Method for Determining Stroke and Setting Initial Kinetic Energy of Air Hammer

Abstract

The present invention belongs to the technical field of oil and gas well drilling, and particularly relates to a method for determining the stroke of an air hammer and setting the initial kinetic energy. First, the piston stroke of the air hammer is calculated and optimized based on the motion parameters. Then, an energy transfer efficiency formula and an air hammer drilling mechanical specific energy equation are established. By combining the air hammer drilling mechanical specific energy equation and the energy transfer efficiency formula, the impact work required for rock breaking is obtained. According to the impact work required for rock breaking, the initial kinetic energy of the air hammer is quantitatively set by changing the number of air compressors. This technical solution realizes the maximum utilization rate of energy, that is, it meets the energy requirements for rock breaking and avoids the influence on the service life of the air hammer caused by excessive initial energy.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas well drilling, and particularly relates to a method for determining the stroke of an air hammer and setting the initial kinetic energy. Background Art

[0002] Air hammer drilling refers to a drilling method in which an air hammer connected to a drill bit applies pressure to the drill string and rotates simultaneously, giving the drill bit high-frequency impact energy for impact rotary drilling. Air hammer drilling has the characteristics of low drilling pressure, low rotational speed, and stable torque, can significantly improve the drilling speed and effectively control the well deviation, and also takes into account the advantage of less damage to the reservoir in gas drilling. Therefore, this drilling method has been widely used in the process of drilling high-steep and hard rock formations.

[0003] In drilling engineering projects, it involves the air hammer making high-frequency reciprocating motions up and down and rotating simultaneously under the action of air compression, hydraulic pressure, etc., converting mechanical energy, continuously impacting the drill bit, and realizing impact or rotary rock breaking.

[0004] Currently, there is a lack of a systematic and standard quantitative evaluation method for the performance of air hammers. During the actual operation of an air hammer, the impact frequency and impact work determine the drilling effect of the air hammer (including downhole environment, footage per bit, working time, and mechanical drilling speed). Due to the lack of special detection means, it is currently impossible to scientifically and quantitatively evaluate the performance of the air hammer before it enters the well. The general practice is to conduct a functional test on the drill floor before the air hammer enters the well, relying on manual experience to judge the working state of the air hammer based on vibration sensation and sound, and qualitatively evaluate the performance of the air hammer. Based on this, there is no reliable basis for determining the stroke of the air hammer and setting the initial kinetic energy, which may lead to poor performance of the air hammer, significant differences in drilling effects after entering the well, and even more seriously, the air hammer may affect its service life due to excessive initial kinetic energy. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for determining the stroke of an air hammer and setting the initial kinetic energy according to the above-mentioned existing technical problems, which can quickly and accurately measure the impact work done by the air hammer, be used to quantitatively evaluate the impact work, optimize its piston stroke and structure, guide the output power of the power source air compressor, and realize the comprehensive optimization and evaluation of the quantitative and qualitative working state of the air hammer. It should be noted that other power tools with similar structures and working principles to the air hammer can also adopt this technical solution.

[0006] The above object of the present invention is achieved by the following technical solutions:

[0007] A method for determining the stroke of an air hammer and setting the initial kinetic energy, characterized by including stroke determination and initial kinetic energy setting;

[0008] The stroke determination is to analyze the motion parameters of the air hammer piston's impact work based on the calculation formula of the air hammer piston's impact work, detect the motion parameters, and then calculate and optimize the air hammer piston stroke based on the motion parameters;

[0009] The initial kinetic energy setting includes the following steps:

[0010] S1. According to the energy flow direction during air hammer impact drilling, establish an energy transfer efficiency formula related to the air hammer piston's impact work and rock-breaking energy;

[0011] S2. Based on the energy source of rock fragmentation in air hammer drilling underground, optimize the R. Teale specific energy equation for machinery to establish the specific energy equation for machinery in air hammer drilling;

[0012] S3. Based on the combination of the energy transfer efficiency formula and the specific energy equation for machinery in air hammer drilling, obtain the energy transfer efficiency of the current air hammer;

[0013] S4. Based on the rock compressive strength, combine the specific energy equation for machinery in air hammer drilling and the energy transfer efficiency formula to obtain the impact work required for rock fragmentation;

[0014] S5. According to the impact work required for rock fragmentation, by changing the number of air compressors, quantitatively set the initial kinetic energy of the air hammer.

