A continuous sand washing process string

Abstract

This invention relates to the field of oilfield well workover technology, specifically to a continuous sand flushing process string, comprising: a conversion joint threadedly connected to the lower outer side of a single tubing section, the lower part of which is inserted and fixedly connected to the upper inner side of the tubing inside the well; a blowout preventer (BOP) sealed and fixed to the lower side of a self-sealing fluid inlet device by a steel ring, and a large four-way valve sealed and fixed to the lower side of the BOP by a steel ring; and a process pipe threadedly inserted and fixed to the lower part of the inner cavity of a special hanger. Through the overall structure of the equipment, the well-washing fluid enters the sand flushing string through the inlet of the self-sealing fluid inlet device, the annular space, and the radial water hole. The returning sand-carrying fluid flows through the second annular space and the return fluid outlet of the large four-way valve to the surface collection tank. Well washing cannot be stopped during the sand flushing process. After the well is cleared, the string is lowered, and the lowering speed is controlled, enabling continuous sand flushing. This reduces labor intensity, ensures safe and fast sand flushing, and improves operational efficiency and safety.

Description

Technical Field

[0001] This invention relates to the field of oilfield well workover technology, and more specifically, to a continuous sand flushing process tubing. Background Technology

[0002] During the exploitation and production of sandstone oil reservoirs, the continuous outflow of liquid from the formation causes formation sand to enter the wellbore. Some of the sand enters the pump barrel along with the liquid in the well, exacerbating the wear of the pump and causing pump leakage or even pump jamming. Some sand deposits downhole, burying the oil layer and reducing oil well production. In severe cases, it can cause the well to shut down. To restore production and liberate the oil layer, it is necessary to remove the sand from the wellbore. Currently, the method of circulating water flushing or sand removal is more common. This involves running a flushing tubing or sand removal pump (sand removal tubing) into the wellbore, and injecting flushing fluid into the well through a high-pressure pump truck to establish oil-casing circulation, flushing the sand in the well, and using the flushing fluid to carry the sand out of the well, lowering the sand level, and allowing the oil well to resume production. However, continuous sand flushing is not possible during single-bar replacement operations, resulting in high labor intensity, low efficiency, and incomplete sand flushing. It also poses a risk to well control due to the inability to install blowout preventers. The field requires a continuous sand flushing process to reduce labor intensity, achieve safe and fast sand flushing, and improve operational efficiency and safety. Summary of the Invention

[0003] This application provides a continuous sand flushing process string to solve the problems of existing equipment not being able to continuously flush sand during single-string operation, as well as the problems of high labor intensity, low efficiency, incomplete sand flushing, and the risk of well control issues caused by the inability to install blowout preventers.

[0004] or,

[0005] To solve, or at least partially solve, the aforementioned technical problems, this application provides a continuous sand flushing process tubing, comprising:

[0006] A single tubing is provided, with a conversion joint threadedly connected to the lower outer side of the single tubing, and the lower part of the conversion joint is inserted and fixedly connected to the upper inner side of the tubing inside the well.

[0007] The self-sealing liquid inlet device has a steel ring sealing and fixing the blowout preventer on its lower side, and the blowout preventer has a steel ring sealing and fixing the large four-way valve on its lower side.

[0008] A dedicated hanger, wherein a process tube is threadedly fixed to the lower part of the inner cavity of the dedicated hanger, and the dedicated hanger is sealed and fixedly connected to the upper inner side of the large cross.

[0009] Optionally, a single oil pipe is movably inserted through the middle of the self-sealing liquid inlet device, blowout preventer, special hanger, and large four-way connector, and the lower part of the single oil pipe is movably inserted into the inner cavity of the process pipe.

[0010] Optionally, the self-sealing liquid inlet device has a liquid inlet located at the middle of its outer side.

[0011] Optionally, the large four-way valve has symmetrically arranged return liquid outlets.

[0012] Optionally, the lower part of the process pipe is movably inserted into the upper part of the inner side of the tubing inside the well.

[0013] Optionally, a sealing element is fitted onto the middle of the outer side of the conversion joint, and the outer side of the sealing element is pressed into contact with the inner wall of the process pipe for sealing.

[0014] Optionally, the adapter is provided with a radial water eye in the middle, and an upper valve ball and a lower valve ball are respectively provided on the upper and lower sides inside the adapter.

