Spherical milling head for oil and gas well and use method of spherical milling head

Abstract

The invention relates to the technical field of petroleum equipment, and particularly discloses an oil and gas well spherical milling head and a using method thereof.The oil and gas well spherical milling head comprises a milling head body, and the outer side surface of the milling head body is fixedly connected with first milling blocks distributed in an annular array; the upper surface of the milling head body is fixedly connected with a mounting block which is coaxially arranged; the mounting block is provided with a supporting and moving mechanism which is elastically supported towards two sides, free ends of two sides of the supporting and moving mechanism are provided with first sliding balls which are in rolling contact with a well wall, the mounting block is provided with pneumatic supporting mechanisms which are distributed towards the outer side in a divergent shape, and the free ends of the pneumatic supporting mechanisms are provided with second grinding and milling blocks. The radial grinding and milling block can be pneumatically supported and adjusted according to the construction pipe diameter, so that the radial grinding and milling block is suitable for construction of various pipe diameters, the application range is wide, the contact friction between the radial grinding and milling block and the well wall when the radial grinding and milling block moves in the well is reduced in an elastic supporting and righting mode, and the radial grinding and milling block has the advantage of protecting the well wall.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum equipment, and in particular to a spherical milling head for oil and gas wells and a use method thereof. Background Art

[0002] With the continuous development and growth of my country's petroleum industry, the passage of time, and the diversification of downhole operations, the maintenance of oil wells has become increasingly important, and the application of grinding and milling tools has become more and more extensive. For example, in the following situations, grinding and milling tools are needed for grinding and milling operations: cement solidification of downhole tubing, packer stuck in the well, repair of downhole deformed or broken casing, and handling of downhole objects that cannot be salvaged during drilling or well repair. Grinding and milling work is everywhere from drilling operations to well repair operations.

[0003] The milling heads currently used are spherical milling heads for oil and gas wells disclosed in Patent No. CN202022989994.8; The main method for this type of milling head to deal with downhole fallen object milling is overhaul drill tool milling. This method is to transmit the transmission torque directly from the wellhead to the downhole fallen object milling position through the drill tool. However, when performing milling operations in highly inclined wells and horizontal wells, it is necessary to replace milling tools of different sizes according to different pipe diameters. The operation is cumbersome and reduces work efficiency. In addition, when the conventional milling head structure is raised or lowered, its outer side has a larger contact area with the well wall, which increases the friction of movement and easily causes damage to the well wall. Summary of the invention

[0004] The purpose of the present invention is to address the defects of the prior art and to provide a spherical milling head for oil and gas wells and a method of using the same, which can pneumatically support and adjust the radial milling block according to the construction pipe diameter, making it suitable for construction of various pipe diameters and having a wide range of applications. It can also reduce the contact friction with the well wall by elastically supporting and straightening, and has the advantage of protecting the well wall.

[0005] The technical solution of the present invention is: a spherical milling head for oil and gas wells, comprising a milling head body, the outer surface of the milling head body is fixedly connected with first milling blocks distributed in a ring array, and the upper surface of the milling head body is fixedly connected with coaxially arranged mounting blocks; The mounting block is provided with a supporting and moving mechanism that elastically supports on both sides, and the free ends on both sides of the supporting and moving mechanism are provided with a first sliding ball for rolling contact with the well wall; The mounting block is provided with a pneumatic support mechanism which is distributed in a divergent shape toward the outside, and each free end of the pneumatic support mechanism is provided with a second milling block for milling the well wall.

[0006] Preferably, a movable through slot is radially provided on the mounting block, and the supporting movement mechanism comprises a positioning rotating rod coaxially arranged with the mounting block, and the positioning rotating rod is rotatably connected in the movable through slot; A gear is fixedly sleeved on the middle part of the positioning rotating rod, and symmetrically arranged torsion springs are sleeved on the upper and lower sides of the positioning rotating rod, and the two ends of the two torsion springs are respectively connected to the gear and the inner surface of the movable through groove; The two ends of the movable through groove are respectively slidably connected with guide blocks, the inner side of the guide block is provided with a rack matched with the gear, the outer side of the guide block is connected with a conical block through a support rod, and the outer edge of the conical block is rollingly connected with the first sliding ball.

[0007] Preferably, a bearing is connected between the upper end of the positioning rotating rod and the top of the inner wall of the movable through groove, and a bearing is connected between the lower end of the positioning rotating rod and the bottom of the inner wall of the movable through groove.