[0015] Preferably, during the stroke determination, detecting the motion parameters includes the following steps:

[0016] a. Based on the calculation formula of impact work Determine the motion parameters to be detected, including the acceleration of the air hammer piston and the stroke time of the air hammer piston; where E 冲 is the impact work of the air hammer, that is, the impact work of the piston during the downward stroke; m 活塞 represents the mass of the piston; t represents the time taken for the piston's downward stroke, that is, the stroke time of the air hammer piston; a represents the acceleration of the air hammer piston;

[0017] b. Install an acceleration sensor and an electric encoder on the air hammer; and connect the acceleration sensor assembly to the corresponding parameter detection equipment;

[0018] c. Start the air hammer. On the premise that the initial velocity v0 of the piston is 0, use the acceleration sensor to detect the acceleration a of the air hammer piston and the stroke time t1 of the air hammer piston, and use the electric encoder to detect the stroke time t2 of the air hammer piston.

[0019] Preferably, during the stroke determination, calculating and optimizing the air hammer piston stroke includes the following steps:

[0020] Based on the piston displacement formula Compare the stroke time t1 of the air hammer piston detected by the acceleration sensor with the stroke time t2 of the air hammer piston detected by the electric encoder; where S is the piston displacement and v0 is the initial piston velocity;

[0021] If t1 = t2, it means that the air hammer is operating at the optimal stroke and there is no need to optimize the piston structure stroke. t = t1 = t2, and the calculated piston displacement S is the optimal piston stroke;

[0022] If t1 > t2, it means that when the air hammer piston speed reaches the maximum, the piston has not yet touched the bottom. Then, according to the piston displacement formula, calculate the corresponding piston displacements using t1 and t2 respectively to obtain the piston displacement difference at the two times; shorten the piston stroke structure design according to the piston displacement difference to make t1 = t2;

[0023] If t1 < t2, it means that when the air hammer piston touches the bottom, its speed has not yet reached the maximum. Then, according to the piston displacement formula, calculate the corresponding piston displacements using t1 and t2 respectively to obtain the piston displacement difference at the two times; extend the piston stroke structure design according to the piston displacement difference to make t1 = t2.

[0024] Preferably, in the step S1 of setting the initial kinetic energy, the energy transfer efficiency formula is where η is the energy transfer efficiency; E 传 is the energy transferred from the piston of the air hammer to the drill bit for rock breaking.

[0025] Preferably, in the step S2 of setting the initial kinetic energy, establishing the air hammer drilling mechanical specific energy equation includes the following steps:

[0026] S21, based on the working principle of the air hammer, analyze the energy sources for rock breaking underground during air hammer drilling. The energy sources include impact work, weight-on-bit work, and torque work;

[0027] S22, based on the analysis results of step S21, establish the basic air hammer drilling mechanical specific energy equation where E is the mechanical specific energy, unit Mpa; E W is the axial energy caused by the weight-on-bit, unit J; E T is the rotational kinetic energy of the drill bit; V is the unit volume of rock broken per minute;

[0028] S23, based on the R.Teale mechanical specific energy equation Expand the air hammer drilling mechanical specific energy equation to obtain where W is the weight-on-bit of the drill bit, unit KN; T is the torque of the drill bit, unit KN.m; n is the rotational speed of the drill bit, unit r / min; v is the mechanical penetration rate of the drill bit, unit m / h; d is the bottom hole diameter, unit cm.

[0029] Preferably, in the step S3 of setting the initial kinetic energy, obtaining the energy transfer efficiency of the current air hammer includes the following steps:

[0030] S31. Based on calculate the impact work done by the current air hammer; wherein, obtain the mass m of the piston according to the structural design data of the current air hammer 活塞 ; the value of a is the acceleration of the air hammer piston detected during the process of determining the stroke; the value of t is the stroke time of the air hammer piston detected by the electronic encoder during the process of determining the stroke;

[0031] S32. Based on calculate the energy transferred from the piston of the current air hammer to the drill bit for rock breaking; wherein, obtain the mass m of the piston according to the structural design data of the current air hammer 钻头 ; v 线速度 is the axial final velocity of the drill bit, which is obtained under the condition of the acceleration of the air hammer piston measured during the process of determining the stroke;

[0032] S33. Based on the energy transfer efficiency formula Combine the calculation results of steps S31 and S32 to calculate the energy transfer efficiency η of the current air hammer.

