An electromechanical back reamer for ocean drilling

Abstract

The application discloses an electric mechanical follow-up pipe drilling coring drill, which is used for ocean drilling and relates to the field of ocean scientific drilling drilling equipment and technology, and comprises a sleeve pipe, a slip ring assembly capable of moving away from the sleeve pipe, a counter-torque assembly, a sealed cabin, a counterweight assembly and a driving circulation drilling machine, wherein the slip ring assembly, the counter-torque assembly, the sealed cabin, the counterweight assembly and the driving circulation drilling machine are connected in series through an armored cable, the driving circulation drilling machine is used for drilling into a rock layer and collecting a rock core sample, and the driving circulation drilling machine works at least in a pre-drilling state, a drilling state and a post-drilling state. The drill bit of the application can be retracted into the drill and be lifted to the ground surface along with the rope coring drill, and the drill bit can be replaced in time when problems such as wear and tear occur, so that the process of lifting the whole drill away from the deck of a drilling ship due to wear and tear of the drill bit is greatly simplified, thereby saving construction time, saving construction cost and improving construction efficiency.

Description

Technical Field

[0001] This invention relates to the field of ocean scientific drilling equipment and technology, specifically to an electromechanical casing drilling core drilling tool for ocean drilling. Background Technology

[0002] With land covering less than 30% of the Earth's surface and the remainder being oceans, research on land alone is insufficient for sustainable development. Future research will increasingly focus on the deep sea. Deep-sea studies aim to understand seafloor spreading, trace the origins of continental mountain ranges, interpret seafloor sedimentation processes, and uncover the root causes of climate change. Ocean drilling is currently the only method to directly obtain physical data from the Earth's deep interior.

[0003] Since launching the Mohorovičić Discharge (Moho) Drilling Program in the late 1950s, the United States has successively implemented the Deep Sea Drilling Program (DSDP), the Ocean Drilling Program (ODP), the Integrated Ocean Drilling Program (IODP), and the International Ocean Discovery Program (IODP) starting in 1968. Over the past 60 years of global oceanographic drilling, nearly 4,000 wells have been drilled in the world's oceans, yielding over 600,000 meters of core samples and a wealth of data. Based on the information obtained, hypotheses of continental drift and seafloor spreading have been verified; the theory of plate tectonics has been established; the laws governing climate evolution have been revealed; the deep biosphere and methane hydrate have been discovered on the seabed; and significant achievements have been made in the study of ocean history, paleoclimate and paleontology, submarine volcanic eruptions, sedimentation, and seabed mineral distribution, driving repeated major breakthroughs in Earth science.

[0004] In oceanographic drilling aimed at penetrating the Mohorovičić discontinuity (the interface between the mantle and crust), the high risks and long operating times at sea result in daily costs reaching millions of RMB. To improve drilling and coring efficiency, wireline coring is frequently employed. The key feature of wireline coring is that it eliminates the need to remove the entire drill string from the borehole. A specialized retrieval device with a steel wire rope is used to lift the core-containing inner tube at the bottom of the borehole through the center hole of the drill string to the surface, obtaining the core sample. This reduces the number of times the drill string needs to be lowered and raised, as well as the auxiliary time spent raising and lowering the drill string, thus improving drilling efficiency. However, when the drill bit at the bottom of the borehole is severely worn and needs replacement, the entire drilling setup still needs to be lifted to the surface for replacement. After replacement, the entire setup must be lowered back down to the original borehole bottom, a process that consumes a significant amount of time. It is estimated that drilling operations in a 3000m deep hole at a water depth of 3000m would take at least 30 hours, resulting in a waste of millions of RMB.

