Drill rod vibration energy collecting device

Abstract

The invention discloses a drill rod vibration energy collecting device which comprises a hollow cylindrical outer shell, a hollow cylindrical inner shell, a coil winding, a permanent magnet, a spiral spring and a sealing plug. The hollow cylindrical inner shell is in interference fit with the interior of the hollow cylindrical outer shell, the coil winding is installed in a coil winding installation groove formed in the outer surface of the hollow cylindrical inner shell, the permanent magnet and the two spiral springs are arranged in the hollow cylindrical inner shell, and the two spiral springs are symmetrically arranged at the two ends of the permanent magnet; the sealing plug is located in the hollow cylindrical outer shell and located at one end of the hollow cylindrical inner shell. The built-in spring-mass system reduces the inherent frequency of the spring-mass system when the drill rod rotates and drills, improves the energy collection efficiency of the device when the drill rod rotates at low frequency, and widens the frequency band range of energy collection; under the condition of a vertical well, energy of circumferential vibration and transverse shimmy of the drill rod can be collected; under the conditions of an inclined shaft and a horizontal well, the rotating energy of the drill rod can be collected.

Description

Technical Field

[0001] The invention relates to the field of mechanical engineering, and in particular to a vibration energy collection device which can stably supply power to underground electronic instruments during oil and gas drilling and production. Background Art

[0002] In drilling operations, real-time measurement and collection of dynamic information of the drilling process is crucial for safe and efficient drilling. Data collection is mainly completed through sensors arranged in the measurement while drilling / logging system. However, how to realize local power supply of downhole sensors is still a technical problem that urgently needs to be solved in this field. Cable drill pipe can realize the power supply and information transmission of the sensor network on the drill pipe. However, cables must be buried in each drill pipe, and coils need to be installed in the joints between the drill pipes. Chemical battery power supply has the disadvantages of limited life, complex packaging process, easy leakage, environmental pollution and fixed size. Designing a local power supply to power downhole wireless communication and electronic instruments can replace cable and battery power supply.

[0003] During rotary drilling, the energy from the rotary table or top drive is transferred to the drill bit through the drill pipe. The drill pipe not only rotates, but also withstands multiple vibrations, including longitudinal vibration, circumferential vibration, lateral oscillation, and vortex. The rotational energy of the drill pipe is necessary and inevitable for transmitting motion; while the vibration energy of the drill pipe is not necessary but inevitable. The vibration of the drill pipe can cause damage to the drill pipe itself, the drill bit, and even the ground equipment. Since the vibration of the drill pipe has a high energy density, how to effectively collect and use the vibration energy of the drill pipe to power downhole wireless communications and electronic instruments has always been a hot issue of concern in the industry.

[0004] At present, various forms of vibration collection devices have been developed. Commonly used vibration energy collection devices mostly use a spring-mass oscillator structure, which has a certain natural frequency, while the three vibration forms of the drill pipe have different frequency band ranges and change with the change of drilling conditions. When the vibration frequency of the drill pipe is the same as the natural frequency of the spring-mass system, resonance will occur, and at this time, the energy collection efficiency is the highest. When the frequencies of the two do not match, the energy collection efficiency will be greatly reduced. In addition, these devices are usually highly selective to the vibration direction of the drill pipe and are difficult to be compatible with multiple vibration directions, which will also limit the energy collection efficiency. Therefore, it is necessary to expand the frequency bandwidth of the vibration energy collection device. At the same time, it is necessary to reduce the dependence of the vibration energy collection device on the vibration direction. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention combines the spring oscillation effect and the centrifugal softening effect of the spring-mass system, and designs a vibration energy collection device based on the drill pipe structure and its vibration characteristics. The structure of the device has the advantages of wide frequency band and good vibration direction compatibility. By adjusting the structure and parameters of the device, it can adapt to the vibration form of the drill pipe that changes at any time, and maintain a high energy collection efficiency under different drilling conditions.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] A drill pipe vibration energy collection device comprises a hollow cylindrical outer shell, a hollow cylindrical inner shell, a coil winding, a permanent magnet, a spiral spring and a sealing plug;

[0008] The hollow cylindrical inner shell is interference fit inside the hollow cylindrical outer shell, the coil winding is installed in a coil winding installation groove provided on the outer surface of the hollow cylindrical inner shell, the permanent magnet and the two spiral springs are arranged inside the hollow cylindrical inner shell, and the two spiral springs are symmetrically arranged at both ends of the permanent magnet; the sealing plug is located inside the hollow cylindrical outer shell and at one end of the hollow cylindrical inner shell.