[0015] Optionally, both the upper and lower valve balls are provided with springs at their lower ends, and the upper valve ball is movably sealed at the upper outlet of the conversion joint, while the lower valve ball is movably sealed inside the radial water eye.

[0016] Optionally, there is a first annular space between the outer side of the single oil pipe and the inner sidewall of the process pipe.

[0017] Optionally, a second annular space is provided between the outer side of the process pipe and the inner side of the well tubing.

[0018] The beneficial effects of this invention are as follows:

[0019] Through the overall structure of the equipment, the well-washing fluid enters the sand-flushing tubing through the inlet of the self-sealing inlet device, the annular space, and the radial water hole. The returning sand-carrying fluid goes through the second annular space and the return outlet of the large four-way valve to the surface collection tank. The well-washing process cannot be stopped during the sand-flushing process. After the well is cleared, the tubing is lowered, the lowering speed is controlled, and the above steps are repeated until the well is clean. Then the well-washing is stopped. This realizes a continuous sand-flushing process, which reduces the labor intensity of the operation, makes sand-flushing safe and fast, and improves the efficiency and safety of the operation. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention.

[0022] Figure 2 This is a structural diagram showing the connection between the self-sealing liquid inlet device and the blowout preventer in an embodiment of the present invention.

[0023] Figure 3 This is an overall structural diagram of the dedicated suspension device and the large four-way connector according to an embodiment of the present invention.

[0024] Figure 4 This is a structural diagram of the adapter connection according to an embodiment of the present invention.

[0025] The markings in the diagram are: 1. Single oil pipe, 2. Self-sealing inlet device, 3. Blowout preventer, 4. Special hanger, 5. Large four-way valve, 6. Process pipe, 7. Adapter, 8. Radial water inlet, 9. Lower valve ball, 10. Upper valve ball, 11. Seal, 12. Second annular space, 13. First annular space, 14. Inlet, 15. Return outlet. Detailed Implementation

[0026] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] It should be noted that all directional indications in the embodiments of the present invention, such as up, down, left, right, front, back, etc., are only used to explain the relative positional relationship and movement of the components in a specific posture as shown in the attached figure. If the specific posture changes, the directional indication will also change accordingly.

[0028] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0029] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0030] In existing technologies, restoring production and liberating the oil layer requires removing the sediment from the wellbore. Currently, the most common method is to use circulating water to flush or remove the sediment. This involves running a flushing tubing or a sediment removal pump tubing into the wellbore, injecting flushing fluid into the well through a high-pressure pump truck to establish oil-casing circulation, flushing the sediment from the well, and using the flushing fluid to carry the sediment out of the well, lowering the sediment level and allowing the oil well to resume production.

[0031] To address the aforementioned issues, this invention proposes a continuous sand flushing process string to solve the problems in existing technologies where equipment cannot continuously flush sand during single-string replacement operations, resulting in high labor intensity, low efficiency, incomplete sand flushing, and the risk of well control issues arising from the inability to install blowout preventers.

[0032] like Figures 1 to 4 As shown, this embodiment provides a continuous sand flushing process tubing, including:

[0033] A single tubing 1, wherein the lower outer side of the single tubing 1 is threadedly connected to a conversion joint 7, and the lower part of the conversion joint 7 is inserted and fixedly connected to the upper inner side of the tubing inside the well.

[0034] The self-sealing liquid inlet device 2, wherein the lower side of the self-sealing liquid inlet device 2 is sealed and fixed by a steel ring for the blowout preventer 3, and the lower side of the blowout preventer 3 is sealed and fixed by a steel ring for the large four-way valve 5;

[0035] The special hanger 4 has a process tube 6 threadedly inserted into the lower part of its inner cavity, and the special hanger 4 is sealed and fixedly connected to the upper inner side of the large cross 5.

[0036] Specifically: Use one or two 27 / 8TBG tubing pipes, with Y241-114-90 / 35 packers and plugs, and run them into the well and suspend them with a hoist. Connect the tubing to the pressure testing line, pressurize it to 10-15-24MPa with a pump truck, and complete the setting of the Y241-114 packer.

[0037] The self-sealing liquid inlet device 2 is a liquid injection mechanism, and the liquid enters from the liquid inlet 14;

[0038] Blowout preventer 3 adopts existing blowout preventers on the market. Blowout preventer 3 is used to close the wellhead during operations such as oil testing, well workover, and well completion to prevent blowout accidents. It combines the functions of full sealing and partial sealing into one, and has the characteristics of simple structure, easy operation, and high pressure resistance. It is a commonly used safety sealing wellhead device in oil fields to prevent blowouts.

