Glass fiber reinforced plastic oil pipe milling tool

Abstract

The utility model relates to the technical field of oil and gas well fallen object milling, in particular to a glass fiber reinforced plastic oil pipe milling tool. The glass fiber reinforced plastic oil pipe milling tool comprises a milling shoe provided with a center water hole, a milling head is arranged at the lower end of the milling shoe, milling teeth are arranged on the milling head, and the milling teeth are distributed in a strip-shaped radiation block shape and are in inclined transition towards the center along the outer edge of the milling head. The milling teeth can be clamped on the outer edge of the port of the glass fiber reinforced plastic oil pipe when the glass fiber reinforced plastic oil pipe is milled, so that the port of the glass fiber reinforced plastic oil pipe shrinks towards the center to reduce tearing of the glass fiber reinforced plastic oil pipe, the glass fiber reinforced plastic oil pipe can be well broken and is not easy to deviate, and the problem that a drill is easy to block during milling is effectively avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of grinding and milling fallen objects in oil and gas wells, and in particular to a glass fiber reinforced plastic oil pipe grinding and milling tool. Background Art

[0002] FRP tubing has been widely used in oil well production tubing due to its corrosion resistance and certain mechanical properties. FRP tubing has weak resistance to internal and external pressures, and is easily broken and falls into the well when filled with sand particles returned by the formation. The conventional practice is to use flat-bottomed milling tools such as grinding shoes for milling. Since the upper end of the broken FRP tubing is irregularly serrated, the contact with the milling shoe during milling is point contact or contact with one side of the pipe wall, which is prone to grinding deviation, and more tearing effect is produced on the FRP tubing. The milled debris is in block and long fiber shape, and the glass fiber cannot be completely broken. The grinding debris is easy to entangle the tubing during the upward circulation process, and it is easy to settle at the large end of the milling shoe during the drilling process, which will block the annulus between the milling shoe and the casing, causing the accident of pipe string drilling.

[0003] The Chinese utility model patent with the authorization announcement number CN202417372U and the authorization announcement date September 5, 2012 discloses a milling shoe for grinding high-pressure fiberglass reinforced plastic oil pipes. The upper part of the milling shoe is provided with threads for connection with the downhole pipe string, the middle part is provided with a main water hole, and the bottom surface is provided with chip grooves evenly distributed along the circumference. The chip grooves are connected with the main water hole to meet the needs of circulation and chip removal under high-speed grinding conditions. Teeth are provided between two adjacent chip grooves to improve the milling efficiency of the oil pipe. When in use, the milling shoe is connected to the drill tool through the external thread provided on the upper part, and the rotation of the drill tool drives the milling shoe to rotate and grind the high-pressure fiberglass reinforced plastic oil pipe.

[0004] The grinding shoe for grinding high-pressure FRP oil pipes provided by the above utility model can be used for grinding FRP oil pipes, but during the grinding process, since the bottom surface of the grinding tool is an inner cone, the grinding will be carried out from the outside of the FRP oil pipe to the inside during grinding. The upper end of the FRP oil pipe is an irregular serrated shape, and during grinding, it will first contact one side of the pipe wall, which is easy to grind off-center and also easy to cause drill jamming. Utility Model Content

[0005] The utility model aims to provide a glass fiber reinforced plastic oil pipe milling tool to solve the problem that the glass fiber reinforced plastic oil pipe milling tool in the prior art is easy to get stuck when milling.

[0006] In order to achieve the above purpose, the fiberglass reinforced plastic oil pipe milling tool of the utility model adopts the following technical scheme:

[0007] A glass fiber reinforced plastic oil pipe milling tool comprises a milling shoe with a central water hole, a milling head at the lower end of the milling shoe, and milling teeth distributed in strip-shaped radiation blocks and inclined to the center along the outer edge of the milling head.

