mud bogging centraliser

Abstract

The embodiment provides a mud balling preventing centralizer for controlling the drilling direction of a drill pipe in a wellbore, at least three first centralizing blocks and second centralizing blocks are longitudinally arranged on the outer wall of a cylindrical main body of the centralizer, so that mud balling between the centralizer and the inner wall of the well is preliminarily avoided. The gaps between the staggered at least three first centralizing blocks and the at least three second centralizing blocks form flow guide grooves with wide ends and narrow middle on the outer wall of the main body. When the drilling fluid carrying the drill cuttings returns upward along the wellbore and passes through the flow guide grooves, the drill cuttings are accelerated in the flow guide grooves and dredged, so that mud balling between the centralizer and the inner wall of the well is further prevented, the drill bit can effectively drill according to the set torque, and the drilling efficiency is improved.

Description

Technical Field

[0001] This application relates to the field of drilling technology, and in particular to a mud-blocking stabilizer. Background Technology

[0002] In oilfield drilling operations, centralizers are needed to control the drilling trajectory of the drill pipe and drill bit, ensuring that the drilling process can create the wellbore required by the engineering design. Centralizers are typically located in the middle of the drill pipe, with sections of drill pipe connected above and below them.

[0003] Conventional centralizers typically employ a triangular spiral structure design, utilizing the contact between the triangular edges and the wellbore wall to centralize the drill pipe, controlling the drilling trajectory of the drill pipe and drill bit, ensuring that the drill pipe remains centered within the wellbore as required by the engineering design during drilling.

[0004] In the process of developing this application, the inventors discovered that during rotary drilling, the helical profile and plane of a conventional stabilizer slow down the return of drill cuttings and drilling fluid, leading to an increase in the equivalent circulating density of drilling fluid near the stabilizer. This, in turn, causes blockage of the stabilizer's flow channels, forming mud bags, increasing the rotational torque of the drill pipe, and thus affecting the mechanical rate of penetration and drilling efficiency. During sliding drilling, a large frictional resistance is generated between the helical flat surface of the conventional stabilizer and the wellbore wall. At the same time, solid particles that cannot be effectively discharged also form mud bags. The combination of these two factors often prevents the pressure applied to the drill pipe from reaching the drill bit, also affecting the mechanical rate of penetration and drilling efficiency. Summary of the Invention

[0005] In view of this, this application provides a mud-blocking stabilizer that can effectively prevent the formation of mud blocks and improve drilling efficiency.

[0006] Specifically, the following technical solutions are included:

[0007] This application provides a mud-blocking stabilizer for controlling the drilling direction of the drill pipe in the wellbore. The stabilizer includes a main body, at least three first stabilizer blocks, at least three second stabilizer blocks, and a guide channel.

[0008] The main body is cylindrical.

[0009] At least three first straightening blocks are circumferentially and equally spaced around the outer wall of the main body, and the extension direction of the first straightening blocks is parallel to the axis of the main body.

[0010] At least three second straightening blocks are circumferentially and equally spaced around the outer wall of the main body, and the extension direction of the second straightening blocks is parallel to the axis of the main body.

[0011] At least three first straightening blocks and at least three second straightening blocks are arranged in an alternating vertical distribution.

[0012] A first guide segment is formed between every two adjacent first straightening blocks, a second guide segment is formed between every pair of staggered adjacent first and second straightening blocks, and a third guide segment is formed between every two adjacent second straightening blocks. The second guide segment has a range whose width is less than the width of the first guide segment and the width of the third guide segment.

[0013] Alternatively, each first guide segment is connected to two second guide segments, and each third guide segment is connected to two second guide segments.

[0014] Alternatively, both ends of each first straightening block and each second straightening block are wedge-shaped.

[0015] Alternatively, the second stabilizer block is closer to the drill bit than the first stabilizer block, and the two sides of the first stabilizer block at the end closest to the drill bit gradually taper inward as it gets closer to the drill bit, while the two sides of the second stabilizer block at the end furthest from the drill bit gradually taper inward as it gets further away from the drill bit.