[0039] After the dedicated hanger 4 and the process pipe 6 are fixedly connected by threads, a lifting short section with a reverse thread is used to connect to the internal thread of the dedicated hanger 4 at the upper end of the process pipe 6 assembly. The dedicated hanger 4 is a device that supports the tubing string and seals the annular space between the tubing and the tubing in the well. The sealing method of the dedicated hanger 4 is that the weight of the tubing is used to sit inside the tubing hanger 5 cone to seal it when the dedicated hanger 4 is connected to the tubing. This method is convenient to operate, allows for fast and safe wellhead replacement, and is therefore commonly used in medium-deep wells and conventional wells.

[0040] The large four-way connector 5 is designed to facilitate the connection between the special hanger 4 and the tubing. It utilizes the weight of the tubing to sit inside the large four-way connector 5 cone and seal it, making it easy to operate and allowing for fast and safe wellhead changes.

[0041] The outer side of the process pipe 6 and the inner side of the well tubing form a second annular space 12;

[0042] The adapter 7 can form two channels, and the two channels are respectively equipped with an upper valve ball 10 and a lower valve ball 9. Both the upper valve ball 10 and the lower valve ball 9 are equipped with springs at their lower parts, so that the two channels can only allow liquid to enter but not exit, thus having a self-sealing function.

[0043] In this embodiment, as Figure 1 As shown: the single oil pipe 1 is movably inserted through the middle of the self-sealing liquid inlet device 2, the blowout preventer 3, the special hanger 4 and the large four-way connector 5, and the lower part of the single oil pipe 1 is movably inserted into the inner cavity of the process pipe 6.

[0044] Specifically: After the single tubing 1 and the adapter 7 are threaded together, they are connected to the tubing inside the well. The lower end of each of the remaining single tubing 1 is connected to the adapter 7. Ensure that the first adapter 7 has entered the process pipe 6 before starting the pump to flush the well. The flushing fluid enters the sand flushing string through the inlet 14 of the self-sealing fluid inlet device 2, the annular space 13 and the radial water hole 8. The returning sand-carrying fluid enters the surface collection tank through the annular space 12 and the well tubing valve of the large four-way valve 5. The well flushing cannot be stopped during the sand flushing process. After flushing, the tubing string is lowered, and the lowering speed is controlled. The above steps are repeated until the well is clean, and then the well flushing is stopped.

[0045] In this embodiment, as Figure 1 and Figure 2As shown: The self-sealing liquid inlet device 2 has a liquid inlet 14 in the middle of its outer side.

[0046] Specifically: Inlet 14 is the liquid inlet.

[0047] In this embodiment, as Figure 1 and Figure 3 As shown: The large four-way valve 5 has symmetrically opened return liquid outlets 15.

[0048] Specifically: Return fluid outlet 15 is the outlet of return fluid, that is, the well washing fluid enters the sand flushing string through the inlet 14 of the self-sealing inlet device 2, the annular space 13, and the radial water hole 8. The returned sand-carrying fluid goes through the second annular space 12 from the return fluid outlet 15 of the large four-way 5 to the surface collection tank.

[0049] In this embodiment, as Figure 1 and Figure 3 As shown: The lower part of the process pipe 6 is movably inserted into the upper part of the inner side of the oil pipe in the well.

[0050] Specifically: the process pipe 6 is designed to create a second annular space 12 between the outer side of the process pipe 6 and the inner side of the well tubing.

[0051] In this embodiment, as Figure 1 and Figure 4 As shown: A sealing element 11 is sleeved on the middle of the outer side of the conversion connector 7, and the outer side of the sealing element 11 is pressed and sealed against the inner wall of the process pipe 6.

[0052] Specifically: the seal 11 is designed to seal the connection between the adapter 7 and the process pipe 6.

[0053] In this embodiment, as Figure 1 As shown: a radial water eye 8 is provided in the middle of the conversion joint 7, and an upper valve ball 10 and a lower valve ball 9 are respectively provided on the upper and lower sides inside the conversion joint 7.

[0054] Specifically, both the upper valve ball 10 and the lower valve ball 9 are equipped with springs at their lower parts, which allows liquid to enter the two channels but not exit, thus enabling a self-sealing function.