[0008] Preferably, a second spherical groove distributed in a ring array is provided on the outer conical surface of the conical block, a second sliding ball is rollingly installed in the second spherical groove, and a first spherical groove is provided on the outer edge end of the conical block, and the first sliding ball is rollingly installed in the first spherical groove.

[0009] Preferably, a mounting cavity is provided inside the mounting block, and a group of movable grooves cooperating with the second milling block are provided around the side wall of the mounting cavity; The pneumatic support mechanism comprises a pressure cylinder coaxially arranged with the mounting block and fixed in the mounting cavity, the top of the pressure cylinder is fixedly connected with an air pipe extending from the top of the mounting block, and the pressure cylinder is coaxially slidably and sealingly connected with a first piston block; A group of shunt tubes corresponding to the positions of the movable grooves are fixedly connected on the outer circumferential surface of the pressure cylinder, and a guide rod extending out of the shunt tube is coaxially slidingly sealed inside the shunt tube. The second milling block is connected to the free end of the guide rod, and a contraction spring is sleeved on the outside of the shunt tube. The two ends of the contraction spring are respectively fixedly connected to the second milling block and the pressure cylinder.

[0010] Preferably, the end of the guide rod located in the shunt pipe is fixedly connected to a second piston block which cooperates with the shunt pipe in a sliding seal.

[0011] Preferably, the horizontal cross-section of the pressure cylinder is a regular polygonal structure, and the diversion pipe is connected to the outer plane position of the pressure cylinder.

[0012] A method for using a spherical milling head for oil and gas wells comprises the following steps: Step 1: When the milling head body is lowered into the well, the first sliding balls on both sides of the support moving mechanism are elastically supported to contact the well wall, so that the milling head body is located at the center of the well and moves, and the first sliding balls form rolling contact with the well wall when lowering into the well; Step 2: When the diameter of the well wall decreases, the supporting moving mechanism is shortened inwards by the pressure from both sides to form an elastic buffer to ensure that it is always in contact with the well wall during movement, thereby reducing movement friction and straightening the milling head body; Step 3: After the milling head body is lowered into the working area, the pneumatic support mechanism is pressurized using a pressure air pump and a conduit, so that the pneumatic support mechanism pushes the second milling block to expand outward and contact the well wall, and then the gas injection is stopped, the pneumatic support mechanism is pressurized, and the milling operation begins; Step 4: After the milling operation is completed, the pneumatic support mechanism is depressurized, the pneumatic support mechanism drives the second milling block to reset, and the milling head body is lifted out of the well.

[0013] Compared with the prior art, the present invention has the following advantages: 1. The present invention realizes automatic adjustment of the grinding diameter of the second grinding and milling block through a pneumatic support mechanism, avoiding the need to replace grinding and milling tools of different sizes according to the pipe diameter, so that it is suitable for construction in various pipe diameters, and has automatic reset after use, a wide range of use, convenient operation, and the effect of improving work efficiency.

[0014] 2. The present invention realizes the effect of elastic support and rolling contact on both sides of the milling head body when it moves in the well wall through the support moving mechanism, and the support distance on both sides is synchronously expanded and contracted by increasing the coordination of gears and racks, so that the milling head body is always in a centered state, avoiding friction with the well wall when moving, thereby protecting the well wall and improving the construction quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the structure of the present invention; Figure 2 This is a three-dimensional diagram of the main structure of the milling head of the present invention; Figure 3 It is a three-dimensional diagram of the installation block structure of the present invention; Figure 4 For the present invention Figure 3 A magnified view of the structure at center; Figure 5 It is a three-dimensional diagram of the conical block structure of the present invention; Figure 6 This is a three-dimensional diagram of the pressure cylinder structure of the present invention; Figure 7 It is a three-dimensional diagram of the shunt pipe structure of the present invention; Figure 8 This is a schematic diagram of the use status of the present invention.

[0016] In the figure: 1. Milling head body; 2. Mounting block; 3. First milling block; 4. Positioning rotating rod; 41. Movable through groove; 42. Gear; 43. Torsion spring; 44. Guide block; 45. Rack; 46. Support rod; 47. Conical block; 48. Second spherical slide groove; 49. Second sliding ball; 410. First spherical slide groove; 411. First sliding ball; 5. Pressure cylinder; 51. Mounting cavity; 52. Movable groove; 53. Air pipe; 54. First piston block; 55. Diverter pipe; 56. Second piston block; 57. Guide rod; 58. Second milling block; 59. Contraction spring; 60. Oil pipe column; 61. Valve. DETAILED DESCRIPTION

[0017] The present invention is further described below with reference to the accompanying drawings and embodiments. Example 1

[0018] like Figures 1 to 8 A spherical milling head for oil and gas wells comprises a milling head body 1, the outer surface of the milling head body 1 is fixedly connected with a first milling block 3 distributed in a ring array, and the upper surface of the milling head body 1 is fixedly connected with a coaxially arranged cylindrical or truncated cone-shaped mounting block 2.