[0016] Alternatively, the second stabilizer block may be closer to the drill bit than the first stabilizer block, and the slope of the wedge at the end of the first stabilizer block away from the drill bit may be greater than the slope of the wedge at the end of the second stabilizer block closer to the drill bit.

[0017] Optionally, the two sides of each first straightening block and each second straightening block are recessed inward.

[0018] Alternatively, the slopes at both ends of each first and second straightening block are wedge-shaped, and the center of the arc surface is closer to the axis of the main body than the arc surface.

[0019] Optionally, each first straightening block has multiple rows of staggered protrusions on its first outer surface, and each second straightening block has multiple rows of staggered protrusions on its second outer surface, wherein the hardness of the material of the protrusions is greater than that of the material of the main body.

[0020] Optionally, the first outer surface of each first straightening block and the second outer surface of each second straightening block are both arc surfaces coaxial with the main body.

[0021] Alternatively, the end of the stabilizer furthest from the drill bit is provided with an internal thread suitable for connection with the drill pipe, and the end of the stabilizer closest to the drill bit is provided with an external thread suitable for connection with the drill pipe.

[0022] The beneficial effects of the technical solutions provided in this application include at least the following:

[0023] This embodiment provides a mud-packing stabilizer for controlling the drilling direction of the drill pipe in the wellbore. At least three first stabilizer blocks and second stabilizer blocks are longitudinally arranged on the outer wall of the cylindrical main body of the stabilizer, thereby initially preventing the formation of mud packs between the stabilizer and the wellbore wall. The gaps between the at least three first stabilizer blocks and at least three second stabilizer blocks, arranged in an alternating pattern, form a guide channel on the outer wall of the main body, wider at both ends and narrower in the middle. When drilling fluid carrying drill cuttings flows back up the well and through the guide channel, it is accelerated within the guide channel, clearing the wellbore and further preventing the formation of mud packs between the stabilizer and the wellbore wall. This allows the drill bit to drill effectively according to the set torque, improving drilling efficiency. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A schematic diagram of a mud-blocking stabilizer provided in an embodiment of this application;

[0026] Figure 2 This is a schematic diagram of the structure of the first and second straightening blocks of the anti-mud-packing straightening device provided in the embodiments of this application.

[0027] The reference numerals in the figure are as follows:

[0028] 1-Main body;

[0029] 2-First straightening block;

[0030] 201-First outer surface

[0031] 3-Second straightening block;

[0032] 301 - Second outer surface;

[0033] 4-Guide channel;

[0034] 401 - First diversion section;

[0035] 402 - Second diversion section;

[0036] 403 - Third diversion section;

[0037] 5-Protrusion. Detailed Implementation

[0038] To make the technical solutions and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0039] In existing technologies, during oilfield drilling operations, centralizers are required to control the wellbore trajectory and ensure that the drilled wellbore is formed according to engineering design requirements. Conventional centralizers generally adopt a triangular helical structure design. During rotary drilling, the helical profile and plane of the conventional centralizer slow down the return of drill cuttings, resulting in an increase in the equivalent circulating density of drilling fluid near the centralizer. This leads to blockage of the centralizer's flow channels, forming mud bags, increasing the drill string rotation torque, and easily causing downhole accidents such as pump stalling and stuck pipe. During sliding drilling, the friction between the conventional centralizer's helical flat surface and the well wall, as well as the cuttings bed formed by solid particles that cannot be effectively discharged, often cause drill string pressure, seriously affecting the mechanical drilling rate and drilling efficiency.

[0040] Currently, many centralizers have been developed and applied in China, but mud packing and drill string pressure still frequently occur, so the effect of conventional centralizers is not ideal.

[0041] This application provides a novel centralizer to address the problems existing in the prior art. The centralizer's cross-shaped centralizing block layout not only instantly increases drilling fluid flow rate and enhances wellbore cleaning, resulting in less cuttings bed accumulation, but also reduces mud bag formation, friction, and resistance, thereby reducing pressure drag and improving the effective transmission of drilling pressure and torque. This has positive implications for preventing downhole accidents and increasing mechanical drilling speed.