[0009] Furthermore, the drill pipe vibration energy collection device also includes a short section for installing the hollow cylindrical shell.

[0010] Furthermore, two sealing grooves are respectively arranged at both ends of the outer surface of the hollow cylindrical shell, and a shell sealing ring is installed in each sealing groove to prevent drilling fluid from invading the gap between the hollow cylindrical shell and the short section.

[0011] Furthermore, the sealing plug is provided with two sealing grooves, and sealing plug sealing rings are installed in the sealing grooves to prevent drilling fluid from invading the inner chamber of the hollow cylindrical inner shell.

[0012] Furthermore, the inner surface of the hollow cylindrical outer shell is provided with a plurality of circumferential grooves and axial grooves, and both ends of the hollow cylindrical inner shell are provided with through holes which are evenly distributed in the circumferential direction and penetrate therethrough, and the through holes are aligned with the circumferential grooves in the axial direction of the hollow cylindrical outer shell and the hollow cylindrical inner shell, thereby ensuring the free flow of gas in the internal chamber of the device and playing a damping role.

[0013] Furthermore, the short section is a hollow cylindrical structure, with male threads and female threads respectively provided at both ends for connecting to the drill rod; a radial non-through hole is provided inside the short section, and the hollow cylindrical shell is installed in the radial non-through hole inside the short section, and one end is tightened by a screw through a cover plate.

[0014] Further, the axial direction of the non-through hole in the radial direction of the short section is perpendicular to the axis of the short section but does not intersect.

[0015] The beneficial effects of the present invention are as follows:

[0016] (1) The spring-mass system built into the drill rod vibration energy collection device of the present invention will produce a centrifugal softening effect when the drill rod rotates during drilling, thereby reducing the natural frequency of the spring-mass system. This improves the energy collection efficiency of the device when the drill rod rotates at a low frequency and broadens the frequency band range of energy collection.

[0017] (2) The drill pipe vibration energy collection device of the present invention can collect the energy of the drill pipe's circumferential vibration and lateral swing in the case of a vertical well; and can collect the energy of the drill pipe's rotation in the case of an inclined well or a horizontal well.

[0018] (3) The device has no moving parts immersed in drilling fluid, which greatly extends the service life and can achieve the purpose of long-term use after one installation.

[0019] (4) The device is easy and firm to install, and no additional processing of the drill pipe is required. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the drill pipe vibration energy collection device installed on the short section.

[0021] Figure 2 This is a transverse cross-sectional view of the drill pipe vibration energy collection device (two energy collection devices are installed in the short section).

[0022] Figure 3 This is a cross-sectional view of the outer shell of the drill pipe vibration energy collection device.

[0023] Figure 4 This is the outer shape of the inner shell of the drill pipe vibration energy collection device.

[0024] In the figure, 1. hollow cylindrical shell, 2. shell sealing ring, 3. hollow cylindrical inner shell, 4. coil winding, 5. permanent magnet, 6. spiral spring, 7. sealing plug, 8. sealing plug sealing ring, 9. vibration energy collection device, 10. short section, 11. cover plate, 12. circumferential groove, 13. axial groove, 14. through hole. DETAILED DESCRIPTION

[0025] The present invention will be described in detail below based on the accompanying drawings and preferred embodiments, and the purpose and effects of the present invention will become more clear. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0026] like Figure 1 and Figure 2As shown, the drill pipe vibration energy collection device 9 is installed in the short section 10, and the drill pipe vibration energy collection device 9 includes a hollow cylindrical outer shell 1, a hollow cylindrical inner shell 3, an outer shell sealing ring 2, a coil winding 4, a permanent magnet 5, two coil springs 6, a sealing plug 7 and a sealing plug sealing ring 8.

