Novel friction reduction and resistance reduction tool with adjustable voltage drop and frequency

Abstract

The utility model belongs to the technical field of petroleum and natural gas drilling engineering downhole tools, and discloses a novel friction and resistance reducing tool with adjustable pressure drop and frequency, which comprises an upper joint, a filter ring, a screw outer cylinder, a screw rotor, a movable valve, a fixed valve, a lower joint, a hollow plug, a hard alloy nozzle and the like, the filter ring is arranged in an inner cavity at the upper end of the screw outer barrel, the screw rotor is arranged in the screw outer barrel, fluid can circulate through a gap between the screw outer barrel and the screw rotor, the hollow screwed plug and the movable valve are arranged at the two ends of the screw rotor respectively, the screw rotor is designed to be hollow, and the fluid can also circulate from an inner cavity of the screw rotor through the hollow screwed plug. According to the tool, the size of pressure drop and the change frequency of the pressure drop can be controlled by controlling the input flow and the opening diameter of the hard alloy nozzle, and the use conditions of different working conditions can be met.

Description

Technical Field

[0001] The utility model belongs to the technical field of downhole tools for oil and natural gas drilling projects, and relates to a novel friction and drag reduction tool with adjustable pressure drop and frequency. Background Art

[0002] As horizontal and highly deviated wells occupy an increasingly larger proportion in drilling projects, the degree of buckling of drilling strings underground is becoming increasingly severe, making the impact of friction between the string and the well wall on the transmission of drilling pressure and drilling speed increasingly obvious. This has also driven almost all conventional drill pipe and tubing operation technologies to develop in the direction of high flexibility and high rigidity. Continuous tubing technology happens to have this characteristic and has therefore developed rapidly. In addition, many domestic and foreign companies and research institutes have designed and developed a number of friction and drag reduction tools based on continuous tubing technology to address the difficulties of drilling operations with buckled tubing strings.

[0003] Although the friction and drag reduction tools commonly used at present can reduce the friction between the tubing and the wellbore wall to a certain extent, there are still some problems. For example, the pressure drop variation range during tool operation is narrow, the pressure drop variation frequency is not rich enough, and the adjustability of the pressure drop variation is relatively poor. The effect that can be achieved for some deep horizontal well sections is relatively limited. In addition, due to many factors such as working principle, structural design, and material selection, the service life of most tools is not long. Summary of the Invention

[0004] The purpose of the utility model is to provide a new friction and drag reduction tool with adjustable pressure drop and frequency, so as to solve the problems of the existing technology, when using general friction and drag reduction tools, such as narrow adjustable range of pressure drop change and pressure drop change frequency in the pipe string, poor adjustability of pressure drop change, and relatively short tool service life.

[0005] In order to solve the above problems, the present invention adopts the following technical solutions:

[0006] A friction and drag reduction tool with adjustable pressure drop and frequency includes an upper joint 1, a screw outer barrel 3 connected to the upper joint 1 by a thread, a filter ring 2 installed in the inner cavity of the upper end of the screw outer barrel 3, a screw rotor 4 installed in the inner cavity of the screw outer barrel 3, a hollow wire plug 8 connected to the upper end of the screw rotor 4 by a thread, a hard alloy nozzle 9 installed in the inner cavity of the lower end of the screw rotor 4, a movable valve 5 installed in the inner cavity of the lower end of the screw rotor, a lower joint 7 connected to the lower end of the screw outer barrel 3 by a thread, and a fixed valve 6 installed in the inner cavity of the lower joint 7.

[0007] The filter ring 2 has both a filter structure 21 and a central axis structure 22. The filter structure 21 filters large particles of impurities that affect the operation, allowing the tool to run smoothly. The central axis structure 22 plays an axial limiting role, reducing the movement inside the tool, weakening the impact of the contact end face of the movable valve 5 assembled at the lower end of the screw rotor 4 and the fixed valve 6 assembled at the upper end of the lower joint 7, thereby improving the life of the rotor and the movable valve 5 and enhancing the reliability of the tool. The specific situation of the function is as follows: in the screw outer tube 3, when the fluid pressure in the upper end cavity is greater than that in the lower end cavity, the screw rotor 4 is pushed downward by the action of the liquid pressure until the movable valve 5 assembled at the lower end of the screw rotor 4 contacts the end face of the fixed valve 6 assembled on the lower joint 7. When the fluid pressure in the lower end cavity is greater than that in the upper end cavity, the screw rotor 4 is affected by the liquid pressure. The screw rotor 4 is pushed upward by the action of the screw plug 8, and the hollow wire plug 8 assembled at the upper end of the screw rotor 4 contacts the end face of the central axis structure 22 of the filter ring 2 assembled at the inner cavity of the upper end of the screw outer tube 3. When the pressure difference direction of the upper and lower cavities of the screw outer tube 3 changes at a certain frequency, the screw rotor 4 will also follow this frequency to axially move and cause impact damage to the parts in contact with it above and below. Especially when the pressure difference is relatively large, the kinetic energy converted to the axial movement of the screw rotor 4 is relatively large, and the impact is even greater. The length of the central axis structure 22 of the filter ring 2 needs to be obtained according to the axial assembly design margin in the tool and the axial space of the upper end cavity of the screw outer tube 3, thereby limiting the movement stroke of the screw rotor 4 to a reasonable tool design assembly margin, thereby achieving the function of reducing the axial movement impact of various parts inside the tool.