[0042] This application provides an anti-mud-packing stabilizer for controlling the drilling direction of the drill pipe in the wellbore, such as... Figure 1 As shown, it includes a main body 1, at least three first straightening blocks 2, at least three second straightening blocks 3, and a guide channel 4. The following is a detailed description of each component:

[0043] The main body 1 is cylindrical.

[0044] Understandably, the stabilizer is suitable to be set in the middle of the drill pipe, with a section of drill pipe connected to the top and bottom of the stabilizer. Therefore, the diameter of the main body 1 can be the same as the diameter of the drill pipe to maintain a smooth transition at the connection between the stabilizer and the drill pipe, and to avoid increasing the resistance during the lowering of the drill pipe and the drilling process.

[0045] Specifically, the main body 1 is hollow and has an internal cavity. This cavity is connected to the pipes inside the drill pipe that are connected to the upper and lower parts of the stabilizer, forming a complete drilling fluid channel. This allows the drilling fluid injected into the drill pipe from the wellhead to flow along the drilling fluid channel to the drill bit and be ejected from the drill bit, thereby transporting the rock cuttings drilled by the drill bit to the surface during the drilling process.

[0046] In some alternative embodiments, the end of the stabilizer furthest from the drill bit is provided with an internal thread suitable for connection with the drill pipe, and the end of the stabilizer closest to the drill bit is provided with an external thread suitable for connection with the drill pipe.

[0047] At least three first straightening blocks 2 are circumferentially and equally spaced around the outer wall of the main body 1, and the extension direction of the first straightening blocks 2 is parallel to the axis of the main body 1.

[0048] Understandably, the first straightening block 2 is elongated, and the direction parallel to its longer side is the extension direction of the first straightening block 2. By longitudinally positioning the first straightening block 2 on the outer wall of the main body 1, and with the extension direction of the first straightening block 2 parallel to the axis of the main body 1, mud pockets can be avoided at the first straightening block 2 during drilling.

[0049] At least three second straightening blocks 3 are circumferentially and equally spaced around the outer wall of the main body 1, and the extension direction of the second straightening blocks 3 is parallel to the axis of the main body 1.

[0050] Understandably, similar to the first straightening block 2, the second straightening block 3 is also elongated, and the direction parallel to its longer side is the extension direction of the second straightening block 3. By longitudinally setting the second straightening block 3 on the outer wall of the main body 1, and with the extension direction of the second straightening block 3 parallel to the axis of the main body 1, mud pockets can be avoided at the second straightening block 3 during drilling.

[0051] The number of first centralizing blocks 2 and second centralizing blocks 3 is greater than or equal to three. The more first centralizing blocks 2 and second centralizing blocks 3 there are, the better the stabilization effect on the drill pipe. However, the gap between the first centralizing blocks 2 and the second centralizing blocks 3 will become smaller, thus affecting the flow rate of drilling fluid. Therefore, preferably, the number of first centralizing blocks 2 and second centralizing blocks 3 can both be three, so as to stabilize the drill pipe while ensuring the smooth flow of drilling fluid.

[0052] When there are three first straightening blocks 2 and three second straightening blocks 3, the three first straightening blocks 2 form a 120° angle with each other. Similarly, the three second straightening blocks 3 also form a 120° angle with each other.

[0053] At least three first straightening blocks 2 and at least three second straightening blocks 3 are arranged in an alternating vertical distribution.

[0054] Specifically, the staggered distribution is similar to the staggered relationship between the teeth on both sides of a zipper when it is closed: the extension direction of the first straightening block 2 is located in the gap between the corresponding two adjacent second straightening blocks 3, the extension direction of the second straightening block 3 is located in the gap between the corresponding two adjacent first straightening blocks 2, and there is an overlapping part between the first straightening block 2 and the second straightening block 3 in the circumferential direction of the outer wall of the main body 1.