[0033] Preferably, in the step S4 of setting the initial kinetic energy, obtaining the impact work required for rock breaking includes the following steps:

[0034] S41. Based on the minimum requirement E = E 岩 for the specific energy of the air hammer drilling machine for rock breaking, and combine with the specific energy formula of the air hammer drilling machine to obtain the physical quantity E of the specific energy 传 Calculation formula

[0035] S42. Start the air hammer on site, and based on the logging or logging-while-drilling instrument, measure the motion parameters of the air hammer, including the weight on bit W of the drill bit, the torque T of the drill bit, the rotational speed n of the drill bit, and the rate of penetration v of the drill bit;

[0036] S43. Obtain the bottom hole diameter d of the well to be drilled on site and the rock type, and based on the rock type, look up the corresponding rock compressive strength E in the rock compressive strength table 岩 ;

[0037] S44. Substitute the relevant parameters obtained in steps S42 and S43 into the physical quantity E 传 calculation formula of the specific energy for calculation, and the calculated E 传 is the energy that the piston of the air hammer needs to transfer to the drill bit for rock breaking;

[0038] S45. Substitute the calculation result of step S44 and the energy transfer efficiency of the current air hammer obtained in step S3 into the energy transfer efficiency formula. Calculate the impact work required for rock breaking.

[0039] Advantages of the present invention:

[0040] 1) By pre-determining the stroke of the air hammer in this technical solution, it is ensured that the theoretical calculation results of various parameters in the later stage are closest to the actual working conditions of the air hammer to the greatest extent, laying a good foundation for improving the accuracy of the initial kinetic energy setting of the air hammer. Further, in this technical solution, the energy transfer efficiency of the air hammer is first determined, and then the required impact work of the air hammer is inversely deduced based on the energy required for rock breaking. In this way, the working parameters of the air compressor can be quantitatively set based on the required impact work of the air hammer to further realize the quantitative setting of the initial kinetic energy of the air hammer. Thus, this technical solution realizes the maximum utilization rate of energy, that is, it meets the energy requirements for rock breaking and avoids the influence on the service life of the air hammer caused by excessive initial energy.

[0041] 2) According to the energy source of the air hammer for drilling and breaking rocks underground, this technical solution optimizes the R. Teale specific mechanical energy equation, combines mechanical energy and air hammer impact energy, and thus establishes the specific mechanical energy equation for air hammer drilling to form a specific mechanical energy of air closer to the actual drilling conditions, laying a reliable foundation for the accuracy of the data deduced by this technical solution.

[0042] 3) This technical solution cleverly uses the rock compressive strength table. By finding the relationship between rock compressive strength and specific mechanical energy and combining it with the specific mechanical energy equation for air hammer drilling, the calculation conditions for the energy transferred from the piston of the air hammer to the drill bit for rock breaking are obtained. The calculation results are reasonable and reliable. On this basis, the required kinetic energy of the air hammer is inversely deduced, which can not only well limit the energy input but also ensure sufficient energy for rock breaking. Description of the Drawings

[0043] Figure 1 It is the basic implementation flowchart of this technical solution. Detailed Implementation Manner

[0044] To make the objectives, technical solutions, and advantages of the invention clearer, the technical solutions in the present invention will be clearly and completely described below in conjunction with the drawings in the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention.

[0045] Therefore, the following detailed description of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts fall within the scope of protection of the present invention.

[0046] Embodiment 1

[0047] This embodiment discloses a method for determining the stroke of an air hammer and setting the initial kinetic energy. As a basic implementation scheme of the present invention, it includes stroke determination and initial kinetic energy setting.

[0048] The stroke of the air hammer piston affects the energy transmission. The stroke determination is to analyze the motion parameters of the air hammer piston's impact work based on the calculation formula of the air hammer piston's impact work, detect the motion parameters, and then calculate and optimize the air hammer piston stroke based on the motion parameters. To ensure that the theoretical calculation results of various parameters in the later stage are closest to the actual working conditions of the air hammer to the greatest extent, and further ensure the accuracy of setting the initial kinetic energy of the air hammer.

[0049] The initial kinetic energy setting includes the following steps:

[0050] S1. According to the energy flow direction during air hammer impact drilling, establish an energy transfer efficiency formula related to the air hammer piston's impact work and rock-breaking energy. The energy transfer efficiency formula mainly reflects the relationship between the air hammer piston's impact work and rock-breaking energy. Thus, it lays a reliable foundation for later inversely inferring the required air hammer piston's impact work based on the required rock-breaking energy.

