Mud-driven hole bottom impactor

Abstract

The invention provides a mud-driven hole bottom impactor. The mud-driven hole bottom impactor comprises an upper connector and a lower connector, the upper end of the outer pipe is connected with the upper connector, and a closed lubricating oil cavity is formed in the outer pipe; the core shaft is coaxially arranged in the outer pipe, and a penetrating slurry channel is formed in the center of the core shaft; the hydraulic component is connected to the lower end of the outer pipe; the heavy hammer is arranged on the outer side of the core shaft in a sleeving manner and axially slides relative to the core shaft; the spring is arranged above the heavy hammer and used for providing reset elastic force for the heavy hammer; the sealing ring is arranged in an annular gap between the mandrel and the outer pipe and used for sealing the lubricating oil cavity; the coring drilling tool is connected to the lower end of the hydraulic component; an energy conversion mechanism is arranged in the hydraulic component and comprises a turbine and a cam set, the turbine is used for driving the cam set, the rotary motion of the turbine is converted into the axial impact motion of a heavy hammer through the cam set, and the problem that the hole bottom impactor depends on low-solid-phase slurry is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of impactors, and in particular to a mud-driven bottom-hole impactor. BACKGROUND

[0002] In the field of geological drilling, especially in low-cost drilling operations such as mineral exploration and engineering investigation within 2000 meters, it is often necessary to implement percussion-rotary coring drilling in hard rock or gravel strata. Such strata have high hardness and strong abrasiveness, and the use of conventional rotary drilling methods results in low mechanical drilling speed and difficulty in ensuring core recovery rate. Practical experience shows that applying axial impact load to the drill bit during drilling can effectively break hard rock, significantly improving mechanical drilling speed and core recovery rate. Therefore, there is an urgent need for a bottom-hole power device that can adapt to low-cost operating environments, has a simple structure, and can reliably generate impact power.

[0003] To generate impact load at the bottom of the hole, the related art usually uses a hydraulic bottom-hole impactor as a solution. Such impactors use drilling mud as the working medium, and convert the hydraulic energy of the mud into periodic mechanical impact through internal hydraulic mechanisms and directly transmit it to the drill bit. Such devices generally include a transducer mechanism, a hammer structure, a flow distribution valve, and a striking assembly, and can add high-frequency impact to rotary drilling to improve rock breaking.

[0004] However, the hydraulic impactor has extremely strict requirements for the cleanliness of the working medium, and usually requires the mass content of sand in the mud to be less than 1%. To meet this condition, a large mud control system must be provided on site, such as a vibrating screen, a sand remover, a centrifuge, etc., resulting in difficulties in equipment relocation, large floor space, and significant increase in operating costs. This not only limits its application in mountainous areas, mining areas, and other conditions-limited sites, but also makes it difficult to meet the strict requirements of economic efficiency in shallow exploration. In addition, high solid-phase particles can cause wear and jamming of hydraulic control components, reducing work reliability and shortening maintenance cycles. Therefore, the related art cannot provide a bottom-hole impactor that is simple in structure, resistant to wear, suitable for high-solid-phase mud driving, and easy to maintain on site without complex mud treatment. SUMMARY

[0005] The present application provides a mud-driven bottom-hole impactor to solve the problem of the dependence of the bottom-hole impactor on low-solid-phase mud.

[0006] The application provides a mud-driven bottom hole impactor, comprising: an upper joint; an outer tube, the upper end of the outer tube being connected with the upper joint, the inside of the outer tube forming a closed lubricating oil cavity; a mandrel, the mandrel being coaxially arranged inside the outer tube, the center of the mandrel being provided with a through mud channel; the upper end of the mandrel being connected with the upper joint; a hydraulic component, the hydraulic component being connected with the lower end of the outer tube; the lower end of the mandrel being connected with the hydraulic component; a heavy hammer, the heavy hammer being sleeved on the outside of the mandrel and axially sliding relative to the mandrel; a spring, the spring being arranged above the heavy hammer and used for providing a reset elastic force for the heavy hammer; a sealing ring, the sealing ring being arranged in the annular gap between the mandrel and the outer tube and used for sealing the lubricating oil cavity and isolating lubricating oil from external mud; a coring drill, the coring drill being connected with the lower end of the hydraulic component; wherein the inside of the hydraulic component is provided with an energy conversion mechanism, the energy conversion mechanism comprising a turbine and a cam set, the turbine being used for driving the cam set to convert the rotary motion of the turbine into the axial impact motion of the heavy hammer.

[0007] The mud-driven bottom hole impactor provided by the application converts the rotary motion of mud into the axial impact motion of the heavy hammer through the energy conversion mechanism in the hydraulic component, thereby reducing the dependence on low solid phase mud, improving the applicability of the impactor under various mud conditions, and solving the problem that the bottom hole impactor depends on low solid phase mud.

[0008] Optionally, the cam set comprises a first cam and a second cam, the first cam and the second cam being symmetrical to each other; the first cam and the second cam being connected with the turbine through a spline structure to realize synchronous rotation.

