Horizontal well reverse circulation continuous sand washing device

Abstract

The invention provides a horizontal well reverse circulation continuous sand washing device. The horizontal well reverse circulation continuous sand washing device comprises a sleeve; the process pipe extends into the sleeve from the head end of the sleeve and extends by a preset distance, a first gap is formed between the outer wall of the process pipe and the inner wall of the sleeve, and the process pipe is communicated with the sleeve; the number of the oil pipe unit is at least one, the oil pipe unit is movably arranged in the process pipe in the extending direction of the process pipe so that the oil pipe unit can enter the tail end of the sleeve through the process pipe, and the oil pipe unit comprises an oil pipe and a commutator arranged on the oil pipe; a second gap is formed between the oil pipe of the oil pipe unit in the process pipe and the process pipe; wherein the reverser has a starting state, and when the reverser is in the starting state, the in-pipe space, close to the tail end of the horizontal section, in the oil pipe communicates with the second gap. By means of the technical scheme, the problem that in the prior art, a sand washing device is poor in adaptability to a horizontal well is effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of the design of sand washing devices for horizontal wells, and more specifically, to a reverse circulation continuous sand washing device for horizontal wells. Background Art

[0002] With the continuous progress of horizontal well development technology, the length of the horizontal section, the number of fractured sections, and the fracturing scale have been increasing year by year. Especially with the large-scale application of "volumetric fracturing" in horizontal wells ("thousands of cubic meters of sand, tens of thousands of cubic meters of fluid", multi-cluster fracturing in segments), problems such as short sand production cycles and large sand production volumes in horizontal wells have become increasingly serious, affecting the effective utilization of production capacity and the smooth implementation of subsequent measures. Therefore, sand washing operations need to be carried out in a timely manner to ensure the smoothness of the wellbore.

[0003] Chinese Patent Invention No. 200710144457.X discloses a continuous sand washing device for horizontal wells. The purpose of the invention is to solve the problem that when using the sand washing string of a conventional vertical well for sand washing, rock cuttings are likely to sink, causing secondary deposition and jamming the pipe string. Although this invention solves the problems of continuous operation and reverse circulation sand washing, due to the complex pipe string combination, it can only be used in horizontal wells where the vertical well section is longer than the sum of the build section and the horizontal section, has high requirements for the tubing and wellhead accessories (the length error of each tubing must be precisely controlled, and the self-sealing wellhead and the total length of the working barrel must be matched), and sand grains are likely to be secondarily deposited in the build section, blocking the fluid flow channel (sand grains are most difficult to pass through the build section, and generally require the critical sand-carrying velocity to be not less than 3 times the terminal settling velocity of sand grains), etc., resulting in poor process adaptability, high supporting costs, and complex on-site construction, making it inconvenient for large-scale application and promotion.

[0004] In view of the above problems in the prior art, no effective solution has been proposed yet. Summary of the Invention

[0005] The main purpose of the present invention is to provide a reverse circulation continuous sand washing device for horizontal wells, so as to at least solve the problem of poor adaptability of the existing sand washing device to horizontal wells.

[0006] To achieve the above purpose, according to one aspect of the present invention, a reverse circulation continuous sand washing device for horizontal wells is provided, including: a casing extending from the wellhead to the end of the horizontal section; a process pipe extending from the head end of the casing into the casing and extending a preset distance, a first gap being formed between the outer wall of the process pipe and the inner wall of the casing, and the process pipe being in communication with the casing; at least one tubing unit movably disposed in the process pipe along the extending direction of the process pipe so that the tubing unit can enter the end of the casing through the process pipe, the tubing unit including a tubing and a commutator disposed on the tubing, a second gap being formed between the tubing of the tubing unit located in the process pipe and the process pipe; wherein, the commutator has a starting state, and when the commutator is in the starting state, the inner space of the tubing near the end of the horizontal section is in communication with the second gap.