[0005] Meanwhile, drilling in bedrock is far more difficult and less efficient than drilling in sedimentary rock (soft rock). According to experimental statistics, the mechanical drilling speed in bedrock is generally 1-2 m / h, and the drill bit life is generally 50-100 m; while in sedimentary rock, the mechanical drilling speed can reach 20-30 m / h, and the drill bit life can reach 500-1000 m. Therefore, in oceanographic scientific drilling aimed at penetrating the Moho discontinuity, dozens or even hundreds of tripping operations will be encountered. Frequent tripping operations will inevitably lead to a significant increase in the total cost of drilling operations. Therefore, it is necessary to design a drilling equipment system that connects to a sampling tube with a cable, allowing the bottom drill bit to be lifted from the bottom of the hole to the operating platform along with the sampling tube. Furthermore, the drilling conditions at the bottom of the ocean are complex, and wellbore instability can easily lead to wellbore collapse and other borehole accidents. Therefore, casing is needed to maintain wellbore stability. In summary, to significantly reduce the operation time of ocean drilling, decrease the overall frequency of drilling tool raising and lowering, and improve the efficiency of core drilling and casing running, it is necessary to design an electromechanical drilling tool for ocean drilling that can simultaneously perform casing running and drilling. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides an electromechanical casing drilling core drilling tool for ocean drilling. The drill bit can be retracted into the tool and raised to the surface with the wireline core drilling tool. When problems such as drill bit wear occur, it can be replaced in time, greatly simplifying the process of lifting the entire drilling tool to the drilling vessel deck due to drill bit wear, thereby saving construction time, reducing construction costs, and improving construction efficiency.

[0007] To achieve the above objectives, the present invention can adopt the following technical solutions:

[0008] An electromechanical casing drilling core drilling tool for ocean drilling, comprising:

[0009] Sleeve; and,

[0010] The components include a slip ring assembly, an anti-torsion assembly, a sealed chamber, a counterweight assembly, and a drive circulation drilling rig that can be detached from the casing.

[0011] The slip ring assembly, the anti-torsion assembly, the sealed chamber, the counterweight assembly, and the drive circulation drill are connected in series via an armored cable. The drive circulation drill is used to drill into the rock formation and collect core samples, and the drive circulation drill operates at least in the pre-drilling state, the drilling state, and the post-drilling state.

[0012] The electromechanical casing drilling and coring tool described above, further, the drive circulation drilling rig includes:

[0013] Core sampling tube, used to store core samples;

[0014] A roller cone arm is circumferentially distributed on the outside of the core sampling tube. The roller cone arm is rotatably arranged around its proximal end and has a roller cone drill bit at its distal end.

[0015] A specially designed torsion spring is used to give the distal end of the roller arm a torque toward the core sampling tube;

[0016] A rotating block, disposed between the core sampling tube and the roller cone arm, rotates to support the opening or retraction of the roller cone arm; and,

[0017] A bottom probe, one end of which is connected to the rotating block, wherein when the bottom probe touches the bottom, it opens the rotating block to cause the gear arm to open and maintain this state by a limiting block.

[0018] The electromechanical casing drilling and coring tool described above, further, the drive circulation drilling rig includes:

[0019] A rock cuttings collection chamber is located above the core sampling tube and is connected to the core sampling tube through a rock cuttings return channel. The upper end of the rock cuttings return channel is also provided with an umbrella-shaped rock cuttings baffle.

[0020] Water pumps are used to provide power for the circulation of drilling fluid during drilling operations;

[0021] A filter screen, disposed between the water pump and the rock cuttings collection chamber; and,

[0022] The lower end cap is located between the core sampling tube and the rock cuttings collection chamber.

[0023] As described above, the electromechanical casing drilling and coring tool further includes a drilling motor, an upper coupling, a reducer, and a lower coupling that are mechanically connected in sequence.

[0024] As described above, the electromechanical casing drilling core drill bit further includes a core of the armored cable comprising a plurality of power lines and signal lines, the plurality of power lines and signal lines being wrapped with a nylon layer and externally wound with steel wire.

[0025] The electromechanical casing drilling core drill as described above further includes an upper sliding block and a lower sliding block that do not rotate simultaneously.

[0026] As described above, the electromechanical casing drilling core tool further includes an outwardly extending anti-torsion steel plate for inserting into a slot opened inside the casing.

[0027] As described above, the electromechanical casing drilling core drill bit further includes electronic components in the sealed chamber.

[0028] As described above, the electromechanical casing drilling core drill bit further includes a plurality of counterweight blocks inside the counterweight assembly.

[0029] The electromechanical casing drilling core drill as described above further includes a cable terminal, a first spring, and an armored cable locking device. The armored cable passes through the cable terminal, and the first spring is disposed below the cable terminal. A displacement encoder for monitoring the contraction of the first spring is installed at the lower end of the first spring. The armored cable locking device is disposed between the first spring and the slip ring assembly, and the armored cable locking device is used to fix and tighten the armored cable.

