A wireline drill pipe with a multi-section thread fitting structure

Abstract

The present invention provides a through-cable drill pipe with a multi-segment thread fitting structure. The through-cable drill pipe includes a plurality of drill pipe short joints connected in sequence. The drill pipe short joint includes a female connector, a drill pipe body, and a male connector fixedly connected in sequence from back to front. Multiple segments of internal threads are provided on the inner wall of the female connector, and multiple segments of external threads are provided on the outer wall of the male connector. Adjacent drill pipe short joints are connected by the cooperation of the multiple segments of internal threads of the female connector and the multiple segments of external threads of the male connector. The through-cable drill pipe with a multi-segment thread fitting structure of the present invention can prevent the drill dropping accident caused by the fracture of the female connector by integrally designing the load-bearing thread and the anti-dropping thread in the female connector and on the male connector. By arranging a T-shaped connecting rod in the male connector, the drill dropping accident caused by the fracture of the male connector can be prevented.

Description

Technical Field

[0001] The present invention belongs to the technical field of underground coal mine drilling tools, relates to a through-wire drill pipe, and specifically relates to a through-wire drill pipe with a multi-segment thread matching structure. Background Technique

[0002] Coal is the main energy source and important chemical raw material in China, supporting the rapid and stable development of China's national economy. The energy resource endowment conditions of "rich in coal, poor in oil, and less in gas" determine that coal will still be the safety cornerstone of China's energy in a relatively long time in the future. As an advanced underground coal mine roadway drilling technology, the measurement-while-drilling (MWD) directional drilling technology has become the most direct and effective technical means in aspects such as mine disaster prevention and control, exploration of hidden disaster-causing geological factors, and coalbed methane resource development.

[0003] The stability and reliability of the MWD drilling tool are the basic guarantees for the smooth implementation of the MWD directional drilling technology. Among them, the through-wire drill pipe is an important part of the MWD drilling tool, and the through-wire drill pipe is used to connect high-precision measuring instruments, non-magnetic drill tools or downhole motor drill tools. Compared with conventional drill pipes and conventional borehole construction, the MWD drilling tool has a higher value, and the cost of the directional boreholes constructed is greater and the cycle is longer. If the through-wire drill pipe breaks during the drilling process, causing the through-wire drill pipe, measuring instrument and downhole motor below the break point to fall into the hole, it will cause significant economic losses and adverse effects.

[0004] However, for the through-wire drill pipes commonly used in the current market, both the male connector and the female connector adopt a single-segment thread connection method. During the drilling process, since the thread engagement body formed by the male connector and the female connector bears both torque and various alternating loads such as tension and bending moment, the roots of the threads of the male connector and the female connector are prone to fatigue fracture, and thus the drill dropping accidents occur frequently. Therefore, how to solve the drill dropping accidents caused by the thread fracture of the male connector and the female connector of the through-wire drill pipe has become the key to the safe and efficient construction of directional boreholes.

[0005] The Chinese patent with the authorization announcement number CN112227975B, by arranging a rib rod with external straight threads at one end in the through hole of the male or female connector of the drill pipe, and arranging internal straight threads in the through hole of the male or female connector, when adjacent drill pipes are screwed together, a bone connection where the threads of the male or female connector are screwed together with each other, and a rib connection where the threads of the rib rod are screwed together with each other are formed, realizing the effective connection of the rib rod thread connection pair after the fracture of the male or female connector. However, in the actual application process, the drill pipe in this invention has the following defects:

[0006] First, both the rib rod and the male connector or the female connector are independent workpieces, and they are fixed together by assembly and then welding. As a result, it is difficult to control the coaxiality between the rib rod and the male connector or between the rib rod and the female connector, which affects the synchronization between the bone connection thread and the rib connection thread. During the process of adding and unscrewing the drill pipe, there is interference between the bone connection thread and the rib connection thread, causing the rib connection thread to bear load and deform.

[0007] Second, to ensure the coaxiality between the external straight thread of the rib rod and the taper thread of the male connector or the female connector, it is necessary to use a high-precision lathe to machine the external straight thread of the rib rod and the taper thread of the male connector or the female connector. In addition, after assembling the rib rod to the male connector or the female connector, it is also necessary to fix the rib rod by electric welding, which increases the production process and is not conducive to mass production.

[0008] Third, since the external straight thread of the rib rod and the taper thread of the male connector or the female connector are not machined on the same body, in order to solve the thread interference existing in the cooperation between the taper threads of the male connector and the female connector and the cooperation between the external straight thread of the rib rod, the internal straight thread of the male connector or the internal straight thread of the female connector during the process of adding or unscrewing the drill pipe, it is required that the cooperation between the external straight thread of the rib rod and the internal straight thread of the male connector or the internal straight thread of the female connector precedes the cooperation between the taper threads of the male connector and the female connector, resulting in the rib rod protruding from the male connector or the female connector by a relatively long distance. During the handling or drilling process, the rib rod will inevitably be knocked and loosened or deformed, reducing the effectiveness of the rib rod thread connection and even causing the entire drill pipe to be scrapped.

[0009] Fourth, since the cooperation between the external straight thread of the rib rod and the internal straight thread of the male connector or the female connector precedes the cooperation between the taper threads of the female connector and the male connector, in order to solve the contact wear between the threads during the unscrewing process of the external straight thread of the rib rod and the internal straight thread of the male connector or the female connector, it is necessary to perform surface hardening treatment on the rib rod to improve its wear resistance, resulting in an increase in material cost.

[0010] Fifth, since the rib rod and the male connector or the female connector are not machined on the same body, and the rib rod needs to be assembled through the central through hole of the male connector or the female connector, considering the tensile strength of the female connector, the male connector and the rib rod comprehensively, the central hole diameter of the rib rod is relatively small, and a central cable-passing device cannot be installed inside it, so a cable-passing drill pipe cannot be formed. Summary of the Invention

[0011] Aiming at the defects and deficiencies existing in the prior art, the purpose of the present invention is to provide a cable-passing drill pipe with a multi-stage thread matching structure to solve the technical problem that the falling drill accident is likely to occur due to the fracture of the male connector and the female connector of the cable-passing drill pipe in the prior art.