[0055] A gap is left between every two adjacent first straightening blocks 2, between every two adjacent second straightening blocks 3, and between every pair of staggered adjacent first straightening blocks 2 and second straightening blocks 3 to allow drilling fluid to pass through. Specifically:

[0056] A first guide segment 401 is formed between every two adjacent first straightening blocks 2, a second guide segment 402 is formed between every pair of staggered adjacent first straightening blocks 2 and second straightening blocks 3, and a third guide segment 403 is formed between every two adjacent second straightening blocks 3. The second guide segment 402 has a range whose width is smaller than the width of the first guide segment 401 and the width of the third guide segment 403.

[0057] With this setup, as the centralizer is lowered, the drilling fluid carrying drill cuttings passes sequentially through the third guide section 403, the second guide section 402, and the first guide section 401. During this process, the guide channel 4, which is wide at both ends and narrow in the middle, accelerates the drilling fluid carrying drill cuttings.

[0058] In some alternative embodiments, each first guide segment 401 is connected to two second guide segments 402, and each third guide segment 403 is connected to two second guide segments 402.

[0059] Understandably, this setup allows the drilling fluid carrying drill cuttings to be divided into two streams in the third guide section 403 as the centralizer is lowered and the drilling fluid in the second guide section 402 passes through the guide channel 4. Then, the two streams of drilling fluid in the second guide section 402 are combined into one stream that flows into the first guide section 401, thereby accelerating the drilling fluid carrying drill cuttings.

[0060] The shapes of the first straightening block 2 and the second straightening block 3 are described in detail below:

[0061] In some alternative embodiments, such as Figure 2 As shown, both ends of each first straightening block 2 and each second straightening block 3 are wedge-shaped.

[0062] Understandably, making both ends of each first straightening block 2 and each second straightening block 3 wedge-shaped can reduce the resistance during the lowering process of the straightener.

[0063] In some alternative embodiments, the second straightening block 3 is closer to the drill bit than the first straightening block 2, and the two sides of the first straightening block 2 at the end closer to the drill bit gradually taper inward as it gets closer to the drill bit, while the two sides of the second straightening block 3 at the end farther from the drill bit gradually taper inward as it gets farther from the drill bit.

[0064] Understandably, between each pair of staggered adjacent first straightening blocks 2 and second straightening blocks 3, a second guide section 402 in the guide channel 4 is formed by the two gradually inward-curving sides of the first straightening block 2 near the drill bit and the two gradually inward-curving sides of the second straightening block 3 away from the drill bit. The second guide section 402 is mainly used to accelerate the drilling fluid.

[0065] In some alternative embodiments, the second straightening block 3 is closer to the drill bit than the first straightening block 2, and the slope of the wedge shape at the end of the first straightening block 2 away from the drill bit is greater than the slope of the wedge shape at the end of the second straightening block 3 closer to the drill bit.

[0066] Understandably, the slope of the wedge at the end of the first centralizing block 2 furthest from the drill bit is greater than the slope of the wedge at the end of the second centralizing block 3 closest to the drill bit. In other words, the wedge at the end of the second centralizing block 3 closest to the drill bit is sharper than the wedge at the end of the first centralizing block 2 furthest from the drill bit, while the wedge at the end of the first centralizing block 2 furthest from the drill bit is blunter than the wedge at the end of the second centralizing block 3 closest to the drill bit. Furthermore, the second centralizing block 3 is closer to the drill bit than the first centralizing block 2. During the centralizer's descent and the drill bit's drilling process, the end of the second centralizing block 3 closest to the drill bit is at the very forefront of the movement and is the first to contact the wellbore. Therefore, setting the wedge at the end of the second centralizing block 3 closest to the drill bit to be sharper than the wedge at the end of the first centralizing block 2 furthest from the drill bit can reduce the resistance during the centralizer's descent. Similarly, when the stabilizer is pulled out of the well, the end of the first stabilizer 2 furthest from the drill bit is the leading end and contacts the well wall first. Therefore, the wedge shape of the end of the first stabilizer 2 furthest from the drill bit is made more blunt than the wedge shape of the end of the second stabilizer 3 closest to the drill bit. This allows the blunter wedge shape of the end of the first stabilizer 2 furthest from the drill bit to be used to trim the well wall during the extraction of the stabilizer.