[0030] Compared with existing technologies, the advantages of this invention are as follows: It applies the armored cable-operated electromechanical drilling tool, already maturely used in glacier drilling, to ocean scientific drilling, combined with reaming and casing-running technology. This simplifies the casing-running procedure in ocean drilling and saves casing-running time. Simultaneously, the internal armored cable-operated electromechanical drilling tool is used for drilling and coring. The specially designed telescopic roller cone reamer and bottom drill bit can be raised and lowered along with the internal electromechanical drilling tool, avoiding the need to lift the entire drilling tool to the offshore drilling platform due to drill bit wear. This significantly saves construction and maintenance time, reduces construction costs, and improves construction efficiency, providing technical support for achieving China's ocean scientific drilling goals. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram of the structure of an electromechanical casing drilling core drilling tool for ocean drilling according to an embodiment of the present invention.

[0033] The components include: 1. Armored cable; 2. Sleeve; 3. Cable terminal; 4. First spring; 5. Armored cable locking device; 6. Slip ring assembly; 7. Anti-torsion knife; 8. Anti-torsion steel plate; 9. Second spring; 10. Locking nut; 11. Sealed chamber; 12. Electronic components; 13. Fixing mechanism; 14. Counterweight device; 15. Counterweight block; 16. Intermediate cable; 17. Drilling motor; 18. Upper coupling; 19. Reduction... 20. Speed ​​reducer; 21. Lower coupling; 22. Water pump; 23. Filter screen; 24. Umbrella-shaped cuttings stop; 25. Cuttings collection chamber; 26. Cuttings return channel; 27. Lower end cap; 28. Core; 29. ​​Core sampling tube; 30. Special tube shoe; 31. Special torsion spring; 32. Roller cone arm; 33. Roller cone bit; 34. Core wedge; 35. Rotary block; 36. Limiting block; 37. Bottom probe rod; 38. Bottom drill bit. Detailed Implementation

[0034] 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 this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0035] Example:

[0036] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, in the embodiments of this invention are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0037] It should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0038] In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified. Furthermore, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0039] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0040] See Figure 1 The purpose of this invention is to provide an electromechanical drilling tool for ocean drilling operations, which can simultaneously perform casing installation and drilling. After each core sampling cycle, the drill bit can be retracted into the drilling tool and lifted to the surface with the wireline core sampling tool. If problems such as drill bit wear occur, it can be replaced in time. In ocean scientific drilling operations aimed at penetrating the Moho discontinuity, this greatly simplifies the process of lifting the entire drilling tool to the drilling vessel deck due to drill bit wear, thereby saving construction time, reducing construction costs, improving construction efficiency, and providing technical support for achieving China's ocean scientific drilling goals.

[0041] An electromechanical casing drilling core sampling tool for ocean drilling includes a casing 2 and a slip ring assembly 6 that can be detached from the casing 2, an anti-torsion assembly, a sealed chamber 11, a counterweight assembly, and a drive circulation drilling rig. The slip ring assembly 6, the anti-torsion assembly, the sealed chamber 11, the counterweight assembly, and the drive circulation drilling rig are connected in series via an armored cable 1. The drive circulation drilling rig is used to drill into rock formations and collect core samples. The drive circulation drilling rig operates at least in the pre-drilling state, the drilling operation state, and the post-drilling state.

[0042] In this embodiment, the casing 2 can be assembled from several segments of casing 2. The casing 2 is connected to each other by threads. One end of the assembled casing 2 is connected to the drilling platform, and the other end extends to the bottom of the hole. At a specific height, the casing 2 has several vertical slots in a ring shape around its perimeter. These slots are used to engage with the anti-torsion steel plate 8 of the anti-torsion assembly. Their function is to allow the anti-torsion cutter 7 to extend out of the slot when the anti-torsion assembly of the internal electromechanical drilling tool opens after the drill bit reaches the bottom, providing anti-torsion during drilling. A specially designed pipe shoe 29 is connected to the portion of the casing 2 at the bottom of the hole. The pipe shoe 29 guides the casing 2 and also acts as a limiter, ensuring that the internal drilling tool does not continue to slide outwards after the drill bit contacts the bottom of the hole. Preferably, the length from the slot of the casing 2 to the special shoe 29 of the casing 2 is approximately equal to the height from the anti-torsion component of the drill bit to the core sampling tube 28; at the same time, a ball bearing is fixedly installed on the inner circumference of the special shoe 29, and the special shoe 29 is made of a wear-resistant material with low frictional resistance to prevent the drill bit from wearing the special shoe 29 during rotation.

