into the second switch groove 616.

[0168] When the lifting load exceeds the locking force of the lower locking claw 609, the second switch sleeve 608 moves upward and the upper locking claw 606 engages with the upper locking space. At this time, the fifth injection port 610 and the fourth injection port 613 separate, thereby closing the unblocking injection device 6 and locking the second switch sleeve 608 with the upper locking claw 606.

[0169] Stop pressurizing, and repeatedly lift and switch tool 9 according to the position of the tubing string to close the other stage unblocking injection device 6. When it is not possible to accurately position and close, remove the control tubing string, replace the positioning tool 8, and then lower the control tubing string to close the unblocking injection device 6 that needs to be closed.

[0170] S7. During the control process, when the positioning tool 8 is stuck with the positioning cylinder 4, a soluble activating material, such as KCL, is pumped into the well to dissolve the positioning sleeve 802, so that the positioning tool 8 can be retrieved normally.

[0171] All components not discussed in detail in this application, as well as the connection methods of these components, are well-known technologies in this field. They can be directly applied and will not be elaborated further.

[0172] In this invention, the term "multiple" refers to two or more unless otherwise explicitly defined. The terms "install," "connect," "link," and "fix" should be interpreted broadly. For example, "connect" can be a fixed connection, a detachable connection, or an integral connection; "link" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0173] In the description of this invention, it should be understood that the terms "upper," "lower," "left," "right," "front," "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or unit referred to must have a specific orientation or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0174] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0175] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A layered sand control and polymer injection integrated tubing string, comprising a downhole tubing string, characterized in that, The downhole tubing includes a layered sand control and polymer injection unit; The layered sand-proof injection unit includes a positioning cylinder, an adjustable sand-proof injection device, and a layered packer.

2. The layered sand-control and polymer injection integrated tubular string according to claim 1, characterized in that, The adjustable sand-control injection device includes a first outer casing, inside which a bridge-type pipe section and a water distribution head are installed; The bridge-type pipe section is tubular, and the pipe wall of the bridge-type pipe section is provided with an axially through bridge-type channel. The upper end of the bridge-type pipe section is connected to the water distribution head, and the lower end of the bridge-type pipe section is connected to the sand prevention and throttling pipe section. The water distribution head is provided with a first injection port, and a water distribution control mechanism covering the first injection port is provided inside the water distribution head. An anti-backflow mechanism covering the first injection port is provided between the water distribution head and the first outer jacket.

3. The layered sand-control and polymer injection integrated tubular string according to claim 2, characterized in that, The water distribution control mechanism includes an upper inner pipe, a first switch sleeve, and a locking control mechanism; The outer wall of the upper inner tube is connected to the upper inner wall of the first outer sleeve, and the lower end of the upper inner tube is connected to the water distribution head; the first switch sleeve is fitted inside the upper inner tube, and the inner wall of the first switch sleeve is provided with a first switch groove; the first switch sleeve and the upper inner tube are connected by a locking control mechanism. The inner wall of the water distribution head is provided with a first convex ring, and the water distribution head is provided with a radially penetrating first injection port on the first convex ring. The outer diameter of the first switch sleeve is the same as the inner diameter of the first convex ring of the water distribution head, and the first switch sleeve is provided with a radially penetrating second injection port. When the first switch sleeve and the upper inner tube are in the closed state, the second injection port is located above the first injection port. When the first switch sleeve and the upper inner tube are in the open state, the first injection port and the second injection port coincide.

4. The layered sand-control and polymer injection integrated tubular string according to claim 3, characterized in that, The locking control mechanism includes a locking ball and a locking spring; The outer wall of the first switch sleeve is provided with a first countersunk hole, the inner wall of the upper inner tube is provided with a locking groove corresponding to the first countersunk hole, and the locking ball and locking spring are disposed in the first countersunk hole; The locking spring pushes the locking ball into the locking groove, thereby locking the first switch sleeve; The locking groove includes an upper locking groove and a lower locking groove. The upper locking groove is used for locking the first switch sleeve in the closed state, and the lower locking groove is used for locking the first switch sleeve in the open state.

5. The layered sand-control and polymer injection integrated tubular string according to claim 2, characterized in that, The anti-backflow mechanism includes an anti-backflow spring and an anti-backflow sleeve; The upper end of the first outer sleeve is provided with a second convex ring, the inner wall of the second convex ring is connected to the outer wall of the upper inner tube, the anti-backflow spring and the anti-backflow sleeve are arranged in the annular space between the first outer sleeve and the upper inner tube, and the anti-backflow spring is located above the water distribution head; The anti-backflow sleeve is provided with a limiting part and a sealing part, and the lower outer wall of the upper inner tube is connected to the upper inner wall of the water distribution head. Under the action of the anti-backflow spring, the limiting part of the anti-backflow sleeve contacts the upper surface of the water distribution head, and under the action of the anti-backflow spring, the sealing part of the anti-backflow sleeve covers the first injection port.

