Drilling tool structure and drilling equipment

Abstract

The invention discloses a drilling tool structure and drilling equipment, the drilling tool structure comprises at least two sections of drilling rods, and the drilling rods are connected in sequence; the rock core sampling mechanisms are arranged in at least two sections of drill rods, and each rock core sampling mechanism comprises a driving assembly, a transmission assembly and a rock core grabbing assembly capable of extending out of the corresponding drill rod; the driving assembly can drive the rock core grabbing assembly to rotate through the transmission assembly and drive the rock core grabbing assembly to extend out of the drill rod, so that the rock core grabbing assembly can drill into a well wall to collect a rock core sample. Compared with a traditional coring tool for collecting rock core samples in a rotary drilling coring mode, the drilling tool structure can conduct sampling while drilling, rock core samples of multiple different target stratums can be collected through one-time drilling operation, and the collecting efficiency of the rock core samples can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of drilling, and particularly relates to a drill string structure and a drilling device. Background Art

[0002] Natural Gas Hydrate (commonly known as combustible ice) is an ice-like crystalline substance formed by natural gas and water under low-temperature and high-pressure conditions, and is widely distributed in deep-sea sediments and permafrost regions on land. During the exploration process of natural gas hydrates, the logging-while-drilling method is usually adopted to identify the occurrence state and physical property characteristic parameters of hydrate reservoirs in real time. At the same time, it is also necessary to obtain core samples of underground rock formations to analyze the formation characteristics.

[0003] In related technologies, core samples are usually collected on the wellbore wall of a well, specifically including the following two collection methods: 1. The method of impact coring on the wellbore wall. Specifically, a coring tool is shot into the wellbore wall by the impact force formed by gunpowder explosion to obtain a core sample, and then the coring tool together with the collected core sample is taken out of the well. However, the core samples obtained by this method are small in volume and irregular in shape, and basically cannot be used for physical analysis and testing; 2. The method of rotary coring into the wellbore wall. Specifically, a coring tool is rotated into the wellbore wall by a driving structure to obtain a core sample, and then the coring tool together with the collected core sample is taken out of the well. This method has a wide range of applicable formations, and the quality of the obtained core samples is better and more complete. Therefore, the method of rotary coring into the wellbore wall is mostly adopted to collect core samples at present.

[0004] However, the coring tool for collecting core samples by the traditional method of rotary coring into the wellbore wall can only collect core samples of a specific target formation each time it enters the well for operation. When it is necessary to collect core samples of multiple different target formations, it can only be achieved through multiple collections. And multiple collections mean that the coring tool needs to enter the well for operation multiple times, and after each entry into the well for operation, the coring tool needs to be fished out to take out the collected core samples, resulting in a low collection efficiency of the core samples. In addition, the coring tool for collecting core samples by the traditional method of rotary coring into the wellbore wall still has the problem of poor integrity of the collected core samples. Summary of the Invention

[0005] The present application aims to at least solve one of the technical problems existing in the prior art. For this purpose, the present application provides a drill string structure that can take samples while drilling, and can collect core samples of multiple different target formations in one drilling operation, which is beneficial to improving the collection efficiency of core samples.

[0006] The present application also provides a drilling device with the above drill string structure.

[0007] The drill string structure according to the first aspect embodiment of the present application includes:

[0008] At least two drill pipes, and the drill pipes are connected in sequence.

[0009] A core sampling mechanism. The core sampling mechanism is arranged inside at least two of the drill pipes. The core sampling mechanism includes a driving assembly, a transmission assembly, and a core grabbing assembly that can extend to the outside of the drill pipe. The driving assembly can drive the core grabbing assembly to rotate through the transmission assembly and drive the core grabbing assembly to extend to the outside of the drill pipe, so that the core grabbing assembly can drill into the wellbore to collect core samples.