[0043] As an optional implementation, in some embodiments, the drive circulation drill includes: a core sampling tube 28, a roller cone arm 31, a special torsion spring 30, a rotating block 34, and a bottom probe rod 36. The core sampling tube 28 is used to store core samples; the roller cone arm 31 is circumferentially distributed outside the core sampling tube 28, rotatably arranged around its proximal end, and has a roller cone bit 32 at its distal end; the special torsion spring 30 provides a torque towards the core sampling tube 28 at the distal end of the roller cone arm 31; the rotating block 34 is disposed between the core sampling tube 28 and the roller cone arm 31, rotating to support the opening or retraction of the roller cone arm 31; one end of the bottom probe rod 36 is connected to the rotating block 34, and when the bottom probe rod 36 touches the bottom, it opens the rotating block 34 to cause the roller cone arm 31 to open, and this state is maintained by a limiting block 35.

[0044] In this embodiment, the roller cone arm 31 is inlaid with roller cone palms via ball bearings and other mechanisms, and these palms are evenly distributed in threes along the circumference of the drill rod. The roller cone palms contain a bearing mechanism, an oil reservoir sealing mechanism, and a nozzle device, while cutting teeth are inlaid on their outer surfaces. The roller cone arm 31 retracts towards its axis under the force of a specially designed torsion spring 30, and a limit block 35 at the lower part of the roller cone arm 31 prevents it from retracting. The driving circulation drill also includes a bottom drill bit 37, which is a diamond-impregnated drill bit. The inner wall of the bottom drill bit 37 has an annular hole through which the probe rod 36 passes. Preferably, the bottom drill bit 37 has three evenly spaced rectangular cavities, with the central cavity facilitating the retraction and expansion of the roller cone arm 31. Furthermore, the probe rod 36 is a hollow cylinder with a contact block welded to the upper part. The lower part, extending beyond the drill bit, can contact the bottom of the hole before the drill bit. After contacting the bottom of the hole, the probe rod 36 will move upward relative to the drill bit. This allows the rotating block 34 to rotate via the contact block, thereby causing the roller cone reaming drill bit to open and begin the reaming drilling operation. Preferably, one end of the rotating block 34 is fixed by a pin, and the rotating block 34 can rotate around the pin. The other end of the rotating block 34 is a smooth inclined surface. When the drill bit reaches the bottom of the hole, the rotating block 34 is pushed by the probe rod 36, which can cause the roller cone arm 31 and roller cone palm to open outward. The diameter of the drill bit after opening is larger than the diameter of the bottom drill bit 37, thus achieving the effect of reaming drilling.

[0045] In the above embodiments, the driving circulation drilling rig further includes: a cuttings collection chamber 24, a water pump 21, a filter screen 22, and a lower end cover 26. The cuttings collection chamber 24 is located above the core sampling tube 28 and is connected to the core sampling tube 28 via a cuttings return channel 25. The upper end of the cuttings return channel 25 is also provided with an umbrella-shaped cuttings baffle 23. The water pump 21 provides drilling fluid circulation power during drilling operations. The filter screen 22 is located between the water pump 21 and the cuttings collection chamber 24. The lower end cover 26 is located between the core sampling tube 28 and the cuttings collection chamber 24. Furthermore, the driving circulation drilling rig also includes a drilling motor 17, an upper coupling 18, a reducer 19, and a lower coupling 20, which are mechanically connected in sequence.