[0051] S2. Based on the energy source of rock fragmentation underground during air hammer drilling, optimize the R. Teale specific energy equation for machinery to establish the specific energy equation for machinery in air hammer drilling (see "Calculation Method of Specific Energy for Machinery in Air Hammer Drilling", published in "Oil Drilling & Production Technology", Vol. 42, No. 2, March 2020, authors: Li Changsheng, Yang Chuanshu, Ma Ying).

[0052] S3. Based on the combination of the energy transfer efficiency formula and the specific energy equation for machinery in air hammer drilling, obtain the energy transfer efficiency of the current air hammer.

[0053] S4. Based on the rock compressive strength, combine the specific energy equation for machinery in air hammer drilling and the energy transfer efficiency formula to obtain the impact work required for rock fragmentation (i.e., impact work).

[0054] S5. Since the energy source of the impact work is the air compressor (i.e., the initial kinetic energy of the air hammer comes from the air compressor), therefore, by setting the output kinetic energy of the air compressor, the required impact work can be given. Specifically: according to the impact work required for rock fragmentation, by changing the number of air compressors, the initial kinetic energy of the air hammer is quantitatively set.

[0055] In summary, by determining the stroke of the air hammer in advance, this technical solution ensures that the theoretical calculation results of various parameters in the later stage are closest to the actual working conditions of the air hammer to the greatest extent, laying a good foundation for improving the accuracy of setting the initial kinetic energy of the air hammer. Further, this technical solution first determines the energy transfer efficiency of the air hammer, and then reversely infers the required impact work of the air hammer based on the energy required for rock breaking. In this way, the working parameters of the air compressor can be quantitatively set based on the required impact work of the air hammer, so as to further realize the quantitative setting of the initial kinetic energy of the air hammer. In this way, this technical solution realizes the maximum utilization rate of energy, that is, it meets the energy requirements for rock breaking and avoids the influence on the service life of the air hammer caused by excessive initial energy.

[0056] Embodiment 2

[0057] This embodiment discloses a method for determining the stroke of an air hammer and setting the initial kinetic energy. As a basic implementation scheme of the present invention, it includes stroke determination and initial kinetic energy setting.

[0058] The stroke determination is to analyze the motion parameters of the air hammer piston's impact work based on the calculation formula of the air hammer piston's impact work, detect the motion parameters, and then calculate and optimize the air hammer piston stroke based on the motion parameters.

[0059] Specifically, detecting the motion parameters includes the following steps:

[0060] a. Based on the calculation formula of impact work Determine the motion parameters to be detected, including the acceleration of the air hammer piston and the stroke time of the air hammer piston; where E 冲 is the impact work of the air hammer, that is, the impact work of the piston's downward stroke; m 活塞 represents the mass of the piston; t represents the time used for the piston's downward stroke, that is, the stroke time of the air hammer piston; a represents the acceleration of the air hammer piston.

[0061] b. Install an acceleration sensor and an electrical encoder on the air hammer; and connect the acceleration sensor assembly to the corresponding parameter detection device. During the process of the air hammer doing impact work, when it moves downward to the lower end point and collides, the acceleration is not zero and is still changing. It is possible that the collision occurs before the speed reaches the maximum. Therefore, the time recorded by the acceleration may not be the optimal stroke time of the air hammer, and an electrical encoder is needed for accurate time measurement. See step c for details.

[0062] c. Start the air hammer. On the premise that the initial velocity v0 of the piston is 0, use the acceleration sensor to detect the acceleration a of the air hammer piston and the stroke time t1 of the air hammer piston, and use the electrical encoder to detect the stroke time t2 of the air hammer piston.

[0063] Among them, the principle of using an electric encoder to detect the stroke time t2 of the air hammer piston is as follows: Only when the piston completes one downstroke and one upstroke does it represent the completion of one stroke work. The electric encoder can detect the total time of one stroke work of the piston. During the upstroke of the piston, a slight rotation action will occur. The upstroke and downstroke can be distinguished by whether the rotation action occurs. The electric encoder can detect the rotation angle and rotation time (i.e., the upstroke time) of the piston. Subtracting the rotation time from the total time of one stroke work gives the stroke time t2 of the air hammer piston.

