A method of drilling tool vibration energy recovery

Abstract

The present application belongs to the field of oil and gas field drilling, and particularly discloses a drilling tool vibration energy recovery method. The method is performed by using a drilling tool vibration energy recovery power generation device, the drilling tool vibration energy recovery power generation device comprises a buffer protection unit and a piezoelectric unit connected with the drilling tool, and the method comprises the following steps: the buffer protection unit is reciprocated in the axial direction by the vibration of the drilling tool, so that a periodic stress change is generated; the piezoelectric unit generates a piezoelectric effect under the periodic stress change, so that an electric current is output to the load of the drilling tool vibration energy recovery power generation device. The present application can effectively recover and reuse the drilling tool vibration energy.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field drilling, and more specifically to a method for recovering energy from drill string vibration. Background Technology

[0002] With the development of artificial intelligence, digital, information-based, and intelligent drilling technologies have emerged. This transformation in drilling technology has also placed new demands on traditional downhole measurement technologies, leading to a trend towards higher-frequency data acquisition, miniaturized design, and distributed installation of measurement devices.

[0003] Existing downhole measurement devices are generally large in size and require the use of turbine downhole generators, which results in significant hydraulic losses during operation. Furthermore, the limited space in downholes drastically reduces the operating time of the corresponding power supply equipment. Summary of the Invention

[0004] The purpose of this invention is to propose a method for recovering drilling tool vibration energy, which can effectively recover and reuse drilling tool vibration energy through a drilling tool vibration energy recovery power generation device, thereby enabling energy recycling during operation.

[0005] According to a first aspect of the present invention, a drill string vibration energy recovery power generation device is provided, comprising a first connector for connection to an upstream portion of the drill string, a second connector for connection to a downstream portion of the drill string, an inner cylinder connected between the first connector and the second connector, a piezoelectric unit and a buffer protection unit respectively sleeved on the inner cylinder, the piezoelectric unit abutting against the buffer protection unit, and an outer cylinder disposed on the outer periphery of the piezoelectric unit and the buffer protection unit, wherein the buffer protection unit is configured to reciprocate axially in response to the vibration of the drill string, thereby driving the piezoelectric unit to generate a piezoelectric effect and output current.

[0006] In one embodiment, the buffer protection unit includes a cylinder liner comprising an inner ring and an outer ring spaced apart from each other and connected at the bottom, defining an annular space between the inner and outer ring spaces, the annular space being filled with magnetorheological fluid; a piston rod disposed within the annular space; and a cylinder liner cover fixedly connected to the cylinder liner and closing the opening of the annular space.

[0007] In one embodiment, the piston rod is configured as a stepped sleeve and includes a smaller diameter body portion and a larger diameter end step, wherein the inner wall of the body portion fits against the outer wall of the inner ring of the cylinder liner, and the outer wall of the end step fits against the inner wall of the outer ring, thereby dividing the annular space into a first annular space and a second annular space.

[0008] In one embodiment, the end step is provided with a channel for connecting the first annular space and the second annular space, wherein a plurality of annular rings are all located on the same circumference.

[0009] In one embodiment, the buffer protection unit includes a permanent magnet located within the annular space and in contact with the outer annular body, and a coil wound around the outer periphery of the cylinder liner, wherein the permanent magnet can act on the magnetorheological fluid by excitation magnetic field.

[0010] In one embodiment, the piezoelectric unit includes a ceramic stack assembly and a control assembly in communication with the ceramic stack assembly and electrically connected to the coil, wherein the ceramic stack assembly is capable of outputting current in response to vibrations of the drill bit for use by the load of the device.

[0011] In one embodiment, the load is the coil and the control assembly. The control assembly can generate a magnetic field in the same direction or opposite direction as the permanent magnet through the coil, thereby superimposing it with the magnetic field of the permanent magnet to form a composite magnetic field and respectively magnetizing or demagnetizing the permanent magnet, thereby changing the state of the magnetorheological fluid.

[0012] In one embodiment, the buffer protection unit includes a first spring disposed in a second annular space within the cylinder liner, for supporting the reciprocating motion of the piston rod within the annular space.