[0019] The mounting block 2 is provided with a supporting and moving mechanism that elastically supports the two sides, and free ends on both sides of the supporting and moving mechanism are provided with first sliding balls 411 for rolling contact with the well wall.

[0020] The mounting block 2 is provided with a pneumatic support mechanism that is distributed in a divergent shape toward the outside, and each free end of the pneumatic support mechanism is provided with a second milling block 58 for milling the well wall.

[0021] The second milling block 58 and the first milling block 3 are both die-casted from a composite material of tungsten carbide ceramic particles and copper alloy, and have higher structural strength.

[0022] When using: Step 1: When the milling head body 1 is lowered into the well, the first sliding balls 411 on both sides are elastically supported by the supporting movement mechanism to contact the well wall, so that the milling head body 1 moves at the center of the well, and the first sliding balls 411 roll and contact the well wall when lowering into the well.

[0023] Step 2: When the diameter of the well wall decreases, the supporting moving mechanism is shortened inwards by the pressure from both sides to form an elastic buffer to ensure that it is always in contact with the well wall during movement, thereby reducing movement friction and straightening the milling head body 1.

[0024] Step three, after the milling head body 1 is lowered into the working area, use a pressure air pump and a conduit to pressurize the pneumatic support mechanism, so that the pneumatic support mechanism pushes the second milling block 58 to expand outward and contact the well wall, then stop the gas injection, hold the pressure on the pneumatic support mechanism, and then use the top drive device to drive the milling operation.

[0025] Step 4: After the milling operation is completed, the pneumatic support mechanism is depressurized, and the pneumatic support mechanism drives the second milling block 58 to reset, and the milling head body 1 is lifted out of the well. Example 2

[0026] This embodiment is further optimized on the basis of the above embodiment, specifically: like Figures 1 to 5 A movable through groove 41 is radially opened on the mounting block 2, and the supporting moving mechanism includes a positioning rotating rod 4 coaxially arranged with the mounting block 2, a bearing is connected between the upper end of the positioning rotating rod 4 and the top of the inner wall of the movable through groove 41, and a bearing is connected between the lower end of the positioning rotating rod 4 and the bottom of the inner wall of the movable through groove 41.

[0027] A gear 42 is fixedly mounted in the middle of the positioning rotating rod 4. A symmetrically arranged torsion spring 43 is mounted on the upper and lower sides of the gear 42 on the positioning rotating rod 4. The two ends of the two torsion springs 43 are respectively connected to the gear 42 and the inner surface of the movable through slot 41.

[0028] The two ends of the movable through groove 41 are slidably connected with guide blocks 44, the inner side of the guide block 44 is provided with a rack 45 that cooperates with the gear 42, the outer side of the guide block 44 is connected to a conical block 47 through a support rod 46, and the outer edge of the conical block 47 is rollingly connected to the first sliding ball 411.

[0029] When the first sliding ball 411 is subjected to radial pressure in the well, it pushes the conical block 47, the support rod 46 and the guide block 44 to move, and the guide block 44 pushes the rack 45 to move. The rack 45 and the gear meshing 42 transmit the transmission to make the conical blocks 47 on both sides shrink inward synchronously, so that the milling head body 1 maintains a centered position in the well.

[0030] The present invention realizes the effect of elastic support and rolling contact on both sides of the milling head body 1 when the milling head body 1 moves in the well wall by supporting the moving mechanism, and the support distance on both sides is synchronously expanded and contracted by increasing the coordination of the gear 42 and the rack 45, so that the milling head body 1 is always in a centered state, avoiding friction with the well wall when moving, thereby protecting the well wall and improving the construction quality. Example 3

[0031] This embodiment is further optimized on the basis of the above embodiment, specifically: like Figure 5A second spherical groove 48 distributed in a ring array is provided on the outer conical surface of the conical block 47, and a second sliding ball 49 is rollingly installed in the second spherical groove 48. A first spherical groove 410 is provided at the outer edge end of the conical block 47, and a first sliding ball 411 is rollingly installed in the first spherical groove 410.

