A downhole power cutter for use in the event of a wireline coring accident

Abstract

The application discloses a downhole power cutting device for a drill pipe in a coring accident, which comprises a downhole power cutting device body and an auxiliary device, wherein the downhole power cutting device body comprises a base, a bearing sleeve, a hydraulic cutter device, a screw motor, a bypass valve, a bearing seat, a single-acting water sealing assembly, a weight and a spear head, and the auxiliary device comprises a lifting and fishing winch, a steel wire rope, a drilling machine and a mud pump; the application can achieve the following effects: simple, quick, convenient, safe and reliable operation, fast and effective solution to the drill pipe cutting in a coring accident, limitation of the influence of the drill pipe cutting in the coring accident within a controllable range, reduction of manpower, material resources and time cost, improvement of the success probability of complex accident treatment, improvement of the drilling construction efficiency and reduction of the probability of abandonment of a drilling hole due to failure of complex accident treatment.

Description

Technical Field

[0001] This invention relates to the field of wireline coring drilling technology, and in particular to a dynamic cutting device for the bottom of the borehole in case of an accident during wireline coring. Background Technology

[0002] Generally, during diamond wireline coring operations in geological core drilling projects, accidents such as stuck drill pipe, buried drill pipe, and burnt drill pipe frequently occur due to complex geological formations or human error. These incidents often prevent the drill pipe and drilling tools from being retrieved from the wellhead. When reverse-threading is used, a number of reverse-threading drill pipes of the same length are required, resulting in significant manpower, material resources, and time expenditure. Furthermore, this process presents safety hazards and numerous additional accidents, severely impacting the efficiency of accident handling.

[0003] Currently, when such accidents occur during deep-hole geological core drilling, the common practice is to use a mechanical hydraulic cutter to cut the faulty drill rod before retrieval. This method requires a number of smaller diameter drill rods of the same length for a single cut. If the number of smaller diameter drill rods is insufficient, segmented cutting is used to cut the drill rods one by one before retrieval. Using the single-cut method requires a number of smaller diameter drill rods of the same length, which is often not feasible on-site. The external sourcing process takes time, potentially leading to missed opportunities for accident handling and escalation. However, the segmented cutting method for retrieval presents problems such as complex procedures, long accident handling cycles, high labor intensity for workers, and numerous secondary safety hazards and additional accidents, severely impacting accident handling efficiency and again potentially leading to missed opportunities for accident handling and escalation. Whether using reverse-clamping or segmented cutting, both require a large amount of material and human resources, and the processing time and effect are subject to uncertain variables. This often leads to missing the best first opportunity for accident handling. Before the accident drill pipe is dealt with, the well wall may collapse, fall off blocks, and rock cuttings may settle in the annular space, causing secondary serious accidents such as most of the drill pipe being stuck or buried. If most of the drill pipe is stuck or buried, it will lead to huge economic losses due to the abandonment of the borehole.

[0004] Therefore, under the current drilling equipment and technology conditions, inventing a simple, quick, and practical power cutting device for the bottom of the borehole in wireline coring accidents is a problem that urgently needs to be solved by those skilled in the art. The goal is to cut off the faulty drill rod and pull it out of the borehole in the first instance before accidents such as stuck drill, buried drill, or burned drill occur during wireline coring operations, to completely cut and grind away the remaining drill bit, and finally to successfully handle complex accidents in a simple and quick manner. Summary of the Invention

[0005] The purpose of this invention is to provide a dynamic cutting device for the bottom of the drill pipe in wireline coring accidents, so as to solve the problems existing in the prior art. It can achieve simple, quick and convenient, safe and reliable operation, and quickly and effectively solve the problem of drill pipe cutting in wireline coring accidents, so as to limit the impact within a controllable range, reduce manpower, material and time costs, improve the success rate of handling complex accidents, improve drilling construction efficiency, and reduce the probability of borehole scrapping due to failure to handle complex accidents.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] This invention provides a bottom-hole dynamic cutting device for drill pipe in case of in-hole wireline coring accidents, comprising a bottom-hole dynamic cutting device body and auxiliary devices. The bottom-hole dynamic cutting device body includes a base, a bearing sleeve, a hydraulic cutter, a screw motor, a bypass valve, a bearing seat, a single-action water sealing assembly, a counterweight, and a retrieval spearhead. The auxiliary devices include a hoisting and retrieval winch, a wire rope, a drilling rig, and a mud pump.

[0008] The interior of the base consists of a threaded hole, a short hole, and a long hole from top to bottom. The threaded hole is used to connect with the bearing sleeve. Water holes communicating with the outside are provided on the side walls of the base on both sides of the top of the long hole. A snap-fit ​​platform is provided on the outer wall of the base, which can make sealing contact with the seat ring of the emergency drill bit.

