Sand washing and bailing tricone bit

Abstract

The utility model provides a sand washing and bailing tricone bit which comprises a bit body, a center channel allowing drilling fluid to flow is formed in the bit body, a palm is arranged on the outer wall of the bit body, and a cone is arranged on the palm and located below the center channel. A connector used for being connected with a drill rod is arranged at the top end of the drill bit body, and the inner diameter of the center channel is larger than that of the drill rod.

Description

Technical Field

[0001] The utility model relates to the field of special downhole tools for petroleum development, in particular to a three-cone drill bit for sand flushing and bailing. Background Art

[0002] Currently, when carbonate oil wells collapse or become buried in sand, the large and uneven size of the sand and gravel blocking the bottom of the wellbore necessitates sand flushing with a crushing drill bit or a grinding shoe drill to clean the bottom and wellbore. Due to the thickness of carbonate fracture-vuggy reservoirs, the sand flushing footage is long, typically ranging from 20m to 800m. To achieve faster drilling and flushing speeds, a three-cone drill bit is typically used for rotary drilling and flushing. Conventional three-cone drill bits currently in use consist of three welded legs, each with a water hole approximately 20mm in diameter slanted downward to circulate the sand flushing fluid. Due to the small size of the water hole, positive circulation drilling and flushing is the only option.

[0003] The three-cone positive circulation drilling and sand flushing in the existing technology have the following problems: (1) For wells with a depth greater than 5500m, the upper 4500m is generally completed with φ244.5mm, φ193.7mm, and φ177.8mm casing, and sand flushing is performed with φ88.9mm tubing or drill pipe. The annular cross-sectional area is large (0.03188m3, 0.01604m3, and 0.01318m3, respectively). Based on the skid-mounted pump displacement of 30m3 / h of the current well repair team equipment capacity, the flow rate is very small (0.261m / s, 0.520m / s, and 0.632m / s, respectively). However, the particle size and density of carbonate cuttings are very large. (1) The degree of sand and debris is large and the sinking speed is fast, so it is difficult to carry sand and debris back to the surface by using ordinary brine; (2) The roundness of the carbonate rock broken by the drill bit is very poor. When moving in the fluid, the friction resistance between the rock and the well wall is very large. The annulus shape is complex and it is easy to form accumulation and blockage at the step; (3) The inner diameter of the conventional three-cone water hole is small, and the reverse circulation is very easy to form blockage at the water hole; (4) Actual construction has proved that the use of adjusting the performance of the sand flushing fluid, including the use of drilling mud, solid-free drilling fluid, and brine with thickeners and viscosity enhancers, has very limited improvement on the ability to return sand and debris to the surface of large wellbores. In addition, it is costly and causes serious environmental pollution, and cannot solve the fundamental problem.

[0004] Therefore, it is desired in the art to provide a sand-flush three-cone drill bit to solve the above technical problems. Utility Model Content

[0005] The utility model aims to provide a three-cone drill bit for sand flushing and bailing, which can solve the problem that reverse circulation is easily blocked and reverse circulation sand flushing and bailing cannot be performed during the current sand flushing and drilling process.

[0006] According to the utility model, a three-cone drill bit for sand bailing is provided, comprising a drill bit body, wherein a central channel allowing the flow of drilling fluid is formed in the drill bit body.

[0007] a leg provided on the outer wall of the drill body, and

[0008] A gear wheel is provided on the leg and below the central channel,

[0009] Wherein, a joint for connecting to a drill rod is provided at the top end of the drill bit body, and the inner diameter of the central channel is larger than the inner diameter of the drill rod.

[0010] In one embodiment, the inner diameter of the joint is not less than the inner diameter of the drill pipe.

[0011] In one embodiment, at least three arc-shaped grooves are arranged at intervals on the outer wall of the drill body, and the legs and the grooves are alternately arranged along the circumference of the drill body.

[0012] In one embodiment, the leg is fixed to the drill body by a locking button.