[0008] The movable valve 5 is designed with an oblique cylindrical special-shaped flow hole, and the geometric center of the lower outlet of the through hole does not coincide with the outer circle center of the end face where the outlet is located. The fixed valve 6 is designed with a straight cylindrical special-shaped flow hole, and the geometric center of the outlet of the hole at the upper end face does not coincide with the outer circle center of the end face. Both are made of cemented carbide material, which is corrosion-resistant and wear-resistant. The exposed end faces of the two are in a surface contact fit relationship. When the screw rotor 4 rotates under the action of the fluid, the movable valve 5 assembled on the screw rotor 3 also rotates. At this time, the circumferential positions of the two change, and then the size of the flow port where the contact end faces of the two overlap also changes. The larger the overlapping flow port, the smaller the fluid flow resistance and the smaller the pressure drop in the tool. Conversely, the greater the pressure drop in the tool, so the pressure drop in the tool changes periodically with the rotation of the screw rotor 4. Therefore, the movable and fixed valves are the important structural basis for this tool to adjust the change in the pressure drop in the tool. At the same time, the shape, number and distribution of the openings of the movable and fixed valves are not limited to a specific form. The core meaning of the openings is to achieve a change in the area of ​​the overlapping flow ports on the contact end faces of the movable and fixed valves within a certain range within one rotation cycle. Because the outlets of the openings of the movable and fixed valves at the contact end faces are not centered, when the two adopt any structure such as a single-hole structure and a distributed multi-hole structure, the coverage range of the end face outlets of the openings of the movable and fixed valves does not exist or does not always exist in a mutual inclusion relationship within one rotation cycle. The overlapping area of ​​the openings of the two movable and fixed valves will always change within one rotation cycle. Therefore, the openings of the movable and fixed valves include single holes or distributed multi-holes.

[0009] The metal part of the screw outer barrel 3 is made of alloy steel, which makes the tool have higher strength, and the rubber part is made of high-quality imported high-temperature resistant hard rubber, which can adapt to harsh working environments and increase the service life of the tool.

[0010] The screw rotor 4 is designed as a multi-head rotor. The surface of the multi-head rotor outer structure 43 is chrome-plated or hard alloy sprayed, which can adapt to various different working environments. The interior is hollow. The cavity formed by the screw rotor 4 and the screw outer barrel 3 due to the difference in the number of heads is the main path for the fluid to circulate in the tool. The fluid can also enter the screw rotor inner cavity 41 from the upper cavity of the screw outer barrel 3 through the hollow wire plug 8 connected to the upper end of the screw rotor 4, and then pass through the hard alloy nozzle 9 to the flow hole of the movable valve 5 at the lower end of the screw rotor 4. Therefore, the screw rotor inner cavity 41 will serve as a second path for the fluid to circulate in the tool. A bypass port 42 is designed at the lower end of the screw rotor 4. The fluid flowing through the second path and the fluid flowing through the main path are combined through this bypass port. For the screw rotor 3, when the flow rate through the main path is constant, the more heads there are, the greater the flow resistance, the lower the rotational speed, and the lower the pressure drop variation frequency. Conversely, the pressure drop variation frequency is higher. Therefore, adjusting the head number of the screw rotor 4 and the screw outer barrel 3 is an important way for this tool to adjust the pressure drop variation frequency. The head number ratio of the screw rotor 4 to the screw outer barrel 3 is 2:3, 3:4...8:9, 9:10, etc., all within the optional matching range.