[0009] The hydraulic cutter includes a hydraulic cutter housing, a conversion connector, a water-sealing steel ball, a plunger, a compression spring, cutting blades, a first thrust ball bearing, a second thrust ball bearing, a compression spring, and a first self-locking nut. The hydraulic cutter housing has a plunger hole and a pusher hole inside. A spindle is located at the bottom of the hydraulic cutter housing, and the top of the hydraulic cutter housing is connected to the screw motor via the conversion connector. The water-sealing steel ball is located in the bottom circular hole of the plunger, and the entrance to the bottom circular hole of the plunger is sealed by the water-sealing steel ball. The cutting blades are installed in cutting grooves provided on the hydraulic cutter housing, and the inner end of each cutting blade is rotatably connected to the hydraulic cutter housing via a spring pin. The inner end of each cutting blade also has... The device is equipped with a locking part that engages with a push rod at the bottom of the plunger. When the plunger moves downward, it pushes and presses against the cutting blade through the locking part, causing the cutting blade to rotate and extend outward from the cutting groove to open for cutting. The hydraulic cutter housing is also equipped with a corresponding pressure relief hole. When the high-pressure chamber formed by the water-sealing steel ball pushes the plunger downward to the pressure relief hole, high-pressure drilling fluid is released. The mandrel is equipped with a thrust ball bearing, a thrust ball bearing, a compression spring, a self-locking nut, and a cotter pin from top to bottom. The bearing sleeve is installed outside the thrust ball bearing, the self-locking nut is threaded to the bottom end of the mandrel, and the compression spring is located between the thrust ball bearing and the self-locking nut.

[0010] The top of the screw motor is connected to the bypass valve, the top of the bypass valve is connected to the bearing housing, the bearing housing has a through hole inside, and a limiting step is provided on the through hole;

[0011] The single-acting water sealing assembly includes a single-acting core column, a third thrust ball bearing, a fourth thrust ball bearing, a second self-locking nut, expansion rubber rings, and iron washers. The top of the single-acting core column extends into the through hole of the counterweight at the top of the single-acting water sealing assembly, and a step is provided at the bottom of the through hole of the counterweight for locking. The bottom shaft of the single-acting core column extends into the bearing seat. Multiple expansion rubber rings are sleeved on the shaft of the single-acting core column between the bearing seat and the counterweight. Iron washers are provided between each expansion rubber ring, and a limiting sleeve extending into the bearing seat is provided at the bottom of the bottom iron washer. The third thrust ball bearing is installed on the single-acting core column between the limiting sleeve and the limiting step in the bearing seat. The fourth thrust ball bearing is installed on the single-acting core column at the bottom of the limiting step, and the bottom of the fourth thrust ball bearing is limited by the second self-locking nut.

[0012] The outer diameter of the hammer is equal to the outer diameter of the expansion rubber ring and the outer diameter of the bearing seat. A through hole is provided inside the hammer, and a water inlet hole is provided on the outer wall of the hammer, connecting the through hole and the external water inlet. The top of the hammer is connected to the spearhead.

[0013] Preferably, the hydraulic cutter further includes a cylindrical pin and a spring retainer. The cylindrical pin is installed at the top of the plunger hole, the spring retainer is installed inside the plunger hole and located at the bottom of the cylindrical pin, and the plunger is disposed at the bottom of the cylindrical pin. The cylindrical pin is used to limit the upward stroke of the water-sealing steel ball, and the spring retainer is used to limit the upward stroke of the plunger.

[0014] Preferably, the hydraulic cutter further includes a cotter pin, which is disposed at the bottom of the self-locking nut and pinned to the spindle. The cotter pin is used to limit the self-locking nut and prevent it from loosening.

[0015] Preferably, the diameter of the plunger hole is larger than the diameter of the pusher hole, the bottom of the plunger hole forms a step to limit the downward stroke of the plunger, and a return spring is sleeved on the top of the push rod. The return spring is located between the plunger and the bottom of the plunger hole. When the plunger moves downward, the return spring is compressed. After the plunger finishes working and releases pressure, the return spring begins to extend, causing the plunger to move upward and return to its original position.

[0016] Preferably, two sets of the first thrust ball bearing and one set of the second thrust ball bearing are provided. The first and second thrust ball bearings are used to realize the single-action performance between the hydraulic cutter and the bearing sleeve.

[0017] Preferably, the cutting blade has three blades, and the cutting blade is made of Fenggang alloy material.

[0018] Preferably, the bottom end of the screw motor is hollow and provided with a tapered thread for connection with the upper tapered thread of the adapter, and the top end of the screw motor is hollow and provided with a tapered thread for connection with the lower tapered thread of the bypass valve.

[0019] Preferably, a cotter pin is pinned to the single-acting core at the bottom of the self-locking nut two. The cotter pin two is used to limit the self-locking nut two and prevent it from loosening.

[0020] Preferably, three sets of the expansion rubber rings are provided, and the expansion rubber rings are expansion rubber components.

[0021] Preferably, the top of the hammer is provided with a stepped hole for mounting the spearhead, and the spearhead is connected to the hammer by a flexible cylindrical pin.

[0022] The present invention achieves the following beneficial technical effects compared to the prior art:

[0023] 1. The borehole bottom power cutting device for wireline coring accidents provided by this invention has a simple structure and process, is easy to operate, and is safe and reliable. It can quickly and effectively solve the problem of wireline coring accident drill rod cutting, limit its impact to a controllable range, reduce manpower, material resources and auxiliary time, improve the success rate of handling complex accidents, improve drilling construction efficiency, and reduce the probability of borehole scrapping due to failure to handle complex accidents.