[0067] In some alternative embodiments, the two sides of each first straightening block 2 and each second straightening block 3 are recessed inward.

[0068] It is understandable that the two sides of each first centralizing block 2 and each second centralizing block 3 are set to be concave inward, specifically, they can be concave arc surfaces, thereby increasing the flow rate of the guide channel 4 and reducing the flow resistance of the drilling fluid.

[0069] In some optional embodiments, the slopes at both ends of each first straightening block 2 and each second straightening block 3 are arc surfaces, and the center of the arc surface is closer to the axis of the main body 1 than the arc surface itself.

[0070] Understandably, setting the slopes at both ends of each wedge-shaped first centralizing block 2 and each second centralizing block 3 as outwardly convex arc surfaces can improve the ability of the first centralizing block 2 and the second centralizing block 3 to adjust the well wall during the lowering of the centralizer.

[0071] In some optional embodiments, each first straightening block 2 has multiple rows of axially staggered protrusions 5 on its first outer surface 201, and each second straightening block 3 has multiple rows of axially staggered protrusions 5 on its second outer surface 301. The material of the protrusions 5 has a harder hardness than the material of the body 1.

[0072] Understandably, the protrusion 5 can increase the friction between the first straightening block 2 and the second straightening block 3 and the well wall, thereby effectively straightening the well wall.

[0073] Specifically, protrusion 5 can be made using cemented carbide.

[0074] In some optional embodiments, the first outer surface 201 of each first straightening block 2 and the second outer surface 301 of each second straightening block 3 are both arc surfaces coaxial with the main body 1.

[0075] Understandably, this configuration increases the contact area between the first centralizing block 2 and the second centralizing block 3 and the well wall, effectively adjusting the well wall and enhancing the stability of the centralizer.

[0076] The shapes of the first straightening block 2 and the second straightening block 3 are described in more detail below:

[0077] The following describes the entire usage process of the anti-mud-pack centralizer in drilling operations, using the structure of the anti-mud-pack centralizer provided in the embodiments of this application as an example:

[0078] In the first step, the stabilizer is connected to the drill pipe and set in the middle of the drill pipe. Two sections of the drill pipe are connected to a stabilizer, and the upper and lower parts of the stabilizer are threaded to a section of the drill pipe.

[0079] The end of the stabilizer furthest from the drill bit is provided with an internal thread suitable for connection with the drill pipe, and the end of the stabilizer closest to the drill bit is provided with an external thread suitable for connection with the drill pipe.

[0080] In the second step, the entire connected mechanism is lowered into the well.

[0081] Since the diameter of the cylindrical main body 1 is the same as the diameter of the drill pipe, it ensures a smooth transition at the connection between the stabilizer and the drill pipe, avoiding increased resistance during the lowering of the drill pipe and the drilling process.

[0082] In the third step, after the drilling is completed, the drilling rig is turned on to rotate the drill rod and drill bit.

[0083] In the fourth step, drilling fluid is injected from the wellhead into the drill pipe.

[0084] Since the main body 1 is hollow and has an internal cavity, the cavity of the stabilizer is connected to the cavity inside the drill pipe connected to the upper and lower parts of the stabilizer, forming a complete pipeline. This allows the drilling fluid injected into the drill pipe from the wellhead to flow along the pipeline to the drill bit and spray out from the drill bit, thereby transporting the rock cuttings drilled by the drill bit to the surface during the drilling process.

[0085] Drilling fluid can be one of the following: water, mud, clay-free flushing fluid, emulsion, foam, and compressed air.

[0086] To straighten the drill pipe and stabilize its drilling direction, a first straightening block 2 and a second straightening block 3 are provided on the outer wall of the main body 1. Specifically, at least three first straightening blocks 2 are circumferentially and equally spaced around the outer wall of the main body 1, and the extending direction of the first straightening blocks 2 is parallel to the axis of the main body 1.

[0087] The first straightening block 2 is elongated, and its extension direction is parallel to its longer side. Since the first straightening block 2 is longitudinally positioned on the outer wall of the main body 1, and its extension direction is parallel to the axis of the main body 1, mud pockets are avoided at the first straightening block 2 during drilling.