[0012] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve:

[0013] A cable - passing drill pipe with a multi - section thread - fitting structure, the cable - passing drill pipe includes a plurality of drill pipe short sections connected in sequence. The drill pipe short section includes a female joint, a drill pipe body, and a male joint fixedly connected in sequence from back to front; multiple sections of internal threads are arranged on the inner wall of the female joint, and multiple sections of external threads are arranged on the outer wall of the male joint. Adjacent drill pipe short sections are connected by the cooperation of the multiple sections of internal threads of the female joint and the multiple sections of external threads of the male joint.

[0014] A T - shaped connecting rod is coaxially arranged inside the male joint, and both ends of the T - shaped connecting rod are located inside the male joint; the female joint, the drill pipe body, the male joint, and both ends of the T - shaped connecting rod are open, and the spaces inside the female joint, the drill pipe body, the male joint, and the T - shaped connecting rod are central cable - passing component installation cavities. A central cable - passing component is arranged inside the central cable - passing component installation cavity. The rear end of the central cable - passing component is arranged inside the female joint, and the front end of the central cable - passing component is arranged inside the T - shaped connecting rod.

[0015] The present invention also has the following technical features:

[0016] Specifically, the female joint includes a female joint main body fixedly connected to the drill pipe body. The space inside the female joint main body is, from front to back, a first transition cavity, a male joint installation section installation cavity, a male joint anti - dropping section setting cavity, a female joint anti - dropping retraction tool cavity, a second transition cavity, a third transition cavity, and a fourth transition cavity in sequence; the male joint is arranged inside the first transition cavity, the male joint installation section installation cavity, the male joint anti - dropping section setting cavity, and the female joint anti - dropping retraction tool cavity.

[0017] Female joint bearing internal threads and female joint anti - dropping internal threads are arranged on the inner wall of the female joint main body. The female joint bearing internal threads are located inside the male joint installation section installation cavity, and the female joint anti - dropping internal threads are located inside the male joint anti - dropping section setting cavity.

[0018] The male joint includes a male joint main body fixedly connected to the drill pipe body. A first shoulder and a second shoulder are arranged on the outer wall of the male joint main body from back to front. The first shoulder and the second shoulder divide the male joint main body into three sections, which are, from back to front, a drill pipe body connection section, a male joint installation section, and a male joint anti - dropping section in sequence.

[0019] Male joint bearing external threads are arranged on the outer wall of the male joint installation section. The rear end of the male joint bearing external threads is flush with the first shoulder, and the front end of the male joint bearing external threads is close to the second shoulder; male joint anti - dropping external threads are arranged on the outer wall of the male joint anti - dropping section. The rear end of the male joint anti - dropping external threads is close to the second shoulder, and the front end of the male joint anti - dropping external threads is flush with the front end of the male joint main body; the groove between the second shoulder and the male joint anti - dropping external threads is a male joint anti - dropping retraction groove.

[0020] The described male joint installation section is fixedly installed in the installation cavity of the male joint installation section through the mutual cooperation of the external thread carried by the male joint and the internal thread carried by the female joint; the male joint anti-falling section is located in the male joint anti-falling section setting cavity and the female joint anti-falling retracting cavity, and there is a clearance fit between the male joint anti-falling retracting groove and the female joint anti-falling internal thread, and there is a clearance fit between the male joint anti-falling external thread and the inner wall of the female joint at the female joint anti-falling retracting cavity.

[0021] Specifically, the inner wall of the female joint body is provided with a first step, a second step, a third step, a fourth step, a fifth step, and a sixth step from back to front.

[0022] The first step and the second step are respectively located at the axial two ends of the installation cavity of the male joint installation section, the third step and the fourth step are respectively located at the axial two ends of the male joint anti-falling section setting cavity, the fifth step is located at the front end of the axial direction of the female joint anti-falling retracting cavity, and the sixth step is located at the front end of the axial direction of the second transition cavity.

[0023] The rear end of the drill pipe body connection section extends out of the female joint body, and the front end face of the drill pipe body connection section abuts against the rear end face of the female joint body; the front end face of the male joint installation section abuts against the second step.

[0024] Specifically, the space of the male joint body is successively the first male joint inner cavity, the second male joint inner cavity, the third male joint inner cavity, the fourth male joint inner cavity, and the fifth male joint inner cavity from front to back; the T-shaped connecting rods are arranged in the second male joint inner cavity, the third male joint inner cavity, and the fourth male joint inner cavity.

[0025] The inner wall of the male joint body is provided with a male joint anti-falling internal thread, and the male joint anti-falling internal thread is located in the fifth male joint inner cavity; a hole-type elastic retaining ring installation groove is arranged in the second male joint inner cavity, and a hole-type elastic retaining ring is installed in the hole-type elastic retaining ring installation groove.

[0026] Specifically, the T-shaped connecting rod includes a T-shaped connecting rod main body arranged in the male joint. A T-shaped connecting rod shoulder is arranged on the outer wall of the T-shaped connecting rod main body. The T-shaped connecting rod shoulder divides the T-shaped connecting rod main body into two sections, which are successively the T-shaped connecting rod large end section and the T-shaped connecting rod small end section from front to back; a T-shaped connecting rod external thread is arranged on the outer wall of the front part of the T-shaped connecting rod small end section;

[0027] The T-shaped connecting rod large end section is located in the second male joint inner cavity, and the rear end of the T-shaped connecting rod large end section is close to the hole-type elastic retaining ring; the T-shaped connecting rod small end section penetrates through the third male joint inner cavity and is fixedly installed in the fourth male joint inner cavity through the T-shaped connecting rod external thread and the male joint anti-falling internal thread.

[0028] Specifically, the space inside the T-shaped connecting rod body is successively a small inner cavity of the T-shaped connecting rod and a large inner cavity of the T-shaped connecting rod from back to front. A T-shaped connecting rod step is arranged on the inner wall of the T-shaped connecting rod body, and the T-shaped connecting rod step is located at the axial rear end of the large inner cavity of the T-shaped connecting rod.

[0029] Specifically, the central cable-passing assembly includes an insulating male connector installed in the female connector. A rear conductive connector is installed inside the rear part of the insulating male connector. A central cable-passing rear installation cavity is opened at the front end of the rear conductive connector, and a conductive spring rear installation cavity is opened at the rear end of the rear conductive connector.

[0030] The central cable-passing assembly further includes an insulating female connector installed in the T-shaped connecting rod. A front conductive connector is installed inside the front part of the insulating female connector. A conductive spring front installation cavity is opened at the front end of the front conductive connector, and a central cable-passing front installation cavity is opened at the rear end of the front conductive connector.