6. The layered sand-control and polymer injection integrated tubular string according to claim 3, characterized in that, The sand-control throttling pipe section includes a lower inner pipe, a polymer injection sleeve, and anti-adsorption filling gravel; The lower end of the inner wall of the bridge-type pipe section is connected to the outer wall of the upper end of the lower inner pipe. The upper inner wall of the injection sleeve is provided with a third protruding ring, the inner wall of the third protruding ring is connected to the outer wall of the lower inner tube, and the third protruding ring is provided with an axial through hole; The upper outer wall of the polymer injection sleeve is connected to the lower end of the first outer sleeve, and the lower end of the polymer injection sleeve is connected to the inner tube through a lower protective sleeve. The polymer injection sleeve is provided with a third injection port, and the annular space between the polymer injection sleeve and the lower inner tube is filled with anti-adsorption gravel.

7. The layered sand-control and polymer injection integrated tubular string according to claim 3, characterized in that, The water distribution head is connected to the bridge-type pipe section via a connecting assembly, which includes a pressure ring and a connector. The lower end of the connector is connected to the inner wall of the bridge-type pipe section, the inner wall of the lower end of the pressure ring is connected to the outer wall of the upper end of the connector, the pressure ring is located below the first convex ring, the outer wall of the pressure ring is connected to the inner wall of the lower end of the water distribution head, and a third sealing ring is provided between the pressure ring and the first convex ring. A fourth sealing ring is provided between the upper inner tube and the first convex ring. The second injection port is above the fourth sealing ring when closed. The lower end of the first switch sleeve is below the third sealing ring. When the lower end face of the first switch sleeve contacts the upper end face of the connector, the second injection port and the first injection port coincide.

8. The layered sand-control and polymer injection integrated tubular string according to claim 6, characterized in that, At least two layered sand-prevention and polymer injection units are provided; The layered sand-prevention and polymer injection unit also includes a blockage-removing injection device; The positioning cylinder, adjustable sand injection device, unblocking injection device, and layered packer are connected through the first oil pipe. The layered packer is located above the adjustable sand-proof injection device and the unblocking injection device, and the positioning cylinder is located below the adjustable sand-proof injection device and the unblocking injection device. One layered sand control and polymer injection unit corresponds to one oil layer; It also includes a control column, which includes a positioning tool and a repeatedly switchable tool. The positioning tool can be positioned with the positioning cylinder, and the repeatedly switchable tool can adjust the adjustable sand injection device and the unblocking injection device. The positioning tool and the repeatedly switchable tool are connected via a second oil pipe.

9. The layered sand-control and polymer injection integrated tubular string according to claim 8, characterized in that, The unblocking injection device includes a second outer sleeve, the lower end of which is connected to an injection sleeve. A fourth protruding ring is provided on the inner wall of the injection sleeve, and a fourth injection port is provided on the fourth protruding ring of the injection sleeve. The second outer sleeve is connected to the second switch sleeve through a bidirectional locking mechanism. The lower end of the second switch sleeve covers and seals the fourth injection port. The second switch sleeve is provided with a fifth injection port. The inner wall of the second switch sleeve is provided with a second switch groove. When the second switch sleeve and the second outer sleeve are in the first locked state, the fourth injection port is sealed by the second switch sleeve. When the second switch sleeve and the second outer sleeve are in the second locked state, the fifth injection port coincides with the fourth injection port.

10. The layered sand-control and polymer injection integrated tubular string according to claim 9, characterized in that, The bidirectional locking mechanism includes an upper retaining ring, a lower retaining ring, a support sleeve, an upper locking claw, and a lower locking claw. A fifth protruding ring is provided on the outer wall of the second switch sleeve. The upper and lower stop rings are fixedly connected to the inner wall of the second outer sleeve, and the inner wall of the second outer sleeve is fixedly connected to the upper and lower stop rings. There is an upper locking space between the upper stop ring and the support sleeve, and there is a lower locking space between the lower stop ring and the support sleeve. The upper end of the fifth protruding ring of the second switch sleeve is connected to the upper locking claw, and the lower end of the fifth protruding ring is connected to the lower locking claw. The upper and lower locking claws are elastic plates, and the ends of the upper and lower locking claws are provided with pawls. The pawls can extend into the upper locking space and the lower locking space under the action of elastic force to lock the second switch sleeve. When the upper locking claw engages with the upper locking space, the fourth injection port is in a sealed state; when the lower locking claw engages with the lower locking space, the fifth injection port coincides with the fourth injection port.

11. The layered sand-control and polymer injection integrated tubular string according to claim 9, characterized in that, The positioning tool includes a tube body, a positioning sleeve is fixedly connected to the outer wall of the tube body, a sixth protruding ring is provided on the outer wall of the positioning sleeve, the upper and lower end faces of the sixth protruding ring are both guide surfaces, and the positioning sleeve is made of a soluble material; The positioning cylinder has a seventh convex ring on its inner wall. The upper and lower end faces of the seventh convex ring are both guide surfaces. The inner diameter of the seventh convex ring of the positioning cylinder decreases from top to bottom. The positioning sleeve can be positioned with a positioning cylinder.