[0011] The hollow wire plug 8 has an inner cavity structure 82 and a bypass port structure 81. Fluid within the upper cavity of the screw outer barrel 3 can flow into the bypass port 81, allowing the hollow wire plug 8 to serve as an inlet to the flow path of the inner cavity of the screw rotor 4, initiating fluid circulation within the inner cavity of the screw rotor 4 and also acting as a buffer structure to protect the screw rotor 4 from impact. Without the hollow wire plug 8 as an independent component, the screw rotor 4 would require a structure with a closed outer circumferential opening at its upper end to contact the filter ring 2 for position control. This inherently limits the screw rotor 4, placing its upper end directly under impact, which would inevitably significantly shorten the service life of the screw rotor 4. Conversely, the use of the hollow wire plug 8 can effectively extend the service life of the screw rotor.

[0012] The carbide nozzle 9 is made of carbide material, which offers high impact and corrosion resistance. Its opening exhibits a small-pore pressure differential characteristic, enabling adjustment of parameters such as the flow rate and velocity of the fluid within its path. Assuming the ratio of the number of screw rotors 4 to the outer barrel 3 remains unchanged, a larger opening in the carbide nozzle 9 allows more fluid to flow through the inner cavity of the screw rotor 4. While maintaining a constant total input flow rate, the flow through the gap between the screw rotor 4 and the outer barrel 3 decreases, reducing the screw rotor's rotational speed and the frequency of pressure drop fluctuations within the tool. Conversely, a smaller or even completely closed opening in the carbide nozzle 9 allows more fluid to flow through the gap between the outer barrel 3 and the screw rotor 4, potentially completely passing through the gap between the screw rotor 4 and the outer barrel 3. This increases the screw rotor's rotational speed and, consequently, the frequency of pressure drop fluctuations within the tool. In summary, the function of the carbide nozzle 9 is to adjust the ratio of the two paths of fluid flow: through the inner cavity of the screw rotor 4 and through the gap between the screw outer barrel 3 and the screw rotor 4, thereby directly affecting the rotation speed of the screw rotor 4 and indirectly controlling the frequency of the pressure drop change in the tool. Therefore, the carbide nozzle 9 is an important structural basis for adjusting the frequency of the pressure drop change in the tool.

[0013] Compared with the prior art, the advantages of the present invention are:

[0014] (1) The dual functions of filtering and limiting of the filter ring 2 make the tool operation process more stable and save space compared with general technology.

[0015] (2) The opening design of the fixed valve 6 and the movable valve 5 can control the change of pressure drop. Compared with general technology, it has a simpler structure and higher strength. In addition, the movable and fixed valves are made of hard alloy material, which further improves the service life of the tool.

[0016] (3) According to the actual working conditions, the frequency band of the tool pressure drop change frequency can be selected by selecting the head ratio of the screw rotor 4 and the screw outer barrel 3. The frequency band of the pressure drop change frequency can also be selected by selecting carbide nozzles 9 of different specifications. By using the two methods in parallel, the frequency band of the tool pressure drop change frequency can be greatly broadened, which is beyond the reach of general technology.

[0017] (4) The metal part of the screw outer barrel 3 is made of alloy steel, the rubber part is made of high-quality imported high-temperature resistant hard rubber, and the screw rotor 4 adopts a surface chrome plating or hard alloy spraying process, which has stronger operational adaptability and improves the service life of the tool.

[0018] (5) The dual flow path structure can feedback different pressure drop changes and pressure drop change frequency bands when opening different input flow rates. Therefore, the pressure drop change range and change frequency band range that this tool can cover by controlling the flow rate alone are much higher than those of general friction and drag reduction tools, and it has the ability to adapt to the working environment that general friction and drag reduction tools do not have. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the structure of the utility model, in which: 1. upper joint, 2. filter ring, 3. screw outer barrel, 4. screw rotor, 5. movable valve, 6. fixed valve, 7. lower joint, 8. hollow wire plug, 9. carbide nozzle;

[0020] Figure 2 21 is a schematic diagram of a filter ring, wherein 22 is a central axis structure and 21 is a filter structure.

[0021] Figure 3 Schematic diagram of a hollow wire plug, in which 81 is a wire plug bypass port, and 82 is a wire plug inner cavity;

[0022] Figure 4 Schematic diagram of a screw rotor, in which 41 is the inner cavity of the rotor, 42 is the rotor bypass port, and 43 is the outer structure of the multi-head rotor;

[0023] Figure 5 This is a schematic diagram of the relative positions of the movable valve and the fixed valve under high pressure in Example 1. In the figure, 51. movable valve contact end surface, 52. movable valve flow cavity, 61. fixed valve contact end surface, 62. fixed valve flow cavity, 561. minimum overlap flow ports of the movable and fixed valves;

[0024] Figure 6 This is a schematic diagram of the relative positions of the moving valve and the fixed valve under low pressure in the implementation case 1. In the figure, 562. The maximum overlap flow port of the moving and fixed valves.