[0013] In one embodiment, a plurality of side teeth are provided at intervals along the longitudinal direction of the leg.

[0014] In one embodiment, the number of the gears is consistent with the number of the legs, and adjacent gears are meshed with each other.

[0015] In one embodiment, a cone shaft for connecting with the leg is provided at the top center of the cone.

[0016] A connecting rod is provided in the leg and is arranged in the longitudinal direction. The first end of the connecting rod is connected to the locking button, and the second end of the connecting rod is connected to the gear shaft.

[0017] In one embodiment, the axial direction of the connecting rod forms an angle of 45° with the axial direction of the gear shaft.

[0018] In one embodiment, the cone is constructed in a hemispherical form, and a side tooth group and a bottom tooth group are provided on the outer wall of the cone. The side tooth group and the bottom tooth group each include a plurality of teeth made of cemented carbide.

[0019] In one embodiment, the number of teeth in the side tooth group is smaller than the number of teeth in the bottom tooth group.

[0020] Compared with the prior art, the advantages of the present invention are:

[0021] First, this device effectively solves the problem of reverse circulation being easily blocked and unable to reversely circulate and flush sand during the current drilling and sand flushing process by expanding and changing the structure of the internal fluid channel. It increases the return speed and returns sand and gravel and other debris at the bottom of the well and in the wellbore, achieving the purpose of efficiently and quickly cleaning the wellbore and establishing oil and gas layer channels.

[0022] In addition, when encountering extra-large particles blocking the pipe string, it is usually at the step between the drill bit body and the joint. Therefore, after the blockage, positive circulation is used to push the extra-large particles back to the cone and crush them again, which can remove the blockage and then continue normal reverse circulation sand flushing and bailing operations.

[0023] Secondly, the device has a simple overall structure, reliable strength, easy processing, and good on-site construction effects. It also has the advantages of high construction efficiency and fast sand flushing and bailing speeds. Furthermore, the device is suitable for all downhole operations in oil and gas fields, and is particularly useful for large-bore sand flushing operations in difficult-to-reach carbonate reservoirs. It can employ both positive and reverse circulation methods to implement downhole operations such as sand flushing, sand bailing, cement plug drilling, and formation drilling, effectively returning particles such as sand, rock cuttings, and cement chips that are difficult to return. It can be used in all oilfield development projects, both domestically and internationally. The benefits become more pronounced as the well depth increases. Each sand flushing and drill-sticking accident is avoided, or each buried oil stratum is uncovered, a well is saved. Therefore, it has broad prospects for promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be described in detail below with reference to the accompanying drawings, in which:

[0025] Figure 1 The structure of the three-cone drill bit for sand bailing according to the present invention is schematically shown.

[0026] In the drawings, like parts are given like reference numerals, but the drawings are not necessarily drawn to scale. DETAILED DESCRIPTION

[0027] To make the technical solutions and advantages of the present invention more clearly understood, exemplary embodiments of the present invention are further described in detail below with reference to the accompanying drawings. It should be understood that the described embodiments are only a portion of the embodiments of the present invention, and are not exhaustive. Furthermore, the embodiments and features of the embodiments of the present invention may be combined with each other unless there is a conflict.

[0028] The present invention will be further described below with reference to the accompanying drawings.

[0029] Figure 1 The structure of a sand bailing three-cone drill bit 100 according to the present invention is schematically shown.

[0030] like Figure 1As shown, the sand-salvaging tri-cone drill bit 100 according to the present invention primarily comprises a drill body 11 and a leg 12 disposed on the outer wall of the drill body 11. The drill body 11 is preferably constructed as a hollow cylindrical structure, and arc-shaped grooves are milled inwardly and equally spaced along the circumference of the outer wall of the drill body 11 to provide sufficient fluid flow and chip removal channels within the annulus between the drill body 11 and the wellbore wall.

[0031] In the present invention, the leg 12 is inlaid and welded on the outer wall of the drill body 11 , and there are three legs 12 and three grooves respectively, and the legs 12 and the grooves are alternately arranged on the outer wall of the drill body 11 along the circumferential direction.