[0064] Based on the above detected motion parameters, calculating and optimizing the stroke of the air hammer piston includes the following steps:

[0065] Based on the piston displacement formula Compare the stroke time t1 of the air hammer piston detected by the acceleration sensor with the stroke time t2 of the air hammer piston detected by the electric encoder. Among them, S is the piston displacement and v0 is the initial velocity of the piston.

[0066] If t1 = t2, it means that the air hammer is operating at the optimal stroke in design, and there is no need to optimize the piston structure stroke. t = t1 = t2, and the calculated piston displacement S is the optimal piston stroke.

[0067] If t1 > t2, it means that when the speed of the air hammer piston reaches the maximum, the piston has not yet touched the bottom. Then, according to the piston displacement formula, calculate the corresponding piston displacements using t1 and t2 respectively to obtain the piston displacement difference at the two times. Shorten the piston stroke structure design according to the piston displacement difference so that t1 = t2.

[0068] If t1 < t2, it means that when the air hammer piston touches the bottom, its speed has not yet reached the maximum. Then, according to the piston displacement formula, calculate the corresponding piston displacements using t1 and t2 respectively to obtain the piston displacement difference at the two times. Lengthen the piston stroke structure design according to the piston displacement difference so that t1 = t2.

[0069] The setting of the initial kinetic energy includes the following steps:

[0070] S1. According to the energy flow direction during the air hammer impact drilling, establish an energy transfer efficiency formula related to the impact work done by the air hammer piston and the rock-breaking energy.

[0071] S2. Based on the energy source of rock fragmentation underground during air hammer drilling, optimize the R. Teale specific energy equation to establish an air hammer drilling specific energy equation.

[0072] S3. Based on the combination of the energy transfer efficiency formula and the air hammer drilling specific energy equation, obtain the energy transfer efficiency of the current air hammer.

[0073] S4. Based on the uniaxial compressive strength of the rock, obtain the impact work required for rock breaking by combining the specific energy equation of air hammer drilling and the energy transfer efficiency formula.

[0074] S5. According to the impact work required for rock breaking, quantitatively set the initial kinetic energy of the air hammer by changing the number of air compressors.

[0075] Embodiment 3

[0076] This embodiment discloses a method for determining the stroke and setting the initial kinetic energy of an air hammer. As a basic implementation scheme of the present invention, it includes stroke determination and initial kinetic energy setting.

[0077] The stroke determination is to analyze the motion parameters of the air hammer piston's impact work based on the calculation formula of the air hammer piston's impact work, detect the motion parameters, and then calculate and optimize the air hammer piston stroke based on the motion parameters.

[0078] Specifically, detecting the motion parameters includes the following steps:

[0079] a. Based on the calculation formula of impact work Determine the motion parameters to be detected, including the acceleration of the air hammer piston and the stroke time of the air hammer piston; where E 冲 is the impact work of the air hammer, that is, the impact work of the piston's downward stroke; m 活塞 represents the mass of the piston; t represents the time used for the piston's downward stroke, that is, the stroke time of the air hammer piston; a represents the acceleration of the air hammer piston.

[0080] b. Install an acceleration sensor and an electric encoder on the air hammer; and connect the acceleration sensor assembly to the corresponding parameter detection device. During the process of the air hammer doing impact work, when it moves downward to the lower end point and collides, the acceleration is not zero and is still changing. It is possible that the collision occurs before the speed reaches the maximum. Therefore, the time recorded by the acceleration may not be the optimal stroke time of the air hammer, and the electric encoder is needed for accurate time measurement. See step c for details.

[0081] c. Start the air hammer. On the premise that the initial velocity v0 of the piston is 0, use the acceleration sensor to detect the acceleration a of the air hammer piston and the stroke time t1 of the air hammer piston, and use the electric encoder to detect the stroke time t2 of the air hammer piston.

[0082] Based on the above detected motion parameters, calculating and optimizing the air hammer piston stroke includes the following steps:

[0083] Based on the piston displacement formula Compare the stroke time t1 of the air hammer piston detected by the acceleration sensor with the stroke time t2 of the air hammer piston detected by the electric encoder; where S is the piston displacement and v0 is the initial piston velocity;

[0084] If t1 = t2, it means that the air hammer is operating at the optimal stroke and there is no need to optimize the piston structure stroke. t = t1 = t2, and the calculated piston displacement S is the optimal piston stroke;

[0085] If t1 > t2, it means that when the air hammer piston speed reaches the maximum, the piston has not yet touched the bottom. Then, according to the piston displacement formula, calculate the corresponding piston displacements using t1 and t2 respectively to obtain the piston displacement difference at the two times; shorten the piston stroke structure design according to the piston displacement difference to make t1 = t2;

[0086] If t1 < t2, it means that when the air hammer piston touches the bottom, its speed has not yet reached the maximum. Then, according to the piston displacement formula, calculate the corresponding piston displacements using t1 and t2 respectively to obtain the piston displacement difference at the two times; extend the piston stroke structure design according to the piston displacement difference to make t1 = t2.