[0025] Figure 7 Schematic diagram of the comparison of the carbide nozzle structures of the first and second implementation cases.

[0026] Figure 8 This is a schematic diagram of the maximum overlapping flow ports of the three-way valve and the fixed valve in the implementation case.

[0027] Figure 9 This is a schematic diagram of the minimum overlapping flow ports of the three-way valve and the fixed valve in the implementation case. DETAILED DESCRIPTION

[0028] The following describes the present invention in detail with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments described herein represent only a portion of the present invention, and not all of its embodiments. All other embodiments derived by persons of ordinary skill in the art based on the embodiments herein without inventive effort are intended to fall within the scope of protection of the present invention.

[0029] Implementation Case 1

[0030] Reference Figure 1 The structure of the utility model is composed of an upper joint 1, a filter ring 2, a screw outer tube 3, a screw rotor 4, a movable valve 5, a fixed valve 6, a lower joint 7, a hollow wire plug 8, a carbide nozzle 9 and other components.

[0031] The working principle of this utility model is:

[0032] The upper joint 1 is connected to the screw outer tube 3 by threads, the filter ring 2 is installed in the inner cavity of the upper end of the screw outer tube 3, the screw outer tube 3 is installed in the screw rotor 4, the hollow wire plug 8 is installed at the upper end of the screw rotor by threads, the carbide nozzle 9 is installed in the inner cavity of the lower end of the screw rotor 4, the movable valve 5 is assembled in the lower end cavity of the screw rotor 4 by interference fit, and the fixed valve 6 is installed in the inner cavity of the threaded end of the lower joint 7 by interference fit. The upper joint 1 is assembled to the upper end of the screw outer tube 3 by threads, and the lower joint 7 is installed at the lower end of the screw outer tube 3 by threads. After the lower joint 7 is connected, the movable valve 5 installed in the lower joint 7 is in surface contact with the end face of the fixed valve 6 installed in the lower cavity of the screw rotor 4.

[0033] In the first step, the circulating fluid in the tool connected above flows into this tool through the upper connector 1.

[0034] Next, the fluid flows through the filter ring 2, and the filter structure 21 filters out large particles of impurities that affect the normal operation of the tool, ensuring smooth operation of the tool. The central axis structure 22 plays the role of axial limit. This structure can ensure that the axial movement of the tool occurs in a smaller range during operation, making the tool operation more stable.

[0035] Next, the fluid enters the inner cavity at the upper end of the screw outer barrel 3. The fluid has two paths through which it can pass. One of the paths is: the fluid flows into the cavity formed by the screw outer barrel 3 and the screw rotor 4 due to the difference in the number of heads. The fluid flows through the cavity and comes to the lower cavity of the screw outer barrel 3. At the same time, under the action of the fluid, the screw rotor 4 rotates.

[0036] Simultaneously, in another path through which the fluid flows, the fluid passes through the bypass port 81 of the hollow wire plug 8 and the inner cavity 82 of the wire plug into the inner cavity 42 of the screw rotor, and reaches the alloy nozzle 9 embedded in the lower inner cavity of the screw rotor 4. The alloy nozzle 9 has a small-hole pressure difference characteristic, which can adjust the flow rate and flow rate of the fluid flowing through the inner cavity path of the screw rotor 4. After flowing through the carbide nozzle 9, the fluid reaches the movable valve 5 and merges with the fluid passing through the gap between the screw rotor 4 and the screw rotor 3.

[0037] Next, the fluid that converges in the lower chamber of the screw outer tube 3 flows into the lower joint 7 through the overlapping flow openings of the contact end surfaces of the dynamic valve 5 and the fixed valve 6. While the fluid passes through the overlapping openings of the dynamic valve 5 and the fixed valve 6, the screw rotor 4, which is driven by the fluid to rotate, drives the dynamic valve 5 assembled at its lower end to rotate, thereby changing the size of the overlapping flow openings of the contact end surfaces, such as Figure 6 When the openings of the two end faces coincide, the fluid flow is best and the pressure drop is minimum, such as Figure 5 When the openings on the contacting end faces of the two are completely misaligned, the fluid flow is the worst and the pressure drop is the largest.