[0024] 2. The borehole bottom power cutting device for in-hole wireline coring accidents provided by the present invention can be quickly lowered into position and lifted to the wellhead using an auxiliary retrieval and lifting device according to actual usage conditions. This enables the rapid cutting of the drill pipe and retrieval of the drill pipe in the event of accidents such as stuck drill, buried drill, or burned drill during diamond wireline coring, thus providing a quick and simplified solution to the accident.

[0025] 3. The hole bottom power cutting device for in-hole wireline coring accident drill rod provided by the present invention uses a screw motor as the hole bottom power drilling tool, but is not limited to a screw motor. Other hole bottom power drilling tools, such as turbine drilling tools, can also be used, which can effectively eliminate the use of small diameter drill rods and effectively reduce the impact of manpower, material resources and time.

[0026] 4. The borehole bottom power cutting device for in-hole rope coring accidents provided by this invention eliminates the need to prepare a large number of reverse-threaded drill rods and small-diameter drill rods. It utilizes an auxiliary retrieval and lifting device combined with a screw motor as the bottom power source, and employs a single-action and water-sealing device to completely replace the previous time-consuming, labor-intensive, and cumbersome processing methods. This effectively reduces operation time, alleviates labor intensity, lowers processing costs, and increases the success rate. Its economic benefits increase significantly with the extension of drilling depth.

[0027] 5. The hole bottom power cutting device for in-hole wireline coring accident drill rod provided by the present invention can be adapted to the specifications of the hole bottom power cutting device according to the actual situation of the in-hole accident drill rod, so as to realize the cutting and elimination of accident drill rod during diamond wireline coring drilling of different specifications (see attached table), but not limited to the screw motor specifications and models in the attached table. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the overall structure of the hole bottom power cutting device of the present invention;

[0030] Figure 2 This is a schematic diagram of the overall structure of the base of the present invention;

[0031] Figure 3 This is a schematic diagram of the overall structure of the bearing sleeve of the present invention;

[0032] Figure 4 This is a schematic diagram of the overall structure of the hydraulic cutter of this invention;

[0033] Figure 5 This is a schematic diagram of the overall structure of the screw motor of the present invention;

[0034] Figure 6 This is a schematic diagram of the overall structure of the bypass valve of the present invention;

[0035] Figure 7 This is a schematic diagram of the overall structure of the bearing housing of the present invention;

[0036] Figure 8 This is a schematic diagram of the overall structure of the single-action water sealing component of the present invention;

[0037] Figure 9 This is a schematic diagram of the overall structure of the counterweight component of the present invention;

[0038] Figure 10 This is a schematic diagram of the overall structure of the spear-catching hook component of the present invention;

[0039] Figure 11 This is a diagram showing the working state of the hole bottom power cutting device of the present invention in its lowered position;

[0040] Figure 12 This is a diagram showing the cutting operation of the hole bottom power cutting device of the present invention;

[0041] In the diagram: 1-base, 11-water eye;

[0042] 2-Bearing sleeve;

[0043] 3-Hydraulic cutter, 31-Sealing steel ball, 32-Plunger, 33-Return spring, 34-Cutter blade, 35-Thrust ball bearing I, 36-Thrust ball bearing II, 37-Compression spring, 38-Self-locking nut I, 39-Cocker pin I, 310-Pressure relief hole, 311-Cylindrical pin, 312-Spring snap ring, 313-Adapter connector, 314-Hydraulic cutter housing, 315-Spring pin;

[0044] 4-Screw motor, 41-Stator, 42-Rotor;

[0045] 5-Bypass valve, 51-Valve orifice;

[0046] 6-Bearing housing, 61-Limiting step;

[0047] 7-Single-acting water sealing assembly, 71-Single-acting core column, 72-Thrust ball bearing III, 73-Self-locking nut II, 74-Cocker pin II, 75-Expansion rubber ring, 76-Iron washer, 77-Thrust ball bearing IV;

[0048] 8 - counterweight, 81 - water inlet;

[0049] 9-Spearhead, 91-Elastic cylindrical pin. Detailed Implementation

[0050] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] The purpose of this invention is to provide a dynamic cutting device for the bottom of the borehole in case of a wireline coring accident, so as to solve the problems existing in the prior art.

[0052] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0053] The borehole bottom power cutting device for in-hole rope coring accidents in this embodiment, such as... Figures 1-10 As shown, the device includes a bottom hole power cutting device body and auxiliary devices. The bottom hole power cutting device body includes a base 1, a bearing sleeve 2, a hydraulic cutter 3, a screw motor 4, a bypass valve 5, a bearing seat 6, a single-action water sealing assembly 7, a counterweight 8, and a retrieval spearhead 9. The auxiliary devices include a hoisting and retrieval winch, a wire rope, a drilling rig, and a mud pump.

[0054] The interior of the base 1 consists of a threaded hole, a short hole, and a long hole from top to bottom. The threaded hole is used to connect with the bearing sleeve 2. Water holes 11 that connect to the outside are opened on the side walls of the base 1 on both sides of the top of the long hole. A snap-fit ​​platform is provided on the outer wall of the base 1. The bottom of the snap-fit ​​platform has a slope, which can make sealing contact with the seat ring of the emergency drill.