[0055] In this embodiment, as Figure 1 and Figure 4 As shown: The lower ends of the upper valve ball 10 and the lower valve ball 9 are both provided with springs, and the upper valve ball 10 is movably sealed at the upper outlet of the conversion joint 7, while the lower valve ball 9 is movably sealed inside the radial water eye 8.

[0056] Specifically: the spring is always in a compressed state, and when liquid enters the upper valve ball 10 and the lower valve ball 9 at the upper end, the two channels are in the open state.

[0057] In this embodiment, as Figure 1 and Figure 4 As shown: There is a first annular space 13 between the outer side of the single oil pipe 1 and the inner sidewall of the process pipe 6.

[0058] Specifically, the well-washing fluid enters the sand-flushing tubing through the inlet 14 of the self-sealing inlet device 2, the first annular space 13, and the radial water hole 8.

[0059] In this embodiment, as Figure 1 and Figure 4 As shown: A second annular space 12 is provided between the outer side of the process pipe 6 and the inner side of the well tubing.

[0060] Specifically: the returned sand-carrying liquid flows through the second annular space 12 and the return liquid outlet 15 of the large four-way 5 to the ground collection tank.

[0061] When the equipment is in use, the single tubing 1 and the adapter 7 are threaded together and connected to the tubing inside the well. The lower end of each of the remaining single tubing 1 is connected to the adapter 7. Ensure that the first adapter 7 has entered the process pipe before starting the pump to flush the well. The flushing fluid enters the sand flushing string through the inlet 14 of the self-sealing inlet device 2, the annular space 13, and the radial water hole 8. The returning sand-carrying fluid enters the surface collection tank through the return fluid outlet 15 of the second annular space 12 and the large four-way connector 5. The well flushing process cannot be stopped. After flushing, the tubing string is lowered, and the lowering speed is controlled. The above steps are repeated until the well is clean, and then the well flushing is stopped.

[0062] Example

[0063] A continuous sand flushing process tubing, comprising:

[0064] A single tubing 1, wherein the lower outer side of the single tubing 1 is threadedly connected to a conversion joint 7, and the lower part of the conversion joint 7 is inserted and fixedly connected to the upper inner side of the tubing inside the well.

[0065] The self-sealing liquid inlet device 2, wherein the lower side of the self-sealing liquid inlet device 2 is sealed and fixed by a steel ring for the blowout preventer 3, and the lower side of the blowout preventer 3 is sealed and fixed by a steel ring for the large four-way valve 5;

[0066] The special hanger 4 has a process tube 6 threadedly inserted into the lower part of its inner cavity, and the special hanger 4 is sealed and fixedly connected to the upper inner side of the large cross 5.

[0067] A continuous sand flushing process tubing string and construction method comprises a single tubing 1, a self-sealing fluid inlet device 2, a blowout preventer 3, a special hanger 4, a large four-way connector 5, a process pipe 6, and a conversion joint 7. The tubing 1 and the conversion joint 7 are connected by threads; the special hanger 4 and the process pipe 6 are connected by threads; and the self-sealing fluid inlet device 2, the blowout preventer 3, and the large four-way connector 5 are sealed and fixed from top to bottom by steel rings.

[0068] The maximum outer diameter of the steel body of the special hanger 4 is smaller than the maximum inner diameter of the blowout preventer 3, and the upper thread of the special hanger 4 is reverse thread.

[0069] The length of process pipe 6 is greater than the sum of the lengths of single oil pipe 1 and conversion joint 7.

[0070] The adapter 7 is provided with a radial water eye 8, and the adapter 7 is provided with an upper valve ball 10 and a lower valve ball 9.

[0071] There is a second annular space 12 between the process pipe 6 and the well tubing.

[0072] The adapter 7 is equipped with a seal 11, which contacts and seals the inner wall of the process pipe 6.

[0073] There is a first annular space 13 between the single oil pipe 1 and the process pipe 6;

[0074] The self-sealing liquid inlet device 2 is equipped with a liquid inlet 14.

[0075] The specific usage method is as follows: First, perform ground installation: Connect the blowout preventer 3 to the large four-way connector 5 with bolts and seal with steel rings to ensure that the blowout preventer 3 is in the fully open position. After the special hanger 4 is fixedly connected to the process pipe 6 by threads, connect the lifting short section with the internal thread of the upper hanger of the process pipe assembly with the reverse buckle. Place the process pipe assembly through the blowout preventer 3 into the large four-way connector 5, rotate the lifting short section forward and pull it out with the reverse buckle. Connect the self-sealing liquid inlet device 2 to the blowout preventer 3 with bolts and seal with steel rings.