[0032] The second sliding ball 49 is added to contact and rotate with a protrusion on the well wall, thereby avoiding collision with the conical block 47 when the well wall is uneven. Example 4

[0033] This embodiment is further optimized on the basis of the above embodiment, specifically: like Figures 1 to 3 A mounting cavity 51 is provided inside the mounting block 2 , and a group of movable grooves 52 cooperating with the second milling block 58 are provided around the side wall of the mounting cavity 51 .

[0034] like Figure 6 and Figure 7 The pneumatic support mechanism includes a pressure cylinder 5 which is coaxially arranged with the mounting block 2 and fixed in the mounting cavity 51 .

[0035] The top of the pressure cylinder 5 is fixedly connected with an air pipe 53 extending from the top of the mounting block 2 , and the inside of the pressure cylinder 5 is coaxially slidably and sealingly connected with a first piston block 54 .

[0036] A group of shunt pipes 55 corresponding to the positions of the movable grooves 52 are fixedly connected on the outer peripheral surface of the pressure cylinder 5. The mounting block 2 has a regular polygonal structure in horizontal cross section, so that the shunt pipes 55 can be easily connected to the outer plane position of the pressure cylinder 5.

[0037] A guide rod 57 extending out of the shunt tube 55 is provided in the shunt tube 55 , and a second piston block 56 which is in sliding and sealing cooperation with the shunt tube 55 is fixedly connected to the end of the guide rod 57 located in the shunt tube 55 .

[0038] The second milling block 58 is connected to the free end of the guide rod 57 . A contraction spring 59 is sleeved on the outside of the shunt pipe 55 . The two ends of the contraction spring 59 are fixedly connected to the second milling block 58 and the pressure cylinder 5 , respectively.

[0039] The present invention realizes automatic adjustment of the grinding diameter of the second grinding and milling block 58 through a pneumatic support mechanism, avoiding the need to replace grinding and milling tools of different sizes according to the pipe diameter, thereby being suitable for construction in various pipe diameters and having automatic reset after use, having a wide range of uses, convenient operation, and the effect of improving work efficiency. Example 5

[0040] This embodiment is a step of using a spherical milling head for oil and gas wells in the above embodiment.

[0041] like Figures 1 to 8 , specifically including the following steps: Step one, connect the present invention to the lower end of the oil pipe string 60, the air pipe 53 is connected to the inner cavity of the oil pipe string 60 through a reducer, the oil pipe string 60 is formed by lowering multiple oil pipes into the well by connecting them end to end, and when the milling head body 1 moves in the well, the first sliding ball 411 rollingly installed on the two conical blocks 47 forms a rolling contact with the well wall, thereby reducing the friction with the well wall during movement.

[0042] Step 2: When the diameter of the well wall decreases or there is a convex part on the well wall, the conical block 47 is contracted and squeezed, and the guide block 44 is driven to move along the movable slot 41 through the support rod 46. The synchronous relative movement of the two guide blocks 44 is synchronized by the rack 45 and the gear 42. When the gear rotates, the torsion spring 43 is deformed by the force; When the diameter of the well wall is restored and expanded, the reset torque of the torsion spring 43 drives the gear 42 to reset and rotate through the positioning rotating rod 4, thereby driving the rack 45 to move, so that the two guide blocks 44 move outward. When the guide blocks 44 move, they push the conical block 47 and the first sliding ball 411 to contact the well wall through the support rod 46; The gear 42 and the rack 45 can be used to coordinate with each other so that the support distances at both ends can be synchronously extended and retracted, so that the milling head body 1 is always kept centered in the well, thereby avoiding contact friction between the milling head body 1 and the well wall.

[0043] Step 3: After the milling head body 1 is lowered into the preset position, a valve 61 is installed on the top of the oil pipe string 60 and a conduit is connected to the pressure air pump. The pressure cylinder 5 is pressurized by the pressure air pump through the oil pipe string 60 and the air pipe 53, so that the first piston block 54 moves downward and the second piston block 56 moves outward; Thereby, the second milling block 58 is driven to move outward through the guide rod 57. At this time, the contraction spring 59 is in a stretched state. The second milling block 58 extends from the movable groove 52 and contacts the well wall. Then, the pressure is stopped, and the valve 61 at the top of the oil pipe string 60 is closed to hold the pressure. After the conduit between the valve 61 and the pressure air pump is removed, the top drive device for drilling is used to drive the oil pipe string 60 to rotate and start the milling operation.

[0044] Step 4, after the milling operation is completed, open the valve 61 to release the pressure in the oil pipe string 60, the air pipe 53, and the pressure cylinder 5. At this time, under the elastic resetting and shortening action of the contraction spring 59, the second milling block 58 is pulled back into the movable groove 52, and then the oil pipe string 60 is lifted to lift the present invention out of the wellhead.