[0009] The symmetrical cam set is connected with the turbine through the spline structure, which helps to maintain the stability of synchronous rotation of the cam, improves the transmission stability, and possibly reduces vibration and eccentric wear in the operation process, thereby improving the working reliability of the energy conversion mechanism.

[0010] Optionally, the hydraulic component further comprises a sliding guide rail; the sliding guide rail being fixed inside the hydraulic component and used for constraining the heavy hammer to slide only in the axial direction of the mandrel.

[0011] The arrangement of the sliding guide rail helps to constrain the movement path of the heavy hammer, reduces the non-axial movement of the heavy hammer in the operation process, thereby improving the accuracy of the impact action and possibly reducing the component wear caused by eccentric wear.

[0012] Optionally, the hydraulic component further comprises a volute and a cover plate; the volute and the cover plate are fixedly connected by a connecting piece, the sliding guide rail is arranged on the volute or the cover plate, and the hydraulic component further comprises a first positioning strip and a second positioning strip arranged inside the hydraulic component, which are used for axially fixing the volute and the cover plate to jointly bear the impact load.

[0013] The volute and the cover plate are fixed by the connecting piece and axially fixed by the positioning strips, which helps to disperse and bear the impact load, improves the overall structure, reduces the risk of component loosening, and possibly improves the stability and service life of the hydraulic component under impact work.

[0014] Optionally, the bottom of the hydraulic component is provided with a replaceable anvil surface, which is used as a direct impact target surface of the weight and transmits the impact work to the coring drill.

[0015] The anvil surface can transmit the impact force of the weight to the coring drill and be replaced after long-term use, thereby reducing the wear of the main structure caused by direct impact, helping to maintain the transmission efficiency of impact work and prolong the service life of related components.

[0016] Optionally, the anvil surface is a cemented carbide ring, the thickness of the anvil surface is greater than or equal to 4 mm, and the anvil surface is mounted on the hydraulic component by a thread or a clamping groove structure.

[0017] The cemented carbide ring anvil surface has a thickness of not less than 4 mm and is mounted by a thread or a clamping groove structure, which helps to improve its impact deformation resistance and wear resistance, thereby reducing the replacement frequency, improving the maintenance convenience, and maintaining the stability of impact work transmission.

[0018] Optionally, the turbine is arranged in the volute, and a fish mouth is further arranged in the volute, which is used to divide and guide the mud flow from the center channel of the core shaft to tangentially impact the blades of the turbine.

[0019] The fish mouth divides and tangentially guides the mud flow to the turbine blades, which helps to improve the conversion efficiency of the kinetic energy of the mud, optimize the starting response of the turbine, and reduce the energy loss during flow.

[0020] Optionally, the upper end surface of the weight is in contact with the spring, the lower end surface of the weight is an impact working surface, and the mass of the weight is configured to generate impact kinetic energy sufficient to break the rock layer under the cooperation of the spring.

[0021] The mass of the weight is configured to cooperate with the spring to convert potential energy into impact kinetic energy, which helps to improve the concentration of impact energy and thus improve the breaking effect on the rock layer.

[0022] Optionally, the mud is high solid phase mud with sand content ≤10%, the impactor generates impact frequency in the range of 8Hz to 25Hz, and the impact frequency is in linear positive correlation with the pumping flow rate of the mud.

[0023] The impactor can work in high solid phase mud with sand content not more than 10%, the impact frequency is in the range of 8Hz to 25Hz, and the frequency is in linear positive correlation with the pumping flow rate of the mud, which helps to expand the adaptability of the impactor to mud medium and provide clear frequency regulation basis for field operation, thereby improving the applicability and controllability of the impactor in complex working conditions.

[0024] Optionally, the overall outer diameter of the impactor ranges from 95mm to 190mm, which is suitable for drilling operations with a hole depth of 50m to 2000m, and the required mud pumping flow rate ranges from 120L / min to 800L / min.

[0025] The outer diameter of the impactor ranges from 95mm to 190mm, which can adapt to a drilling depth of 50m to 2000m, and the required mud pumping flow rate ranges from 120L / min to 800L / min, which helps to expand the applicable range of the impactor under different hole diameters and hole depths, and provides operational flexibility for the selection of pumping equipment.

[0026] From the above technical solutions, the present application provides a mud-driven hole bottom impactor, which comprises: an upper joint; an outer pipe, the upper end of the outer pipe being connected with the upper joint, the inside of the outer pipe forming a closed lubricating oil cavity; a mandrel, the mandrel being coaxially arranged inside the outer pipe, the center of the mandrel being provided with a through mud passage; the upper end of the mandrel being connected with the upper joint; a hydraulic component, the hydraulic component being connected with the lower end of the outer pipe; the lower end of the mandrel being connected with the hydraulic component; a weight, the weight being sleeved on the outside of the mandrel and axially sliding relative to the mandrel; a spring, the spring being arranged above the weight and used for providing reset elastic force for the weight; a sealing ring, the sealing ring being arranged in the annular gap between the mandrel and the outer pipe and used for sealing the lubricating oil cavity and isolating the lubricating oil from the external mud; a coring tool, the coring tool being connected with the lower end of the hydraulic component; wherein, the inside of the hydraulic component is provided with an energy conversion mechanism, the energy conversion mechanism comprising a turbine and a cam set, the turbine being used to drive the cam set to convert the rotary motion of the turbine into the axial impact motion of the weight through the cam set, thereby solving the problem of dependence of the hole bottom impactor on low solid phase mud. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, for those skilled in the art, other drawings can also be obtained based on these drawings without any creative effort.