[0055] The hydraulic cutter 3 includes a hydraulic cutter housing 314, a conversion connector 313, a water-sealing steel ball 31, a plunger 32, a compression spring 37, cutting blades 34, a first thrust ball bearing 35, a second thrust ball bearing 36, a compression spring 37, and a first self-locking nut 38. The hydraulic cutter housing 314 has a plunger hole and a pusher hole inside. A spindle is located at the bottom of the hydraulic cutter housing 314, and the top of the hydraulic cutter housing 314 is connected to a screw motor 4 via the conversion connector 313. The water-sealing steel ball 31 is located in the bottom circular hole of the plunger 32, and the entrance to the bottom circular hole of the plunger 32 is sealed by the water-sealing steel ball 31. The cutting blades 34 are installed in cutting grooves provided on the hydraulic cutter housing 314, and the inner end of each cutting blade 34 is connected to the hydraulic cutter housing 314 via a spring pin 315. 4. Rotary connection: The inner end of the cutting blade 34 is also provided with a snap-fit ​​part, which is connected to the push rod at the bottom of the plunger 32. When the plunger 32 moves downward, it drives and presses the cutting blade 34 through the snap-fit ​​part, causing the cutting blade 34 to rotate and extend outward from the cutting groove to open into the cutting working state. The hydraulic cutter housing 314 is also provided with a pressure relief hole 310. When the high pressure chamber formed by the water-sealing steel ball 31 pushes the plunger 32 downward to the pressure relief hole, the high pressure drilling fluid is released. The core shaft is equipped with a thrust ball bearing 35, a second thrust ball bearing 36, a compression spring 37, a self-locking nut 38, and a cotter pin 39 from top to bottom. The bearing sleeve 2 is covered outside the thrust ball bearing 35. The self-locking nut 38 is threadedly connected to the bottom end of the core shaft. The compression spring 37 is located between the second thrust ball bearing 36 and the self-locking nut 38.

[0056] The top of the screw motor 4 is connected to the bypass valve 5, and the top of the bypass valve 5 is connected to the bearing housing 6. The bearing housing 6 has a through hole inside, and a limiting step 61 is provided on the through hole.

[0057] The single-acting water sealing assembly 7 includes a single-acting core column 71, a third thrust ball bearing 72, a fourth thrust ball bearing 77, a second self-locking nut 73, an expansion rubber ring 75, and an iron washer 76. The top of the single-acting core column 71 extends into the through hole of the counterweight 8 at the top of the single-acting water sealing assembly 7, and the bottom of the through hole of the counterweight 8 is provided with a step for locking. The bottom shaft of the single-acting core column 71 extends into the bearing seat 6. Multiple expansion rubber rings 75 are sleeved on the shaft of the single-acting core column 71 between the bearing seat 6 and the counterweight 8. An iron washer 76 is provided between each expansion rubber ring 75, and the bottom of the bottom iron washer 76 is provided with a limiting sleeve that extends into the bearing seat 6. The third thrust ball bearing 72 is installed on the single-acting core column 71 between the limiting sleeve and the limiting step in the bearing seat 6. The fourth thrust ball bearing 77 is installed on the single-acting core column 71 at the bottom of the limiting step. The bottom of the fourth thrust ball bearing 77 is limited by the second self-locking nut 73.

[0058] The outer diameter of the hammer 8 is equal to the outer diameter of the expansion rubber ring 75 and the outer diameter of the bearing seat 6. A through hole is provided inside the hammer 8, and an external water inlet hole 81 is provided on the outer wall of the hammer 8. The water inlet hole 81 is an inclined hole that slopes upward and outward. The top of the hammer 8 is connected to the retrieval spearhead 9. The outside of the hammer 8 is a long cylindrical part with the same diameter as the expansion rubber ring 75. When the main body of the bottom hole power cutting device is lowered into position, the hammer 8 compresses the expansion rubber ring 75 downward by its own weight, so that the outer edge of the expansion rubber ring 75 is compressed and expanded and fits tightly against the inner wall of the emergency drill pipe, and the inner edge of the expansion rubber ring 75 fits tightly against the outer edge of the single-moving core column 71 to achieve a sealing effect. The upper part of the retrieval spearhead 9 is a conical retrieval spear hook, which is used for the retrieval spearhead 9 to be self-locked with the retrieval winch and the wire rope auxiliary device retrieval spear hook, so as to realize the lowering and lifting operation of the bottom hole power cutting device inside the emergency drill pipe.

[0059] In this specific embodiment, the lower section of the base 1 has a slightly smaller outer diameter. When the bottom hole power cutting device body is lowered into position, the lower section of the base 1 is inserted into the emergency drill string and the seat ring, thus stabilizing the bottom hole power cutting device body. The base 1 is designed with a slightly larger outer diameter in the middle section and a sloped lower part. The sloped lower part of the middle section tightly sits and fixes with the sloped surface of the drill string seat ring, while also providing a seal. The slightly larger outer diameter in the middle section of the base 1 reduces the gap between the base 1 and the emergency drill string, achieving stability for the bottom hole power cutting device. The upper section of the elongated hole of the base 1 has 2-3 water holes 11 for high-pressure drilling fluid to flow into the bottom of the well and the outer annulus.