[0031] The rear end of the central cable-passing is arranged in the central cable-passing rear installation cavity. The front end of the central cable-passing penetrates through the drill pipe body and is installed in the central cable-passing front installation cavity. The rear part of the conductive spring is installed in the conductive spring front installation cavity, and the front part of the conductive spring extends into the conductive spring rear installation cavity of the adjacent short drill pipe section.

[0032] Specifically, the rear end of an insulating wire pipe is installed inside the front part of the insulating male connector. The front end of the insulating wire pipe penetrates through the drill pipe body and is installed inside the rear part of the insulating female connector. The insulating wire pipe is coaxially arranged outside the central cable-passing. A stabilizer is coaxially arranged outside the insulating wire pipe, and the stabilizer is installed in the drill pipe body.

[0033] Specifically, a rear positioning retaining ring is fixedly arranged in the third transition cavity. The rear end of the insulating male connector is located in the installation cavity of the male connector installation section, and the front end of the insulating male connector passes through the rear positioning retaining ring and is fixed in the female connector.

[0034] A front positioning retaining ring is fixedly arranged at the T-shaped connecting rod step. The rear end of the insulating female connector extends out of the T-shaped connecting rod and extends into the inner cavity of the second male connector. The front part of the insulating female connector passes through the front positioning retaining ring and is fixed in the T-shaped connecting rod, and the front end of the insulating female connector extends into the inner cavity of the fifth male connector.

[0035] Specifically, sealing rings are arranged between the insulating wire pipe and the insulating male connector, between the insulating wire pipe and the insulating female connector, between the rear conductive connector and the insulating female connector, and between the front conductive connector and the insulating male connector.

[0036] Compared with the prior art, the present invention has the following beneficial technical effects:

[0037] (Ⅰ) The through-wire drill pipe with a multi-segment thread fitting structure of the present invention, during the drilling construction process, if the load-bearing internal thread of the female joint breaks, through the cooperation structure of the anti-drop cutter groove of the male joint, the anti-drop internal thread of the female joint, the anti-drop external thread of the male joint and the inner wall of the female joint, it can still ensure the effective connection in the axial direction between the male joint and the female joint, so that all the drill tools deeper than the break point can be lifted out.

[0038] During the drilling construction process, if the load-bearing external thread of the male joint near the rear end breaks, the part of the external thread deeper than the break point of the load-bearing external thread of the male joint can still mesh with the load-bearing internal thread of the female joint to form a connection body, and the T-shaped connecting rod can still ensure the effective connection in the axial direction between the part shallower than the break point of the male joint and the above connection body, so that all the drill tools deeper than the break point can be lifted out.

[0039] Based on the above analysis, it can be seen that for the through-wire drill pipe with a multi-segment thread fitting structure of the present invention, by integrally designing the load-bearing thread and the anti-drop thread on the female joint and the male joint, it can prevent the drill dropping accident caused by the breakage of the female joint; by setting a T-shaped connecting rod in the male joint, it can prevent the drill dropping accident caused by the breakage of the male joint.

[0040] (Ⅱ) The through-wire drill pipe with a multi-segment thread fitting structure of the present invention, in which the T-shaped connecting rod, the anti-drop external thread of the male joint and the anti-drop internal thread of the female joint are not stressed during the drilling process, and only after the load-bearing external thread of the male joint and the load-bearing internal thread of the female joint break, the anti-drop external thread of the male joint and the anti-drop internal thread of the female joint can play a role, ensuring the reliability of the anti-drop function.

[0041] (Ⅲ) The through-wire drill pipe with a multi-segment thread fitting structure of the present invention, the drill pipe short section of the through-wire drill pipe is connected through the cooperation of the multi-segment internal thread of the female joint and the multi-segment external thread of the male joint, which can prevent the occurrence of drill dropping accidents. A central through-wire component is arranged inside the through-wire drill pipe, enabling the through-wire drill pipe to have functions such as transmitting signals and conducting electric current. That is, while meeting the construction requirements of measurement-while-drilling directional drilling, the construction safety is also improved.

[0042] (Ⅳ) The through-wire drill pipe with a multi-segment thread fitting structure of the present invention, the load-bearing external thread of the male joint of adjacent drill pipe short sections cooperates with the load-bearing internal thread of the female joint, and during the drilling construction process, jointly bears loads such as torque, pulling out, feeding, and bending moment output by the drill rig, and can ensure that the drill rig realizes functions such as drilling, pulling out the drill, and lowering the drill. Brief Description of the Drawings

[0043] Figure 1 It is a schematic diagram of the overall structure of the through-wire drill pipe with a multi-segment thread fitting structure.

[0044] Figure 2 It is a schematic diagram of the structure of the female joint.

[0045] Figure 3 It is a structural schematic diagram of the male connector.

[0046] Figure 4 It is an assembly schematic diagram of the female connector and the male connector.

[0047] Figure 5 It is a schematic diagram of the design parameters of the female connector and the male connector.

[0048] Figure 6 It is a structural schematic diagram of the T-shaped connecting rod.

[0049] Figure 7 It is an assembly schematic diagram of the male connector and the T-shaped connecting rod.

[0050] Figure 8 It is a connection schematic diagram of the female connector and the male connector when the external thread of the male connector bearing breaks.

[0051] Figure 9 It is a connection schematic diagram of the female connector and the male connector when the external thread of the female connector bearing breaks.

[0052] Figure 10 It is an assembly schematic diagram of adjacent drill pipe short joints.

