An axial cam type vibration impactor

Abstract

The application discloses an axial cam type vibration impactor for forming axial impact load by adopting a cam structure, which mainly comprises an upper joint, a spiral turbine, a cam shaft, a ball, a spring assembly, a vibration starting body, a lower joint and the like. The turbine is arranged on the upper end of the cam shaft and cooperates with the outer step surface of the cam shaft. The centralizing bearing is arranged on the outer ring of the upper end of the cam shaft. The above-mentioned components are compressed by the threaded connection between the water distribution head and the cam shaft, and the whole is arranged in the inner cavity of the shell. The upper joint is connected with the shell through the threaded connection and cooperates with the upper end surface of the centralizing bearing to realize the axial positioning. The impact load acting on the drill bit at the well bottom can be generated during the working process of the tool. The rotary motion transmitted by the ground turntable can form the dynamic load of the rotary impact on the drill bit, which is beneficial to improving the rock breaking efficiency of the drill bit, thereby improving the mechanical drilling speed and greatly improving the single drilling depth in the drilling process of the deep well and the ultra-deep well.

Description

Technical Field

[0001] This invention relates to an axial cam-type vibration impactor that uses a cam structure to generate axial impact load, belonging to the technical field of downhole rotary drilling speed-up tools in the oil and gas development process. Background Technology

[0002] In recent years, oil and gas exploration drilling has gradually shifted towards deep, hard formations, increasing the likelihood of encountering formations with "three highs" (high rock hardness, high rock drillability, and high rock abrasiveness). The drilling pressure required by the drill bit is largely provided by the weight of the drill collars, and this rigid pressure application method severely impacts the mechanical drilling rate and the working life of the drill bit and bottom hole tool assembly. Improving drilling efficiency, reducing drilling costs, and extending the working life of bottom hole tools have become hot research topics in the industry. In conventional drilling operations, drilling pressure is usually applied by the weight of the drill string, combined with hydraulic jetting to remove cuttings. However, in deep and ultra-deep well drilling, hydraulic losses along the drilling path increase significantly. With the surface pump power remaining constant, the available hydraulic horsepower of the bottom hole drill bit drops sharply, leading to a significant reduction in hydraulic rock breaking and removal capabilities. This results in the inability to remove bottom hole cuttings in a timely manner, causing repeated breaking and even drill bit mud buildup, ultimately reducing drilling efficiency and mechanical drilling rate. Improving drilling speed in deep and ultra-deep wells has become a hot research topic for scholars both domestically and internationally. Among these methods, percussion drilling technology generates impact energy at a certain frequency on the drill bit. Combined with circumferential rotational torque, this creates a swirling cutting effect at the bottom of the well, altering the stress state of the rock. Given the inherently poor impact resistance of hard rock formations, intermittent impact loading induces shearing and rock breaking, further expanding surface cracks and fissures, reducing their mechanical strength. This, in turn, improves the mechanical drilling speed and overall work efficiency in rock-breaking drilling.

[0003] Existing solutions generally employ axial impact, airflow impact, or a mixed airflow and axial impact formula. For example, in the existing patent solution CN112593846A, an axial impact vibration drilling tool with modulated impact characteristics is disclosed. It includes an upper connector, a bypass valve, a screw motor, a housing, a power input shaft, a universal joint, a centralizing bearing, an axial vibration generating device, and a lower connector. The axial vibration generating device includes a starting shaft, balls, a plane bearing, a spring assembly, and a cam body. The screw motor is driven by downhole drilling fluid, and the starting shaft is rotated by the universal joint. The balls on the outer stepped surface of the middle part of the starting shaft move in the guide groove at the upper end of the cam body. The guide groove is a spatial cam-shaped track with a periodic step height difference. When the balls move on the guide groove, they will periodically rise and fall. This invention can increase drill bit pressure at the bottom of the well, thereby improving the mechanical drilling rate and increasing the mechanical drilling rate of the corresponding target formation. It can also adjust the impact vibration characteristics in accordance with the rock properties of different formations, thereby achieving optimal rock breaking efficiency and improving the mechanical drilling rate of the corresponding target formation. Similar designs include CN216922010U, CN116136150A, and CN206129207U.