[0013] In one embodiment, the buffer protection unit includes a support platform fixedly connected to the top end of the piston rod, and a second spring disposed between the support platform and the cylinder liner cover.

[0014] In one embodiment, the inner diameter of the support platform is larger than the outer diameter of the inner cylinder, and the outer diameter of the support platform is smaller than the inner diameter of the outer cylinder.

[0015] According to a second aspect of the present invention, a method for recovering energy from drill string vibration is provided. The method uses a drill string vibration energy recovery power generation device, the drill string vibration energy recovery power generation device including a buffer protection unit connected to the drill string and a piezoelectric unit abutting against the buffer protection unit. The method includes the following steps: the buffer protection unit is reciprocated axially by the vibration of the drill string, thereby generating periodic stress changes; the piezoelectric unit generates a piezoelectric effect under the periodic stress changes, thereby outputting current to the load of the drill string vibration energy recovery power generation device.

[0016] In one embodiment, the buffer protection unit includes a cylinder liner comprising an inner ring and an outer ring spaced apart from each other and connected at the bottom, defining an annular space between the inner and outer rings, the annular space being filled with a magnetorheological fluid; a permanent magnet located within the annular space; and a coil wound around the cylinder liner and serving as a load.

[0017] In one embodiment, the method further includes generating a magnetic field in the same direction or opposite direction to the permanent magnet by acting on the coil through the piezoelectric unit, thereby performing a magnetization operation or a demagnetization operation on the permanent magnet, respectively.

[0018] In one embodiment, the method further includes generating a magnetic field in the same direction as the permanent magnet by acting on the coil through the piezoelectric unit under normal operating conditions, so that the magnetorheological fluid is in a first change state, thereby putting the buffer protection unit in a high stiffness mode to transmit the vibration energy of the drill bit.

[0019] In one embodiment, the method further includes generating a magnetic field opposite to that of the permanent magnet by acting on the coil through the piezoelectric unit under a high G-value impact state, so that the magnetorheological fluid is in a second change state, thereby putting the buffer protection unit in a low stiffness mode to buffer the high G-value impact.

[0020] In one embodiment, the method further includes a preliminary step for determining a reference strength of the magnetic field of the permanent magnet.

[0021] In one embodiment, the method further includes measuring the residual magnetic field strength of the permanent magnet in real time using the piezoelectric unit and comparing it with the reference strength, and performing the demagnetization operation or the magnetization operation on the permanent magnet when the residual magnetic field strength is greater than or less than the reference strength, until the residual magnetic field strength is equal to the reference strength.

[0022] In one embodiment, the piezoelectric unit includes a ceramic stack assembly and a control assembly in communication with the ceramic stack assembly, wherein the control assembly is electrically connected to the coil, and the method further includes measuring the residual magnetic field strength of the permanent magnet in real time through the control assembly.

[0023] In one embodiment, the buffer protection unit further includes: a cylinder liner comprising an inner ring body and an outer ring body spaced apart from each other and connected at the bottom, defining an annular space between the inner ring body and the outer ring body, and a piston rod disposed within the annular space, comprising a body portion with a smaller diameter and an end step with a larger diameter, wherein the inner wall of the body portion fits against the outer wall of the inner ring body of the cylinder liner, and the outer wall of the end step fits against the inner wall of the outer ring body, thereby dividing the annular space into a first annular space and a second annular space.

[0024] In one embodiment, the end step is provided with a plurality of channels for connecting the first annular space and the second annular space, all of which are on the same circumference. The method further includes: allowing the magnetorheological fluid to flow through the channels between the first annular space and the second annular space by reciprocating the buffer protection unit in the axial direction. Attached Figure Description

[0025] The invention will now be described in detail with reference to the accompanying drawings, in which:

[0026] Figure 1 The schematic diagram illustrates the structure of the drill vibration energy recovery and power generation device according to the present invention;

[0027] Figure 2 This is a schematic diagram of the inner cylinder in the drill vibration energy recovery and power generation device according to the present invention;

[0028] Figure 3 The schematic diagram illustrates the structure of the buffer protection unit in the drill vibration energy recovery and power generation device according to the present invention;

[0029] Figure 4 This is a schematic diagram of the piezoelectric unit in the drill vibration energy recovery and power generation device according to the present invention;

[0030] Figure 5 A cross-sectional view of the cylinder liner in the drill vibration energy recovery power generation device according to the present invention;

[0031] Figure 6 This is a cross-sectional view of the cylinder liner cover in the drill vibration energy recovery power generation device according to the present invention.