[0053] The meanings of each label in the figure are as follows: 1 - female connector, 2 - drill pipe body, 3 - male connector, 4 - T-shaped connecting rod, 5 - installation cavity for the central cable-passing component, 6 - central cable-passing component, 7 - circlip for hole, 8 - rear positioning retaining ring, 9 - front positioning retaining ring, 10 - stabilizer, 11 - sealing ring;

[0054] 101 - female connector body, 102 - first transition cavity, 103 - installation cavity for the male connector installation section, 104 - cavity for setting the anti-drop section of the male connector, 105 - anti-drop retraction groove of the female connector, 106 - second transition cavity, 107 - third transition cavity, 108 - fourth transition cavity, 109 - internal thread for the female connector bearing, 110 - anti-drop internal thread of the female connector, 111 - first step, 112 - second step, 113 - third step, 114 - fourth step, 115 - fifth step, 116 - sixth step;

[0055] 301 - male connector body, 302 - first shoulder, 303 - second shoulder, 304 - external thread for the male connector bearing, 305 - anti-drop external thread of the male connector, 306 - anti-drop retraction groove of the male connector, 307 - first internal cavity of the male connector, 308 - second internal cavity of the male connector, 309 - third internal cavity of the male connector, 310 - fourth internal cavity of the male connector, 311 - fifth internal cavity of the male connector, 312 - anti-drop internal thread of the male connector, 313 - installation groove for the circlip for hole;

[0056] 401 - T - shaped connecting rod body, 402 - T - shaped connecting rod shoulder, 403 - T - shaped connecting rod through - hole, 404 - T - shaped connecting rod external thread, 405 - T - shaped connecting rod small inner cavity, 406 - T - shaped connecting rod large inner cavity, 407 - T - shaped connecting rod step;

[0057] 601 - Insulated male connector, 602 - Insulated female connector, 603 - Rear conductive connector, 604 - Front conductive connector, 605 - Central cable - passing, 606 - Conductive spring, 607 - Insulated wire tube;

[0058] 30101 - Drill pipe rod body connection section, 30102 - Male connector installation section, 30103 - Male connector anti - dropping section;

[0059] 40101 - T - shaped connecting rod large - end section, 40102 - T - shaped connecting rod small - end section;

[0060] 60301 - Central cable - passing rear installation cavity, 60302 - Conductive spring rear installation cavity;

[0061] 60401 - Conductive spring front installation cavity, 60402 - Central cable - passing front installation cavity.

[0062] The technical solution of the present invention will be further described below in conjunction with embodiments. Specific embodiments

[0063] In the present invention, the multi - segment thread - fitting structure is specifically as follows:

[0064] The male connector load - bearing external thread 304 and the female connector load - bearing internal thread 109 are mutually fitted and connected. There is a clearance between the male connector anti - dropping relief groove 306 and the female connector anti - dropping internal thread 110, and there is a clearance between the male connector anti - dropping external thread 305 and the inner wall of the female connector 1 at the female connector anti - dropping relief cavity 105.

[0065] It should be noted that all the components used in the present invention, without special instructions, are components known in the art.

[0066] Complying with the above - mentioned technical solution, the following specific embodiments of the present invention are given. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent transformations made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0067] Embodiment:

[0068] This embodiment provides a cable - passing drill pipe with a multi - segment thread - fitting structure, as Figure 1 shown, including a plurality of drill pipe short joints connected in sequence. The drill pipe short joint includes a female connector 1, a drill pipe rod body 2, and a male connector 3 fixedly connected in sequence from the rear to the front; adjacent drill pipe short joints are connected through the mutual cooperation of the female connector 1 and the male connector 3.

[0069] A T-shaped connecting rod 4 is coaxially arranged inside the male connector 3, and both ends of the T-shaped connecting rod 4 are located inside the male connector 3; both ends of the female connector 1, the drill pipe body 2, the male connector 3, and the T-shaped connecting rod 4 are open, and the spaces inside the female connector 1, the drill pipe body 2, the male connector 3, and the T-shaped connecting rod 4 are the central cable assembly installation cavities 5, and a central cable assembly 6 is arranged inside the central cable assembly installation cavity 5. The rear end of the central cable assembly 6 is arranged inside the female connector 1, and the front end of the central cable assembly 6 is arranged inside the T-shaped connecting rod 4.

[0070] In this embodiment, the front end face of the female connector 1 and the rear end face of the drill pipe body 2 are fixedly connected by welding, and the rear end face of the male connector 3 and the front end face of the drill pipe body 2 are fixedly connected by welding.

[0071] In this embodiment, the outer wall of the drill pipe body 2 is processed with a structure of a compound of spiral grooves and edges to enhance the hole-forming ability of the drill pipe.

[0072] As a specific solution of this embodiment, as Figure 2 shown, the female connector 1 includes a female connector main body 101 fixedly connected to the drill pipe body 2. The spaces inside the female connector main body 101 are, from front to back, a first transition cavity 102, a male connector installation section installation cavity 103, a male connector anti-falling section setting cavity 104, a female connector anti-falling and retracting tool cavity 105, a second transition cavity 106, a third transition cavity 107, and a fourth transition cavity 108; the male connector 3 is arranged inside the first transition cavity 102, the male connector installation section installation cavity 103, the male connector anti-falling section setting cavity 104, and the female connector anti-falling and retracting tool cavity 105.

[0073] Female connector bearing internal threads 109 and female connector anti-falling internal threads 110 are arranged on the inner wall of the female connector main body 101. The female connector bearing internal threads 109 are located inside the male connector installation section installation cavity 103, and the female connector anti-falling internal threads 110 are located inside the male connector anti-falling section setting cavity 104.

[0074] As Figure 3 shown, the male connector 3 includes a male connector main body 301 fixedly connected to the drill pipe body 2. A first shoulder 302 and a second shoulder 303 are arranged on the outer wall of the male connector main body 301 from back to front. The first shoulder 302 and the second shoulder 303 divide the male connector main body 301 into three sections, which are, from back to front, a drill pipe body connection section 30101, a male connector installation section 30102, and a male connector anti-falling section 30103.

[0075] On the outer wall of the male joint installation section 30102, there is a male joint bearing external thread 304. The rear end of the male joint bearing external thread 304 is flush with the first shoulder 302, and the front end of the male joint bearing external thread 304 is close to the second shoulder 303. On the outer wall of the male joint anti-falling section 30103, there is a male joint anti-falling external thread 305. The rear end of the male joint anti-falling external thread 305 is close to the second shoulder 303, and the front end of the male joint anti-falling external thread 305 is flush with the front end of the male joint body 301. The groove between the second shoulder 303 and the male joint anti-falling external thread 305 is the male joint anti-falling relief groove 306.

[0076] As Figure 4 shown, the male joint installation section 30102 is connected through the mutual cooperation of the male joint bearing external thread 304 and the female joint bearing internal thread 109 and is fixedly installed in the male joint installation section installation cavity 103. The male joint anti-falling section 30103 is located in the male joint anti-falling section setting cavity 104 and the female joint anti-falling relief cavity 105. There is a clearance fit between the male joint anti-falling relief groove 306 and the female joint anti-falling internal thread 110, and there is a clearance fit between the male joint anti-falling external thread 305 and the inner wall of the female joint 1 at the female joint anti-falling relief cavity 105.