[0045] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0046] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A spherical milling head for oil and gas wells, comprising a milling head body, the outer surface of which is fixedly connected with first milling blocks distributed in a circular array, Features: A coaxially arranged mounting block is fixedly connected to the upper surface of the milling head body; The mounting block is provided with a supporting and moving mechanism that elastically supports on both sides, and the free ends on both sides of the supporting and moving mechanism are provided with a first sliding ball for rolling contact with the well wall; The mounting block is provided with a pneumatic support mechanism which is distributed in a divergent shape toward the outside, and each free end of the pneumatic support mechanism is provided with a second milling block for milling the well wall.

2. A spherical milling head for oil and gas wells according to claim 1, Features: The mounting block is provided with a movable through slot in the radial direction, and the supporting and moving mechanism comprises a positioning rotating rod coaxially arranged with the mounting block, and the positioning rotating rod is rotatably connected in the movable through slot; A gear is fixedly sleeved on the middle part of the positioning rotating rod, and symmetrically arranged torsion springs are sleeved on the upper and lower sides of the positioning rotating rod, and the two ends of the two torsion springs are respectively connected to the gear and the inner surface of the movable through groove; The two ends of the movable through groove are respectively slidably connected with guide blocks, the inner side of the guide block is provided with a rack matched with the gear, the outer side of the guide block is connected with a conical block through a support rod, and the outer edge of the conical block is rollingly connected with the first sliding ball.

3. A spherical milling head for oil and gas wells according to claim 2, Features: A bearing is connected between the upper end of the positioning rotating rod and the top of the inner wall of the movable through slot, and a bearing is connected between the lower end of the positioning rotating rod and the bottom of the inner wall of the movable through slot.

4. The spherical milling head for oil and gas wells according to claim 2, Features: The outer conical surface of the conical block is provided with a second spherical groove distributed in a ring array, and a second sliding ball is rollingly installed in the second spherical groove. The outer edge end of the conical block is provided with a first spherical groove, and the first sliding ball is rollingly installed in the first spherical groove.

5. The spherical milling head for oil and gas wells according to claim 1, Features: The installation block is provided with an installation cavity inside, and the side wall of the installation cavity is provided with a group of movable grooves cooperating with the second milling block. The pneumatic support mechanism comprises a pressure cylinder coaxially arranged with the mounting block and fixed in the mounting cavity, the top of the pressure cylinder is fixedly connected with an air pipe extending from the top of the mounting block, and the pressure cylinder is coaxially slidably and sealingly connected with a first piston block; A group of shunt tubes corresponding to the positions of the movable grooves are fixedly connected on the outer circumferential surface of the pressure cylinder, and a guide rod extending out of the shunt tube is coaxially slidingly sealed inside the shunt tube. The second milling block is connected to the free end of the guide rod, and a contraction spring is sleeved on the outside of the shunt tube. The two ends of the contraction spring are respectively fixedly connected to the second milling block and the pressure cylinder.

6. A spherical milling head for oil and gas wells according to claim 5, Features: The end of the guide rod located in the shunt pipe is fixedly connected with a second piston block which cooperates with the shunt pipe in a sliding seal.

7. The spherical milling head for oil and gas wells according to claim 5, Features: The horizontal cross section of the pressure cylinder is a regular polygonal structure, and the diverter pipe is connected to the outer plane position of the pressure cylinder.

8. A method for using a spherical milling head for oil and gas wells according to any one of claims 1 to 7, Features: The following steps are involved: Step 1: When the milling head body is lowered into the well, the first sliding balls on both sides of the support moving mechanism are elastically supported to contact the well wall, so that the milling head body is located at the center of the well and moves, and the first sliding balls form rolling contact with the well wall when lowering into the well; Step 2: When the diameter of the well wall decreases, the supporting moving mechanism is shortened inwards by the pressure from both sides to form an elastic buffer to ensure that it is always in contact with the well wall during movement, thereby reducing movement friction and straightening the milling head body; Step 3: After the milling head body is lowered into the working area, the pneumatic support mechanism is pressurized using a pressure air pump and a conduit, so that the pneumatic support mechanism pushes the second milling block to expand outward and contact the well wall, and then the gas injection is stopped, the pneumatic support mechanism is pressurized, and the milling operation begins; Step 4: After the milling operation is completed, the pneumatic support mechanism is depressurized, the pneumatic support mechanism drives the second milling block to reset, and the milling head body is lifted out of the well.

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