[0007] Further, there are multiple tubing units, and the multiple tubing units are connected in a chain structure. The structures of the multiple tubing units are set identically, and adjacent tubing units are communicated through tubing couplings.

[0008] Further, a plug valve is arranged in each tubing unit. The plug valve is arranged close to the commutator and is used to stop the fluid in the pipe space when the commutator fails.

[0009] Further, the horizontal well reverse circulation continuous sand washing device further includes: a casing flange connected to the installation foundation; a production cross valve connected to the casing flange. Part of the process pipe is arranged inside the production cross valve. The process pipe is connected to the production cross valve through a hanger. A third gap is formed between the outer wall of the process pipe and the inner wall of the production cross valve, and the third gap is communicated with the first gap. The production cross valve has at least one pump truck port, and the pump truck port is communicated with the third gap.

[0010] Further, the pump truck port, the third gap, and the first gap form an input channel for pumping the reverse flushing fluid.

[0011] Further, the production cross valve has a production port. The tubing unit enters the process pipe through the production port. A fourth gap is formed between the tubing of the tubing unit located in the production port and the inner wall of the production cross valve, and the fourth gap is communicated with the second gap.

[0012] Further, the pipe space, the second gap, and the fourth gap form an output channel for pumping the reverse flushing fluid.

[0013] Further, the horizontal well reverse circulation continuous sand washing device further includes a wellhead self-sealing device. The wellhead self-sealing device has an inner cavity, and the inner cavity is communicated with the fourth gap. An opening is provided on the side wall of the inner cavity, and the opening is communicated with the sand settling tank.

[0014] Further, a lifting clamp is arranged at the top of the wellhead self-sealing device, and the lifting clamp is connected to the wellhead self-sealing device.

[0015] Further, a sand washing tool is connected to one of the multiple tubing units that is closest to the end of the horizontal section.

[0016] Applying the technical solution of the present invention, by providing at least one tubing unit, and the tubing unit is movably arranged in the process pipe along the extension direction of the process pipe, the device can be adapted to various horizontal wells. When the commutator is in the starting state, the inner space of the tubing near the end of the horizontal section communicates with the second gap, so that the sand washing cycle does not need to discharge fluid through the tubing, ensuring that the tubing can be continuously lowered into the horizontal well, and constructing a continuous reverse circulation sand washing channel. Adopting the technical solution of the present application effectively solves the problem of poor adaptability of the sand washing device in the prior art to horizontal wells. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 FIG. 9 shows a schematic structural diagram of a first embodiment of a horizontal well reverse circulation continuous sand washing device according to the present invention;

[0019] Figure 2 FIG. 13 shows a schematic structural diagram of a second embodiment of a horizontal well reverse circulation continuous sand washing device according to the present invention;

[0020] Figure 3 FIG. 17 shows a schematic structural diagram of a third embodiment of a horizontal well reverse circulation continuous sand washing device according to the present invention;

[0021] Figure 4 FIG. 21 shows a schematic structural diagram of a fourth embodiment of a horizontal well reverse circulation continuous sand washing device according to the present invention.

[0022] Among them, the above-mentioned drawings include the following reference numerals:

[0023] 2, tubing collar; 3, elevators; 4, wellhead self-sealing; 5, tubing component section; 6, hanger; 7, production cross valve; 8, process pipe; 9, casing flange;

[0024] 10, plug valve; 11, commutator; 12, centralizer; 14, sand washing tool;

[0025] 20, casing; 21, first gap; 22, tubing unit; 221, tubing; 23, second gap; 24, inner space of the pipe; 25, third gap; 26, pump truck port; 27, fourth gap; 28, sand settling tank. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0027] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0028] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be interchanged under appropriate circumstances so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0029] Now, exemplary embodiments according to the present application will be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many different forms and should not be construed as being limited only to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of the present application is thorough and complete, and the concept of these exemplary embodiments is fully conveyed to those of ordinary skill in the art. In the drawings, for clarity, the thickness of layers and regions may be enlarged, and the same reference numerals are used to denote the same devices, and thus their description will be omitted.