[0060] In this specific embodiment, the outer shell of the hydraulic cutter 3 is set to the corresponding specifications of the upper section (see attached table), and the appropriate specifications of the bottom hole power cutting device can be selected according to the specifications of the emergency drill rod (see attached table).

[0061] In this specific embodiment, the hydraulic cutter 3 further includes a cylindrical pin 311 and a spring retainer 312. The cylindrical pin 311 is installed at the top of the plunger hole, the spring retainer 312 is installed inside the plunger hole and located at the bottom of the cylindrical pin 311, and the plunger 32 is disposed at the bottom of the cylindrical pin 311. The cylindrical pin 311 is used to limit the upward stroke of the water-sealing steel ball 31, and the spring retainer 312 is used to limit the upward stroke of the plunger 32.

[0062] In this specific embodiment, the hydraulic cutter 3 also includes a cotter pin 39, which is disposed at the bottom of the self-locking nut 38 and pinned to the spindle. The cotter pin 39 is used to limit the self-locking nut 38 and prevent it from loosening.

[0063] In this specific embodiment, the diameter of the plunger hole is larger than the diameter of the pusher hole. The bottom of the plunger hole forms a step that limits the downward stroke of the plunger 32. A return spring 33 is sleeved on the top of the push rod. The return spring 33 is located between the plunger 32 and the bottom of the hole. When the plunger 32 moves downward, the return spring 33 is compressed. After the plunger 32 finishes working and the pressure is released, the return spring 33 begins to extend, causing the plunger 32 to move upward and return to its original position.

[0064] In this specific embodiment, two sets of thrust ball bearing 35 and one set of thrust ball bearing 36 are provided. The thrust ball bearing 35 and the thrust ball bearing 36 are used to realize the single-action performance between the hydraulic cutter 3 and the bearing sleeve 2.

[0065] In this specific embodiment, the cutting blade 34 is provided with three blades, and the cutting blade 34 is made of Fenggang alloy material.

[0066] In this specific embodiment, the screw motor 4 includes a housing, a stator 41 and a rotor 42. The bottom end of the screw motor 4 is hollow and has a tapered thread for connecting with the upper tapered thread of the adapter 313. The top end of the screw motor 4 is hollow and has a tapered thread for connecting with the lower tapered thread of the bypass valve 5. The housing of the bypass valve 5 is provided with a valve hole 51 that communicates with the internal circular hole.

[0067] In this specific embodiment, a cotter pin 74 is pinned to the single-acting core 71 at the bottom of the self-locking nut 73. The cotter pin 74 is used to limit the self-locking nut 73 and prevent it from loosening.

[0068] In this specific embodiment, three sets of expansion rubber rings 75 are provided, and each expansion rubber ring 75 is an expansion rubber component. The expansion rubber rings 75 are matched to the specifications of the drill pipe inner bore and the outer diameter of the single-acting mandrel 71. The expansion rubber rings 75 and the outer diameter of the single-acting mandrel 71 are manufactured to match. The inner and outer diameters of the iron washer 76 are consistent with those of the expansion rubber rings 75, and the thickness of the iron washer 76 is such that it can withstand the expansion pressure of the expansion rubber rings 75 without deformation.

[0069] In this specific embodiment, the top of the hammer 8 is provided with a stepped hole for mounting the spearhead 9, and the spearhead 9 is connected to the hammer 8 by an elastic cylindrical pin 91.

[0070] Specifications and fits for each structure

[0071]

[0072] The work process is as follows:

[0073] After the inspected and maintained bottom hole power cutting device body is lowered into place using a lifting and retrieval winch and wire rope, the lifting and retrieval winch and wire rope are normally disengaged from the retrieval spearhead 9 and pulled out of the hole. At this time, the expansion rubber ring 75 expands under the compression of the hammer 8 and the iron washer 76, sealing the expansion rubber ring 75 with the inner wall of the accident drill rod and the single-moving core column 71.

[0074] Next, securely seal the drilling rig, mud pump pipeline auxiliary devices, and emergency drill rod. At this point, the installation of the bottom hole power cutting device is complete, and the bottom hole power cutting device is ready to cut.

[0075] Furthermore, check the performance of the drilling rig vertical shaft and mud pump equipment, as well as the sealing condition of the drilling fluid delivery pipeline.

[0076] Furthermore, start the mud pump to deliver drilling fluid to the drill pipe in the well. Use a shut-off valve to gradually increase the pump flow rate and pressure. The pump flow rate should be controlled to reach the normal working pressure of the screw motor and hydraulic cutter (2.0-2.5MPa). When the rated working pressure is reached, the drilling fluid flows from the water inlet holes 81 (3-5 holes) of the hammer 8 into the inner hole of the single-acting core 71 and flows downward into the bypass valve 5 and the screw motor 4. Under the action of the drilling fluid flow rate and pressure, the screw motor 4 starts to rotate, thereby driving the hydraulic cutter 3 to start rotating.