[0046] Specifically, drilling fluid carrying cuttings returns from the annular gap between the core sampling tube 28 and the core 27, and enters the cuttings return channel 25 through a reducing connector. The upper end of the cuttings return channel 25 is designed with an umbrella-shaped cuttings baffle 23. After passing through the baffle, the drilling fluid carrying cuttings generates a downward velocity component. However, because the drilling fluid outlet reserved in the cuttings collection chamber 24 is located above the cuttings collection chamber 24, the flow direction of the drilling fluid in the cuttings collection chamber 24 will change 180 degrees after passing through the baffle. Since the density of cuttings particles is greater than that of drilling fluid, the difference in flow direction between the cuttings particles and the drilling fluid allows the cuttings particles to settle better within the cuttings collection chamber 24. A filter screen 22 is fixed at the drilling fluid outlet above the cuttings collection chamber 24, which can perform secondary filtration of the drilling fluid, effectively ensuring that the cuttings are collected within the cuttings collection chamber 24 and preventing cuttings from entering the water pump 21 with the drilling fluid, causing pump wear. Furthermore, the core sampling tube 28 is connected below the cuttings collection chamber 24. The core sampling tube 28 is hollow inside, allowing the core 27 to gradually rise and be stored inside the core sampling tube 28 during drilling and sampling. The drilling motor 17 and the reducer 19 serve as power components that drive the rotation of the lower core drilling tool at the bottom of the hole, transmitting rotational power and torque downwards to the drill tool. The water pump 21, through its pumping action, collects the drilling fluid carrying cuttings into the corresponding cuttings collection chamber 24 via a circulation channel. Preferably, the drilling motor 17 is a bottom-hole servo AC motor, and the water pump 21 is a centrifugal water pump.

[0047] As an optional implementation, in some embodiments, the core of the armored cable 1 includes several power lines and signal lines, which are wrapped with a nylon layer and externally wound with steel wire. In this embodiment, the armored cable 1 contains several power lines and signal lines, wrapped in a high-pressure resistant and corrosion-resistant sealing nylon layer, and externally wound with steel wire. The power lines pass sequentially through the internal channels of the cable terminal 3, the armored cable locking device 5, the slip ring assembly 6, the anti-torsion assembly, the core sampling tube 28, the sealed chamber 11, and the counterweight device 14, until they connect to the drilling motor 17 inside the drive circulation drilling rig to drive the rotation of the lower drill string and the circulation of drilling fluid by the water pump 21 below. The signal lines pass sequentially through the internal channels of the cable terminal 3, the armored cable locking device 5, the slip ring assembly 6, and the anti-torsion assembly, until they connect to various sensors and other components inside the sealed chamber 11. Furthermore, the power lines and signal lines of the armored cable 1 are connected by a pressure-resistant sealed plug when passing through various devices of the drill string.

[0048] As an optional implementation, in some embodiments, the slip ring assembly 6 includes an upper sliding block and a lower sliding block that do not rotate simultaneously. In this embodiment, the slip ring assembly 6 is internally divided into upper and lower parts, with a rolling bearing and a tapered roller bearing installed in the middle. This ensures that when the lower part of the drill bit in the slip ring assembly 6 rotates, the upper part will not rotate with it, thus preventing the armored cable 1 from becoming entangled and damaged.

[0049] As an optional implementation, in some embodiments, the anti-torque assembly has an outwardly extending anti-torque steel plate 8, which is used to insert into a slot opened inside the casing 2. In this embodiment, in order to balance the torque generated during drilling, the anti-torque assembly is located at the lower end of the slip ring component, and four anti-torque cutters 7 are connected around it by a linkage mechanism. The radial extension of the anti-torque cutters 7 can be adjusted by the lower locking nut 10 and the second spring 9. Both the upper and lower ends of the anti-torque cutter 7 are arc-shaped, which facilitates the insertion and exit of the slot opened at a specific height in the casing 2.

[0050] As an optional implementation, in some embodiments, the sealed chamber 11 is equipped with electronic components 12. In this embodiment, the sealed chamber 11 can house the drill string's internal control and detection system. Various sensor components, such as temperature sensors, pressure sensors, and azimuth sensors, as well as some devices for monitoring the bottom of the borehole, are installed inside via a fixing mechanism 13. It can operate without leakage under a liquid environment pressure of 30 MPa, preventing drilling fluid from entering and damaging the circuit board, while also reducing the pressure resistance requirements of the electronic components 12. The signals are connected via signal lines and transmitted to the control console of the drilling platform.