[0028] Figure 1 The internal structure schematic diagram of the mud-driven bottom hole impactor provided by the embodiment of the present application is shown in the figure.

[0029] Figure 2 The A-A cross-sectional structure schematic diagram of the mud-driven bottom hole impactor provided by the embodiment of the present application is shown in the figure.

[0030] Figure 3 The external structure schematic diagram of the hydraulic component of the mud-driven bottom hole impactor provided by the embodiment of the present application is shown in the figure.

[0031] Figure 4 The impact process schematic diagram of the mud-driven bottom hole impactor provided by the embodiment of the present application is shown in the figure.

[0032] Illustration:

[0033] In the figure, 1 is an upper joint, 2 is a sealing ring, 3 is a spring, 4 is a mandrel, 5 is a weight, 6 is an outer tube, 7 is a hydraulic component, 701 is a volute, 702 is a cover plate, 703 is a sliding guide rail, 704 is a first cam, 705 is a second cam, 706 is a turbine, 707 is a fish mouth, 708 is a first sliding bearing, 709 is a second sliding bearing, 710 is a first positioning strip, 711 is a second positioning strip, 712 is an anvil surface, 8 is a lubricating oil cavity, and 9 is a coring drill. DETAILED DESCRIPTION

[0034] The embodiments will be described in detail below with examples shown in the drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following embodiments do not represent all the embodiments consistent with the present application. They are only examples of systems and methods consistent with some aspects of the present application.

[0035] To solve the problem that the bottom hole impactor is dependent on low solid phase mud, see Figures 1-4The embodiment of the present application provides a mud-driven bottom-hole impactor, which comprises: an upper joint 1; an outer pipe 6, the upper end of the outer pipe 6 is connected with the upper joint 1, and the inside of the outer pipe 6 forms a closed lubricating oil cavity 8; a mandrel 4, the mandrel 4 is coaxially arranged in the inside of the outer pipe 6, and the center of the mandrel 4 is provided with a mud channel; the upper end of the mandrel 4 is connected with the upper joint 1; a hydraulic component 7, the hydraulic component 7 is connected with the lower end of the outer pipe 6; the lower end of the mandrel 4 is connected with the hydraulic component 7; a heavy hammer 5, the heavy hammer 5 is sleeved on the outside of the mandrel 4 and axially slides relative to the mandrel 4; a spring 3, the spring 3 is arranged above the heavy hammer 5 and is used for providing the heavy hammer 5 with a reset elastic force; a sealing ring 2, the sealing ring 2 is arranged in the annular gap between the mandrel 4 and the outer pipe 6 and is used for sealing the lubricating oil cavity 8 and isolating the lubricating oil from the external mud; a coring drill 9, the coring drill 9 is connected with the lower end of the hydraulic component 7; wherein, the inside of the hydraulic component 7 is provided with an energy conversion mechanism, the energy conversion mechanism comprises a turbine 706 and a cam set, the turbine 706 is used for driving the cam set, so that the rotary motion of the turbine 706 is converted into the axial impact motion of the heavy hammer 5 through the cam set.

[0036] It should be understood that the upper end of the upper joint 1 is connected with a drill pipe string. The lower end of the hydraulic component 7 can be connected with the coring drill 9 through threads; the specific structure of the energy conversion mechanism arranged in the inside of the hydraulic component 7 is that the turbine 706 and the cam set are linked through a transmission shaft, when the mud flows into the hydraulic component 7 through the mud channel of the mandrel 4, the high-speed flowing mud impacts the turbine 706 blade to make the turbine 706 rotate, the rotary motion of the turbine 706 is transmitted to the cam set through the transmission shaft, the cam in the cam set rotates synchronously with the transmission shaft, the contour curve of the cam is used to push the driven part matched with the cam, and then the heavy hammer 5 is driven to periodically slide axially along the mandrel 4.

[0037] The sealing ring 2 arranged in the annular gap between the mandrel 4 and the outer pipe 6 is not a single sealing ring 2 structure, but at least two sealing rings 2 are arranged axially along the mandrel 4, and a sealing buffer cavity is formed between adjacent sealing rings 2, through the combination of the multiple sealing design and the buffer structure, the sealing performance of the lubricating oil cavity 8 is effectively improved, the external mud is prevented from penetrating and polluting the lubricating oil, and meanwhile, the leakage of the lubricating oil is avoided to affect the normal work of the impactor.