[0032] In other embodiments, a plurality of arc-shaped grooves may be provided, as long as the number of legs 12 is consistent with the number of arc-shaped grooves and the two are alternately distributed.

[0033] In one embodiment, Figure 1 As shown, the sand-fighting three-cone drill bit 100 further includes a cone 13 disposed on the leg 12. In the present invention, three cones 13 are provided, and each cone 13 is arranged in a one-to-one correspondence with the leg 12. The three cones 13 are arranged obliquely on the leg 12, allowing adjacent cones 13 to mesh with each other, facilitating subsequent forward and reverse circulation well flushing operations.

[0034] In this utility model, if Figure 1 As shown, a connector 14 is provided at the top of the drill bit body 11, and the device can be fixedly connected to the drill pipe via the connector 14. Furthermore, a central channel 111 is formed within the drill bit body 11, allowing the flow of drilling fluid. Preferably, the inner diameter of the connector 14 is not less than that of the drill pipe, and the inner diameter of the central channel 111 is larger than that of the drill pipe. This increases the upward and downward flow rate, thereby resolving the current problem of reverse circulation easily getting stuck during sand drilling and flushing, preventing reverse circulation from flushing sand.

[0035] In the present invention, the connector 14 is a 2-7 / 8" male threaded connector with a length of about 100 mm and is connected to a 2-7 / 8" drill pipe, thereby providing a fluid channel and transmitting rotational torque to the drill body 11 during drilling.

[0036] The conventional three-cone drill bit currently used is made of three legs welded together, and each leg has a water hole with a diameter of about φ20mm opened obliquely downward to circulate the sand flushing fluid. Due to the small water hole, only positive circulation drilling and sand flushing can be adopted. Compared with the existing technology, the present invention chooses to directly set a central channel 111 with a larger flow area in the drill bit body 11. In other words, the present device effectively solves the problem that the reverse circulation is easily blocked and cannot be reversely circulated during sand drilling and sand flushing by expanding and changing the internal fluid channel structure (if calculated according to the 3-1 / 2" oil pipe-2-7 / 8" drill pipe string channel), thereby increasing the return speed and returning sand and gravel and other debris at the bottom of the well and in the wellbore, so as to achieve the purpose of efficiently and quickly cleaning the wellbore and establishing an oil and gas layer channel.

[0037] In this utility model, reverse circulation of wellbore fluid is performed through the central channel 111, allowing downward drilling and flushing to achieve faster footage while simultaneously returning solid particles such as sand, rock cuttings, and cement chips. When an oversized particle blocks the tubing, typically at the step between the drill bit body 11 and the connector 14 (a 100mm diameter converted to 3-1 / 2" becomes 70.2mm diameter, or a 100mm diameter converted to 2-7 / 8" becomes 54.64mm diameter), positive circulation is used to push the oversized particle back to the cone for further crushing, thus clearing the blockage. Normal reverse circulation sand flushing and bailing operations can then resume.

[0038] In one embodiment, the legs 12 are constructed as a foot-shaped metal block with a smaller upper portion and a larger lower portion. Each leg 12 has a cylindrical through-hole within which a connecting rod 16 is longitudinally disposed, connecting a locking button 121 to the gear shaft 15 (described below). Preferably, the first end (top end) of the connecting rod 16 is connected to the locking button 121, and the second end (bottom end) of the connecting rod 16 is connected to the gear shaft 15.

[0039] Preferably, the leg 12 can be securely mounted on the outer wall of the drill body 11 via the locking button 121 and the connecting rod 16 , thereby improving the stability and firmness of the cone 13 during construction operations.

[0040] In one embodiment, Figure 1 As shown, a plurality of spaced-apart side teeth 122 are provided along the longitudinal direction of the leg 12. Preferably, the side teeth 122 can rotate on their own, thereby enabling the sand-bailing three-cone drill bit 100 to have a stronger crushing ability during downhole operation.