[0088] At least three second straightening blocks 3 are circumferentially and equally spaced around the outer wall of the main body 1, and the extension direction of the second straightening blocks 3 is parallel to the axis of the main body 1.

[0089] Understandably, similar to the first straightening block 2, the second straightening block 3 is also elongated, and the direction parallel to its longer side is the extension direction of the second straightening block 3. Since the second straightening block 3 is longitudinally positioned on the outer wall of the main body 1, and the extension direction of the second straightening block 3 is parallel to the axis of the main body 1, mud pockets are avoided at the second straightening block 3 during drilling.

[0090] The number of first centralizing blocks 2 and second centralizing blocks 3 are both three, which ensures the stability of the drill pipe while ensuring the smooth flow of drilling fluid.

[0091] When there are three first straightening blocks 2 and three second straightening blocks 3, the three first straightening blocks 2 are at a 120° angle to each other. Similarly, the three second straightening blocks 3 are also at a 120° angle to each other, so as to achieve an evenly spaced surrounding arrangement.

[0092] At least three first straightening blocks 2 and at least three second straightening blocks 3 are arranged in an alternating vertical distribution.

[0093] Specifically, the staggered distribution is similar to the staggered relationship between the teeth on both sides of a zipper when it is closed: the extension direction of the first straightening block 2 is located in the gap between the corresponding two adjacent second straightening blocks 3, the extension direction of the second straightening block 3 is located in the gap between the corresponding two adjacent first straightening blocks 2, and there is an overlapping part between the first straightening block 2 and the second straightening block 3 in the circumferential direction of the outer wall of the main body 1.

[0094] A gap is left between every two adjacent first straightening blocks 2, between every two adjacent second straightening blocks 3, and between every pair of staggered adjacent first straightening blocks 2 and second straightening blocks 3 to allow drilling fluid to pass through. Specifically:

[0095] A first guide segment 401 is formed between every two adjacent first straightening blocks 2, a second guide segment 401 is formed between every pair of staggered adjacent first straightening blocks 2 and second straightening blocks 3, and a third guide segment 403 is formed between every two adjacent second straightening blocks 3. The second guide segment 401 has a range whose width is smaller than the width of the first guide segment 401 and the width of the third guide segment 403.

[0096] With this configuration, as the centralizer is lowered and the drilling fluid carrying drill cuttings passes through the third guide section 403, the second guide section 402, and the first guide section 401 in sequence, the guide channel 4, which is wide at both ends and narrow in the middle, accelerates the drilling fluid carrying drill cuttings.

[0097] In some alternative embodiments, each first guide segment 401 is connected to two second guide segments 402, and each third guide segment 403 is connected to two second guide segments 402.

[0098] As the stabilizer is lowered and the drill pipe and drill bit are drilling, the drilling fluid carrying drill cuttings passes through the guide channel 4. The drilling fluid in the third guide section 403 is first divided into two streams in the second guide section 402. Then, the two streams in the second guide section 402 are combined into one stream that flows into the first guide section 401. This accelerates the drilling fluid carrying drill cuttings and prevents the formation of mud bags.

[0099] like Figure 2 As shown, both ends of each first straightening block 2 and each second straightening block 3 are wedge-shaped.

[0100] By making both ends of each first straightening block 2 and each second straightening block 3 wedge-shaped, the resistance during the lowering process of the straightener is reduced.

[0101] The second straightening block 3 is closer to the drill bit than the first straightening block 2. The two sides of the end of the first straightening block 2 that is closer to the drill bit gradually taper inward as it gets closer to the drill bit, and the two sides of the end of the second straightening block 3 that is farther away from the drill bit gradually taper inward as it gets farther away from the drill bit.

[0102] Between each pair of staggered adjacent first centralizing blocks 2 and second centralizing blocks 3, a second guiding section 402 is formed in the guiding channel 4, relying on the two gradually inward-curving sides of the first centralizing block 2 near the drill bit and the two gradually inward-curving sides of the second centralizing block 3 away from the drill bit. The second guiding section 402 is mainly used to accelerate the drilling fluid and prevent the formation of mud bags.