[0032] In the accompanying drawings, the same parts use the same reference numerals. The drawings are not drawn to scale. Detailed Implementation

[0033] The invention will now be further described with reference to the accompanying drawings. For ease of explanation, the directional term "upstream" or similar directional terms used in this specification refer to the direction closer to the wellhead, i.e. Figure 1 The term "downstream" or similar directional terms refer to the direction away from the wellhead, i.e. Figure 1 The bottom direction.

[0034] Figure 1 The schematic diagram shows the structure of the drill vibration energy recovery and power generation device 100 according to the present invention. Figure 2 This is a schematic diagram of the inner cylinder 30 in the drill string vibration energy recovery and power generation device 100. Figure 1 and Figure 2As shown, according to a first aspect of the present invention, a drill vibration energy recovery power generation device 100 includes a first connector 10, a second connector 20, and an inner cylinder 30. The first connector 10 has threads on its outer periphery, thereby forming a threaded connection with the upstream portion of the drill bit. The inner cylinder 30 also has threads on its outer periphery, thereby forming a threaded connection with the first connector 10. Furthermore, the first connector 10 is constructed as a frustum and has a flow channel with the same diameter as the inner cylinder 30 inside. This effectively prevents fluid flowing from the first connector 10 from eroding and damaging the structure of the inner cylinder 10. The second connector 20 has threads on its outer periphery, thereby forming a threaded connection with the downstream portion of the drill bit. The inner cylinder 30 also has threads on its outer periphery, thereby forming a threaded connection with the second connector 20. The second connector 20 is constructed as a cylindrical structure with a gradually changing diameter and has a flow channel with the same diameter as the inner cylinder 30 inside. This effectively prevents fluid flowing from the inner cylinder 30 from forming eddies within the second connector 20.

[0035] According to the present invention, such as Figure 1 As shown, the drill string vibration energy recovery power generation device 100 further includes a piezoelectric unit 40, a buffer protection unit 50, and an outer cylinder 80. The outer cylinder 80 is sleeved on the outer periphery of the piezoelectric unit 40 and the buffer protection unit 50. The piezoelectric unit 40 is sleeved on the outer periphery of the inner cylinder 30 and is located near the first connector 10. The buffer protection unit 50 is sleeved on the outer periphery of the inner cylinder 30 and is located near the second connector 20. Furthermore, the piezoelectric unit 40 and the buffer protection unit 50 abut against each other. According to the present invention, the buffer protection unit 50 can reciprocate axially on the inner cylinder 30 in response to the vibration of the drill string, thereby driving the piezoelectric unit 40 to generate a piezoelectric effect and output current.

[0036] According to the present invention, the buffer protection unit 50 includes a cylinder liner 51. Figure 5 This is a cross-sectional view of the cylinder liner 51 in the drill string vibration energy recovery and power generation device 100. (See image below.) Figure 5As shown, the cylinder liner 51 includes an inner ring 52 and an outer ring 53 spaced apart from each other and connected at the bottom, and an annular space 54 is defined between the inner ring 52 and the outer ring 53. The annular space 54 is filled with a magnetorheological fluid (not shown in the figure). The magnetorheological fluid is a suspension composed of tiny soft magnetic particles with high magnetic permeability and low hysteresis, and a non-magnetic liquid. Under zero magnetic field conditions, it exhibits Newtonian fluid characteristics with low viscosity and high fluidity, while under a strong magnetic field, it exhibits Bingham fluid characteristics with high viscosity and low fluidity. Magnetorheological fluids and their properties are well known to those skilled in the art. In this document, the magnetorheological fluid includes a first changed state and a second changed state. In the first changed state, the magnetorheological fluid transitions to a state with higher viscosity and lower fluidity. In the second changed state, the magnetorheological fluid transitions to a state with lower viscosity and higher fluidity.