[0008] Beneficial effect: The fiberglass reinforced plastic oil pipe milling tool of the utility model is an improved invention. Specifically, by setting the milling teeth on the milling shoe to be distributed in strip-shaped radiation blocks and transitioning along the outer edge of the milling head toward the center, the milling teeth can be stuck on the outer edge of the fiberglass reinforced plastic oil pipe port when milling the fiberglass reinforced plastic oil pipe, so that the fiberglass reinforced plastic pipe port shrinks toward the center to reduce the tearing of the fiberglass reinforced plastic oil pipe, and the fiberglass reinforced plastic oil pipe can be better broken, not easy to be ground off, and the problem of easy drill jamming during milling is effectively avoided.

[0009] Furthermore, a guide support mechanism for guiding and straightening the fiberglass reinforced plastic oil pipe is provided at the lower end of the milling head.

[0010] Furthermore, the milling teeth include long teeth and short teeth, and the short teeth are arranged between the long teeth.

[0011] Furthermore, the outer surface of the guide support mechanism is welded with hard alloy for drilling and milling the glass fiber reinforced plastic oil pipe.

[0012] Furthermore, the shape of the head of the guiding and supporting mechanism is arc-shaped or conical.

[0013] Furthermore, the guide support mechanism is provided with a central through hole, and the central through hole is communicated with the central water hole.

[0014] Furthermore, a flow groove is provided on the outer periphery of the grinding shoe.

[0015] Furthermore, the number of the flow grooves is no less than 4, and the flow grooves are evenly distributed axially along the outer peripheral surface of the grinding shoe.

[0016] Furthermore, peripheral water holes for flushing grinding chips between the grinding and milling teeth are arranged around the central water hole, and the peripheral water holes are arranged between the grinding and milling teeth and inclined outwards.

[0017] Furthermore, the peripheral water holes are connected to the central water holes, and the number of the peripheral water holes is no less than 4. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a specific embodiment of the glass fiber reinforced plastic oil pipe grinding and milling tool of the utility model;

[0019] Figure 2 yes Figure 1 Schematic diagram of the structure of the fiberglass pipe milling tool viewed from above.

[0020] In the figure: 1. grinding shoe; 2. grinding head; 201. grinding teeth; 3. guide support mechanism; 301. cemented carbide; 302. center through hole; 4. upper joint; 41. internal thread; 5. flow groove; 601. center water eye; 602. peripheral water eye. DETAILED DESCRIPTION

[0021] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0022] The grinding shoe for grinding high-pressure FRP oil pipe disclosed in the prior art can be used for grinding FRP oil pipe, but during the grinding process, since the bottom surface of the grinding tool is an inner cone, it will be milled from the outside of the FRP oil pipe to the inside during grinding. The upper end of the FRP oil pipe is an irregular sawtooth shape, and it will first contact one side of the pipe wall during grinding, which is easy to grind off-center and also easy to cause drill jam. In view of the above problems, the utility model designs a FRP oil pipe grinding tool. The core concept of the utility model is to set the grinding teeth to be strip-shaped and radially distributed, and to transition from the outer edge of the grinding head to the center. During grinding, the grinding teeth can be stuck on the outer edge of the FRP oil pipe port, so that the FRP pipe port shrinks toward the center to reduce the tearing of the FRP oil pipe, so as to prevent drill jam.

[0023] Based on the above invention concept, Figure 1 As shown, a fiberglass oil pipe grinding and milling tool of the utility model comprises a grinding shoe 1 provided with a central water hole 601, a grinding head 2 is provided at the lower end of the grinding shoe 1, and the grinding head 2 is provided with grinding teeth 201, which are distributed in strip-shaped radiation blocks and transition obliquely toward the center along the outer edge of the grinding head 2.