[0041] In this utility model, if Figure 1As shown, a gear shaft 15 for connecting to the leg 12 is provided at the top center of the gear 13, and the gear 13 can form a 45° angle with the connecting rod 16 under the action of the gear shaft 15, that is, the axial direction of the gear shaft 15 and the axial direction of the connecting rod 16 form a 45° angle.

[0042] Therefore, the three cones 13 can contact each other to fully block the bottom of the central channel 111. When encountering oversized particles blocking the pipe string, the oversized particles can be pushed back to the cones 13 by adopting positive circulation to be crushed again, thereby ensuring the continuation of normal reverse circulation sand flushing and bailing operations.

[0043] In one embodiment, the cone 13 is constructed as a hemispherical metal blank with cemented carbide teeth evenly distributed along the latitude line. Specifically, the outer wall of the cone 13 is provided with a spaced-apart side tooth group 131 and a bottom tooth group 132. Each side tooth group 131 and bottom tooth group 132 includes a plurality of teeth made of cemented carbide.

[0044] Preferably, the number of teeth of the side tooth group 131 is smaller than the number of teeth of the bottom tooth group 132 .

[0045] In the present invention, the teeth are perpendicular to the spherical surface and outward, so when the drill bit body 11 rotates under the torque of the pipe string, the gear 13 will rotate along its own gear shaft 15, and the rotation direction (equatorial plane) is at a 45° angle to the revolution direction of the pipe string. When the gear 13 rotates, the teeth roll and rub rapidly on the ground at the bottom of the well, and impact and crush ground obstacles or stir soft sand particles, thereby driving debris or sand and gravel into the liquid flow and into the chip discharge channel.

[0046] Ideally, the device can be sized appropriately for drilling, grinding, and sand bailing operations based on the well section being treated. Furthermore, the device can perform both reverse circulation and positive circulation sand bailing. It is important to note that the weight on bit (WOB) of this device should be controlled within 100 kN.

[0047] The working principle of this device is to integrate the three small-diameter channels in the conventional three-cone wheel body into a large-diameter channel, namely the central channel 111, so as to ensure that the inner diameter of the channel (for example, φ100mm) is larger than the inner diameter of the drill pipe (for example, φ70.2mm), and the inner diameter of the joint is equal to the inner diameter of the drill pipe (for example, 3-1 / 2" is φ70.2mm, and 2-7 / 8" is φ54.64mm), thereby greatly reducing the risk of drill bit blockage and realizing reverse circulation drilling and flushing of the wellbore and smooth chip removal.

[0048] Therefore, the device is connected to the bottom of the pipe string and inserted into the well. After drilling down to the sand surface, cement plug surface or bottom of the well, the turntable is rotated to drive the kelly and the pipe string, and the semi-closed gate of the blowout preventer, the annular blowout preventer or the rotating control head are closed. Then, the well fluid can be reversely circulated through the reverse circulation channel of the device, and the drilling and milling and flushing downwards can obtain faster footage while returning solid particles such as sand, rock cuttings, cement cuttings, etc. in the well.

[0049] However, when encountering oversized particles blocking the pipe string, generally at the step between the drill bit body 11 and the joint 14 (φ100mm changes to 3-1 / 2" to φ70.2mm or φ100mm changes to 2-7 / 8" to φ54.64mm), the positive circulation is used to push the oversized particles back to the cone and crush them again, which can remove the blockage and then continue the normal reverse circulation sand flushing and bailing operation.

[0050] Compared with the prior art, the advantages of the present invention are:

[0051] First, this device effectively solves the problem of reverse circulation being easily blocked and unable to reversely circulate and flush sand during the current drilling and sand flushing process by expanding and changing the structure of the internal fluid channel. It increases the return speed and returns sand and gravel and other debris at the bottom of the well and in the wellbore, achieving the purpose of efficiently and quickly cleaning the wellbore and establishing oil and gas layer channels.