[0038] In addition, the specific way in which the spring 3 provides the heavy hammer 5 with a reset elastic force is that the upper end of the spring 3 abuts against the spring seat in the inside of the outer pipe 6, and the lower end is sleeved on the spring mounting section of the upper part of the heavy hammer 5, when the heavy hammer 5 moves downward under the action of the cam set, the spring 3 is compressed to accumulate elastic potential energy, when the pushing action of the cam set disappears, the spring 3 releases the elastic potential energy to push the heavy hammer 5 to reset upward, so that the reciprocating impact motion of the heavy hammer 5 is realized.

[0039] The mud-driven bottom-hole impactor provided by the application converts the kinetic energy of the mud into the periodic axial impact of the weight 5 through the turbine 706 and the cam set in the hydraulic component 7. The application allows the field "original mud" containing ≤10% of sand to be directly used as the working medium without the matching solid control equipment, has the advantages of simple structure, reliable work, small wear, long service life, convenient relocation and low cost, and is particularly suitable for low-cost impact-rotary coring drilling in hard rock and gravel strata with a depth of 2000 meters or less, and solves the problem of dependence of the bottom-hole impactor on low solid-phase mud.

[0040] In some embodiments, the cam set includes a first cam 704 and a second cam 705, which are mutually symmetrical; the first cam 704 and the second cam 705 are connected with the turbine 706 through the spline structure to realize synchronous rotation.

[0041] It should be understood that the spline structure, as a commonly used circumferential fixed connection method, usually has a tooth shape of rectangle, involute or triangle, etc., and realizes the torque transmission of the first cam 704, the second cam 705 and the turbine 706 through the meshing between the teeth. In the assembly process, the inner wall of the shaft hole of the turbine 706 is provided with an inner spline, and the connecting end of the first cam 704 and the second cam 705 is provided with an outer spline matched with the inner spline, and the two are precisely connected through the axial sliding of the spline, so that the relative circumferential rotation does not occur in the rotation process, so as to ensure that the first cam 704 and the second cam 705 can maintain the same speed and direction of rotation as the turbine 706. This connection method not only has large torque transmission and high centering accuracy, but also has good guiding property, which is convenient for the installation and positioning of the cam set in the axial direction of the turbine 706, and can also effectively disperse stress, avoid the premature failure of the connecting components due to excessive local stress, and further improve the stability and service life of the transmission system of the impactor.

[0042] The symmetrical cam set is connected with the turbine 706 through the spline structure, which helps to maintain the stability of the synchronous rotation of the cam, improves the transmission stability, and may reduce the vibration and eccentric wear in the operation process, thereby improving the working reliability of the energy conversion mechanism.

[0043] In some embodiments, the hydraulic component 7 further includes a sliding guide rail 703; the sliding guide rail 703 is fixed inside the hydraulic component 7 and is used to constrain the weight 5 to slide only in the axial direction of the core shaft 4.

[0044] It should be understood that the fixed manner of the sliding guide rail 703 and the hydraulic component 7 can adopt welding, bolting or an integrated forming process, and the inner wall thereof is usually precisely ground to form a smooth guide surface. The outer periphery of the weight 5 is provided with a guide groove or flange matched with the sliding guide rail 703, and when the weight 5 moves axially on the mandrel 4, the guide groove or flange is tightly fitted with the inner wall of the sliding guide rail 703, thereby strictly limiting the radial displacement of the weight 5 and ensuring that the movement track of the weight 5 always keeps consistent with the axis of the mandrel 4. This constraint mechanism can effectively avoid the yawing phenomenon of the weight 5 due to centrifugal force or water flow impact during high-speed reciprocating motion, reduce unnecessary friction between the weight 5 and the mandrel 4, reduce energy loss, and also prevent the weight 5 from colliding with other structures inside the hydraulic component 7, further improving the stability and safety of the impactor work. In addition, the provision of the sliding guide rail 703 also provides convenience for subsequent maintenance and replacement of the weight 5, and only the corresponding fixed structure needs to be disassembled to overhaul the guide rail and the weight 5, without the need to disassemble the entire hydraulic component 7.

[0045] The provision of the sliding guide rail 703 helps to constrain the movement path of the weight 5, reduces its non-axial movement during work, thereby improving the accuracy of the impact action and possibly reducing the component wear caused by eccentric wear.

[0046] In some embodiments, the hydraulic component 7 further comprises a volute 701 and a cover plate 702; the volute 701 and the cover plate 702 are fixedly connected through a connecting piece, the sliding guide rail 703 is arranged on the volute 701 or the cover plate 702, and the hydraulic component 7 further comprises first and second positioning strips 710 and 711 for axially fixing the volute 701 and the cover plate 702 to jointly bear the impact load.