[0087] The initial kinetic energy setting includes the following steps:

[0088] S1. According to the energy flow direction during air hammer impact drilling, establish an energy transfer efficiency formula related to the air hammer piston impact work and rock-breaking energy. Specifically: When the air hammer is impact drilling, there are mainly two aspects of energy transfer. One part of the energy is the kinetic energy E 传 transferred from the air hammer to the drill bit for rock-breaking, and one part of the energy is the kinetic energy E 反弹 that causes the air hammer to rebound. Based on this, there is E 冲 = E 传 + E 反弹 . Since the action time of E 反弹 on the bottom is relatively small and is often not easily detected by the sensor in the experiment, the energy relationship transferred downward to the drill bit can be simplified as follows: E 传 = ηE 冲 . Then, the energy transfer efficiency formula is where η is the energy transfer efficiency; E 传 is the energy transferred from the piston of the air hammer to the drill bit for rock-breaking.

[0089] S2. Based on the energy source of rock-breaking underground during air hammer drilling, optimize the R. Teale specific energy equation to establish the air hammer drilling specific energy equation. Specifically, establishing the air hammer drilling specific energy equation includes the following steps:

[0090] S21. Based on the working principle of the air hammer, analyze the energy sources for rock fragmentation downhole during air hammer drilling. The energy sources include impact work, weight-on-bit work, and torque work.

[0091] S22. Based on the analysis results of step S21, establish the basic air hammer drilling specific mechanical energy equation where E is the specific mechanical energy in MPa; E W is the axial energy caused by the weight-on-bit in J; E T is the rotational kinetic energy of the bit; V is the unit volume of rock fragmented per minute.

[0092] S23. Based on the R. Teale specific mechanical energy equation Expand the air hammer drilling specific mechanical energy equation to obtain where W is the weight-on-bit of the bit in KN; T is the torque of the bit in KN·m; n is the rotational speed of the bit in r / min; v is the mechanical penetration rate of the bit in m / h; d is the bottom hole diameter in cm.

[0093] S3. Based on the combination of the energy transfer efficiency formula and the air hammer drilling specific mechanical energy equation, obtain the energy transfer efficiency of the current air hammer, which specifically includes the following steps:

[0094] S31. Based on calculate the impact work of the current air hammer; where the mass m of the piston is obtained according to the structural design data of the current air hammer 活塞 ; the value of a is the acceleration of the air hammer piston detected during the determination of the stroke; the value of t is the stroke time of the air hammer piston detected by the electric encoder during the determination of the stroke.

[0095] S32. Based on calculate the energy transferred from the piston of the current air hammer to the bit for rock fragmentation; where the mass m of the piston is obtained according to the structural design data of the current air hammer 钻头 ; v 线速度 is the axial final velocity of the bit, which is obtained under the condition of the acceleration of the air hammer piston measured during the determination of the stroke; specifically, v 线速度 = a 钻头 t 钻头 ; a 钻头 can be detected by an acceleration sensor. After the bit completes one downstroke, it will also generate a rotary motion. Based on this, t can be detected based on the principle of the electric encoder detecting the stroke time t2 of the air hammer piston. 钻头 .

[0096] S33. Based on the energy transfer efficiency formula as Based on the calculation results of steps S31 and S32, calculate the energy transfer efficiency η of the current air hammer.