[0038] In the final step, the fluid flows out of the tool through the lower connector.

[0039] In summary, during operation, the pressure drop within the tubing string undergoes a cycle with each rotation of the screw rotor 4. This cycle occurs at a specific frequency, generating axial pulses of the corresponding frequency and inducing a water hammer effect. This causes the coiled tubing to undergo small movements similar to a wave-shaped function curve, converting the static friction between the tubing string and casing into kinetic friction. The length of a single cycle influences the frequency of the pressure drop variation, which is determined by the speed of the screw rotor 4. Higher speeds result in higher frequencies, while lower speeds result in lower frequencies. The speed of the screw rotor 4 is influenced by the hole specifications of the selected carbide nozzle 9 and the number of rotors and outer barrels. Therefore, the oscillation frequency is adjustable within a certain range. Furthermore, by enabling different flow rates, the dual flow path structure will respond to different pressure drop variation ranges and frequency bands. This gradient flow adjustment covers a much wider pressure drop and frequency range than conventional friction and drag reduction tools, resulting in a more effective friction and drag reduction tool and greater adaptability to various scenarios.

[0040] Implementation Case 2

[0041] like Figure 7On the basis of implementation case 1, the slender inner hole flow structure of the carbide nozzle 9 is changed to a shorter structure with a larger inner diameter, and the contraction change of the aperture is made smoother. Compared with case 1, this structure increases the flow rate of the fluid circulating in the screw rotor 4, reduces the flow rate between the screw outer tube 3 and the screw rotor 4, and reduces the speed of the screw rotor 4 to obtain a lower pressure drop change frequency. The significance of this case is that: under the premise of ensuring that the purpose of use is achieved, the smaller change frequency reduces the wear of various parts in the tool, thereby extending the service life of the tool to a certain extent, thereby reducing drilling costs.

[0042] Implementation Case 3

[0043] Case 3 is based on Case 1, and the decentralized dynamic valve opening design is changed to an integrated opening, such as Figure 8 、 Figure 9 As one of the hole-opening methods, the integral hole-opening can also produce the desired effect of varying the size of overlapping holes within a certain range.

Claims

1. A novel friction and drag reduction tool with adjustable pressure drop and frequency, characterized by: The invention comprises an upper joint (1), a screw outer barrel (3) connected to the upper joint (1), a filter ring (2) installed in the inner cavity of the upper end of the screw outer barrel, a screw rotor (4) installed in the screw outer barrel (3) and rotatable, a hollow wire plug (8) installed at the upper end of the screw rotor (4), a hard alloy nozzle (9) installed in the inner cavity of the lower end of the screw rotor (4), a movable valve (5) installed at the lower end of the screw rotor (4), a lower joint (7) connected to the lower end of the screw outer barrel (3), and a fixed valve (6) installed in the inner cavity of the lower joint (7).

2. The novel friction and drag reduction tool with adjustable pressure drop and frequency according to claim 1 is characterized by: The filter ring (2) has a filtering structure and also has a central axis structure for limiting position. The filter ring (2) can not only filter the fluid but also limit the axial movement of the screw rotor (4).

3. The novel friction and drag reduction tool with adjustable pressure drop and frequency according to claim 1 is characterized by: The movable valve (5) and the fixed valve (6) are made of hard alloy material, and the matching relationship between the two is end face contact. Both are designed with holes that are not centered with the outer circle of the end face, and the holes are single holes or distributed multi-hole structures.

4. The novel friction and drag reduction tool with adjustable pressure drop and frequency according to claim 1 is characterized by: The screw rotor (4) adopts a hollow design, and the inner cavity of the screw rotor (4) serves as a second path for the fluid to circulate within the tool.

5. The novel friction and drag reduction tool with adjustable pressure drop and frequency according to claim 1 is characterized by: The carbide nozzle (9) is made of carbide material. The specifications of the opening of the carbide nozzle (9) can indirectly control the flow rate flowing through the gap between the screw rotor (4) and the screw outer barrel (3), thereby controlling the rotation speed of the screw rotor (4) and further controlling the frequency of change of the pressure drop in the tool.

6. The novel friction and drag reduction tool with adjustable pressure drop and frequency according to claim 1, characterized in that: The hollow wire plug (8) serves as the entrance of the flow path of the inner cavity of the screw rotor (4), and cooperates with the filter ring (2) to play an axial limiting role on various parts in the tool.

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