[0004] Other pneumatic impact solutions, such as CN103291214A, disclose a novel hydraulic impact device for accelerating drilling in hard formations, employing a combination of a turbine and a rotating head as the control structure for hydraulic pulses. Drilling fluid generates torque on the power shaft via the turbine assembly. This torque, through the connection between the power shaft and the rotating head, drives the rotating head to rotate. The contact between the rotating head and the impact cylinder end face creates periodic flow and closure of the flow channels, causing pressure changes on the impact cylinder. Under the combined action of spring force, the impact cylinder performs axial reciprocating vibration motion. This axial reciprocating vibration is transmitted to the lower connector via a connecting mechanism, generating pulse impacts of a certain frequency under the control of the connecting mechanism. This vibration is transmitted to the drill bit, generating axial impact force. The interaction between the drill bit and the impactor's housing transmits the torque provided by the drilling equipment, driving the drill bit to complete the drilling operation. Simultaneously, the impact of the impactor on the drill bit improves rock-breaking efficiency, thus accelerating drilling.

[0005] Other cam- and starter-based composite solutions, such as CN116927651A, disclose a mechanical impact-high-pressure jet combined rock-breaking device. This device uses a specific method or apparatus to generate impact vibrations while the drill bit rotates. The instantaneous stress concentration from the high-frequency vibrations causes internal rock fissures to form and rapidly expand, weakening the rock's strength. Simultaneously, conventional drilling fluid is partially or completely pressurized and sprayed onto the damaged and weakened rock surface, penetrating the fissures generated by the vibration impact. The fissures expand and converge under the splitting action of the high-pressure jet, creating conditions for subsequent drill bit cutting and breaking, thus improving the breaking efficiency. This invention also discloses a mechanical impact-high-pressure jet combined rock-breaking method, which improves drilling speed, shortens well construction cycles, and enables economical and efficient extraction of oil and gas resources.

[0006] However, although the above solutions can enhance the effect of impact drilling by utilizing the flow of drilling fluid or the mechanical axial impact generated by the cam, the cams in the above designs all have protrusions on the radial surface at the bottom of the wheel body, and these protrusions are one-dimensional, or in other words, the protrusions are discrete and discontinuous. This makes the contact between the protrusions and the bottom vibrator one-dimensional and discontinuous. In particular, the pressure on the multiple scattered arched protrusions is the greatest at the tip of the protrusion, making them prone to damage. Moreover, the contact position between the protrusions and the vibrator is the same in each rotation cycle, resulting in a short lifespan. Summary of the Invention

[0007] Based on the above-mentioned technical problems, the present invention provides an axial cam-type vibratory impactor that uses a cam structure to form an axial impact load, which can generate a high-frequency impact on the drill bit at the bottom of the well, and achieve a rotary drilling operation mode in conjunction with the rotational motion provided by the ground turntable.

[0008] The technical solution adopted in this invention is:

[0009] An axial cam-type vibration impactor that uses a cam structure to generate axial impact load mainly includes an upper connector, a water distribution head, a centralizing bearing, a spiral turbine, a camshaft, ball bearings, a spring assembly, a vibration starter, a lower connector, and a housing.

[0010] The spiral turbine is sleeved on the upper end of the camshaft, and is fitted and fixed to the outer stepped surface of the camshaft. The centering bearing is set on the outer ring of the upper end of the camshaft. The water distributor is threadedly connected to the end of the camshaft to press the above components together and place the whole in the inner cavity of the housing. The upper connector is threadedly connected to the housing and is fitted with the upper end face of the centering bearing at the threaded connection to achieve axial positioning.

[0011] A ball bearing is arranged in the groove at the upper end of the vibration starter and engages with the cam track of the camshaft. The cam track is a series of smooth concave cavities formed on the outermost radial circumference of the bottom of the camshaft. The concave cavities cover the entire radial circumference of the bottom of the camshaft, and the width of each concave cavity is gradually different. The ball bearing can roll in the cam track cavity. A spring assembly is arranged in the annular cavity formed by the camshaft and the vibration starter. The lower end of the vibration starter is connected to the lower connector by a thread, and the lower connector can be directly connected to the drill bit at the bottom of the well. A spline sleeve is arranged at the spline groove position of the lower connector to form a spline fit. The upper end of the spline sleeve is connected to the housing, so that the tool is completely enclosed. Before each well run or periodically, the size of the balls on the vibratory starter is changed. The size of the balls is between the maximum and minimum width of each concave cavity. During operation, high-speed flowing drilling fluid enters the tool body through the upper connector. The drilling fluid impacts the spiral turbine, causing the turbine and camshaft to rotate at high speed. There is a certain axial height difference on the cam track on the camshaft. The rotation of the camshaft causes the balls to roll on the cam track. Through cooperation with the spring assembly, the periodic axial vibration of the vibratory starter is achieved. The threaded connection between the vibratory starter and the lower connector can generate periodic axial vibration impact at the bottom of the well.