[0077] In this embodiment, the thread profiles of the female joint bearing internal thread 109 and the female joint anti-falling internal thread 110 are the same and are synchronous threads, which are machined in one clamping by a lathe to ensure the coaxiality of the female joint bearing internal thread 109 and the female joint anti-falling internal thread 110. The thread profiles of the male joint bearing external thread 304 and the male joint anti-falling external thread 305 are the same and are synchronous threads, which are machined in one clamping by a lathe to ensure the coaxiality of the male joint bearing external thread 304 and the male joint anti-falling external thread 305.

[0078] In this embodiment, the specific process of machining the two external threads of the male joint 3 on the same body is as follows: First, machine the contour structures of the male joint anti-falling external thread 305, the male joint anti-falling relief groove 306, and the male joint bearing external thread 304. Then, select a thread cutting tool that meets the design requirements, write a program to make the starting points of the male joint bearing external thread 304 and the male joint anti-falling external thread 305 the same during machining, and then use the same tool to machine the male joint bearing external thread 304 and the male joint anti-falling external thread 305 in sequence, so as to ensure the synchronization of the two external threads. The process of machining the two internal threads of the female joint 1 on the same body as the two external threads of the male joint 3 is basically the same.

[0079] In this embodiment, since the two sections of internal threads of the female joint 1 and the two sections of external threads of the male joint 3 are machined integrally, that is, the coaxiality of the external thread 304 for load bearing of the male joint and the anti-dropping external thread 305 of the male joint is the same, and the coaxiality of the internal thread 109 for load bearing of the female joint and the anti-dropping internal thread 110 of the female joint is the same. Therefore, the coaxiality of the anti-dropping external thread 305 of the male joint and the anti-dropping internal thread 110 of the female joint during the assembly process can be ensured. And due to the integral design, the anti-dropping external thread 305 of the male joint and the anti-dropping internal thread 110 of the female joint come into contact before the anti-dropping external thread 305 of the male joint and the anti-dropping internal thread 110 of the female joint, which can effectively reduce the total length of the male joint 3.

[0080] In this embodiment, the length of the anti-dropping relief groove 306 of the male joint is greater than the length of the anti-dropping internal thread 110 of the female joint. After the female joint 1 and the male joint 3 are screwed together, the anti-dropping internal thread 110 of the female joint is located within the anti-dropping relief groove 306 of the male joint, thereby ensuring that the anti-dropping internal thread 110 of the female joint is not stressed during the drilling process.

[0081] In this embodiment, as Figure 5 shown, when the major diameter of the external thread 304 for load bearing of the male joint is initially in contact with the minor diameter of the internal thread 109 for load bearing of the female joint, the distance between the first shoulder 302 and the rear end face of the female joint 1 is denoted as L1, and the total length of the anti-dropping external thread 305 of the male joint and the anti-dropping relief groove 306 of the male joint is denoted as L2, and L2 is less than L1. This design method enables the external thread 304 for load bearing of the male joint and the internal thread 109 for load bearing of the female joint to come into contact first during the mating process of the female joint 1 and the male joint 3, and the anti-dropping external thread 305 of the male joint and the anti-dropping internal thread 110 of the female joint to come into contact later. Thus, during the mating process of the anti-dropping external thread 305 of the male joint and the anti-dropping internal thread 110 of the female joint, they can be straightened by the mating body of the external thread 304 for load bearing of the male joint and the internal thread 109 for load bearing of the female joint.

[0082] In this embodiment, when designing the two sections of internal threads of the female joint 1 and the two sections of external threads of the male joint 3, the rated pulling force of the drilling rig, the assembly of the cable-connected drill pipe, and the required hole diameter for water passing under a certain safety factor are comprehensively considered, and an appropriate thread profile, especially the pitch, is designed. The specific design principle is: the shear resistance of the single-pitch thread teeth of the anti-dropping external thread 305 of the male joint and the internal thread 109 for load bearing of the female joint must exceed the rated pulling force of the drilling rig under a certain safety factor; the tensile capacity at the anti-dropping relief groove 306 of the male joint must exceed the rated pulling force of the drilling rig under a certain safety factor.

[0083] As a specific solution of this embodiment, as Figure 2 shown, on the inner wall of the female joint body 101, a first step 111, a second step 112, a third step 113, a fourth step 114, a fifth step 115, and a sixth step 116 are provided from the rear to the front;

[0084] The first step 111 and the second step 112 are respectively located at the axial two ends of the installation cavity 103 of the male connector installation section. The third step 113 and the fourth step 114 are respectively located at the axial two ends of the anti-falling section setting cavity 104 of the male connector. The fifth step 115 is located at the front end of the anti-falling and retracting cavity 105 of the female connector. The sixth step 116 is located at the front end of the second transition cavity 106.

[0085] The rear end of the drill pipe body connection section 30101 extends out of the female connector main body 101, and the front end face of the drill pipe body connection section 30101 abuts against the rear end face of the female connector main body 101. The front end face of the male connector installation section 30102 abuts against the second step 112.

[0086] As a specific solution of this embodiment, as Figure 3 shown, the space of the male connector main body 301 from front to back is successively the first male connector inner cavity 307, the second male connector inner cavity 308, the third male connector inner cavity 309, the fourth male connector inner cavity 310 and the fifth male connector inner cavity 311. The T-shaped connecting rod 4 is arranged in the second male connector inner cavity 308, the third male connector inner cavity 309 and the fourth male connector inner cavity 310.

[0087] The inner wall of the male connector main body 301 is provided with an anti-falling internal thread 312 of the male connector, and the anti-falling internal thread 312 of the male connector is located in the fifth male connector inner cavity 311. A snap ring installation groove 313 for a snap ring is arranged in the second male connector inner cavity 308, and a snap ring 7 for a snap ring is installed in the snap ring installation groove 313 for a snap ring.

[0088] In this embodiment, the diameters of the first male connector inner cavity 307, the second male connector inner cavity 308, the third male connector inner cavity 309, the fourth male connector inner cavity 310 and the fifth male connector inner cavity 311 decrease in sequence.