[0051] As an optional implementation, in some embodiments, the counterweight assembly contains a plurality of counterweight blocks 15. In this embodiment, different numbers of counterweight blocks 15 can be added to the counterweight device 14 as needed, thereby adjusting the maximum drilling pressure during each drilling run. Furthermore, the counterweight assembly contains an intermediate cable 16, one end of which is connected to the electronic device 12 inside the sealed chamber 11, and the other end is connected to the drilling motor 17.

[0052] As an optional implementation, in some embodiments, the drill bit further includes a cable terminal 3, a first spring 4, and an armored cable locking device 5. The armored cable 1 passes through the cable terminal 3, and the first spring 4 is disposed below the cable terminal 3. A displacement encoder for monitoring the contraction of the first spring 4 is installed on the first spring 4. The armored cable locking device 5 is disposed between the first spring 4 and the slip ring assembly 6, and is used to fix and tighten the armored cable 1. In this embodiment, the armored cable 1 passes through the cable terminal 3, and the steel wire rope on the outside of the armored cable 1 is unwound, rewound, and fixed to the armored cable locking device 5 below at this position. The internal power line and signal line are transmitted downward from the middle channel. Furthermore, this device is equipped with a first spring 4. Since the lifting and lowering of the drill bit are accomplished through the armored cable 1, when the armored cable 1 is under stress, it may generate instantaneous tension and strain on the internal power and signal lines at the cable terminal 3, which could easily damage the power and signal lines. At this time, the first spring 4 can play a certain buffering role. At the same time, a displacement encoder is also fixedly installed at the lower end of the first spring 4. The displacement encoder can monitor the contraction of the first spring 4 in real time. By using Hooke's law, the load-bearing situation of the armored cable 1 can be obtained in real time, thereby obtaining the drilling pressure applied by the drill bit to the bottom rock. In addition, the armored cable locking device 5 can fix and tighten the armored cable 1, and at the same time transmit the power and signal lines from its interior to the lower part.

[0053] To better understand this invention, the working principle of this invention will be briefly explained below.

[0054] After the drill string assembly is completed, the casing 2 is tightened by the orifice clamp of the drilling platform, and the drill string is lowered to the bottom of the hole along the inner wall of the casing 2 via the armored cable 1. During the lowering of the drill string, a specially designed torsion spring 30, acting on the outer wall of the drill bit body, causes the roller cone arm 31 to retract inward into the drill bit. A limit block 35 at the lower part of the roller cone arm 31 prevents it from retracting too much, which could affect the subsequent coring and sampling. When the drill string approaches the bottom of the hole, the anti-torsion steel plate 8 of the anti-torsion assembly extends out of the drill string under the action of the second spring 9, fitting perfectly into the groove on the inner wall of the casing 2. Subsequently, the bottom probe rod 36 inside the bottom drill bit 37 contacts the bottom of the hole first. As the drill string continues to fall, the bottom probe rod 36 moves upward relative to the drill bit, thereby pushing the rotating block 34 through the contact block at the upper part of the bottom probe rod 36, thus causing the roller cone arm 31 to open. At this moment, the outer step of the core sampling tube 28 of the drill bit falls exactly on the step of the specially made tube shoe 29, and the hole enlargement drilling operation begins.

[0055] The drilling motor 17 of the electromechanical drilling tool is started by controlling the operation room of the drilling platform. The water pump 21, cuttings collection chamber 24, core sampling tube 28, and drill bit at the bottom of the drilling tool begin to rotate. The upper part of the electromechanical drilling tool (including cable terminal 3, slip ring assembly 6, anti-torque assembly, sealed chamber 11, counterweight device 14, and the motor part driving the circulating drilling rig) does not rotate due to the anti-torque effect of the anti-torque assembly. During the rotary core drilling process, as the drilling tool descends, the casing 2 is also conveyed downwards by the clamping device at the top of the drilling platform. Core 27 continuously enters the core sampling tube 28, while the cuttings generated during drilling are carried by the drilling fluid in a local reverse circulation at the bottom of the hole. The cuttings are collected in the cuttings collection chamber 24, while the drilling fluid continues to circulate until the core sampling tube 28 is full of core 27, at which point the motor is turned off and drilling stops.