[0037] Figure 3 This is a cross-sectional view of the buffer protection unit 50 in the drill vibration energy recovery and power generation device 100. According to the present invention, the buffer protection unit 50 further includes a piston rod 60 and a cylinder liner cover 55. Figure 3 As shown, the piston rod 60 is disposed within the annular space 54 and is capable of reciprocating motion within the annular space 54. Its function will be described in detail below. Figure 6 In one embodiment shown, the top of the cylinder liner cover 55 is threaded to form a threaded connection with the cylinder liner 51, thereby sealing the opening at the top of the annular space 54. In this way, the interior of the cylinder liner 51 forms a sealed space, thereby restricting the flow space of the magnetorheological fluid and preventing leakage.

[0038] In one embodiment of the present invention, such as Figure 3 As shown, the piston rod 60 is constructed as a stepped sleeve, including a smaller diameter upstream main body portion 61 and a larger diameter downstream end step 62. The inner wall of the main body portion 61 fits against the outer wall of the inner ring 52 of the cylinder liner 51, and the outer wall of the end step 62 fits against the inner wall of the outer ring 53, thereby separating the annular space 54 to form a first annular space 541 upstream and a second annular space 542 downstream.

[0039] According to the present invention, such as Figure 3As shown, a plurality of channels 543 are provided in the end step 62 of the piston rod 60, and all the channels 543 are arranged on the same circumference. One end of the channel 543 communicates with the first annular space 541, and the other end communicates with the second annular space 542. In this way, when the piston rod 60 reciprocates within the annular space 54, the magnetorheological fluid in the first annular space 541 and the magnetorheological fluid in the second annular space 542 can flow between each other. In one embodiment of the present invention, the channels 543 are arranged at an angle. Specifically, the opening at the top of the channel 543 is located close to the inner wall of the outer annular body 53 of the cylinder liner 51, while the opening at the bottom of the channel 543 is located close to the outer wall of the inner annular body 52 of the cylinder liner 51. In this way, the magnetorheological fluid can more easily flow into the first annular space 541 or the second annular space 542 through the channels 543.

[0040] In one embodiment of the present invention, such as Figure 3 As shown, the buffer protection unit 50 also includes a first spring 57. The first spring 57 is disposed in the second annular space 542 within the cylinder liner 51 and abuts against the bottom of the end step 62 of the piston rod 60, thereby providing sufficient support force for the piston rod 60 to reciprocate within the annular space 54.

[0041] According to the present invention, such as Figure 3 As shown, the buffer protection unit 50 also includes a permanent magnet 70 and a coil 56. The permanent magnet 70 is disposed within the annular space 54, and its outer wall is in contact with the inner wall of the outer ring 53 of the cylinder liner 51. In other words, the inner wall of the permanent magnet 70 forms the outer boundary of the annular space 54. The permanent magnet 70 can provide an excitation magnetic field, which acts on the magnetorheological fluid, thereby changing the state of the magnetorheological fluid to cooperate with the first spring 57 in supporting the reciprocating motion of the piston rod 60 within the annular space 54. The coil 56 is wound around the outer circumference of the cylinder liner 51 and acts as a carrier to adjust the magnetic field of the permanent magnet 70. Its function will be described in detail below.

[0042] In one embodiment of the present invention, the outer wall of the end step 62 of the piston rod 60 is in contact with a portion of the inner wall of the permanent magnet 70, and the inner wall of the end step 62 of the piston rod 60 is in contact with the outer wall of the inner ring 52 of the cylinder liner 51. In this way, the piston rod 60 can reciprocate more smoothly and steadily within the annular space 54 between the inner ring 52 and the outer ring 53.