[0089] In this embodiment, the snap ring 7 for a snap ring can prevent the T-shaped connecting rod 4 from loosening, and further prevent the T-shaped connecting rod 4 from disengaging from the anti-falling internal thread of the male connector 1 and breaking.

[0090] As a specific solution of this embodiment, as Figure 6 and Figure 7 shown, the T-shaped connecting rod 4 includes a T-shaped connecting rod main body 401 arranged in the male connector 3. A T-shaped connecting rod shoulder 402 is arranged on the outer wall of the T-shaped connecting rod main body 401. The T-shaped connecting rod shoulder 402 divides the T-shaped connecting rod main body 401 into two sections, which are successively the large end section 40101 of the T-shaped connecting rod and the small end section 40102 of the T-shaped connecting rod from front to back. A T-shaped connecting rod external thread 404 is arranged on the outer wall of the front part of the small end section 40102 of the T-shaped connecting rod. A T-shaped connecting rod through hole 403 is opened at the rear end of the large end section 40101 of the T-shaped connecting rod.

[0091] The large end section 40101 of the T-shaped connecting rod is located within the inner cavity 308 of the second male connector, and the rear end of the large end section 40101 of the T-shaped connecting rod is close to the circlip for hole 7. The small end section 40102 of the T-shaped connecting rod penetrates through the inner cavity 309 of the third male connector and is fixedly installed within the inner cavity 310 of the fourth male connector through the external thread 404 of the T-shaped connecting rod and the internal thread 312 for preventing the male connector from falling off.

[0092] In this embodiment, the inner diameters of the inner cavity 307 of the first male connector, the inner cavity 308 of the second male connector, the inner cavity 309 of the third male connector, the inner cavity 310 of the fourth male connector, and the inner cavity 311 of the fifth male connector decrease in sequence. The outer diameter of the main body 401 of the T-shaped connecting rod is smaller than the inner diameter of the inner cavity 309 of the third male connector, and the external thread 404 of the T-shaped connecting rod and the internal thread 312 for preventing the male connector from falling off adopt a clearance fit to ensure that the T-shaped connecting rod 4 is not stressed during the drilling process.

[0093] In this embodiment, as Figure 4 shown, when the male connector bearing external thread 304 and the female connector bearing internal thread 109 are in a stressed state, due to the fitting clearance between the external thread 305 for preventing the male connector from falling off of the male connector and the inner wall of the female connector 1 at the anti-back-off cavity 105 of the female connector, at this time, the T-shaped connecting rod 4, the external thread 305 for preventing the male connector from falling off of the male connector, and the internal thread 110 for preventing the female connector from falling off are not stressed.

[0094] As Figure 8 shown, when the large end D of the male connector bearing external thread 304 breaks, the T-shaped connecting rod 4 can ensure the effective connection between the female connector 1 and the male connector 3 on both sides axially outside D.

[0095] As Figure 9 shown, when the large end P of the female connector bearing internal thread 109 breaks, since the external thread 305 for preventing the male connector from falling off of the male connector is axially limited by the internal thread 110 for preventing the female connector from falling off, at this time, the female connector 1 and the male connector 3 can still maintain an effective connection.

[0096] As a specific solution of this embodiment, as Figure 6 shown, the space within the main body 401 of the T-shaped connecting rod is sequentially the small inner cavity 405 and the large inner cavity 406 of the T-shaped connecting rod from the rear to the front. A T-shaped connecting rod step 407 is provided on the inner wall of the main body 401 of the T-shaped connecting rod, and the T-shaped connecting rod step 407 is located at the axial rear end of the large inner cavity 406 of the T-shaped connecting rod.

[0097] In this embodiment, the pore diameters of the small inner cavity 405 and the large inner cavity 406 of the T-shaped connecting rod can meet the passage of fluid media such as water and air during drilling, and can also meet the requirements of cooling the drill bit and flushing the drill cuttings.

[0098] As a specific solution of this embodiment, as Figure 1As shown in the figure, the central cable-passing assembly 6 includes an insulating male connector 601 installed inside the female connector 1. A rear conductive connector 603 is installed inside the rear part of the insulating male connector 601. A central cable-passing rear installation cavity 60301 is provided at the front end of the rear conductive connector 603, and a conductive spring rear installation cavity 60302 is provided at the rear end of the rear conductive connector 603.

[0099] The central cable-passing assembly 6 further includes an insulating female connector 602 installed inside the T-shaped connecting rod 4. A front conductive connector 604 is installed inside the front part of the insulating female connector 602. A conductive spring front installation cavity 60401 is provided at the front end of the front conductive connector 604, and a central cable-passing front installation cavity 60402 is provided at the rear end of the front conductive connector 604.

[0100] The rear end of the central cable-passing 605 is arranged inside the central cable-passing rear installation cavity 60301. The front end of the central cable-passing 605 penetrates through the drill pipe rod body 2 and is installed inside the central cable-passing front installation cavity 60402. The rear part of a conductive spring 606 is installed inside the conductive spring front installation cavity 60401, and the front part of the conductive spring 606 extends into the conductive spring rear installation cavity 60302 of the adjacent drill pipe short joint.

[0101] In this embodiment, the front conductive connector 604, the central cable-passing 605, the rear conductive connector 603, and the conductive spring 606 are in close contact to form a current path.

[0102] As a specific solution of this embodiment, as Figure 1 shown, the rear end of an insulating wire pipe 607 is installed inside the front part of the insulating male connector 601. The front end of the insulating wire pipe 607 penetrates through the drill pipe rod body 2 and is installed inside the rear part of the insulating female connector 602. The insulating wire pipe 607 is coaxially arranged outside the central cable-passing 605, and a stabilizer 10 is coaxially arranged outside the insulating wire pipe 607. The stabilizer 10 is installed inside the drill pipe rod body 2.

[0103] In this embodiment, the specification of the stabilizer 10 matches the inner diameter of the drill pipe rod body 2 to ensure that it can be fixedly installed inside the drill pipe rod body 2. The stabilizer 10 plays a role in supporting and positioning the insulating wire pipe 607 and the central cable-passing 605.

[0104] As a specific solution of this embodiment, as Figure 1 shown, a rear positioning retaining ring 8 is fixedly arranged inside the third transition cavity 107. The rear end of the insulating male connector 601 is located inside the installation cavity 103 of the male connector installation section, and the front end of the insulating male connector 601 passes through the rear positioning retaining ring 8 and is fixed inside the female connector 1.