[0047] It should be understood that the volute 701 and the cover plate 702 are important components of the hydraulic part 7, and the stability of their connection is directly related to the structural strength and working reliability of the impactor as a whole. The selection of the connecting piece needs to consider the size of the impact load, the corrosiveness of the working environment, and the convenience of installation. Common connecting pieces include high-strength bolts, positioning pins, etc. Through these connecting pieces, the volute 701 and the cover plate 702 can be tightly combined together to form a closed hydraulic space, so as to ensure that the mud can flow in the part according to the preset flow channel, thereby effectively driving the weight 5 to perform impact action. The first positioning strip 710 and the second positioning strip 711 are arranged to further limit the axial position of the volute 701 and the cover plate 702 on the basis of the connection of the connecting piece. When the impactor is working, the reciprocating motion of the weight 5 will inevitably generate a large axial impact load on the volute 701 and the cover plate 702. If only the connecting piece is relied on to bear these loads, long-term use may cause the connecting piece to loosen, deform, or even break. The first positioning strip 710 and the second positioning strip 711 cooperate with the corresponding positioning grooves or positioning holes on the volute 701 and the cover plate 702 to disperse the axial impact load to the overall structure of the volute 701 and the cover plate 702, avoid local stress concentration, thereby enhancing the ability of the volute 701 and the cover plate 702 to bear impact load together, and prolonging the service life of the hydraulic part 7. In addition, the presence of the positioning strip can also play a role in quick positioning during installation, improve the assembly accuracy of the volute 701 and the cover plate 702, ensure that other components such as the sliding guide rail 703 can be accurately installed at the preset position, and then ensure the cooperation accuracy between the parts of the impactor, thereby improving the working performance of the impactor.

[0048] By fixing the volute 701 and the cover plate 702 through the connecting piece and axially fixing them through the positioning strip, it is helpful to disperse and bear the impact load, improve the overall structure, thereby reducing the risk of part loosening and possibly improving the stability and life of the hydraulic part 7 under impact work.

[0049] In some embodiments, the hydraulic component 7 further comprises a first sliding bearing 708 and a second sliding bearing 709, the turbine 706 is connected with the first sliding bearing 708 and the second sliding bearing 709, the first sliding bearing 708 is sleeved on one end of the turbine 706 close to the transmission shaft, and the second sliding bearing 709 is installed on the other side of the turbine 706 away from the transmission shaft, and the two are in close fit with the inner and outer rings of the turbine 706 respectively. This double-bearing support structure can effectively limit the radial runout of the turbine 706 during high-speed rotation, ensure that the turbine 706 always maintains coaxial with the inner wall of the volute 701, and avoid water loss and component wear caused by eccentric operation. At the same time, the sliding bearing is made of wear-resistant ceramic material, and its surface is treated with special lubrication, which can form a stable oil film in the mud medium, reduce the friction coefficient when the turbine 706 rotates, reduce energy loss, and further improve the transmission efficiency of the impactor. In addition, the interference fit design between the bearing and the turbine 706 can also enhance the integrity of the connection, so that the turbine 706 will not displace when subjected to axial impact force, thereby ensuring the stability and reliability of power transmission.

[0050] In some embodiments, the bottom of the hydraulic component 7 is provided with a replaceable anvil surface 712, which is used as a direct impact target surface of the weight 5 and transmits impact work to the coring drill 9.

[0051] It should be understood that the anvil surface 712 is a key interface for impact energy transmission, and its material selection and structural design directly affect the working efficiency and service life of the impactor. In actual application, due to the high-frequency impact of the weight 5 and the rigid contact with the coring drill 9, the anvil surface 712 will continuously bear a large impact force and friction force, and after long-term use, it is easy to have problems such as surface indentation, cracking or excessive wear. The replaceable anvil surface 712 can be quickly disassembled and replaced when it reaches the wear limit, without the need to disassemble the entire hydraulic component 7 or even the impactor main body, greatly shortening the maintenance time of the equipment and reducing the maintenance cost.

[0052] In some embodiments, the anvil surface 712 is a cemented carbide ring, the thickness of the anvil surface 712 is greater than or equal to 4 mm, and the anvil surface 712 is installed on the hydraulic component 7 through a threaded or clamping groove structure.

[0053] It should be understood that the hard alloy material itself has very high hardness and wear resistance, and its hardness is usually up to HRA85 or above, which can effectively resist the surface plastic deformation caused by the impact of the heavy hammer 5, and the thickness design of 4mm or above provides sufficient structural support for the transmission of impact energy, avoiding the bending or breaking of the anvil surface 712 during the impact process due to insufficient thickness. The installation is carried out by using a threaded or clamping groove structure, which not only can ensure the connection strength between the anvil surface 712 and the hydraulic component 7, prevent loosening or falling during the impact process, but also can realize quick disassembly and assembly - the threaded connection can be fixed and separated by rotating, and the clamping groove structure can be replaced by axial insertion and pulling, both of which do not need to rely on complex tools, further improving the convenience of maintenance operation. This design makes it possible for the operator to quickly complete the replacement operation on site when the anvil surface 712 is worn out, significantly reducing the downtime caused by equipment maintenance, and ensuring the continuity of drilling operations.