[0010] The drill tool structure according to the embodiment of the present application has at least the following beneficial effects: When the drill bit of the drill tool structure stops drilling to end the drilling operation, the part of the drill tool structure located inside the well can be driven to move up and down, so that the drill pipe with the core sampling mechanism inside moves to the target formation. Subsequently, the driving assembly is started, so that the driving assembly drives the core grabbing assembly to rotate through the transmission assembly and drives the core grabbing assembly to extend to the outside of the drill pipe, so that the core grabbing assembly drills into the wellbore of the target formation to collect core samples. Subsequently, the core grabbing assembly with the collected core samples is retracted into the drill pipe, and finally the drill tool structure is retracted to obtain the collected core samples. Among them, the core sampling mechanism is arranged inside at least two drill pipes. When collecting core samples, all the drill pipes with the core sampling mechanism inside can be driven to move to different target formations one by one to collect core samples. Compared with the traditional core sampling tool that uses rotary drilling to take cores, the drill tool structure of the embodiment of the present application can sample while drilling, and can collect core samples of multiple different target formations in one drilling operation, which is beneficial to improving the collection efficiency of core samples.

[0011] According to some embodiments of the present application, a first channel for accommodating the core sampling mechanism is arranged inside the corresponding drill pipe. The first channel has a first channel inlet end and a first channel outlet end. The first channel inlet end is used for pumping drilling fluid, and the first channel outlet end penetrates the outer side wall of the drill pipe. The driving assembly includes a positive displacement motor stator and a positive displacement motor rotor. The positive displacement motor stator is slidably arranged inside the first channel, and the positive displacement motor rotor is rotatably arranged inside the positive displacement motor stator and acts on the transmission assembly.

[0012] According to some embodiments of the present application, a second channel is provided inside each drill pipe, which axially penetrates the drill pipe along the axis of the drill pipe. The second channel is used for pumping drilling fluid. An installation channel is provided at the head end of the drill pipe with the core sampling mechanism inside. The second channel has a second channel inlet end and a second channel outlet end. The first channel inlet end and the second channel inlet end are both connected to the installation channel. A sealing ring is fixedly provided in the installation channel. A diversion pipe is inserted through the sealing ring. One end of the diversion pipe is inserted into the second channel inlet end, and the other end of the diversion pipe is provided with an annular blocking portion for blocking the drilling fluid from flowing towards the first channel inlet end. A pin for fixing the two is provided between the annular blocking portion and the sealing ring. The diversion pipe can break the pin and slide relative to the sealing ring when subjected to an external force to release the blockage of the annular blocking portion on the drilling fluid. Among the drill pipes with the core sampling mechanism inside, the inner diameters of the diversion pipes decrease one by one, so that the inner diameter of the diversion pipe closer to the drill bit in any two diversion pipes is smaller than the inner diameter of the diversion pipe farther from the drill bit.

[0013] According to some embodiments of the present application, the first channel has a first section and a second section. The drive assembly is arranged in the first section, and the transmission assembly and the core grabbing assembly are arranged in the second section. The second section is inclined or curved so that the core grabbing assembly can extend out of the drill pipe in a posture inclined to the axis of the drill pipe.

[0014] According to some embodiments of the present application, an inclined or curved groove is provided on the outer side wall of the drill pipe with the core sampling mechanism inside. A pressing plate fixedly connected to the drill pipe is covered at the groove. The pressing plate and the groove enclose at least part of the second section.

[0015] According to some embodiments of the present application, the transmission assembly includes a flexible transmission shaft and a flexible housing sleeved outside the flexible transmission shaft. The screw motor rotor acts on the flexible transmission shaft and the flexible housing. The flexible transmission shaft can be bent and deformed and is used for transmitting torque. The flexible housing can be bent and deformed and is used for transmitting thrust and tension.

[0016] According to some embodiments of the present application, an elastic reset structure is provided between the screw motor rotor and the transmission assembly. The elastic reset structure is used to drive the core grabbing assembly extending out of the drill pipe to retract into the drill pipe.