[0024] Among the above components, Figure 1 In the illustrated embodiment, the shape of the mill shoe 1 is cylindrical, the diameter of the upper end of the mill shoe 1 is smaller than the diameter of the lower end, and the diameter of the lower end is larger than the outer diameter of the FRP oil pipe, so as to facilitate covering the pipe opening of the FRP oil pipe. An upper joint 4 is provided at the upper end of the mill shoe 1, and an internal thread 41 is provided on the upper joint 4, which can be conveniently connected to the downhole pipe string and lowered into the wellbore.

[0025] In such Figure 1 and Figure 2In the embodiment shown, the outer periphery of the lower end of the mill shoe 1 is provided with a flow groove 5, and the number of the flow grooves 5 is 4, which are evenly distributed along the axial direction of the outer peripheral surface of the mill shoe 1. The flow grooves 5 can increase the annular flow area of ​​the oil pipe and the casing, so that the wear debris can be smoothly washed away from the annulus to form a circulation, and when the oil pipe is lifted, the flow grooves 5 can also make the wear debris on the upper part of the mill shoe 1 fall into the well along the flow grooves, avoiding the accumulation of wear debris in the annulus and preventing the drill from getting stuck. In some other embodiments, the flow grooves 5 can also be set to 5 or 6, without special restrictions, as long as it is ensured that the wear debris can be smoothly washed away without getting stuck. The bottom of the lower end of the mill shoe 1 is a milling head 2, and the milling head 2 is welded with milling teeth 201. The milling teeth 201 include long teeth and short teeth. The short teeth are arranged between the long teeth, which can increase the density of the milling teeth 201 and improve the milling efficiency. Taking into account the fiber characteristics of the FRP oil pipe, the grinding and milling teeth 201 are set to be distributed in strip-shaped radiation blocks, and are inclined to transition toward the center along the outer edge of the grinding and milling head 2, with a high outside and a low inside. During grinding and milling, they can be stuck on the outer edge of the FRP oil pipe port, so that the FRP pipe port shrinks toward the center to reduce the tearing of the FRP oil pipe and is not easy to be worn off-center, so the FRP oil pipe can be better broken. The grinding and milling teeth 201 themselves are made of wear-resistant hard alloy steel materials boron carbide and 40CrMnMo, and can efficiently grind the FRP oil pipe into uniform granular debris, which is easy to return and not easy to produce long strip fragments to avoid drill jamming. In some other embodiments, the material of the grinding and milling teeth 201 can also be other wear-resistant and impact-resistant hard alloy materials.

[0026] In such Figure 1 and Figure 2 In the embodiment shown, a guide support mechanism 3 is provided at the lower end of the milling head 2. The guide support mechanism 3 is cylindrical and located in the middle of the milling head 2. Its diameter is smaller than the diameter of the milling shoe 1. In order to make the guide support mechanism 3 match the shape of the inner wall of the FRP oil pipe, the shape of the head of the guide support mechanism 3 is set to be an arc shape, which can guide the milling shoe to smoothly enter the inner cavity of the FRP oil pipe, and perform internal and external milling under the central support to prevent the milling shoe from deviating from the inner wall of the casing. In some other embodiments, the head shape of the guide support mechanism 3 can also be set to be conical. Cemented carbide 301 is welded on the outer surface of the guide support mechanism 3, which is used for drilling and milling the FRP oil pipe, so that the FRP oil pipe can achieve a better milling effect and improve the milling efficiency under the internal and external clamping milling of the guide support mechanism 3 and the milling teeth 201.

[0027] In such Figure 1 and Figure 2In the illustrated embodiment, the mill shoe 1 is provided with water holes which pass through from top to bottom, and the water holes include a central water hole 601 arranged at the center of the mill shoe and peripheral water holes 602 arranged around the central water hole. There are four peripheral water holes 602, which are connected to the central water hole 601, are inclined outwardly at the bottom of the mill shoe 1 and are located between the milling teeth 201 to avoid the milling teeth 201 and are evenly distributed, so that well washing fluid can pass through and a jet can be formed through the peripheral water holes 602, so that the grinding chips can be quickly washed away and returned to the ground with the well washing fluid, thereby accelerating drilling and improving the milling efficiency. A central through hole 302 is provided on the guide support mechanism 3, and the central through hole 302 is communicated with the water hole, and forms a central channel with the central water hole 601. The well washing fluid can quickly wash away the grinding chips around the guide support mechanism 3 through the central channel to improve the grinding efficiency. In some other embodiments, the peripheral water holes 602 are also set to more than 4, and their positions can also be adjusted according to actual conditions without special restrictions, as long as they can ensure that they can wash away the grinding chips around the casing.