12. The layered sand-control and polymer injection integrated tubular string according to claim 11, characterized in that, The reversible switchable tool includes a body, which is tubular, and a second countersunk hole is provided on the side wall of the body. A switch valve is provided at the bottom of the second countersunk hole. A cover plate is provided on the side wall of the main body at the second countersunk hole. A return spring is provided between the cover plate and the switch valve. A switch block is provided on the end face of the switch valve near the cover plate. When the switch valve compresses the return spring, the switch block can extend out of the second countersunk hole and the cover plate. The inner wall of the body is provided with a pressure hole, which is connected to the bottom of the second countersunk hole.

13. A construction method for a layered sand-control and polymer-injection integrated pipe, characterized in that, Includes the following steps: Prepare a layered sand control and polymer injection unit with the same number of oil layers. Set the anti-adsorption filling gravel filling amount of the sand control throttling pipe section according to the oil layer condition. Assemble the downhole tubing string, run the downhole tubing string into the well, and set it. The layered sand control and polymer injection unit or the unblocking injection device is opened, the control column is lowered, and the positioning tool and positioning cylinder are positioned so that the repeatedly switchable tool corresponds to the first or second switch slot. The repeatedly switchable tool is then lowered to open the layered sand control and polymer injection unit or the unblocking injection device. When the layered sand control and polymer injection unit or unblocking injection device is closed, the control column is lowered and positioned with the positioning tool and positioning cylinder so that the reversible tool corresponds to the first or second switch slot. The reversible tool is then lifted to close the layered sand control and polymer injection unit or unblocking injection device. The injection and unblocking operations are achieved by controlling the layered sand-prevention and agglomeration unit and the unblocking injection device.

14. The construction method of a layered sand-control and polymer injection integrated tubular column according to claim 13, characterized in that, During the injection construction, a positioning tool with an appropriate outer diameter is selected according to the required control level, and the control string is assembled. When the control string is lowered into the well and the positioning tool is lowered to the corresponding positioning cylinder, the resistance between the positioning sleeve and the positioning tool indicates to the surface personnel that the position has been reached. At this time, the fixed distance is raised so that the switch valve corresponds to the first switch slot in the adjustable sand injection device that needs to be adjusted, and pressure is applied to the second tubing. The pressure acts on the switch valve through the pressure hole, the switch valve compresses the reset spring, moves outward, and the switch block is locked into the first switch slot. The downward movement of the tool allows for repeated opening and closing, which in turn moves the first switch sleeve downward, causing the adjustable sand injection device to change from a closed state to an open state. When the second oil pipe stops pressurizing, the switch valve moves inward under the action of the return spring, and the switch block retracts. Based on the surface flow rate, when the required flow rate can be achieved, the adjustment is terminated; when further adjustment is needed, another adjustable sand injection device is activated. Raise the reversible switch tool according to the position of the tubing string, so that the reversible switch tool corresponds to the first switch slot in the other stage of the adjustable sand control injection device. If the opening cannot be accurately positioned, remove the control tubing string, replace the positioning tool, and then lower the control tubing string to open the adjustable sand control injection device until the required flow rate is reached. When it is necessary to shut down the adjustable sand control injection device, the control string is lowered into the well, and the first switch sleeve is lifted by the reversible tool to change the adjustable sand control injection device from the open state to the closed state.

15. The construction method of a layered sand-control and polymer injection integrated tubular column according to claim 13, characterized in that, During the unblocking operation, a positioning tool with a suitable outer diameter is selected, the control string is assembled, and the control string is lowered into the well. The positioning tool is used to align the switch valve with the second switch slot in the unblocking injection device that needs to be adjusted. Pressure is applied into the second tubing, and the switch block is inserted into the second switch slot. The tool that can be repeatedly switched on and off is lowered to change the second switch sleeve from the first locked state to the second locked state, thereby opening the unblocking injection device. Stop pressurizing, and repeatedly switch the tool up and down according to the position of the tubing string to activate another stage of the unblocking injection device. If the device cannot be accurately positioned and activated, remove the control tubing string, replace the positioning tool, and then lower the control tubing string to activate the unblocking injection device that needs to be activated. After unblocking is completed, a control column is lowered, and the second switch sleeve is lifted using a reversible tool, changing the second switch sleeve from the second locked state to the first locked state, thereby closing the unblocking injection device.

16. A construction method for a layered sand-control and polymer injection integrated tubular column according to claim 14 or 15, characterized in that, During the control process, when the positioning tool gets stuck with the positioning sleeve, a soluble activating material is pumped into the well to dissolve the positioning sleeve, allowing the positioning tool to be retrieved normally.

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