[0056] When core sampling is completed and the drill string needs to be lifted, drilling is first stopped, and the armored cable 1 is raised. At this time, the core 27 moves downward relative to the bottom drill bit 37, and the core wedge 33 tightens, cutting the core 27 and storing it in the core sampling tube 28. Meanwhile, the roller arm 31 retracts inward under the action of the special torsion spring 30, returning to the drill string. The contact block above the bottom probe rod 36 falls onto the step of the bottom drill bit 37. The anti-torsion assembly at the top of the drill string is retracted into the casing 2 until the drill string is raised to the surface and removed from the casing 2. After removing the core 27 and cleaning the cuttings from the cuttings collection chamber 24, the core sampling tube 28, the cuttings collection chamber 24, and the drill bit are connected. The drill string is then lowered along the inner wall of the casing 2 to the bottom of the hole via the armored cable 1 to begin the next drilling operation.

[0057] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0058] The above embodiments are merely illustrative of the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made based on the essence of the content of the present invention should be covered within the scope of protection of the present invention.

Claims

1. An electromechanical casing drilling core drilling tool for ocean drilling, characterized in that, include: casing; as well as, The slip ring assembly, anti-torsion assembly, sealing chamber, counterweight assembly, and drive circulation drilling rig are detachable from the casing. The slip ring assembly, the anti-torsion assembly, the sealed chamber, the counterweight assembly, and the drive circulation drilling rig are connected in series via an armored cable. The drive circulation drilling rig is used to drill into rock formations and collect core samples. The drive circulation drilling rig operates at least in the pre-drilling state, the drilling operation state, and the post-drilling state. The drive circulation drilling rig includes: Core sampling tubes are used to store core samples; A roller cone arm is circumferentially distributed on the outside of the core sampling tube. The roller cone arm is rotatably arranged around its proximal end and has a roller cone drill bit at its distal end. A specially designed torsion spring is used to give the distal end of the roller arm a torque toward the core sampling tube; A rotating block, disposed between the core sampling tube and the roller cone arm, rotates to support the opening or retraction of the roller cone arm; and, A bottom probe, one end of which is connected to the rotating block, wherein when the bottom probe touches the bottom, it opens the rotating block to cause the gear arm to open and maintain this state by a limiting block.

2. The electromechanical casing drilling core drilling tool according to claim 1, characterized in that, The drive circulation drilling rig includes: A rock cuttings collection chamber is located above the core sampling tube and is connected to the core sampling tube through a rock cuttings return channel. The upper end of the rock cuttings return channel is also provided with an umbrella-shaped rock cuttings baffle. Water pumps are used to provide power for the circulation of drilling fluid during drilling operations; A filter screen, disposed between the water pump and the rock cuttings collection chamber; and, The lower end cap is located between the core sampling tube and the rock cuttings collection chamber.

3. The electromechanical casing drilling core drilling tool according to claim 1, characterized in that, The drive circulation drilling rig also includes a drilling motor, an upper coupling, a reducer, and a lower coupling, which are mechanically connected in sequence.

4. The electromechanical casing drilling core drilling tool according to claim 1, characterized in that, The core of the armored cable includes several power lines and signal lines, which are wrapped with a nylon layer and externally wound with steel wire.

5. The electromechanical casing drilling core drilling tool according to claim 1, characterized in that, The slip ring assembly includes an upper sliding block and a lower sliding block that do not rotate simultaneously.

6. The electromechanical casing drilling core drilling tool according to claim 1, characterized in that, The anti-torsion assembly has an outwardly extending anti-torsion steel plate, which is used to insert into a slot opened inside the sleeve.

7. The electromechanical casing drilling core drilling tool according to claim 1, characterized in that, The sealed chamber is equipped with electronic devices.

8. The electromechanical casing drilling core drilling tool according to claim 1, characterized in that, The counterweight assembly contains several counterweight blocks.

9. The electromechanical casing drilling core drilling tool according to claim 1, characterized in that, It also includes a cable terminal, a first spring, and an armored cable locking device. The armored cable passes through the cable terminal, and the first spring is disposed below the cable terminal. A displacement encoder for monitoring the contraction of the first spring is installed at the lower end of the first spring. The armored cable locking device is disposed between the first spring and the slip ring assembly, and the armored cable locking device is used to fix and tighten the armored cable.

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