[0054] In some embodiments, the turbine 706 is arranged in the volute 701, and a fish mouth 707 is arranged in the volute 701, which is used to divide and guide the mud flow from the central passage of the mandrel 4 to the blades of the tangential impact turbine 706.

[0055] It should be understood that the fish mouth 707 can have a tapered streamline structure, the inlet end of which is communicated with the outlet of the central passage of the mandrel 4, and the internal flow channel gradually narrows from the inlet to the outlet, so that the mud flow entering the fish mouth 707 gradually accelerates during the flow process, forming a jet with high kinetic energy. At the same time, the outlet direction of the fish mouth 707 forms a certain angle with the tangent direction of the blade of the turbine 706, and this angle is accurately calculated to ensure that the accelerated mud flow impacts the blade of the turbine 706 at the best angle, and maximizes the conversion of the pressure energy and kinetic energy of the mud into the rotational mechanical energy of the turbine 706. Through this structural design, when the mud flows out of the central passage of the mandrel 4, it first enters the fish mouth 707, and the flow beam is converged and accelerated in the fish mouth 707, and then acts on the stress surface of the blade of the turbine 706 in a tangential impact manner, pushing the turbine 706 to rotate at high speed around its axis, providing a continuous and stable power source for the impact action of the hole bottom impactor. This energy conversion method has high efficiency, can effectively utilize the energy in the mud circulation system, reduce energy loss, and thus improve the working performance of the entire impactor and the drilling efficiency.

[0056] Specific working principle is: drilling mud from the upper joint 1 into, through the center channel of the mandrel 4, into the volute 701 of the hydraulic components 7. Fish mouth 707 will be divided into two parts along the tangential flow of turbine 706, the kinetic energy of the mud drive turbine 706 rotation. Turbine 706 through the spline belt drive cam group synchronous rotation. Cam group in the process of rotation, its profile crest will periodically lift the weight 5, the weight 5 to overcome the spring 3 of the elastic force upward movement, the process is energy storage phase.

[0057] When the cam group over the crest, the weight 5 in the spring 3 of the restoring force and its own gravity, the rapid downward reposition, and with a huge kinetic energy impact on the anvil surface 712, produce a high frequency of axial impact work. The impact work through the anvil surface 712 directly to the lower end of the core drill 9, acting on the drill bit and rock formation.

[0058] So the cycle, the cam group every rotation of a week, the weight 5 is completed once "down - reposition - impact" cycle, thus forming the frequency and mud pump volume is proportional to the stable impact.

[0059] In some embodiments, the upper end of the weight 5 and spring 3, the lower end of the weight 5 is the impact surface, the weight 5 of the mass is configured to produce enough impact kinetic energy to break the rock formation under the cooperation of the spring 3.

[0060] It should be understood that the mass parameter of the weight 5 is determined according to the design impact work of the impactor, the spring coefficient of the spring 3, and the desired impact frequency. During the operation of the impactor, when the turbine 706 drives the related transmission mechanism to convert the rotary mechanical energy into the upward movement of the weight 5, the weight 5 compresses the spring 3, and the spring 3 stores elastic potential energy. At this time, the greater the mass of the weight 5, the greater the gravitational potential energy it possesses at the same rising height, and the degree of compression of the spring 3 also increases accordingly, and the elastic potential energy stored also increases. When the transmission mechanism releases the constraint on the weight 5, the elastic potential energy of the spring 3 is quickly converted into the kinetic energy of the downward movement of the weight 5, and the gravitational potential energy of the weight 5 itself also acts together to make the weight 5 obtain a greater downward acceleration. Since the lower end surface of the weight 5 is the impact working surface, the huge kinetic energy carried by the weight 5 is instantly transmitted to the rock stratum at the moment of contact with the rock stratum. Through the rapid release of this energy, the rock stratum is effectively broken. In addition, the mass of the weight 5 and the spring 3 need to reach a dynamic balance. If the mass is too small, even if the elastic potential energy of the spring 3 is large, the impact kinetic energy may not be enough due to the insufficient inertia of the weight 5, and the hard rock stratum cannot be broken. If the mass is too large, a larger spring 3 force may be needed to drive, which not only increases the load of the transmission mechanism, but also may affect the impact frequency, thereby reducing the overall breaking efficiency. Therefore, accurately configuring the matching relationship between the mass of the weight 5 and the parameters of the spring 3 is a key design link to ensure that the impact working surface can stably generate impact kinetic energy sufficient to break rock strata of different hardness.

[0061] In some embodiments, the mud is a high solid phase mud with a sand content of ≤10%, the impactor generates an impact frequency in the range of 8-25 Hz, and the impact frequency is in a linear positive correlation with the pumping flow rate of the driving mud.