[0012] Preferably, the impactor uses a spiral turbine as the drilling fluid power conversion unit. The spiral turbine has advantages such as simple structure, small size, low energy consumption, and high output speed. It can achieve high-speed output with relatively low drilling fluid power consumption. Moreover, the spiral turbine generates a concentric rotational motion, which will not cause radial vibration of the tool body and will not interfere with the electronic components connected to the tool. Thus, it can provide stable and reliable output characteristics in deep and ultra-deep wells without excessively consuming the already insufficient drilling fluid power.

[0013] Preferably, the camshaft is directly connected to the spiral turbine. Under the impact of the drilling fluid, the spiral turbine will rotate at high speed and drive the ball bearings to rotate on the cam track through the camshaft, so that the vibration starter will be axially impacted by the axial height difference of the cam track.

[0014] Preferably, by adjusting the number of grooves on the upper end face of the vibrator and the design parameters of the cam track on the camshaft, the frequency of the axial impact load output by the tool can be adapted to strata rocks of different strengths, thereby increasing the stratum applicability of the impactor and expanding its application range.

[0015] The beneficial technical effects of this invention are:

[0016] This invention utilizes a specially designed cam track with a continuous, non-uniform or gradually varying width track cavity. By changing the size of the steel balls on the starter before each well run or periodically, the contact area of ​​the cam track during downhole operations is altered, thus significantly extending the lifespan of the cam track. This overcomes the design flaws of traditional systems where contact and compression occur only at the protruding points, leaving other areas unused. Furthermore, it retains the ability of the helical turbine to convert the kinetic energy of the drilling fluid into mechanical energy, and through the interaction of the balls and the cam track, it generates axial high-frequency impact vibration. This high-frequency impact energy is applied to the drill bit through the lower connector and further applied to the rock action surface at the bottom of the well. By coordinating the rotational motion provided by the surface turntable, a swirling impact effect is created on the drill bit at the bottom of the well, which can enhance the design for increasing the mechanical drilling speed in deep wells with hard rock formations. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0018] Figure 2 This is a simplified three-dimensional structural diagram of a spiral turbine.

[0019] Figure 3 and Figure 4 This is a simplified structural diagram of a camshaft.

[0020] Figure 5 and Figure 6 This is a simplified structural diagram of the initiating vibrator.

[0021] Figure 7 This is a waveform diagram of the impact load generated in an indoor test simulation of the present invention.

[0022] In the diagram: 1-Upper connector, 2-Water distributor, 3-Centering bearing, 4-Spiral turbine, 5-Positioning sleeve, 6-Camshaft, 7-Ball bearing, 8-Spring assembly, 9-Vibration starter, 10-Housing, 11-Spline sleeve, 12-Lower connector. Detailed Implementation

[0023] Example 1

[0024] This invention converts a small portion of the drilling fluid's kinetic energy into mechanical energy using a spiral turbine, which drives the camshaft to rotate. This rotation further causes balls to roll within cam tracks on the camshaft. Due to the axial height difference of the cam tracks, the vibrating element achieves periodic axial impact through the interaction of the balls and tracks, as well as the spring assembly. This high-frequency impact energy is applied to the rock surface at the bottom of the well via the drill bit, effectively increasing instantaneous stress concentration. Combined with the rotational motion (torque) provided by the surface turntable, this creates a swirling impact on the drill bit at the bottom of the well, significantly improving rock breaking efficiency, increasing the mechanical drilling rate, and extending the single drilling depth. This invention features a simple tool design, high energy conversion efficiency, and low drilling fluid energy consumption, making it suitable for accelerating drilling in hard rock formations in deep and ultra-deep wells, significantly increasing the mechanical drilling rate in hard rock formations.

[0025] Example 2

[0026] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0027] Referring to the attached drawings, an axial cam-type vibratory impactor that uses a cam structure to generate axial impact load is cylindrical in shape and mainly includes an upper connector 1, a water distributor 2, a spiral turbine 4, a camshaft 6, ball bearings 7, a spring assembly 8, a vibration starter 9, a housing 10, and a lower connector 12. The spiral turbine 4 is sleeved on the upper end of the camshaft 6 and mates with the outer stepped surface 61 of the camshaft 6. A straightening bearing 3 is sleeved on the outer ring of the upper end of the camshaft 6. The water distributor 2 is threadedly connected to the end of the camshaft 6 to press the above components together and place the whole in the inner cavity of the housing 10. The upper connector 1 is threadedly connected to the housing 10 and mates with the upper end face of the straightening bearing 3 at the threaded connection to achieve axial positioning.