[0028] When grinding the FRP oil pipe, the upper joint 4 of the grinding shoe 1 of the grinding tool is threadedly connected to the lowermost end of the oil pipe. When the pipe string rotates, it will drive the grinding tool to rotate, and the head of the guide support mechanism 3 will guide the grinding shoe 1 to enter the inner cavity of the FRP oil pipe to drill and grind the FRP oil pipe. At the same time, the strip-shaped radial grinding teeth 201 on the grinding head 2 contact the FRP oil pipe port and get stuck on the outer edge of the FRP oil pipe port, so that the FRP pipe port shrinks toward the center. Under the action of the central support, internal and external grinding is performed to break the FRP oil pipe in the wellbore, and the grinding chips will gather around the flow groove 5. At the same time, the well washing fluid will pass through the pipe string and spray out from the central water eye 601 and the outer water eye 602 to circulate the well and wash the well, and the grinding chips around the flow groove 5 are washed away and returned to the ground with the well washing fluid, thereby realizing the grinding of the FRP oil pipe and improving the grinding efficiency.

[0029] When drilling, the grinding chips on the upper part of the grinding shoe 1 fall into the well through the flow groove 5, which effectively avoids the problem of drill sticking.

Claims

1. A fiberglass reinforced plastic oil pipe milling tool, comprising a milling shoe with a central water hole, a milling head at the lower end of the milling shoe, and a milling tooth on the milling head, characterized in that: The grinding teeth are distributed in strip-shaped, radiating blocks and are inclined to transition toward the center along the outer edge of the grinding head.

2. The fiberglass reinforced plastic oil pipe milling tool according to claim 1, characterized in that: The lower end of the milling head is provided with a guide support mechanism for guiding and straightening the glass fiber reinforced plastic oil pipe.

3. The fiberglass reinforced plastic oil pipe milling tool according to claim 1 or 2, characterized in that: The milling teeth include long teeth and short teeth, and the short teeth are arranged between the long teeth.

4. The fiberglass reinforced plastic oil pipe milling tool according to claim 2, characterized in that: The outer surface of the guide support mechanism is welded with hard alloy used for drilling and milling glass fiber reinforced plastic oil pipes.

5. The fiberglass reinforced plastic oil pipe milling tool according to claim 4, characterized in that: The shape of the head of the guiding and supporting mechanism is arc-shaped or conical.

6. The fiberglass reinforced plastic oil pipe milling tool according to claim 5, characterized in that: The guiding support mechanism is provided with a central through hole, and the central through hole is communicated with the central water hole.

7. The fiberglass reinforced plastic oil pipe milling tool according to claim 1, characterized in that: The outer periphery of the grinding shoe is provided with a flow groove.

8. The fiberglass reinforced plastic oil pipe milling tool according to claim 7, characterized in that: The number of the flow grooves is no less than 4, and the flow grooves are evenly distributed axially along the outer peripheral surface of the grinding shoe.

9. The fiberglass reinforced plastic oil pipe milling tool according to claim 1, characterized in that: Peripheral water holes for flushing grinding chips between the grinding and milling teeth are arranged around the central water hole. The peripheral water holes are arranged between the grinding and milling teeth and are inclined outwards.

10. The fiberglass reinforced plastic oil pipe milling tool according to claim 9, characterized in that: The peripheral water holes are connected to the central water hole, and the number of the peripheral water holes is no less than 4.

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