[0077] Furthermore, the drilling fluid flows into the sealed high-pressure chamber at the top of the hydraulic cutter 3. As the flow rate and pressure of the drilling fluid increase, under the sealing action of the water-sealing steel ball 31, the drilling fluid pushes the plunger 32 downward to the pressure relief hole 310. At this time, the cutting blade 34 of the hydraulic cutter 3 extends outward and opens to the cutting working state under the downward pressure of the plunger 32. In addition, the drilling fluid continues to flow downward to the water hole 11 of the base 1, and flows downward to the internal circular hole of the base 1 to the emergency drill bit and even the bottom of the well.

[0078] Furthermore, when the flow rate and pump pressure are increased to the normal level and the rated working pressure of the screw motor 4 is reached, the screw motor 4 continues to rotate, thereby driving the cutting blade 34 of the hydraulic cutter 3 to cut the drill pipe in the circumference. During the cutting, the flow rate and pump pressure of the mud pump can be increased slowly, so that the cutting blade 34 of the hydraulic cutter 3 can continue to expand the cutting size as the cutting depth increases. At the same time, the speed of the screw motor 4 can be appropriately increased (from the initial 100 r / min to 200 r / min in the later stage) to speed up the cutting progress of the drill pipe in the emergency.

[0079] Finally, when the cutting time reaches 60 to 90 minutes, the cutting blade 34 of the hydraulic cutter 3 cuts the faulty drill pipe, the pump pressure drops, and the delivery of drilling fluid can be stopped, completing one cutting operation of the faulty drill pipe.

[0080] Before use, the borehole bottom power cutting device for wireline coring accidents in the present invention needs to be assembled and debugged.

[0081] Specific assembly and debugging steps: First, check that all parts meet specifications and dimensions, and that there are no burrs, dirt, or sand on the surface or in the holes. Lubricate the thrust ball bearing and set it aside. Simultaneously, check the performance indicators of the purchased screw motor 4 and bypass valve 5 to ensure they meet usage requirements. Then, assemble the bottom hole power cutting device. The specific steps are as follows:

[0082] First step, assemble the waterjet cutter 3: install the three cutting blades 34 into the holes at the bottom of the housing of the waterjet cutter 3 using spring pins 315, and check the free movement of the three cutting blades 34 in the slots to ensure flexibility;

[0083] Furthermore, the sealing steel ball 31 is inserted into the plunger 32, and a cylindrical pin 311 is inserted into the plunger hole to limit the stroke of the sealing steel ball 31.

[0084] Next, the return spring 33 is fitted into the lower small diameter of the plunger 32. Then, the plunger 32 and the return spring 33 are installed together into the upper round hole of the water cutter 3. At this time, check the situation of the plunger 32 and the return spring 33 pressing against the three cutting blades 34. It is advisable that when the top stroke of the plunger 32 is pressed down to the water eye 310, the three cutting blades 34 are fully extended outward and in the cutting working state. After checking, the spring retainer 312 is installed into the spring groove of the water cutter 3 to limit the stroke of the plunger 32.

[0085] Next, connect the lower external thread of the adapter 313 to the upper internal thread of the water jet cutter 3;

[0086] Next, install two sets of thrust ball bearings 35 on the lower step of the waterjet cutter 3. Then, fit the bearing sleeve 2 onto the bearing and the lower spindle of the waterjet cutter 3. Next, fit one set of thrust ball bearing 36 and the compression spring 37 onto the lower spindle of the waterjet cutter 3. Next, install the self-locking nut 38 onto the thread of the lower spindle of the waterjet cutter 3. The locking stroke of the self-locking nut 38 should be such that the bearing sleeve 2 and the spindle of the waterjet cutter 3 can rotate freely. Next, insert the cotter pin 39 into the hole of the lower spindle of the waterjet cutter 3 to prevent the self-locking nut 38 from turning back. At this point, the assembly of the waterjet cutter 3 is completed.

[0087] The second step is to assemble the single-acting water sealing component 7 and the counterweight 8: First, insert the single-acting core column 71 into the inner hole of the counterweight 8 for installation. Then, cross-fit the iron washer 76 and the expansion rubber ring 75 onto the single-acting core column 71. Finally, fit the thrust ball bearing 72 onto the single-acting core column 71.

[0088] Furthermore, the bearing housing 6 is fitted onto the single-acting mandrel 71, the thrust ball bearing 72 is fitted onto the single-acting mandrel 71, and the self-locking nut 73 is installed on the lower thread of the single-acting mandrel 71. The locking stroke of the self-locking nut 73 is such that the bearing housing 6 and the single-acting mandrel 71 can rotate freely. Then, the cotter pin 74 is inserted into the lower hole of the single-acting mandrel 71 to restrict the self-locking nut 73 from rewinding. At this point, the assembly of the single-acting water sealing assembly 7, the bearing housing 6, and the counterweight 8 is completed.

[0089] The third step is to assemble the various functional components: First, connect the lower thread of the bearing sleeve 2 of the assembled waterjet cutter 3 to the upper thread of the base.

[0090] Furthermore, the upper external thread of the adapter 313 is connected to the lower internal thread of the screw motor 4;

[0091] Furthermore, the lower external thread of the bypass valve 5 is connected to the upper internal thread of the screw motor 4;

[0092] Furthermore, the lower external thread of the bearing seat 6 assembled on the single-acting water sealing assembly 7 is connected to the upper internal thread of the bypass valve 5;

[0093] Furthermore, the upper part of the counterweight 8 assembled on the single-action sealing component 7 is connected to the spearhead 9 using an elastic cylindrical pin 91 to complete the assembly of the bottom hole power cutting device; the single-action performance of the bottom hole power cutting device is checked again, and if it does not meet the requirements, it is adjusted in time.