[0043] Figure 4 This is a schematic diagram of the piezoelectric unit 40 in the drill vibration energy recovery and power generation device 100. According to the present invention, as... Figure 4As shown, the piezoelectric unit 40 includes a ceramic stack assembly 41 and a control assembly 42 connected to the ceramic stack assembly 41. The ceramic stack assembly 41 generates a compressive force in response to the vibration of the drill bit. Specifically, the piezoelectric unit 40 and the buffer unit 50 reciprocate together under their own inertia, causing a reciprocating compressive force between the piezoelectric ceramics in the ceramic stack assembly 41. Furthermore, during its reciprocating motion, the piezoelectric unit 40 contacts and compresses with the first connector 10 and the support platform 63, thereby loading and unloading the stress on the piezoelectric unit 40. In this way, the piezoelectric module 40 can effectively recover the vibration energy of the drill bit, thereby generating a piezoelectric effect and outputting current.

[0044] According to one embodiment of the present invention, the current generated by the piezoelectric unit 40 is shunt through the control assembly 42. A portion of the current is used to supply other downhole tools; the other portion is used to monitor and adjust the parameters of the buffer protection unit 50 in real time, thereby changing the state of the magnetorheological fluid to suit different frequency vibrations of the drill string.

[0045] In one embodiment of the present invention, the carrier comprises two parts. One part of the carrier consists of the coil 56 and the control assembly 42, used for magnetizing or demagnetizing the permanent magnet 70; the other part of the carrier consists of other downhole tools, such as distributed measurement devices. Their functions will be described in detail below.

[0046] According to one embodiment of the present invention, the control assembly 42 can generate a magnetic field in the same or opposite direction as the permanent magnet 70 via the coil 56, thereby superimposing it with the magnetic field of the permanent magnet 70 to form a composite magnetic field, thus achieving the function of magnetizing or demagnetizing the permanent magnet 70. The viscosity and fluidity of the magnetorheological fluid also change with the composite magnetic field. In this way, the drill vibration energy recovery power generation device 100 can more easily adjust and monitor the strength of the magnetic field of the buffer protection unit 50.

[0047] According to one embodiment of the present invention, when the control assembly 42 generates a magnetic field in the same direction as the permanent magnet 70 through the coil 56, the combined magnetic field strength of the coil 56 magnetic field and the permanent magnet 70 magnetic field is enhanced, and the magnetorheological fluid is in a first change state. That is, the magnetorheological fluid transforms into a state with higher viscosity and lower fluidity, resulting in greater stiffness of the combination of the magnetorheological fluid and the first spring 57, thereby providing greater support force to the piston rod 60. When the control assembly 42 generates a magnetic field in the opposite direction to the permanent magnet 70 through the coil 56, the combined magnetic field strength of the coil 56 magnetic field and the permanent magnet 70 magnetic field is reduced, and the magnetorheological fluid is in a second change state. That is, the magnetorheological fluid transforms into a state with lower viscosity and higher fluidity, resulting in less stiffness of the combination of the magnetorheological fluid and the first spring 57, thereby providing less support force to the piston rod 60. At this time, the piezoelectric module 40 will push the support platform 63 of the buffer protection unit 50 (described below) downward under the action of inertia and impact, thereby buffering the high acceleration impact borne by the piezoelectric module 40.

[0048] In such Figure 3 In one embodiment shown, the tip of the piston rod 60 extends outward from the opening of the annular space 54. According to the invention, as... Figure 3 As shown, the buffer protection unit 50 includes a support platform 63 and a second spring 64. The support platform 63 is fixedly connected to the top end of the piston rod 60, thereby limiting the axial movement range of the piston rod 60. The second spring 64 is sleeved on the outer periphery of the piston rod 60 and is located between the support platform 63 and the cylinder liner cover 55. The second spring 64 provides some support for the reciprocating motion of the piston rod 60 within the annular space 54. In one embodiment of the invention, the inner diameter of the support platform 63 is larger than the outer diameter of the inner cylinder 30, and the outer diameter of the support platform 63 is smaller than the inner diameter of the outer cylinder 80.