[0027] The hollow cylindrical inner shell 3 is interference fit inside the hollow cylindrical outer shell 1. Two sealing grooves are arranged at both ends of the outer surface of the hollow cylindrical outer shell 1. A shell sealing ring 2 is installed in each sealing groove to prevent drilling fluid from invading the gap between the hollow cylindrical outer shell 1 and the short section 10. Figure 3 As shown, the inner surface of the hollow cylindrical shell 1 is provided with a plurality of circumferential grooves 12 and axial grooves 13. Figure 4 As shown, both ends of the hollow cylindrical inner shell 3 are provided with through holes 14 that are evenly distributed along the circumferential direction and penetrate through the hollow cylindrical inner shell 3. The through holes 14 of the hollow cylindrical inner shell 3 and the circumferential grooves 12 on the inner surface of the hollow cylindrical outer shell 1 are aligned in the axial direction of the entire drill pipe vibration energy collection device 9, ensuring the free flow of gas in the internal chamber of the device and playing a damping role. Figure 1 As shown, the coil winding 4 is installed in the coil winding installation groove provided on the outer surface of the hollow cylindrical inner shell 3, the permanent magnet 5 and the two coil springs 6 are installed inside the hollow cylindrical inner shell 3, the two coil springs 6 are symmetrically arranged at both ends of the permanent magnet 5, and a gap is provided between the permanent magnet 5 and the two coil springs 6. The ends of the two coil springs 6 away from the permanent magnet 5 can be fixed or can move freely. By numerically solving the dynamic equation of the drill rod-energy collection device coupling system, it is obtained that when the gap is less than or equal to 0, the system is monostable, and there is a stable equilibrium point corresponding to the place where the potential energy of the spring-mass system is the lowest. When the gap is greater than 0, the system is bistable.

[0028] The sealing plug 7 is installed inside the hollow cylindrical outer shell 1 and is located at one end of the hollow cylindrical inner shell 3, clamping the hollow cylindrical inner shell 3. Two sealing grooves are provided on the sealing plug 7, and the sealing plug sealing ring 8 is located in the sealing groove to prevent drilling fluid from invading the inner chamber of the hollow cylindrical inner shell 3.

[0029] like Figure 2 As shown, two hollow cylindrical shells 1 are installed in the short section 10. The short section 10 is a hollow cylindrical structure, and a non-through hole is arranged inside along the radial direction. The two hollow cylindrical shells 1 are located in the non-through hole, and one end is tightened by a screw through a cover plate 11. The non-through hole opened inside the short section 10 is perpendicular to the axis of the short section 10, but may or may not intersect with the axis. Male threads and female threads are respectively arranged at both ends of the short section 10, and are connected to the drill pipe. The outer diameter of the short section 10 can be the same as the outer diameter of the drill pipe, or slightly larger, and the inner diameter of the short section 10 is greater than or equal to the inner diameter of the drill pipe. The length of the short section 10 is determined according to needs. Multiple hollow cylindrical shells 1 can be installed in the short section 10 at the same time to increase the power of energy collection.

[0030] The working principle of the vibration energy harvesting device is as follows:

[0031] When the spring-mass system inside the vibration energy collection device 9 is disturbed, the permanent magnet 5 oscillates back and forth along the axis of the hollow cylindrical inner shell 3, and an induced current is generated in the coil winding 4. The coil winding 4 is connected to an external circuit, which can realize energy storage or directly power electronic equipment. The structure and installation form of the vibration energy collection device enable it to simultaneously collect the energy of lateral swing, torsional vibration, and continuous rotation of the drill rod, which can be verified by the dynamic equation of the drill rod-energy collection device coupling system. In a rotating system such as a drill rod, the vibration energy collection device will produce a centrifugal softening effect, which is conducive to the energy collection of ultra-low frequency drill rod rotation motion and improves the energy collection efficiency.

[0032] The vibration energy harvesting device not only obtains energy from the vibration of the drill string, but also affects the vibration of the drill string. First, the dynamic equation of the drill string-energy harvesting device coupling system is established through the Lagrange equation. Then, according to the actual drilling and production conditions, the boundary conditions and initial conditions of the equation can be determined. Finally, the performance of the vibration energy harvesting device can be calculated. The relevant dimensions and parameters of the components of the vibration energy harvesting device used are shown in Table 1, and the relevant dimensions and parameters of the drill pipe and bottom hole assembly are shown in Table 2.