[0097] S4. Generally, the minimum mechanical specific energy should be equal to the compressive strength of the rock to break the rock. Therefore, based on the compressive strength of the rock, the impact work required for rock breaking can be obtained by combining the mechanical specific energy equation of air hammer drilling and the energy transfer efficiency formula. Specifically, it includes the following steps:

[0098] S41. Based on the minimum requirement E = E of the mechanical specific energy of air hammer drilling for rock breaking 岩 , combine the mechanical specific energy formula of air hammer drilling to obtain the physical quantity E of the mechanical specific energy 传 calculation formula

[0099] S42. Start the air hammer on site, and based on logging or while-drilling instruments, measure the motion parameters of the air hammer, including the weight on bit W of the drill bit, the torque T of the drill bit, the rotational speed n of the drill bit, and the rate of penetration v of the drill bit;

[0100] S43. Obtain the bottom hole diameter d and rock type of the well to be drilled on site, and based on the rock type, look up the corresponding compressive strength E of the rock in the rock compressive strength table 岩 ;

[0101] S44. Substitute the relevant parameters obtained in steps S42 and S43 into the physical quantity E of the mechanical specific energy 传 calculation formula for calculation, and the calculated E 传 is the energy that the piston of the air hammer needs to transfer to the drill bit for rock breaking;

[0102] S45. Substitute the calculation result of step S44 and the energy transfer efficiency of the current air hammer obtained in step S3 into the energy transfer efficiency formula to calculate the impact work required for rock breaking.

[0103] S5. According to the impact work required for rock breaking, by changing the number of air compressors, quantitatively set the initial kinetic energy of the air hammer.

[0104] Example 4

[0105] This example discloses a method for determining the stroke and setting the initial kinetic energy of an air hammer. As a basic implementation scheme of the present invention, that is, in step S5 of Examples 1, 2, or 3, the basis for changing the number of air compressors is:

[0106]

[0107] E 空压机 = P 总 t;

[0108] where η空压机 is the energy transfer efficiency of the air compressor; E 空压机 is the total output work of the air compressor; P 总 is the total output power of the air compressor, and t is the time of a downward stroke of the air hammer. Under the condition that the structure of the air hammer itself and its connection structure with the air compressor remain unchanged, η 空压机 is basically fixed. Under the condition of the same t, E 冲 and E 空压机 are obtained respectively, and then η 空压机 can be obtained.

[0109] Based on the above basis, when η 空压机 is known, after obtaining the impact work required for rock breaking according to step S4, based on the formula the initial kinetic energy of the air hammer (i.e., the total output work E 空压机 ) can be calculated. Then, based on E 空压机 = P 总 t, the total output power P 总 of the air compressor is calculated. Let the output power of each air compressor be P, then the number of air compressors is calculated by . When the calculated n is an integer, the number of air compressors is n. When the calculated n is a decimal, the number of air compressors is the smallest integer greater than n.

Claims

1. Method for determining the stroke of an air hammer and setting the initial kinetic energy, characterized in that Including stroke determination and initial kinetic energy setting; The stroke determination is to analyze the motion parameters of the air hammer piston's impact work based on the calculation formula of the air hammer piston's impact work, detect the motion parameters, and then calculate and optimize the air hammer piston stroke based on the motion parameters; Detecting the motion parameters includes the following steps: a. Calculation formula based on impact work , determine the motion parameters to be detected, including the acceleration of the air hammer piston and the stroke time of the air hammer piston; where is the impact work of the air hammer, that is, the impact work of the piston during the downward stroke; represents the mass of the piston; represents the time taken for the downward stroke of the piston, that is, the stroke time of the air hammer piston; represents the acceleration of the air hammer piston; b. Install an acceleration sensor and an electric encoder on the air hammer; and connect the acceleration sensor assembly to the corresponding parameter detection device; c. Start the air hammer. On the premise that the initial velocity of the piston is , use an acceleration sensor to detect the acceleration of the air hammer piston and the stroke time of the air hammer piston , and use an electric encoder to detect the stroke time of the air hammer piston ; Calculating and optimizing the air hammer piston stroke includes the following steps: Based on the piston displacement formula , compare the travel time of the air hammer piston detected by the acceleration sensor with the travel time of the air hammer piston detected by the electric encoder ; where is the piston displacement, is the initial piston velocity; If , it means that the air hammer is operating at the optimal stroke in design, and there is no need to optimize the piston structure stroke. , the calculated piston displacement is the optimal piston stroke; If , it means that when the air hammer piston speed reaches the maximum, the piston has not yet touched the bottom. Then, according to the piston displacement formula, use and respectively to calculate the corresponding piston displacements to obtain the piston displacement difference at two times; shorten the piston stroke structure design according to the piston displacement difference so that ; If , it means that when the air hammer piston touches the bottom and its speed has not reached the maximum, according to the piston displacement formula, the corresponding piston displacements are calculated respectively using and to obtain the piston displacement difference at two times; the piston stroke structure design is extended according to the piston displacement difference so that ; The initial kinetic energy setting includes the following steps: S1. According to the energy flow direction during air hammer impact drilling, establish an energy transfer efficiency formula related to the air hammer piston's impact work and rock-breaking energy; S2. Based on the energy source of rock fragmentation underground during air hammer drilling, optimize the R. Teale specific energy equation for mechanical energy to establish the specific energy equation for mechanical energy in air hammer drilling; S3. Based on the combination of the energy transfer efficiency formula and the specific energy equation for mechanical energy in air hammer drilling, obtain the current energy transfer efficiency of the air hammer; S4. Based on the rock compressive strength, combine the specific energy equation for mechanical energy in air hammer drilling and the energy transfer efficiency formula to obtain the impact work required for rock fragmentation; S5. According to the impact work required for rock fragmentation, change the number of air compressors to quantitatively set the initial kinetic energy of the air hammer.