[0030] A horizontal well is a type of well in oil and gas production, and its wellbore extends horizontally at the bottom of the well, having a greater horizontal length compared to traditional vertical wells. The design and drilling technology of horizontal wells enable oil and gas to flow into the wellbore more effectively, increasing production and reducing the requirements for environmental and surface equipment in some special cases.

[0031] The horizontal well has the following characteristics:

[0032] 1. The horizontal section of the horizontal well can penetrate more oil or gas layers, thereby increasing production capacity. By extending the oil and gas flow path, production is increased.

[0033] 2. The design of the horizontal well helps to more effectively exploit oil and gas reservoirs, increasing the recovery rate of oil and gas. This is very important for the economic benefits of oil and gas production.

[0034] 3. Compared with multi-borehole vertical wells, horizontal wells usually only require one wellhead, reducing the surface footprint and mitigating the environmental impact.

[0035] 4. Since horizontal wells extend horizontally underground, surface equipment can be located far from sensitive areas, reducing surface interference and making them suitable for areas where environmental protection is required.

[0036] 5. Horizontal wells perform more excellently under certain geological conditions, especially in the case of horizontal layered oil and gas reservoirs, such as shale gas and tight oil.

[0037] Therefore, problems such as the complex pipe string combination of existing horizontal well sand washing devices being poorly adaptable to horizontal wells, having high requirements for tubing and wellhead matching, and sand grains being prone to secondary deposition in the deviated section to block the liquid flow channel urgently need to be solved, which has become the key to improving the application level of horizontal wells.

[0038] Combined with Figures 1 to 4 As shown, according to a specific embodiment of the present application, a horizontal well reverse circulation continuous sand washing device is provided to solve the technical problems in the prior art, such as the complex pipe string combination being poorly adaptable to horizontal wells, having high requirements for tubing and wellhead matching, and sand grains being prone to secondary deposition in the deviated section to block the liquid flow channel.

[0039] To achieve the above object, according to one aspect of the present invention, a horizontal well reverse circulation continuous sand washing device is provided, including: a casing 20, the casing 20 extends from the wellhead to the end of the horizontal section; a process pipe 8, the process pipe 8 extends into the casing 20 from the head end of the casing 20 and extends a preset distance, a first gap 21 is formed between the outer wall of the process pipe 8 and the inner wall of the casing 20, and the process pipe 8 communicates with the casing 20; a tubing unit 22, there is at least one tubing unit 22, the tubing unit 22 is movably arranged in the process pipe 8 along the extending direction of the process pipe 8, so that the tubing unit 22 can enter the end of the casing 20 through the process pipe 8, the tubing unit 22 includes a tubing 221 and a commutator 11 arranged on the tubing 221, a second gap 23 is formed between the tubing 221 of the tubing unit 22 located in the process pipe 8 and the process pipe 8; wherein, the commutator 11 has a starting state, when the commutator 11 is in the starting state, the inner space 24 of the tubing 221 near the end of the horizontal section communicates with the second gap 23. The end refers to the end far from the wellhead.

[0040] By applying the technical solution of the present invention, at least one tubing unit 22 is provided, and the tubing unit 22 is movably provided in the process pipe 8 along the extension direction of the process pipe 8, so that the device can adapt to various horizontal wells. When the commutator 11 is in the start-up state, the inner space 24 near the end of the horizontal section in the tubing 221 is connected to the second gap 23, so that the sand flushing cycle does not need to discharge fluid through the tubing, ensuring that the tubing can be continuously lowered into the horizontal well, and a continuous reverse circulation sand flushing channel is constructed. The technical solution of the present application effectively solves the problem that the sand flushing device in the prior art has poor adaptability to horizontal wells.