[0094] Finally, before operation, connect the bottom hole power cutting device to the drilling rig and mud pump pipeline on site, start the mud pump to conduct a surface test, verify the good performance of the bottom hole power cutting device and collect various working parameters to guide the working status of the bottom hole power cutting device when it is lowered into the well.

[0095] The specific operating steps are as follows:

[0096] Step 1: When a stuck drill pipe, buried drill pipe, or burnt drill pipe occurs during diamond wireline coring drilling and the drill pipe cannot be lifted and retrieved normally, connect the reserved bottom hole power cutting device's retrieval tip 9 to the lifting and retrieval winch and the wire rope to the retrieval hook. Then, use the lifting and retrieval winch to send the bottom hole power cutting device into the drill pipe where the accident occurred, to the seat ring of the wireline coring tool in the borehole. After confirming that it is in place, engage the ejector to pull the wire rope and retrieval hook out of the wellhead (see...). Figure 11 Note that before installing and lowering the bottom hole power cutting device, the core sample inner tube assembly should be retrieved from the wellhead to ensure that the part of the drill string where the bottom hole power cutting device will be installed is intact and in good condition.

[0097] Step 2: Connect the drilling rig vertical shaft, mud pump pipeline and emergency drill pipe at the wellhead, and check all instruments and meters to ensure they are in good working order.

[0098] Step 3: Start the mud pump. After confirming that the mud pump is working properly, gradually increase the drilling fluid injection rate into the drill pipe in the well, while carefully observing the instruments. Once the pump flow rate and pressure reach the operating parameters of the bottom hole power cutting device, stabilize the pump flow rate and pressure. The bottom hole power cutting device will then begin cutting operations (see...). Figure 12 ), carefully observe the working condition of the bottom hole power cutting device in the well. If there is any abnormality, check and eliminate the hidden danger in time. If necessary, stop the machine for inspection and continue the cutting work after the hidden danger is eliminated. During the cutting work, pay attention to the pressure gauge. When the cutting time is reached and the pressure suddenly drops, it can be confirmed that the cutting of the faulty drill pipe has been completed.

[0099] Step 4: After the cutting work is completed, disconnect the drilling rig vertical shaft and mud pump pipeline, lower the retrieval wire rope and retrieval hook along the accident drill pipe at the wellhead, and lower it to the retrieval head 9 of the bottom hole power cutting device. Then, pull the bottom hole power cutting device out of the wellhead.

[0100] Step 5: Reconnect the drilling rig vertical shaft and mud pump pipeline to the faulty drill pipe at the wellhead, send drilling fluid into the well and start the drilling rig for a test rotation. If there is no reverse torque during rotation and no pressure buildup on the pump pressure gauge, the cutting can be confirmed to be completed normally. Next, completely pull the faulty drill pipe out of the wellhead. Then, use grinding and milling methods to completely destroy the remaining faulty drill tools. This will quickly and efficiently complete the handling of a complex accident.

[0101] Finally, after disassembling and separating the main body base 1, bearing sleeve 2, hydraulic cutter 3, screw motor 4, bypass valve 5, bearing seat 6, single-action water sealing assembly 7, counterweight 8, spearhead 9 and other parts of the hole bottom power cutting device, applying oil for maintenance, replacing the damaged cutting blade 34, and reassembling it completely for the next use.

[0102] This invention has illustrated its principles and implementation methods using specific examples. The descriptions of these embodiments are merely illustrative of the method and its core ideas; furthermore, those skilled in the art will recognize that modifications may be made to the specific implementation methods and application scope based on the principles of this invention. Therefore, the content of this specification should not be construed as limiting the invention.