[0105] A front positioning retaining ring 9 is fixedly arranged at the step 407 of the T-shaped connecting rod; the rear end of the insulating female joint 602 extends out of the T-shaped connecting rod 4 and extends into the inner cavity 308 of the second male joint, the front part of the insulating female joint 602 passes through the front positioning retaining ring 9 and is fixed inside the T-shaped connecting rod 4, and the front end of the insulating female joint 602 extends into the inner cavity 311 of the fifth male joint.

[0106] In this embodiment, the front positioning retaining ring 9 and the rear positioning retaining ring 8 respectively play a role in supporting and positioning the insulating male joint 601 and the insulating female joint 602.

[0107] As a specific solution of this embodiment, as Figure 1 shown, a sealing ring 11 is arranged between the insulating pipe 607 and the insulating male joint 601, a sealing ring 11 is arranged between the insulating pipe 607 and the insulating female joint 602, a sealing ring 11 is arranged between the rear conductive joint 603 and the insulating female joint 602, and a sealing ring 11 is arranged between the front conductive joint 604 and the insulating male joint 601.

[0108] In this embodiment, an overcurrent channel is arranged in the central cable assembly installation cavity 5 outside the central cable assembly 6. The overcurrent channel can ensure the passage of fluid media such as water and air during drilling. The sealing ring 11 is used to seal the mating gap between components to prevent water flow from entering the central cable assembly 6 and damaging the central cable 605.

[0109] In this embodiment, the connection process of adjacent short drill pipe joints is as follows:

[0110] Step 1: Install the stabilizer 10 into the central through hole of the drill pipe body 2, and then place the rear positioning retaining ring 8 at the sixth step 116.

[0111] Step 2: After threadedly connecting the insulating male joint 601 and the insulating pipe 607, pass them through the central through holes of the rear positioning retaining ring 8 and the stabilizer 10.

[0112] Step 3: Place the front positioning retaining ring 9 at the step 407 of the T-shaped connecting rod, then pass the insulating female joint 602 through the central through hole of the front positioning retaining ring 9, and fixedly connect it to the insulating pipe 607 by threading.

[0113] Step 4: Threadedly connect the rear end of the central cable 605 to the rear conductive joint 603, then pass the front end of the central cable 605 through the inner hole of the insulating male joint 601, and tightly connect it to the front conductive joint 604 by threading.

[0114] After connecting two adjacent short drill pipe joints, as Figure 10As shown in the figure, the conductive spring 606 of the No. 1 drill pipe sub-section enters the rear conductive joint 603 of the No. 2 drill pipe sub-section, and the front conductive joint 604, the central cable 605, the rear conductive joint 603 and the conductive spring 606 are in close contact to form a connection body. This connection body is sealed by the mating body of the insulating female joint 602 of the No. 1 drill pipe sub-section and the insulating male joint 601 of the No. 2 drill pipe sub-section to ensure that after adjacent drill pipe sub-sections are connected, the cable-connected drill pipe formed can stably transmit signals and conduct current.

Claims

1. A cable-through drill pipe with a multi-section thread fitting structure, characterized in that, It includes multiple drill pipe short joints connected in sequence. The drill pipe short joint includes a female joint (1), a drill pipe body (2), and a male joint (3) fixedly connected in sequence from back to front. Multiple internal threads are provided on the inner wall of the female joint (1), and multiple external threads are provided on the outer wall of the male joint (3). Adjacent drill pipe short joints are connected by the cooperation of the multiple internal threads of the female joint (1) and the multiple external threads of the male joint (3). A T-shaped connecting rod (4) is coaxially arranged in the male joint (3), and both ends of the T-shaped connecting rod (4) are located in the male joint (3). Both ends of the female joint (1), the drill pipe body (2), the male joint (3), and the T-shaped connecting rod (4) are open. The space inside the female joint (1), the drill pipe body (2), the male joint (3), and the T-shaped connecting rod (4) is a central cable-passing component installation cavity (5). A central cable-passing component (6) is arranged in the central cable-passing component installation cavity (5). The rear end of the central cable-passing component (6) is arranged in the female joint (1), and the front end of the central cable-passing component (6) is arranged in the T-shaped connecting rod (4). The female joint (1) includes a female joint main body (101) fixedly connected to the drill pipe body (2). The space inside the female joint main body (101) is, from front to back, a first transition cavity (102), a male joint installation section installation cavity (103), a male joint anti-falling section setting cavity (104), a female joint anti-falling retracting tool cavity (105), a second transition cavity (106), a third transition cavity (107), and a fourth transition cavity (108). The male joint (3) is arranged in the first transition cavity (102), the male joint installation section installation cavity (103), the male joint anti-falling section setting cavity (104), and the female joint anti-falling retracting tool cavity (105). A female joint bearing internal thread (109) and a female joint anti-falling internal thread (110) are provided on the inner wall of the female joint main body (101). The female joint bearing internal thread (109) is located in the male joint installation section installation cavity (103), and the female joint anti-falling internal thread (110) is located in the male joint anti-falling section setting cavity (104). The male joint (3) includes a male joint main body (301) fixedly connected to the drill pipe body (2). A first shoulder (302) and a second shoulder (303) are provided on the outer wall of the male joint main body (301) from back to front. The first shoulder (302) and the second shoulder (303) divide the male joint main body (301) into three sections, which are, from back to front, a drill pipe body connection section (30101), a male joint installation section (30102), and a male joint anti-falling section (30103). On the outer wall of the male joint installation section (30102), there is a male joint bearing external thread (304). The rear end of the male joint bearing external thread (304) is flush with the first shoulder (302), and the front end of the male joint bearing external thread (304) is close to the second shoulder (303). On the outer wall of the male joint anti-falling section (30103), there is a male joint anti-falling external thread (305). The rear end of the male joint anti-falling external thread (305) is close to the second shoulder (303), and the front end of the male joint anti-falling external thread (305) is flush with the front end of the male joint body (301). The groove between the second shoulder (303) and the male joint anti-falling external thread (305) is the male joint anti-falling relief groove (306). The male joint installation section (30102) is connected and fixedly installed in the male joint installation section installation cavity (103) through the mutual cooperation of the male joint bearing external thread (304) and the female joint bearing internal thread (109). The male joint anti-falling section (30103) is located in the male joint anti-falling section setting cavity (104) and the female joint anti-falling relief cavity (105). There is a clearance fit between the male joint anti-falling relief groove (306) and the female joint anti-falling internal thread (110), and there is a clearance fit between the male joint anti-falling external thread (305) and the inner wall of the female joint (1) at the female joint anti-falling relief cavity (105). The space of the male joint body (301) from front to back is successively the first male joint inner cavity (307), the second male joint inner cavity (308), the third male joint inner cavity (309), the fourth male joint inner cavity (310), and the fifth male joint inner cavity (311). The second male joint inner cavity (308), the third male joint inner cavity (309), and the fourth male joint inner cavity (310) are provided with T-shaped connecting rods (4). On the inner wall of the male joint body (301), there is a male joint anti-falling internal thread (312), and the male joint anti-falling internal thread (312) is located in the fifth male joint inner cavity (311). In the second male joint inner cavity (308), there is a hole retaining ring installation groove (313), and a hole retaining ring (7) is installed in the hole retaining ring installation groove (313). The T-shaped connecting rod (4) includes a T-shaped connecting rod main body (401) arranged in the male joint (3). On the outer wall of the T-shaped connecting rod main body (401), there is a T-shaped connecting rod shoulder (402). The T-shaped connecting rod shoulder (402) divides the T-shaped connecting rod main body (401) into two sections, which are successively the T-shaped connecting rod large end section (40101) and the T-shaped connecting rod small end section (40102) from front to back. On the outer wall of the front part of the T-shaped connecting rod small end section (40102), there is a T-shaped connecting rod external thread (404). The large end section (40101) of the T-shaped connecting rod is located within the inner cavity (308) of the second male connector, and the rear end of the large end section (40101) of the T-shaped connecting rod is close to the circlip for hole (7); the small end section (40102) of the T-shaped connecting rod penetrates through the inner cavity (309) of the third male connector and is fixedly installed within the inner cavity (310) of the fourth male connector through the external thread (404) of the T-shaped connecting rod and the anti-falling internal thread (312) of the male connector.