[0028] A ball bearing 7 is arranged in the groove 91 at the upper end of the vibration starter 9 and engages with the cam track 62 of the camshaft 6. The cam track 62 is a series of smooth concave cavities formed on the outermost radial circumferential surface at the bottom of the camshaft. The series of concave cavities cover the entire radial circumferential surface at the bottom of the camshaft, and the width of each concave cavity is gradually different. The ball bearing 7 can roll in the cam track cavity. A spring assembly 8 is arranged in the annular cavity formed by the camshaft 6 and the vibration starter 9. The lower end of the vibration starter 9 is connected to the lower connector 12 by a thread, and the lower connector 12 can be directly connected to the drill bit at the bottom of the well. A spline sleeve 11 is arranged at the spline groove position of the lower connector 12 to form a spline engagement. The upper end of the spline sleeve 11 is connected to the housing 10, so that the tool is completely enclosed. Before each well run or periodically, the size of the balls on the vibrating body is changed. The size of the balls is between the maximum and minimum width of each concave cavity. During operation, high-speed flowing drilling fluid enters the tool body through the upper connector 1. The drilling fluid impacts the spiral turbine 4, causing the turbine and camshaft 6 to rotate at high speed. There is a certain axial height difference on the cam track on the camshaft 6. The rotation of the camshaft 6 causes the balls 7 to roll on the cam track. Through cooperation with the spring assembly 8, the periodic axial vibration of the vibrating body 9 is achieved. The periodic axial vibration impact can be generated at the bottom of the well by the threaded connection between the vibrating body 9 and the lower connector 12.

[0029] Furthermore, the impactor uses a spiral turbine 4 as the drilling fluid power conversion unit. The spiral turbine 4 has advantages such as simple structure, small size, low energy consumption, and high output speed. It can achieve high-speed output with relatively low drilling fluid power consumption. Moreover, the spiral turbine 4 generates a concentric rotational motion, which will not cause radial vibration of the tool body and will not interfere with the electronic components connected to the tool. Thus, it can provide stable and reliable output characteristics in deep and ultra-deep wells without excessively consuming the already insufficient drilling fluid power.

[0030] Furthermore, the camshaft 6 is directly connected to the spiral turbine 4. Under the impact of the drilling fluid, the spiral turbine 4 will generate high-speed rotation, and drive the ball bearing 7 to rotate on the cam track through the camshaft 6, so that the vibration starter 9 will be axially impacted by the axial height difference of the cam track.

[0031] Furthermore, by adjusting the number of grooves on the upper end face of the vibration starter 9 and the design parameters of the cam track on the camshaft 6, the frequency of the axial impact load output by the tool can be adapted to strata rocks of different strengths, thereby increasing the stratum applicability of the impactor and expanding its application range.

[0032] Furthermore, a drain hole 63 is provided on the side of the step 64 of the camshaft 6 to discharge the drilling fluid that has passed through the spiral turbine 4 through the lower connector.

[0033] Example 3

[0034] The working process of this invention is roughly as follows:

[0035] In actual use, drilling fluid enters the tool body through the upper connector 1, passes through the water distributor 2, and enters the flow hole of the centralizing bearing 3, further driving the spiral turbine 4 to rotate, and further driving the camshaft 6 to rotate at high speed. Since the ball bearings 7 are set in the groove at the upper end of the vibration starter 9 and can slide in the cam track of the camshaft 6, the axial height difference of the cam track will cause the vibration starter 9 to generate axial high-frequency vibration. Moreover, the amplitude and frequency of this high-frequency vibration can be adjusted by the design parameters of the spiral turbine, the cam track, and the number of ball bearings. The axial high-frequency vibration generated on the vibration starter 9 will be transmitted to the bottom hole drill bit that is threadedly connected to it through the lower connector 12. Therefore, the tool of the present invention can generate axial high-frequency impact load on the bottom hole drill bit. Combined with the rotational torque provided by the surface turntable, it can generate a rotational impact effect on the drill bit, forming a rotary impact drilling operation mode, which is beneficial to improving the rock breaking efficiency of the drill bit, thereby increasing the mechanical drilling speed and significantly increasing the single drilling depth in the drilling process of deep and ultra-deep wells. The tool of this invention has advantages such as simple design structure, high energy conversion efficiency, and low drilling fluid energy consumption. It can be applied to the drilling speed-up project of hard rock formations in deep and ultra-deep wells, and significantly improve the mechanical drilling speed of hard rock formations.