[0049] In one embodiment of the present invention, such as Figure 3 As shown, wear-resistant rings and sealing rings are provided on the inner wall of the support platform 63 (not shown), on the outer periphery of the end step 62 of the piston rod 60, and on the inner wall of the cylinder liner 51, so that each part of the drill vibration energy recovery power generation device 100 has good sealing and wear resistance.

[0050] According to a second aspect of the present invention, a method for recovering drill string vibration energy is provided. This method utilizes a drill string vibration energy recovery power generation device 100 to recover drill string vibration energy. Specifically, the recovery of drill string vibration energy is achieved through the coordinated operation of the buffer protection unit 50 and the piezoelectric unit 40 as described above, and the recovered vibration energy is ultimately used as electrical energy to power the load of the drill string vibration energy recovery power generation device 100, thereby achieving a recycling effect.

[0051] The drill string vibration energy recovery method according to the present invention specifically includes the following steps:

[0052] Step 1: The vibration of the drill bit causes the piston rod 60 in the buffer protection unit 50 to reciprocate in the axial direction, thereby generating periodic stress changes (the vibration energy of the drill bit is converted into the mechanical energy of the piston rod 60).

[0053] Step 2: The piezoelectric unit 40 generates a piezoelectric effect under the periodic stress change in step 1, thereby outputting current to power the load of the drill vibration energy recovery power generation device 100 (the mechanical energy of the piston rod 60 and the piezoelectric unit 40 is converted into electrical energy).

[0054] As described above, the buffer protection unit 50 includes a cylinder liner 51 disposed inside. The cylinder liner 51 defines the position of the annular space 54 by an inner ring body 52 and an outer ring body 53, and the annular space 54 is filled with magnetorheological fluid. In addition, a coil 56 is wound around the outer periphery of the cylinder liner 51.

[0055] According to one embodiment of the present invention, a permanent magnet 70 is further disposed inside the annular space 54. A piezoelectric unit 40 is connected to the permanent magnet 70 via a coil 56, thereby adjusting the magnetic field strength of the permanent magnet 70. Specifically, the piezoelectric unit 40 can act on the coil 56 and generate a magnetic field in the same or opposite direction as the permanent magnet 70, thereby adjusting the magnetic field strength of the permanent magnet 70 by magnetization or demagnetization.

[0056] According to one embodiment of the present invention, during the normal operation of the drill string vibration energy recovery power generation device 100, the magnetic field strength generated by the permanent magnet 70 gradually decreases due to the combined effect of the reciprocating motion of the piston rod 60 and the downhole temperature change. Therefore, it is necessary to generate a magnetic field in the same direction as the permanent magnet 70 by using the piezoelectric unit 40 to act on the coil 56 for magnetization. Simultaneously, the magnetorheological fluid in the annular space 54 transforms into a state with higher viscosity and lower fluidity under the influence of the current, thereby effectively reducing the flow velocity of the magnetorheological fluid between the first annular space 541 and the second annular space 542 connected by the channel 543. This allows the buffer protection unit 50 to transition to a high-stiffness mode, facilitating stress propagation from drill string vibration.

[0057] According to one embodiment of the present invention, during the normal operation of the drill vibration energy recovery power generation device 100, the magnetic field strength generated by the permanent magnet 70 gradually increases due to the impact of a high G-value on the buffer protection unit 50. Therefore, it is necessary to generate a magnetic field opposite to that of the permanent magnet 70 by the piezoelectric unit 40 acting on the coil 56 for demagnetization. Simultaneously, the magnetorheological fluid in the annular space 54, under the influence of the current, transforms into a state with lower viscosity and higher fluidity, thereby effectively increasing the flow velocity of the magnetorheological fluid between the first annular space 541 and the second annular space 542 connected by the channel 543. This further causes the buffer protection unit 50 to transform into a low-stiffness mode to more easily buffer the high G-value impact. Within the scope of the present invention, the term "high G-value" can be determined according to actual conditions, such as the mass and strength of the piezoelectric unit 40 and the piston rod 60. This is well known to those skilled in the art and will not be elaborated further.