[0103] The two sides of each first straightening block 2 and each second straightening block 3 are concave inward.

[0104] The two sides of each first centralizing block 2 and each second centralizing block 3 are set to be concave inward, specifically, they can be concave arc surfaces, which can increase the flow rate of the guide channel 4 and reduce the flow resistance of the drilling fluid.

[0105] The slopes at both ends of each wedge-shaped first straightening block 2 and each second straightening block 3 are arc surfaces, and the center of the arc surface is closer to the axis of the main body 1 than the arc surface itself.

[0106] By setting the slopes at both ends of each wedge-shaped first centralizing block 2 and each second centralizing block 3 to be outwardly convex arc surfaces, the ability of the first centralizing block 2 and the second centralizing block 3 to adjust the well wall during the lowering of the centralizer can be improved.

[0107] Each first straightening block 2 has multiple rows of axially staggered protrusions 5 on its first outer surface 201, and each second straightening block 3 has multiple rows of axially staggered protrusions 5 on its second outer surface 301. The material of the protrusions 5 has a harder hardness than the material of the main body 1.

[0108] The protrusion 5 can increase the friction between the first straightening block 2 and the second straightening block 3 and the well wall, thereby effectively repairing the well wall.

[0109] Specifically, protrusion 5 can be made using cemented carbide.

[0110] The first outer surface 201 of each first straightening block 2 and the second outer surface 301 of each second straightening block 3 are both arc surfaces coaxial with the main body 1.

[0111] This configuration increases the contact area between the first centralizing block 2 and the second centralizing block 3 and the well wall, effectively adjusting the well wall and enhancing the stability of the centralizer.

[0112] The second straightening block 3 is closer to the drill bit than the first straightening block 2. The slope of the wedge shape at the end of the first straightening block 2 away from the drill bit is greater than the slope of the wedge shape at the end of the second straightening block 3 closer to the drill bit.

[0113] The slope of the wedge at the end of the first centralizing block 2 furthest from the drill bit is greater than the slope of the wedge at the end of the second centralizing block 3 closest to the drill bit. In other words, the wedge at the end of the second centralizing block 3 closest to the drill bit is sharper than the wedge at the end of the first centralizing block 2 furthest from the drill bit, while the wedge at the end of the first centralizing block 2 furthest from the drill bit is blunter than the wedge at the end of the second centralizing block 3 closest to the drill bit. Furthermore, the second centralizing block 3 is closer to the drill bit than the first centralizing block 2. During the centralizer's descent and drill bit advance, the end of the second centralizing block 3 closest to the drill bit is at the very forefront of the advance and contacts the wellbore first. Therefore, setting the wedge at the end of the second centralizing block 3 closest to the drill bit to be sharper than the wedge at the end of the first centralizing block 2 furthest from the drill bit can reduce resistance during the centralizer's descent.

[0114] In the fifth step, after the drill bit has completed drilling, the drill pipe and centralizer are pulled out of the well.

[0115] When the stabilizer is pulled out of the well, the end of the first stabilizer 2 furthest from the drill bit is the leading end and makes contact with the well wall first. Therefore, the wedge shape of the end of the first stabilizer 2 furthest from the drill bit is made more blunt than the wedge shape of the end of the second stabilizer 3 closest to the drill bit. This allows the more blunt wedge shape of the end of the first stabilizer 2 furthest from the drill bit to be used to trim the well wall during the extraction of the stabilizer.

[0116] The drilling operation is complete once the drill pipe and centralizer are completely pulled out of the well.