2. The method for determining the stroke and setting the initial kinetic energy of the air hammer according to claim 1, characterized in that, In the step S1 of setting the initial kinetic energy, the energy transfer efficiency formula is ; where is the energy transfer efficiency; is the energy transferred from the piston of the air hammer to the drill bit for rock breaking.

3. The method for determining the stroke and setting the initial kinetic energy of the air hammer according to claim 2, characterized in that, In step S2 of the initial kinetic energy setting, establishing the specific energy equation for mechanical energy in air hammer drilling includes the following steps: S21. Based on the working principle of the air hammer, analyze the energy source of rock fragmentation underground during air hammer drilling, and the energy source includes impact work, weight-on-bit work, and torque work; S22. Establish a basic air hammer drilling mechanical specific energy equation based on the analysis results of step S21 ; where is the mechanical specific energy, with the unit of Mpa; is the axial energy caused by the drilling pressure, with the unit of J; is the rotational kinetic energy of the drill bit; is the unit volume of rock broken per minute S23, based on the R. Teale mechanical energy equation Expand the mechanical energy equation for air hammer drilling to obtain ; where is the weight on bit, in KN; is the torque on bit, in KN.m; is the rotary speed of the bit, in r / min; is the rate of penetration of the bit, in m / h; is the bottom hole diameter, in cm.

4. The method for determining the stroke and setting the initial kinetic energy of the air hammer according to claim 3, characterized in that, In step S3 of the initial kinetic energy setting, obtaining the current energy transfer efficiency of the air hammer includes the following steps: S31, based on calculate the impact work done by the current air hammer; wherein, obtain the mass of the piston according to the structural design data of the current air hammer ; The value of is the acceleration of the air hammer piston detected during the process of determining the stroke; The value of is the stroke time of the air hammer piston detected by the electric encoder during the process of determining the stroke; S32, based on calculate the energy transferred from the piston of the current air hammer to the drill bit for rock breaking; wherein, the mass of the piston is obtained according to the structural design data of the current air hammer ; is the axial final velocity of the drill bit, and is obtained under the condition of the acceleration of the air hammer piston measured during the determination of the stroke; S33. Based on the energy transfer efficiency formula, combine the calculation results of steps S31 and S32 to calculate the energy transfer efficiency of the current air hammer .

5. The method for determining the stroke and setting the initial kinetic energy of the air hammer according to claim 4, characterized in that In step S4 of the initial kinetic energy setting, obtaining the impact work required for rock fragmentation includes the following steps: S41, based on the minimum requirement of the mechanical specific energy of air hammer drilling for rock breaking , combined with the mechanical specific energy formula of air hammer drilling , obtain the physical quantity of the mechanical specific energy calculation formula ; S42. Start the air hammer on-site and measure the motion parameters of the air hammer based on logging or measurement-while-drilling instruments, including the weight on bit of the drill bit , the torque of the drill bit , the rotational speed of the drill bit , the rate of penetration of the drill bit ; S43, obtain the bottom hole diameter of the well to be drilled on site and the rock type, and look up the corresponding rock compressive strength in the rock compressive strength table based on the rock type ; S44. Substitute the relevant parameters obtained in steps S42 and S43 into the physical quantity of mechanical specific energy for calculation according to the calculation formula, and the thus calculated is the energy that the piston of the air hammer needs to transfer to the drill bit for rock breaking; S45. Substitute the calculation result of step S44 and the energy transfer efficiency of the current air hammer obtained in step S3 into the energy transfer efficiency formula to calculate the impact work required for rock breaking.

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