[0058] As described above, the piezoelectric unit 40 includes a ceramic stack assembly 41 and a control assembly 42 connected to the ceramic stack assembly 41. The ceramic stack assembly 41 is capable of supplying current to the control assembly 42. The control assembly 42 is electrically connected to the coil 56. In one embodiment of the invention, the control assembly 42 is capable of measuring the residual magnetic field strength of the permanent magnet 70 in real time, and generating a magnetic field in the positive or negative direction of the permanent magnet 70 via the coil 56 to perform magnetization or demagnetization.

[0059] According to the drilling vibration energy recovery method of the present invention, a preliminary step is included before the start of the first step: adjusting the parameters of the buffer protection unit 50 to determine the reference strength of the magnetic field of the permanent magnet 70. Specifically, this includes the following steps:

[0060] Step 1: Based on indoor tests, obtain the mapping relationship between the magnetic field strength value and the stiffness value of the buffer protection unit.

[0061] Step 2: Calculate the emergency stiffness value of the buffer protection unit 50 based on the actual parameters of the tool (including but not limited to the mass, strength, and expected maximum impact of the piezoelectric unit 40 and piston rod 60).

[0062] Step 3: Calculate the median G-value of drill string vibration based on the well data. Based on indoor impact tests, select the stiffness value that allows the piezoelectric unit to output current meeting the usage requirements as the reference stiffness (this can also be user-defined).

[0063] Step 4: Based on the mapping relationship between magnetic field strength and stiffness in Step 1, calculate the magnetic field strength corresponding to the reference stiffness as the reference strength.

[0064] Those skilled in the art can also determine the reference strength of the magnetic field of permanent magnet 70 in a variety of different ways, which is well known to those skilled in the art and will not be described in detail here.

[0065] According to the present invention, the piezoelectric unit 40 can measure the residual magnetic field strength of the permanent magnet 70 in real time and compare it with the aforementioned reference strength. When the piezoelectric unit 40 detects that the residual magnetic field strength of the permanent magnet 70 is greater than the reference strength, the control assembly 42 generates a magnetic field opposite to that of the permanent magnet 70 through the coil 56, thereby demagnetizing the permanent magnet 70 until the residual magnetic field strength is equal to the reference strength. When the piezoelectric unit 40 detects that the residual magnetic field strength of the permanent magnet 70 is less than the reference strength, the control assembly 42 generates a magnetic field in the same direction as that of the permanent magnet 70 through the coil 56 to remagnetize the permanent magnet 70 until the residual magnetic field strength is equal to the reference strength.

[0066] In one embodiment of the invention, the piezoelectric unit 40 generates a piezoelectric effect and outputs current under stress changes. This current is then shunted through the control assembly 42. A portion of the current is used to supply other downhole tools; the other portion is used to monitor and adjust the parameters of the buffer protection unit 50 in real time, thereby changing the state of the magnetorheological fluid to suit different frequency vibrations of the drilling tool. Specifically, when the piezoelectric unit 40 detects in real time that the residual magnetic field strength of the permanent magnet 70 is not equal to the reference strength, it supplies power to the coil 56 through the control assembly 42 to generate a magnetic field that is positively or negatively related to the permanent magnet 70, thus forming a composite magnetic field with the permanent magnet 70's magnetic field. This, in turn, adjusts the parameters of the buffer protection unit 50 by magnetization or demagnetization. At this time, the magnetorheological fluid adjusts its viscosity and flowability according to the change in magnetic field strength to suit different frequency vibrations of the drilling tool.

[0067] In one embodiment of the present invention, the buffer protection unit 50 operates in a high-stiffness mode. When the buffer protection unit 50 encounters a sudden high impact force, the ceramic stack assembly 41 will discharge instantaneously. After detecting the abnormal current or voltage, the piezoelectric unit 40 controls the coil 56 to generate a high-intensity magnetic field opposite to that of the permanent magnet 70, thereby rapidly reducing the magnetic field strength. As a result, the magnetorheological fluid transitions to a state with lower viscosity and higher fluidity, and the buffer protection unit 50 rapidly changes from a high-stiffness mode to a low-stiffness mode, thus providing a faster and more effective buffering effect.