[0041] Further, there are multiple oil pipe units 22, and the multiple oil pipe units 22 are connected in a chain structure. The multiple oil pipe units 22 are arranged with the same structure, and the adjacent oil pipe units 22 are connected through the oil pipe coupling 2. That is, the number of oil pipe units 22 can be selected arbitrarily. Each oil pipe unit 22 is provided with an oil pipe 221 and a commutator 11. Adjacent oil pipe units 22 are connected through the oil pipe coupling 2.

[0042] like Figure 1 As shown, three commutators 11 are shown, which are divided into an upper commutator, a middle commutator, and a lower commutator along the upstream to downstream direction of the entire device (i.e., the direction from above the ground to the end of the horizontal well depth), corresponding to three different tubing units. The upper commutator is Figure 1 The top commutator 11, the lower commutator is Figure 1 The rightmost commutator 11.

[0043] Now combine Figure 1 The operation of multiple tubing units is described as follows: at the first moment, the tubing unit including the lower commutator enters the process pipe and starts the sand flushing operation, and the fluid is discharged from the second gap 23 formed between the lower commutator (at this time in the start-up state) and the process pipe 8; at the second moment, the tubing unit of the lower commutator enters deeper into the horizontal well, and at this time the tubing unit including the middle commutator enters the process pipe 8, the lower commutator is closed, and the tubing unit including the middle commutator is in the start-up state, and the fluid is discharged from the second gap 23 formed between the middle commutator and the process pipe 8. At this time, the tubing unit including the middle commutator has not entered the process pipe 8. It is foreseeable that at the next moment, it will move to the existing position of the tubing unit of the middle commutator (that is, the process pipe 8), and the tubing unit of the middle commutator will also move to the position of the tubing unit of the lower commutator at the second moment. That is to say, only the tubing unit located in the process pipe is in the start-up state. By setting the number of tubing units, different horizontal wells can be adapted.

[0044] like Figure 2Shows the flow direction of the liquid during the continuous cycle of the lower commutator (representing the commutator of the tubing unit that has passed through the process pipe). As Figure 3 Shows the flow direction of the liquid during the continuous cycle of the middle commutator (representing the commutator of the tubing unit inside the process pipe). As Figure 2 Shows the flow direction of the liquid during the continuous cycle of the upper commutator (representing the commutator of the tubing unit that has not entered the process pipe yet).

[0045] Furthermore, a plug valve 10 is provided in each tubing unit 22. The plug valve 10 is arranged close to the commutator 11 and is used to stop the fluid in the pipe space 24 when the commutator 11 fails. As Figure 1 Shows the tubing component section 5, which is a component part of the tubing 221. The plug valve 10 is arranged downstream of the tubing component section 5.

[0046] Furthermore, the horizontal well reverse circulation continuous sand washing device further includes: a casing flange 9, which is connected to the installation base; a production four-way valve 7, which is connected to the casing flange 9. Part of the process pipe 8 is arranged inside the production four-way valve 7. The process pipe 8 is connected to the production four-way valve 7 through a hanger 6. A third gap 25 is formed between the outer wall of the process pipe 8 and the inner wall of the production four-way valve 7. The third gap 25 is communicated with the first gap 21. The production four-way valve 7 has at least one pump truck port 26, and the pump truck port 26 is communicated with the third gap 25. The installation base can be the ground.

[0047] Furthermore, the pump truck port 26, the third gap 25, and the first gap 21 form an input channel for pumping the reverse flushing fluid.

[0048] Furthermore, the production four-way valve 7 has a production port. The tubing unit 22 enters the process pipe 8 through the production port. A fourth gap 27 is formed between the tubing of the tubing unit 22 located in the production port and the inner wall of the production four-way valve 7. The fourth gap 27 is communicated with the second gap 23.