[0052] In addition, when encountering oversized particles blocking the pipe string, it is usually at the step between the drill bit body 11 and the joint 14. Therefore, after the blockage, the positive circulation is used to push the oversized particles back to the cone and crush them again, which can remove the blockage and then continue the normal reverse circulation sand flushing and bailing operation.

[0053] Secondly, the device has a simple overall structure, reliable strength, easy processing, and good on-site construction effects. It also has the advantages of high construction efficiency and fast sand flushing and bailing speeds. Furthermore, the device is suitable for all downhole operations in oil and gas fields, and is particularly useful for large-bore sand flushing operations in difficult-to-reach carbonate reservoirs. It can employ both positive and reverse circulation methods to implement downhole operations such as sand flushing, sand bailing, cement plug drilling, and formation drilling, effectively returning particles such as sand, rock cuttings, and cement chips that are difficult to return. It can be used in all oilfield development projects, both domestically and internationally. The benefits become more pronounced as the well depth increases. Each sand flushing and drill-sticking accident is avoided, or each buried oil stratum is uncovered, a well is saved. Therefore, it has broad prospects for promotion and application.

[0054] In the description of this utility model, 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. Therefore, features specified as "first" or "second" may explicitly or implicitly include one or more of such features.

[0055] In the present invention, unless otherwise clearly specified and limited, terms such as "installed", "connected", "connected", and "fixed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two components.

[0056] For those skilled in the art, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0057] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Those skilled in the art may easily make changes or modifications within the scope disclosed herein, and such changes or modifications shall be encompassed within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of protection of the claims.

Claims

1. A three-cone drill bit for sand bailing, characterized in that: include: A drill bit body (11) is formed with a central channel (111) for allowing drilling fluid to flow, a leg (12) provided on the outer wall of the drill body (11), and a gear wheel (13) disposed on the leg (12) and below the central channel (111), A joint (14) for connecting to a drill rod is provided at the top end of the drill body (11), and the inner diameter of the central channel (111) is larger than the inner diameter of the drill rod.

2. The sand bailing three-cone drill bit according to claim 1, characterized in that: The inner diameter of the joint (14) is not less than the inner diameter of the drill rod.

3. The three-cone drill bit for sand bailing according to claim 2, characterized in that: At least three arc-shaped grooves are arranged at intervals on the outer wall of the drill body (11), and the legs (12) and the grooves are alternately arranged along the circumference of the drill body (11).

4. The sand bailing three-cone drill bit according to claim 3, characterized in that: The leg (12) is fixed to the drill body (11) via a locking button (121).

5. The three-cone drill bit for sand bailing according to any one of claims 1 to 4, characterized in that: A plurality of side teeth (122) are arranged at intervals along the longitudinal direction of the leg (12).

6. The three-cone drill bit for sand bailing according to any one of claims 1 to 4, characterized in that: The number of the gears (13) is consistent with the number of the legs (12), and adjacent gears (13) are meshed with each other.

7. The three-cone drill bit for sand bailing according to claim 4, characterized in that: A gear shaft (15) for connecting with the leg (12) is provided at the top center of the gear (13). A connecting rod (16) is provided in the leg (12) and is arranged longitudinally. The first end of the connecting rod (16) is connected to the locking button (121), and the second end of the connecting rod (16) is connected to the gear shaft (15).

8. The three-cone drill bit for sand bailing according to claim 7, characterized in that: The axial direction of the connecting rod (16) and the axial direction of the gear shaft (15) form an angle of 45°.

9. The three-cone drill bit for sand bailing according to any one of claims 1 to 4, characterized in that: The gear (13) is constructed in a hemispherical form, and a side tooth group (131) and a bottom tooth group (132) arranged at intervals are provided on the outer wall of the gear (13), and the side tooth group (131) and the bottom tooth group (132) both include a plurality of teeth made of cemented carbide.

10. The three-cone drill bit for sand bailing according to claim 9, characterized in that: The number of teeth of the side tooth group (131) is smaller than the number of teeth of the bottom tooth group (132).

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