[0036] In the above process, the cam track 62 is a series of smooth concave cavities formed on the outermost radial circumferential surface of the bottom of the camshaft. These concave cavities cover the entire radial circumferential surface of the bottom of the camshaft, and the width of each concave cavity is designed to be gradually different. The ball bearings 7 can roll in the cam track cavity. The size of the ball bearings on the vibration starter is changed before each well run or periodically. The size of the ball bearings is between the maximum and minimum width of each concave cavity. This makes the final contact position between each concave cavity of the cam track cavity on the same camshaft and the ball bearing different at different time periods or different well run positions. Therefore, the wear is evened out, and the service life is greatly improved.

[0037] This invention utilizes a specially designed cam track with a continuous, non-uniform or gradually varying width track cavity. By changing the size of the steel balls on the vibrator before each well run or periodically, the contact area of ​​the cam track during downhole operations is altered, significantly extending its lifespan. This overcomes the shortcomings of traditional designs where contact and compression occur only at the raised areas, leaving other areas unused. Furthermore, it retains the ability of the helical turbine to convert the kinetic energy of the drilling fluid into mechanical energy, and through the interaction of the balls and the cam track, generates axial high-frequency impact vibration. This high-frequency impact energy is applied to the drill bit via the lower connector and further applied to the rock surface at the bottom of the well. By coordinating the rotational motion provided by the surface turntable, a swirling impact effect is created on the drill bit at the bottom of the well, which can improve the mechanical drilling speed design for deep wells in hard rock formations.

[0038] Any technical content not mentioned above can be achieved by adopting or drawing upon existing technologies.

[0039] It should be noted that any equivalent substitutions or obvious modifications made by those skilled in the art based on the teachings of this specification should be within the scope of protection of this invention.

Claims

1. An axial cam-type vibratory impactor, characterized in that: Includes upper connector, water distribution head, centering bearing, spiral turbine, camshaft, ball bearings, spring assembly, vibration starter, lower connector, and housing. The spiral turbine is sleeved on the upper end of the camshaft, and is fitted and fixed to the outer stepped surface of the camshaft. The centering bearing is set on the outer ring of the upper end of the camshaft. The water distributor is threadedly connected to the end of the camshaft to press the above components together and place the whole in the inner cavity of the housing. The upper connector is threadedly connected to the housing and is fitted with the upper end face of the centering bearing at the threaded connection to achieve axial positioning. A ball bearing is arranged in the groove at the upper end of the vibration starter and engages with the cam track of the camshaft. The cam track is a series of smooth concave cavities formed on the outermost radial circumference of the bottom of the camshaft. The concave cavities cover the entire radial circumference of the bottom of the camshaft, and the width of each concave cavity is gradually different. The ball bearing can roll in the cam track cavity. A spring assembly is arranged in the annular cavity formed by the camshaft and the vibration starter. The lower end of the vibration starter is connected to the lower connector by a thread, and the lower connector can be directly connected to the drill bit at the bottom of the well. A spline sleeve is arranged at the spline groove position of the lower connector to form a spline fit. The upper end of the spline sleeve is connected to the housing, so that the tool is completely enclosed. Before each well run or periodically, the size of the balls on the vibratory body is changed. The size of the balls is between the maximum and minimum width of each concave cavity. During operation, high-speed flowing drilling fluid enters the impactor through the upper connector. The drilling fluid impacts the spiral turbine, causing the turbine and camshaft to rotate at high speed. There is a certain axial height difference on the cam track on the camshaft. The rotation of the camshaft causes the balls to roll on the cam track. Through cooperation with the spring assembly, the periodic axial vibration of the vibratory body is achieved. The threaded connection between the vibratory body and the lower connector can generate periodic axial vibration impact at the bottom of the well.

2. The axial cam-type vibratory impactor according to claim 1, characterized in that: The camshaft is directly connected to the spiral turbine. Under the impact of the drilling fluid, the spiral turbine will rotate at high speed and drive the balls to rotate on the cam track through the camshaft, so that the vibration starter will be axially impacted by the axial height difference of the cam track.

3. An axial cam-type vibratory impactor according to claim 1, characterized in that: By adjusting the number of grooves on the upper end face of the vibrator and the design parameters of the cam track on the camshaft, the frequency of the axial impact load output by the tool can be adapted to rock formations of different strengths, thereby increasing the geological applicability of this impactor and expanding its application range.

4. An axial cam-type vibratory impactor according to claim 1, characterized in that: A drain hole is provided on the side of the step of the camshaft to discharge the drilling fluid that has passed through the spiral turbine through the lower connector.

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