Claims

1. A dynamic cutting device for bottom hole cutting of drill rods in emergency wireline coring, characterized in that: The device includes a bottom hole power cutting device body and auxiliary devices. The bottom hole power cutting device body includes a base, bearing sleeve, hydraulic cutter, screw motor, bypass valve, bearing seat, single-action water sealing assembly, counterweight and retrieval spearhead. The auxiliary devices include a lifting and retrieval winch, wire rope, drilling rig and mud pump. The interior of the base consists of a threaded hole, a short hole, and a long hole from top to bottom. The threaded hole is used to connect with the bearing sleeve. Water holes communicating with the outside are provided on the side walls of the base on both sides of the top of the long hole. A snap-fit ​​platform is provided on the outer wall of the base, which can make sealing contact with the seat ring of the emergency drill bit. The hydraulic cutter includes a hydraulic cutter housing, a conversion connector, a water-sealing steel ball, a plunger, a compression spring, cutting blades, a first thrust ball bearing, a second thrust ball bearing, and a self-locking nut. The hydraulic cutter housing has a plunger hole and a pusher hole inside. A spindle is located at the bottom of the hydraulic cutter housing, and the top of the hydraulic cutter housing is connected to the screw motor via the conversion connector. The water-sealing steel ball is located in the bottom circular hole of the plunger, and the entrance to the bottom circular hole of the plunger is sealed by the water-sealing steel ball. The cutting blades are installed in cutting grooves provided on the hydraulic cutter housing, and the inner end of each cutting blade is rotatably connected to the hydraulic cutter housing via a spring pin. The inner end of each cutting blade is also provided with... The hydraulic cutter housing is equipped with a locking part that engages with the push rod at the bottom of the plunger. When the plunger moves downward, it presses against the cutting blade through the locking part, causing the cutting blade to rotate and extend outward from the cutting groove to open into a cutting working state. The housing of the hydraulic cutter is also equipped with a pressure relief hole. When the high-pressure chamber formed by the water-sealing steel ball pushes the plunger downward to the pressure relief hole, high-pressure drilling fluid is released. The mandrel is equipped with a thrust ball bearing, a thrust ball bearing, a compression spring, a self-locking nut, and a cotter pin from top to bottom. The bearing sleeve is provided outside the thrust ball bearing, the self-locking nut is threaded to the bottom end of the mandrel, and the compression spring is located between the thrust ball bearing and the self-locking nut. The top of the screw motor is connected to the bypass valve, the top of the bypass valve is connected to the bearing housing, the bearing housing has a through hole inside, and a limiting step is provided on the through hole; The single-acting water sealing assembly includes a single-acting core column, a third thrust ball bearing, a fourth thrust ball bearing, a second self-locking nut, expansion rubber rings, and iron washers. The top of the single-acting core column extends into the through hole of the counterweight at the top of the single-acting water sealing assembly and engages with the step provided at the bottom of the through hole of the counterweight. The bottom shaft of the single-acting core column extends into the bearing seat. Multiple expansion rubber rings are sleeved on the shaft of the single-acting core column between the bearing seat and the counterweight. Iron washers are provided between each expansion rubber ring. The bottom of the bottom iron washer is provided with a limiting sleeve that extends into the bearing seat. The third thrust ball bearing is installed on the single-acting core column between the limiting sleeve and the limiting step in the bearing seat. The fourth thrust ball bearing is installed on the single-acting core column at the bottom of the limiting step. The bottom of the fourth thrust ball bearing is limited by the second self-locking nut. The outer diameter of the hammer is equal to the outer diameter of the expansion rubber ring and the outer diameter of the bearing seat. A through hole is provided inside the hammer, and an external water inlet hole communicating with the through hole is provided on the outer wall of the hammer. The top of the hammer is connected to the spearhead.

2. The borehole bottom power cutting device for in-hole wireline coring accidents according to claim 1, characterized in that: The hydraulic cutter also includes a cylindrical pin and a spring retainer. The cylindrical pin is installed at the top of the plunger hole, and the spring retainer is installed inside the plunger hole and located at the bottom of the cylindrical pin. The plunger is located at the bottom of the cylindrical pin. The cylindrical pin is used to limit the upward stroke of the water-sealing steel ball, and the spring retainer is used to limit the upward stroke of the plunger.

3. The borehole bottom dynamic cutting device for in-hole wireline coring accidents according to claim 1, characterized in that: The hydraulic cutter also includes a cotter pin, which is located at the bottom of the self-locking nut and pinned to the spindle. The cotter pin is used to limit the self-locking nut and prevent it from loosening.

4. The borehole bottom power cutting device for emergency wireline coring drill pipe according to claim 1, characterized in that: The diameter of the plunger hole is larger than the diameter of the pusher hole. The bottom of the plunger hole forms a step that limits the downward stroke of the plunger. A return spring is sleeved on the top of the push rod. The return spring is located between the plunger and the bottom of the plunger hole. When the plunger moves downward, the return spring is compressed. After the plunger finishes working and releases pressure, the return spring begins to extend, causing the plunger to move upward and return to its original position.

5. The borehole bottom dynamic cutting device for in-hole wireline coring accidents according to claim 1, characterized in that: Two sets of the first thrust ball bearing and one set of the second thrust ball bearing are provided. The first and second thrust ball bearings are used to realize the single-action performance between the hydraulic cutter and the bearing sleeve.

6. The borehole bottom dynamic cutting device for in-hole wireline coring accidents according to claim 1, characterized in that: The cutting blade has three blades.

7. The borehole bottom dynamic cutting device for in-hole wireline coring accidents according to claim 1, characterized in that: The bottom end of the screw motor is hollow and has a tapered thread for connecting with the upper tapered thread of the adapter. The top end of the screw motor is hollow and has a tapered thread for connecting with the lower tapered thread of the bypass valve.

8. The borehole bottom power cutting device for in-hole wireline coring accidents according to claim 1, characterized in that: A cotter pin is pinned to the single-acting core at the bottom of the self-locking nut two. The cotter pin two is used to limit the self-locking nut two and prevent it from loosening.

9. The borehole bottom dynamic cutting device for in-hole wireline coring accidents according to claim 1, characterized in that: The expansion rubber rings are provided in 3 sets, and the expansion rubber rings are expansion rubber components.

10. The borehole bottom power cutting device for emergency wireline coring drill pipe according to claim 1, characterized in that: The top of the hammer is provided with a stepped hole for mounting the spearhead, and the spearhead is connected to the hammer by a flexible cylindrical pin.

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