[0068] According to the drilling tool vibration energy recovery method of the present invention, the method completes the drilling tool vibration energy recovery work through a drilling tool vibration energy recovery power generation device 100. This method effectively recovers and reuses drilling tool vibration energy by converting it into electrical energy, thereby improving the energy utilization rate of the entire drilling system.

[0069] 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 can easily make changes or modifications within the scope of the present invention, and such changes or modifications should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for recovering vibration energy from drilling tools, said method using a drilling tool vibration energy recovery power generation device (100), The drill vibration energy recovery and power generation device (100) includes a buffer protection unit (50) and a piezoelectric unit (40) that abuts against the buffer protection unit (50). The method includes the following steps: The vibration of the drill bit causes the buffer protection unit (50) to reciprocate axially, thereby generating periodic stress changes. The piezoelectric unit (40) generates a piezoelectric effect under the periodic stress change, thereby outputting current to the load of the drill vibration energy recovery power generation device (100). The buffer protection unit (50) includes a cylinder liner (51) defining an annular space (54) filled with magnetorheological fluid; a permanent magnet (70) located within the annular space (54); and a coil (56) wound around the cylinder liner (51) and serving as a load. The piezoelectric unit (40) includes a ceramic stack assembly (41) and a control assembly (42) communicating with the ceramic stack assembly (41). The control assembly (42) is electrically connected to the coil (56). The method further includes: The residual magnetic field strength of the permanent magnet (70) is measured in real time by the control assembly (42); The buffer protection unit (50) also includes a cylinder liner (51), which includes an inner ring body (52) and an outer ring body (53) that are spaced apart from each other and connected at the bottom, defining an annular space (54) between the inner ring body (52) and the outer ring body (53). The piston rod (60) disposed in the annular space (54) includes a main body part (61) with a smaller diameter and an end step (62) with a larger diameter. The inner wall of the main body part (61) is fitted with the outer wall of the inner ring body (52) of the cylinder liner (51), and the outer wall of the end step (62) is fitted with the inner wall of the outer ring body (53), thereby dividing the annular space (54) into a first annular space (541) and a second annular space (542). The end step (62) is provided with a plurality of channels (543) for connecting the first annular space (541) and the second annular space (542) with the annular rings all on the same circumference. The method further includes: the reciprocating motion of the buffer protection unit (50) in the axial direction to make the magnetorheological fluid flow through the channels (543) between the first annular space (541) and the second annular space (542).

2. The method for recovering drill vibration energy according to claim 1, characterized in that, The method further includes: The piezoelectric unit (40) acts on the coil (56) to generate a magnetic field that is in the same direction or opposite direction to the permanent magnet (70), thereby performing magnetization or demagnetization operations on the permanent magnet (70) respectively.

3. The method for recovering drill string vibration energy according to claim 1, characterized in that, The method further includes: Under normal operating conditions, the piezoelectric unit (40) acts on the coil (56) to generate a magnetic field in the same direction as the permanent magnet (70), so that the magnetorheological fluid is in the first change state, thereby putting the buffer protection unit (50) in a high stiffness mode to transmit the vibration energy of the drill bit.

4. The method for recovering drill vibration energy according to claim 1, characterized in that, The method further includes: Under high G-value impact, the piezoelectric unit (40) acts on the coil (56) to generate a magnetic field opposite to that of the permanent magnet (70), causing the magnetorheological fluid to be in a second change state, thereby putting the buffer protection unit (50) in a low stiffness mode to buffer the high G-value impact.

5. The method for recovering drill vibration energy according to claim 2, characterized in that, The method also includes a preliminary step for determining the reference strength of the magnetic field of the permanent magnet (70).

6. The method for recovering drill vibration energy according to claim 5, characterized in that, The method further includes: The residual magnetic field strength of the permanent magnet (70) is measured in real time by the piezoelectric unit (40) and compared with the reference strength. When the residual magnetic field strength is greater than or less than the reference strength, the permanent magnet (70) is demagnetized or magnetized until the residual magnetic field strength is equal to the reference strength.

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