[0076] Next, perform a wellhead sealing test: Run 1-2 27 / 8TBG tubing sections, a Y241-114-90 / 35 packer, and a plug into the well, suspending them with a hoist. Connect the tubing to the pressurization line, and pressurize the wellhead to 10-15-24MPa using a pump truck. The Y241-114 packer will then be set. Depressurize the pump truck, disconnect the pressurization line, close the blowout preventer (BOP) 3, close the tubing valves inside the well, connect the wellbore fluid outlet of the self-sealing fluid inlet device 2 to the pressurization line, and pressurize to 21MPa for wellhead sealing test. After the sealing test, depressurize the wellhead, ensuring the BOP 3 is fully open. Raise 6-8 tons of tubing to release the Y241-114 packer and remove the wellhead sealing string.

[0077] Next, prepare the surface process: install the well washing pipeline pump truck suction pipe connection on the self-sealing liquid inlet device 2, connect the oil pipe valve in the well of the large four-way valve 5 to the well washing return liquid outlet 15 to the surface liquid collection tank, and the well washing process is established.

[0078] Next, the sand-flush tubing is lowered: the sand-flush pen tip is connected to a 27 / 8TBG tubing, and the tubing is lowered to probe the sand surface. If sand is encountered during the lowering process, the lowering of the tubing is stopped immediately, and 1 to 2 27 / 8TBG tubings are pulled out.

[0079] Finally, the sand flushing process is carried out: the single tubing 1 and the adapter 7 are threaded together and connected to the tubing in the well. The lower end of each of the remaining single tubing 1 is connected to the adapter 7. Ensure that the first adapter 7 has entered the process pipe before starting the pump to flush the well. The flushing fluid enters the sand flushing string through the inlet 14 of the self-sealing fluid inlet device 2, the annular space 13, and the radial water hole 8. The returning sand-carrying fluid enters the surface collection tank through the return fluid outlet 15 of the second annular space 12 and the large four-way connector 5. The well flushing process cannot be stopped. After flushing, the tubing string is lowered, and the lowering speed is controlled. The above steps are repeated until the well is clean, and then the well flushing is stopped.

[0080] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A continuous sand flushing process tubing, characterized in that, include: A single tubing (1) has a conversion joint (7) threadedly connected to the lower outer side of the single tubing (1), and the lower part of the conversion joint (7) is inserted and fixedly connected to the upper inner side of the tubing in the well. The self-sealing liquid inlet device (2) is sealed and fixed to the blowout preventer (3) by a steel ring on the lower side, and the blowout preventer (3) is sealed and fixed to the large four-way valve (5) by a steel ring on the lower side. A special hanger (4) is provided, with a process tube (6) threadedly inserted into the lower part of the inner cavity of the special hanger (4), and the special hanger (4) is sealed and fixedly connected to the upper part of the inner side of the large cross (5). The single oil pipe (1) is movably inserted through the middle of the self-sealing liquid inlet device (2), the blowout preventer (3), the special hanger (4) and the large four-way connector (5), and the lower part of the single oil pipe (1) is movably inserted into the inner cavity of the process pipe (6). The lower part of the process pipe (6) is movably inserted into the upper part of the inner side of the well tubing; A sealing element (11) is sleeved on the middle of the outer side of the conversion joint (7), and the outer side of the sealing element (11) is pressed and sealed against the inner wall of the process pipe (6). The conversion connector (7) is provided with a radial water eye (8) in the middle, and an upper valve ball (10) and a lower valve ball (9) are provided on the upper and lower sides of the inside of the conversion connector (7). The lower ends of the upper valve ball (10) and the lower valve ball (9) are both provided with springs, and the upper valve ball (10) is movably sealed at the upper outlet of the conversion joint (7), and the lower valve ball (9) is movably sealed inside the radial water eye (8). There is a first annular space (13) between the outer side of the single oil pipe (1) and the inner side wall of the process pipe (6). A second annular space (12) is provided between the outer side of the process pipe (6) and the inner side of the well tubing.

2. The continuous sand flushing process tubing according to claim 1, characterized in that: The self-sealing liquid inlet device (2) has a liquid inlet (14) at the middle of its outer side.

3. The continuous sand flushing process tubing according to claim 1, characterized in that: The large four-way valve (5) has symmetrically opened return liquid outlets (15).

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