[0062] It should be understood that the sand content ≤ 10% defined herein is a parameter threshold determined by comprehensively considering the flow capacity of the internal flow passage of the impactor and the wear condition of the parts. If the sand content of the mud is too high and exceeds this limited value, the sand particles will exacerbate the abrasion of the driving parts such as the valve core, cylinder, etc. during high-speed flow, and long-term operation may cause the increase of the fitting clearance, causing leakage or power transmission efficiency to decrease. At the same time, too much sand particles deposited may block the mud channel, affecting the normal reversing and action continuity of the impactor. The impact frequency range is set to 8Hz to 25Hz, which is based on the dual consideration of the drilling efficiency of different rock layers and the structural strength of the impactor in actual engineering. 8Hz as the lower limit frequency can ensure the effective accumulation and release of impact energy when breaking soft rock layers, avoiding the waste of single impact kinetic energy or slow drilling speed due to too low frequency; 25Hz as the upper limit frequency ensures that the parts of the impactor will not be damaged due to excessive fatigue stress in high-frequency reciprocating motion on the basis of the existing material strength and transmission mechanism response speed, while also ensuring that the mud pumping system has enough time to complete the suction and discharge process to maintain stable power output. As for the linear positive correlation between impact frequency and mud pumping flow, its essence is that the reversing action of the impactor depends on the pushing of the mud. When the pumping flow increases, the volume of mud entering the impactor per unit time increases, the speed of the valve core reversing is accelerated, and the reciprocating motion period of the impact hammer is shortened, so the impact frequency is correspondingly increased; on the contrary, when the pumping flow decreases, the valve core reversing speed slows down, and the impact frequency decreases accordingly. This linear relationship makes it possible for the operator to accurately control the working frequency of the impactor by conveniently adjusting the output flow of the mud pump to adapt to the differentiated needs of impact energy and drilling speed under different geological conditions, and to improve the flexibility and controllability of the entire drilling operation.

[0063] In some embodiments, the overall outer diameter of the impactor ranges from 95mm to 190mm, suitable for drilling operations with a hole depth of 50m to 2000m, and the required mud pumping flow ranges from 120L / min to 800L / min.

[0064] It should be understood that the overall outer diameter range of the impactor, the applicable hole depth range, and the mud pumping flow range defined herein are not the only limitations of the technical solution, but are preferred implementation ranges based on the compatibility of current mainstream drilling equipment, the needs of common geological exploration scenarios, and the existing industrial manufacturing level. In actual application, the overall outer diameter, applicable hole depth, and mud pumping flow of the impactor can be adaptively adjusted by the technician according to specific drilling targets, formation conditions, drilling equipment models, and construction requirements, etc. For example, for some special shallow micro-drilling operations, the overall outer diameter of the impactor can be designed to be less than 95 mm, and the corresponding mud pumping flow can also be reduced to below 120 liters per minute; while for resource exploration or special engineering construction of ultra-deep holes, the overall outer diameter of the impactor can also be appropriately increased to more than 190 mm under the premise that the material strength, durability of the transmission mechanism, and the capacity of the mud pumping system allow, and the applicable hole depth breaks through 2000 meters, and the mud pumping flow can also be increased to more than 800 liters per minute according to the power requirement and the frequency requirement of the impactor. Such parameter adjustment based on the core technical principle is within the protection scope of the present application, and aims to fully exert the performance advantages of the mud-driven bottom impactor by flexibly adapting to different application scenarios.

[0065] Example 1

[0066] A field test was conducted in a certain bedrock marker well, with a drilling depth of 950 meters and a drilled formation of hard pebble gravel. The drilling parameters used were: pump volume 350 L / min, pump pressure 2.5 MPa.

[0067] The impactor used had the following specifications: outer diameter 120 mm, length 2 m, weight 5 mass 50 kg, cam lift 14 mm, spring 3 stiffness 28 N / mm.

[0068] The mud used had the following properties: density 1.18 g / cm 3 , sand content 4.2%, and no desander or other solid control equipment was used throughout the process.

[0069] Test results: The average mechanical drilling speed reached 1.9 m / h, which was 78% higher than that of the adjacent drilling hole using pure rotary drilling method. The core recovery rate reached 93%.

[0070] From the above technical scheme, the embodiment of the present application provides a mud-driven hole bottom impactor, which comprises: an upper joint 1; an outer pipe 6, the upper end of the outer pipe 6 is connected with the upper joint 1, and the inside of the outer pipe 6 forms a closed lubricating oil cavity 8; a mandrel 4, the mandrel 4 is coaxially arranged in the inside of the outer pipe 6, and the center of the mandrel 4 is provided with a penetrating mud channel; the upper end of the mandrel 4 is connected with the upper joint 1; a hydraulic component 7, the hydraulic component 7 is connected with the lower end of the outer pipe 6; the lower end of the mandrel 4 is connected with the hydraulic component 7; a heavy hammer 5, the heavy hammer 5 is sleeved on the outside of the mandrel 4 and axially slides relative to the mandrel 4; a spring 3, the spring 3 is arranged above the heavy hammer 5 and is used for providing the heavy hammer 5 with a reset elastic force; a sealing ring 2, the sealing ring 2 is arranged in the annular gap between the mandrel 4 and the outer pipe 6 and is used for sealing the lubricating oil cavity 8 and isolating the lubricating oil from the external mud; a coring drilling tool 9, the coring drilling tool 9 is connected with the lower end of the hydraulic component 7; wherein, the inside of the hydraulic component 7 is provided with an energy conversion mechanism, the energy conversion mechanism comprises a turbine 706 and a cam set, the turbine 706 is used for driving the cam set to convert the rotary motion of the turbine 706 into the axial impact motion of the heavy hammer 5 through the cam set, and the problem that the hole bottom impactor is dependent on low solid phase mud is solved.