[0117] The beneficial effects of the technical solutions provided in this application include at least the following:

[0118] This application provides an anti-mud-packing stabilizer for controlling the drilling direction of the drill pipe in the wellbore. At least three first stabilizer blocks 2 and second stabilizer blocks 3 are longitudinally arranged on the outer wall of the cylindrical main body 1 of the stabilizer, thereby initially preventing the formation of mud packs between the stabilizer and the wellbore wall. The gaps between the at least three staggered first stabilizer blocks 2 and at least three second stabilizer blocks 3 form a guide channel 4 on the outer wall of the main body 1, which is wide at both ends and narrow in the middle. When drilling fluid carrying drill cuttings flows back up the well and through the guide channel 4, it is initially accelerated in the narrowest second guide section 402 of the guide channel 4. Furthermore, as the drilling fluid carrying drill cuttings passes through the guide channel 4, the drilling fluid in the third guide section 403 is first divided into two streams in the second guide section 402, and then the two streams in the second guide section 402 converge into one stream flowing into the first guide section 401, thereby providing a secondary acceleration to the drilling fluid carrying drill cuttings. Increasing the drilling fluid flow rate can effectively clear the well, thereby further preventing the formation of mud bags between the centralizer and the well wall, allowing the drill bit to drill effectively according to the set torque, thus improving drilling efficiency.

[0119] In this application, it should be understood that the terms “first” and “second” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0120] The above description is only for the purpose of enabling those skilled in the art to understand the technical solution of this application, and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A mud-blocking stabilizer for controlling the drilling direction of the drill pipe in the wellbore, characterized in that, The straightener includes a main body (1), at least three first straightening blocks (2), at least three second straightening blocks (3), and a guide channel (4). The main body (1) is cylindrical; The at least three first straightening blocks (2) are circumferentially and equally spaced around the outer wall of the main body (1), and the extension direction of the first straightening blocks (2) is parallel to the axis of the main body (1); The at least three second straightening blocks (3) are circumferentially and equally spaced around the outer wall of the main body (1), and the extension direction of the second straightening blocks (3) is parallel to the axis of the main body (1); The at least three first straightening blocks (2) and the at least three second straightening blocks (3) are arranged in an alternating vertical distribution; A first guide segment (401) is formed between every two adjacent first straightening blocks (2), a second guide segment (402) is formed between every pair of staggered adjacent first straightening blocks (2) and second straightening blocks (3), and a third guide segment (403) is formed between every two adjacent second straightening blocks (3). The second guide segment (402) has a range with a width smaller than the width of the first guide segment (401) and the width of the third guide segment (403). The first straightening block (2) and the second straightening block (3) are both elongated strips. Both ends of each first straightening block (2) and each second straightening block (3) are wedge-shaped. The second straightening block (3) is closer to the drill bit than the first straightening block (2). The wedge shape at the end of the second straightening block (3) closer to the drill bit is sharper than the wedge shape at the end of the first straightening block (2) farther from the drill bit. The wedge shape at the end of the first straightening block (2) farther from the drill bit is blunter than the wedge shape at the end of the second straightening block (3) closer to the drill bit. Each of the first guide segments (401) is connected to two of the second guide segments (402), and each of the third guide segments (403) is connected to two of the second guide segments (402). The two sides of the first straightening block (2) near the drill bit gradually taper inward as it approaches the drill bit, and the two sides of the second straightening block (3) away from the drill bit gradually taper inward as it moves away from the drill bit. The two sides of each of the first straightening blocks (2) and each of the second straightening blocks (3) are concave inward.

2. The centralizer according to claim 1, characterized in that, The slopes at both ends of each of the first straightening block (2) and each of the second straightening blocks (3) are wedge-shaped, and the center of the arc surface is closer to the axis of the main body (1) than the arc surface.

3. The centralizer according to claim 1, characterized in that, Each of the first straightening blocks (2) has multiple rows of axially staggered protrusions (5) on its first outer surface (201), and each of the second straightening blocks (3) has multiple rows of axially staggered protrusions (5) on its second outer surface (301). The material of the protrusions (5) has a hardness greater than that of the material of the main body (1).

4. The centralizer according to claim 1, characterized in that, The first outer surface (201) of each of the first straightening blocks (2) and the second outer surface (301) of each of the second straightening blocks (3) are arc surfaces coaxial with the main body (1).

5. The centralizer according to claim 1, characterized in that, The end of the stabilizer furthest from the drill bit is provided with an internal thread suitable for connection with the drill pipe, and the end of the stabilizer closest to the drill bit is provided with an external thread suitable for connection with the drill pipe.

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