2. The through-tubing drill pipe with a multi-segment screw-thread matching structure according to claim 1, wherein, On the inner wall of the described female connector body (101), there are successively arranged a first step (111), a second step (112), a third step (113), a fourth step (114), a fifth step (115), and a sixth step (116) from the rear to the front; The first step (111) and the second step (112) are respectively located at the axial two ends of the installation cavity (103) of the male connector installation section, the third step (113) and the fourth step (114) are respectively located at the axial two ends of the anti-falling section setting cavity (104) of the male connector, the fifth step (115) is located at the axial front end of the anti-falling relief cavity (105) of the female connector, and the sixth step (116) is located at the axial front end of the second transition cavity (106); The rear end of the drill pipe body connection section (30101) extends outside the female connector body (101), and the front end face of the drill pipe body connection section (30101) abuts against the rear end face of the female connector body (101); the front end face of the male connector installation section (30102) abuts against the second step (112).

3. The through-tubing drill pipe with a multi-section thread engagement structure according to claim 1, characterized in that, The space within the T-shaped connecting rod body (401) is successively the small inner cavity (405) and the large inner cavity (406) of the T-shaped connecting rod from the rear to the front. On the inner wall of the T-shaped connecting rod body (401), there is a T-shaped connecting rod step (407), and the T-shaped connecting rod step (407) is located at the axial rear end of the large inner cavity (406) of the T-shaped connecting rod.

4. The through-rope drill pipe with a multi-segment thread fitting structure according to claim 3, characterized in that, The described central cable assembly (6) includes an insulating male connector (601) installed within the female connector (1), and a rear conductive connector (603) is installed within the rear part of the insulating male connector (601); a central cable rear installation cavity (60301) is provided at the front end of the rear conductive connector (603), and a conductive spring rear installation cavity (60302) is provided at the rear end of the rear conductive connector (603); The central cable assembly (6) further includes an insulating female connector (602) installed within the T-shaped connecting rod (4), and a front conductive connector (604) is installed within the front part of the insulating female connector (602); a conductive spring front installation cavity (60401) is provided at the front end of the front conductive connector (604), and a central cable front installation cavity (60402) is provided at the rear end of the front conductive connector (604); The rear end of the central cable (605) is arranged within the central cable rear installation cavity (60301), and the front end of the central cable (605) penetrates through the drill pipe body (2) and is installed within the central cable front installation cavity (60402); the rear part of the conductive spring (606) is installed within the conductive spring front installation cavity (60401), and the front part of the conductive spring (606) extends into the conductive spring rear installation cavity (60302) of the adjacent drill pipe short section.

5. The through-tubing drill pipe with a multi-segment screw-thread matching structure according to claim 4, wherein The rear end of an insulating pipe (607) is installed inside the front part of the described insulating male connector (601). The front end of the insulating pipe (607) penetrates through the drill pipe body (2) and is installed inside the rear part of the insulating female connector (602). The insulating pipe (607) is coaxially arranged outside the central cable (605). A stabilizer (10) is coaxially arranged outside the insulating pipe (607), and the stabilizer (10) is installed inside the drill pipe body (2).

6. The through-tubing drill pipe with a multi-section thread fitting structure according to claim 5, characterized in that, A rear positioning retaining ring (8) is fixedly arranged inside the described third transition cavity (107). The rear end of the insulating male connector (601) is located inside the installation cavity (103) of the male connector installation section. The front end of the insulating male connector (601) passes through the rear positioning retaining ring (8) and is fixed inside the female connector (1). A front positioning retaining ring (9) is fixedly arranged at the T-shaped connecting rod step (407). The rear end of the insulating female connector (602) extends out of the T-shaped connecting rod (4) and extends into the inner cavity (308) of the second male connector. The front part of the insulating female connector (602) passes through the front positioning retaining ring (9) and is fixed inside the T-shaped connecting rod (4). The front end of the insulating female connector (602) extends into the inner cavity (311) of the fifth male connector.

7. The through-tubing drill pipe with a multi-segment screw thread mating structure as described in claim 6, wherein, A sealing ring (11) is arranged between the insulating pipe (607) and the insulating male connector (601). A sealing ring (11) is arranged between the insulating pipe (607) and the insulating female connector (602). A sealing ring (11) is arranged between the rear conductive connector (603) and the insulating female connector (602). A sealing ring (11) is arranged between the front conductive connector (604) and the insulating male connector (601).

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