[0071] The similar parts between the embodiments provided by the present application can be referred to each other, the specific embodiments provided above are only several examples under the general concept of the present application and do not constitute the limitation of the protection scope of the present application. For the person skilled in the art, any other embodiments expanded on the basis of the present application scheme without creative labor belong to the protection scope of the present application.

Claims

1. A mud-driven downhole hammer, characterized by, The utility model relates to a core drill tool, which comprises: an upper joint (1); an outer tube (6) having an upper end connected to the upper joint (1) and an inner part forming a closed lubricating oil cavity (8); a mandrel (4) coaxially arranged inside the outer tube (6) and having a mud passage passing through the center thereof, the upper end of the mandrel (4) being connected to the upper joint (1); a hydraulic component (7) connected to the lower end of the outer tube (6), the lower end of the mandrel (4) being connected to the hydraulic component (7); a heavy hammer (5) sleeved on the outer side of the mandrel (4) and axially sliding relative to the mandrel (4); a spring (3) arranged above the heavy hammer (5) and providing a reset elastic force for the heavy hammer (5); a sealing ring (2) arranged in the annular gap between the mandrel (4) and the outer tube (6) and used for sealing the lubricating oil cavity (8) and isolating lubricating oil from external mud; a core drill tool (9) connected to the lower end of the hydraulic component (7); wherein the hydraulic component (7) is internally provided with an energy conversion mechanism, the energy conversion mechanism comprising a turbine (706) and a cam set, the turbine (706) being used to drive the cam set to convert the rotary motion of the turbine (706) into the axial impact motion of the heavy hammer (5) through the cam set.

2. The mud-driven pore-impinger of claim 1, wherein, The cam set comprises a first cam (704) and a second cam (705), the first cam (704) and the second cam (705) being mutually symmetrical; the first cam (704) and the second cam (705) are connected with the turbine (706) through a spline structure to realize synchronous rotation.

3. The mud-driven pore-densifier of claim 1, wherein, The hydraulic component (7) further comprises a sliding guide rail (703); the sliding guide rail (703) is fixed inside the hydraulic component (7) and is used for restricting the heavy hammer (5) to slide only in the axial direction of the mandrel (4).

4. The mud-driven pore-impinger of claim 3, wherein, The hydraulic component further comprises a volute (701) and a cover plate (702); the volute (701) and the cover plate (702) are fixedly connected through a connecting piece, the sliding guide rail (703) is arranged on the volute (701) or the cover plate (702), and the hydraulic component (7) is further provided with a first positioning strip (710) and a second positioning strip (711) for axially fixing the volute (701) and the cover plate (702) to jointly bear impact load.

5. The mud-driven pore-densifier of claim 1, wherein, The bottom of the hydraulic component (7) is provided with a replaceable anvil surface (712) used as a direct impact target surface of the heavy hammer (5) and for transmitting impact work to the core drill tool (9).

6. The mud-driven pore-impinger of claim 5, wherein, The anvil surface (712) is a hard alloy ring, the thickness of the anvil surface (712) is greater than or equal to 4 mm, and the anvil surface (712) is mounted on the hydraulic component (7) through a thread or a clamping groove structure.

7. The mud-driven pore-impinger of claim 4, wherein, The turbine (706) is arranged in the volute (701), and a fish mouth (707) is arranged in the volute (701) to divide and guide the mud flow from the central passage of the core shaft (4) to impact the blades of the turbine (706) tangentially.

8. The mud-driven pore-densifier of claim 1, wherein, The upper end surface of the weight (5) is in contact with the spring (3), and the lower end surface of the weight (5) is an impact working surface. The mass of the weight (5) is configured to generate impact kinetic energy sufficient to break the rock stratum under the cooperation of the spring (3).

9. The mud-driven pore-impinger of claim 7, wherein, The mud is high solid phase mud with sand content ≤10%, the impact frequency generated by the impactor ranges from 8 Hz to 25 Hz, and the impact frequency is in a linear positive correlation with the pumping flow rate of the mud.

10. The mud-driven pore-impinger of claim 9, wherein, The overall outer diameter of the impactor ranges from 95 mm to 190 mm, which is suitable for drilling operations with a hole depth of 50 m to 2000 m, and the required mud pumping flow rate ranges from 120 L / min to 800 L / min.

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