[0049] Combined with the above embodiments, as Figure 1As shown in the figure, this application (from top to bottom) mainly consists of an upper commutator, tubing collar 2, elevators 3, wellhead self-sealing 4, tubing 221, hanger 6, production cross valve 7, process pipe 8, casing flange 9, plug valve 10, middle commutator, centralizer 12, lower commutator, and sand washing tool 14. The device can be divided into a wellhead part (wellhead self-sealing 4, hanger 6, production cross valve 7, casing flange 9), a process pipe part (process pipe 8, centralizer 12), and a downhole string and supporting tools (upper commutator, tubing collar 2, tubing 221, elevators 3, plug valve 10, middle commutator, lower commutator, sand washing tool 14). The wellhead part mainly controls the inflow and outflow of the liquid and seals the annulus between the tubing and the casing; the process pipe cooperates to achieve continuous pipe running and separate the liquid flow; the process pipe string and the supporting tools achieve continuous pipe running and guide the liquid flow to change phase.

[0050] Preferably, the diameter of the internal space 24 of the pipe is larger than the second gap 23, and a pressurizing effect is formed by the Bernoulli effect, so as to ensure that the fluid with sand can be ejected smoothly.

[0051] Furthermore, the internal space 24 of the pipe, the second gap 23, and the fourth gap 27 form an output channel for the reverse flushing fluid to be pumped out.

[0052] In an alternative embodiment, the connection and continuous running process of the process pipe 8 during the operation is as follows:

[0053] The first step: First, lower the process pipe 8 (the centralizer 12 is welded on the outer surface of the process pipe 8) to near the window entry point, and then suspend the process pipe 8 in the production cross valve 7 with the hanger 6.

[0054] The second step: Lower the downhole string and supporting tools (from bottom to top, the sand washing tool 14 and the tubing 221) above the sand surface.

[0055] The third step: Connect the lower commutator and start pumping to establish a reverse circulation for running in. Then, a plug valve 10 is connected to each tubing collar 2 (initially closed, and opened before entering the wellhead self-sealing after connecting the upper tubing).

[0056] The fourth step: If the length of the horizontal section exceeds the length of the process pipe 8, connect the middle commutator and then repeat the third step. During this process, the length of the pipe string needs to be calculated accurately to ensure that the lower commutator exits the process pipe 8 and the middle commutator enters the process pipe 8.

[0057] The fifth step: If the length of the horizontal section exceeds twice the length of the process pipe 8, connect the upper commutator and then repeat the third step. During this process, the length of the pipe string also needs to be calculated accurately to ensure that the middle commutator exits the process pipe 8 and the upper commutator enters the process pipe 8.

[0058] The sixth step: By analogy, if the length of the horizontal section exceeds three times the length of the process pipe 8, connect another commutator switch and repeat the third step. All the commutator switches are the same tool.

[0059] Furthermore, the horizontal well reverse circulation continuous sand washing device further includes a wellhead self-sealing device 4, which has an inner cavity. The inner cavity communicates with the fourth gap 27, and there is an opening on the side wall of the inner cavity, and the opening communicates with the sand settling tank 28.

[0060] The flow direction of the liquid during the continuous circulation is as Figure 1 shown. The fluid route during the pumping process: pump truck → the third gap 25 → the annulus between the process pipe 8 and the casing (the first gap 21) → the annulus between the sand washing string and the casing (i.e., the gap between the sand washing tool 14 and the casing 20). The fluid route during the return process: sand washing tool 14 → inside the lower commutator → inside the tubing 221 (the inner space 24) → inside the middle commutator → the annulus between the middle commutator and the process pipe 8 (the second gap 23) → the lower annulus of the wellhead self-sealing device 4 (the fourth gap 27) → the sand settling tank 28. Figure 1 The pump truck port 26 is also shown in

[0061] Furthermore, a lifting clamp 3 is arranged on the top of the wellhead self-sealing device 4, and the lifting clamp 3 is connected to the wellhead self-sealing device 4.