[0033] Table 1 Dimensions and parameters of some parts of the device

[0034]

[0035] Table 2 Dimensions and parameters of drill pipe and bottom hole assembly

[0036]

[0037] The results show that a single vibration energy harvester can harvest energy over a wide frequency range under the excitation of circumferential vibration and lateral shimmy. In vertical wells, the output power of a single vibration energy harvester increases with the depth of the drill pipe. Specifically, the average output power near the wellhead is about 2 milliwatts, while the maximum output power near the bottom of the well can reach 2.0W. In deviated wells, the output power is related to both the drill pipe depth and the well inclination, and increases with the increase of the well inclination. Within a larger range of drill string speeds, when the well inclination is 10 degrees, the output power is several milliwatts. When the well inclination is 20 degrees, the output power is tens of milliwatts. Therefore, the output power of a single vibration energy harvester can meet the new power requirements of most downhole sensors.

[0038] Those skilled in the art can understand that the above are only preferred examples of the invention and are not intended to limit the invention. Although the invention is described in detail with reference to the above examples, those skilled in the art can still modify the technical solutions recorded in the above examples or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, etc. made within the spirit and principle of the invention shall be included in the protection scope of the invention.

Claims

1. A drill pipe vibration energy collection device, characterized in that: It comprises a hollow cylindrical outer shell (1), a hollow cylindrical inner shell (3), a coil winding (4), a permanent magnet (5), a helical spring (6) and a sealing plug (7); The hollow cylindrical inner shell (3) is interference-fitted inside the hollow cylindrical outer shell (1); the coil winding (4) is installed in a coil winding installation groove provided on the outer surface of the hollow cylindrical inner shell (3); the permanent magnet (5) and the two coil springs (6) are arranged inside the hollow cylindrical inner shell (3), and the two coil springs (6) are symmetrically arranged at both ends of the permanent magnet (5); the sealing plug (7) is located inside the hollow cylindrical outer shell (1) and at one end of the hollow cylindrical inner shell (3).

2. The drill pipe vibration energy collection device according to claim 1, characterized in that: The drill pipe vibration energy collection device also includes a short section (10) for mounting the hollow cylindrical shell (1).

3. The drill pipe vibration energy collection device according to claim 2, characterized in that: Two sealing grooves are respectively arranged at both ends of the outer surface of the hollow cylindrical outer shell (1), and a shell sealing ring (2) is installed in each sealing groove to prevent drilling fluid from invading the gap between the hollow cylindrical outer shell (1) and the short section (10).

4. The drill pipe vibration energy collection device according to claim 1, characterized in that: The sealing plug (7) is provided with two sealing grooves, and sealing plug sealing rings (8) are installed in the sealing grooves to prevent drilling fluid from invading the inner chamber of the hollow cylindrical inner shell (3).

5. The drill pipe vibration energy collection device according to claim 1, characterized in that: The inner surface of the hollow cylindrical outer shell (1) is provided with a plurality of circumferential grooves (12) and axial grooves (13), and both ends of the hollow cylindrical inner shell (3) are provided with through holes (14) that are evenly distributed along the circumference and penetrate through the hollow cylindrical outer shell (1). The through holes (14) are aligned with the circumferential grooves (12) along the axial direction of the hollow cylindrical outer shell (1) and the hollow cylindrical inner shell (3), thereby ensuring the free flow of gas in the internal chamber of the device and playing a damping role.

6. The drill pipe vibration energy collection device according to claim 2, characterized in that: The short section (10) is a hollow cylindrical structure, with male threads and female threads respectively provided at both ends for connection with a drill pipe; a non-through hole along the radial direction is provided inside the short section (10); the hollow cylindrical shell (1) is installed in the non-through hole along the radial direction inside the short section (10), and one end is tightened by a screw through a cover plate (11).

7. The drill pipe vibration energy collection device according to claim 2, characterized in that: The axial direction of the non-through hole in the radial direction of the short section (10) is perpendicular to the axis of the short section (10) but does not intersect.

Images