[0062] In an alternative embodiment, it can be seen from the flow direction of the liquid during the continuous circulation in the above embodiment that after the process pipe 8 is lowered, the combination of some horizontal sections, build-up sections and the above return channels is changed. If a 2-7 / 8" UPTBG tubing (outer diameter 73 mm, inner diameter 62 mm) and a process pipe 8 (outer diameter 114 mm, inner diameter 102 mm) are selected in a 5-1 / 2" completion casing (inner diameter 124.26 mm), a pump injection displacement of only 318 L / min can meet the requirement that the return speed in the build-up section (the section where sand grains are most difficult to pass through) is greater than 6 times the terminal settling velocity of sand grains, and finally all the sand grains in the horizontal section can smoothly return from the wellbore to the sand settling tank 28.

[0063] Furthermore, a sand washing tool 14 is connected to one of the tubing units 22 closest to the end of the horizontal section.

[0064] It is recommended to select sand washing fluids such as low-concentration guar gum well washing fluid, nitrogen foam sand washing well washing fluid, and low-loss gel well washing fluid, etc., which are convenient for carrying sand back out.

[0065] After the circulation is normal, lower the process pipe string for construction. After lowering every 3 tubing strings, slowly lift 1 tubing string and then continue to drill down. Pay attention to observing the hook load of the construction pipe string during the drilling operation.

[0066] If the hook load slowly decreases, stop drilling down (the circulation cannot be stopped), move the pipe string up and down several times and increase the displacement (a small amount of acid solution can also be added). Continue the operation until the hook load is normal, until the expected position is reached.

[0067] If the ground power fails and drilling down cannot continue, it is necessary to continuously circulate until the power is restored and then continue drilling down.

[0068] If the pump truck breaks down and the circulation cannot be established, quickly lift the pipe string to 100 meters above the build-up section. After the pump truck is repaired and the circulation is established, continue to drill down.

[0069] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects: A reverse circulation continuous sand washing device for horizontal wells provided by the present application has a relatively simple pipe string, is well adapted to horizontal wells, has low requirements for tubing and wellhead matching, and sand grains are easily returned to the wellbore without forming secondary deposition. It belongs to the technical field of oilfield workover under the condition of casing completion. This device has revolutionized the existing sand washing method, greatly improving the construction efficiency, reducing the operation risk, saving nearly 50,000 yuan per well, and shortening the construction period by 3-4 days. At the same time, the application of this invention is conducive to further improving the level of reverse circulation continuous sand washing in horizontal wells.

[0070] The present invention designs the wellhead part, process pipe, downhole pipe string and supporting tools as a whole for the first time. On the premise of realizing continuous reverse circulation sand washing operation with one trip of pipe string, it maximally avoids the risk of re-deposition of the returned material in the build-up section from the process source, reduces the dependence on the pump injection displacement during operation and the risk of stuck pipe construction. The present invention can realize continuous drilling with the on-site construction pipe string and common plug valves, and only one reversing switch needs to be supported every process pipe length, greatly improving the efficiency and the practicability of the process.

[0071] For the sake of description, spatial relative terms, such as "above...", "on top of...", "on the upper surface of...", "above", etc., may be used here to describe the spatial position relationship of one device or feature to other devices or features as shown in the figures. It should be understood that the spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is inverted, the device described as "above other devices or structures" or "on top of other devices or structures" will then be positioned "below other devices or structures" or "beneath other devices or structures". Thus, the exemplary term "above" can include both orientations of "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and corresponding explanations are made for the spatial relative descriptions used here.

[0072] In addition to the above, it should also be noted that the "one embodiment", "another embodiment", "embodiment", etc. mentioned in this specification refer to the specific features, structures or characteristics described in connection with the embodiment being included in at least one embodiment generally described in this application. The same expression appearing in multiple places in the specification does not necessarily refer to the same embodiment. Further, when describing a specific feature, structure or characteristic in connection with any one embodiment, it is intended that implementing such feature, structure or characteristic in connection with other embodiments also falls within the scope of the present invention.

[0073] In the above embodiments, the descriptions of the respective embodiments have their own emphases. For parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0074] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A horizontal well reverse circulation continuous sand washing device, characterized in that Comprising: A casing (20) extending from the wellhead to the end of the horizontal section; A process pipe (8) extending into the casing (20) from the head end of the casing (20) and extending a preset distance. A first gap (21) is formed between the outer wall of the process pipe (8) and the inner wall of the casing (20), and the process pipe (8) communicates with the casing (20); A tubing unit (22), with at least one tubing unit (22) movably arranged in the process pipe (8) along the extension direction of the process pipe (8) so that the tubing unit (22) can enter the end of the casing (20) through the process pipe (8). The tubing unit (22) includes a tubing (221) and a commutator (11) arranged on the tubing (221). A second gap (23) is formed between the tubing (221) of the tubing unit (22) located in the process pipe (8) and the process pipe (8); Wherein, the commutator (11) has a starting state. When the commutator (11) is in the starting state, the internal space (24) of the tubing (221) near the end of the horizontal section communicates with the second gap (23).

2. The continuous sand washing device for horizontal well reverse circulation according to claim 1, characterized in that, There are multiple tubing units (22), and the multiple tubing units (22) are connected into a chain structure. The multiple tubing units (22) are arranged in the same structure, and adjacent tubing units (22) communicate with each other through tubing couplings (2).

3. The horizontal well reverse circulation continuous sand washing device according to claim 2, wherein A plug valve (10) is arranged in each tubing unit (22), and the plug valve (10) is arranged close to the commutator (11). The plug valve (10) is used to cut off the fluid in the internal space (24) when the commutator (11) fails.

4. The horizontal well reverse circulation continuous sand washing device according to claim 1, wherein, The horizontal well reverse circulation continuous sand washing device further includes: A casing flange (9) connected to the installation base; An oil production four-way valve (7) connected to the casing flange (9). Part of the process pipe (8) is arranged inside the oil production four-way valve (7). The process pipe (8) is connected to the oil production four-way valve (7) through a hanger (6). A third gap (25) is formed between the outer wall of the process pipe (8) and the inner wall of the oil production four-way valve (7), and the third gap (25) communicates with the first gap (21). The oil production four-way valve (7) has at least one pump truck port (26), and the pump truck port (26) communicates with the third gap (25).

5. The horizontal well reverse circulation continuous sand washing device according to claim 4, wherein, The pump truck port (26), the third gap (25), and the first gap (21) form an input channel for pumping the reverse flushing fluid.

6. The horizontal well reverse circulation continuous sand washing device according to claim 4, characterized in that, The oil production four-way valve (7) has an oil production port, and the tubing unit (22) enters the process pipe (8) through the oil production port. A fourth gap (27) is formed between the tubing (221) of the tubing unit (22) located in the oil production port and the inner wall of the oil production four-way valve (7), and the fourth gap (27) communicates with the second gap (23).

7. The horizontal well reverse circulation continuous sand washing device according to claim 6, characterized in that, The inner space of the pipe (24), the second gap (23) and the fourth gap (27) form an output channel for the reverse flush fluid to be pumped out.

8. The horizontal well reverse circulation continuous sand washing device according to claim 6, characterized in that The horizontal well reverse circulation continuous sand washing device further includes a wellhead self-sealing (4). The wellhead self-sealing (4) has an inner cavity, the inner cavity communicates with the fourth gap (27), and an opening is provided on the side wall of the inner cavity, and the opening communicates with the sand settling tank (28).

9. The horizontal well reverse circulation continuous sand washing device according to claim 8, characterized in that, A lifting clamp (3) is arranged on the top of the wellhead self-sealing (4), and the lifting clamp (3) is connected to the wellhead self-sealing (4).

10. The reverse circulation continuous sand washing device for horizontal wells according to claim 1, characterized in that, A sand washing tool (14) is connected to one of the plurality of tubing units (22) that is closest to the end of the horizontal section.

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