[0017] According to some embodiments of the present application, a pressure relief hole communicating with the first channel is provided on the side wall of the drill pipe with the core sampling mechanism inside.

[0018] According to some embodiments of the present application, the core grabbing assembly includes a sampling cylinder and cutting teeth. One end of the sampling cylinder is an open end, the other end of the sampling cylinder is connected to the transmission assembly, and the cutting teeth are arranged at the open end of the sampling cylinder.

[0019] According to some embodiments of the present application, the core grabbing assembly further includes a clamping structure for clamping the collected core sample.

[0020] The drilling equipment according to the second aspect embodiment of the present application includes a drill string structure according to the first aspect embodiment of the present application above.

[0021] The additional aspects and advantages of the present application will be partially given in the following description, partially become apparent from the following description, or be understood through the practice of the present application. Description of the Drawings

[0022] The above and / or additional aspects and advantages of the present application will become apparent and be easily understood from the description of the embodiments in conjunction with the following drawings, where:

[0023] Figure 1 is a partial cross-sectional view of a drill pipe with a core sampling mechanism inside after hiding the core sampling mechanism in an embodiment of the present application;

[0024] Figure 2 is Figure 1 a partial enlarged view of part A in

[0025] Figure 3 is a partial cross-sectional view of a drill pipe with a core sampling mechanism inside after hiding the pressing plate in an embodiment of the present application;

[0026] Figure 4 is Figure 3 a partial enlarged view of part B in

[0027] Figure 5 is Figure 3 a schematic diagram of the structure shown after hiding the core sampling mechanism;

[0028] Figure 6 is a half-sectional view of a drill pipe with a core sampling mechanism inside after hiding the pressing plate in an embodiment of the present application;

[0029] Figure 7 is Figure 6 a partial enlarged view of part C in

[0030] Figure 8 is Figure 6 a schematic diagram of the structure shown after hiding the core sampling mechanism;

[0031] Figure 9Schematic diagram of the flow path of drilling fluid when the drill pipe with a core sampling mechanism inside is not blocked by a sphere in a specific embodiment of the present application;

[0032] Figure 10 Schematic diagram of the flow path of drilling fluid when the drill pipe with a core sampling mechanism inside is blocked by a sphere in a specific embodiment of the present application;

[0033] Figure 11 Partial sectional view schematic diagram of the transmission component and the core grasping component in a specific embodiment of the present application;

[0034] Figure 12 Is Figure 11 Partial enlarged view schematic diagram at position D in

[0035] Figure 13 Sectional view schematic diagram of a housing unit in the flexible housing in a specific embodiment of the present application;

[0036] Figure 14 Structural schematic diagram of a diverter joint in a specific embodiment of the present application.

[0037] Reference numerals:

[0038] Sphere M;

[0039] Drill pipe 100, first channel 110, first channel inlet end 110a, first channel outlet end 110b, first section 111, second section 112, limit step 113, second channel 120, second channel inlet end 120a, second channel outlet end 120b, installation channel 130, groove 140, pressure relief hole 150;

[0040] Screw motor stator 210, screw motor rotor 220;

[0041] Sealing ring 310, diversion pipe 320, annular blocking portion 321, pin 330;

[0042] Diverter joint 400, diversion hole 410;

[0043] Pressing plate 500;

[0044] Flexible transmission shaft 610, transmission shaft main body 611, first connection portion 612, second connection portion 613, flexible housing 620, first sub-unit 621, second sub-unit 622, spherical joint 623, third connection portion 624, fourth connection portion 625;

[0045] Connecting shaft 710, limiting portion 711, helical spring 720, washer 730;

[0046] Sampling cylinder 810, cutting teeth 820, annular mounting groove 821, snap ring 830, elastic portion 831, guiding inclined surface 8311. Detailed implementation manners

[0047] The embodiments of the present application will be described in detail below. The examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and should not be construed as a limitation to the present application.

[0048] In the description of the present application, it should be understood that if orientation descriptions are involved, such as the orientations or positional relationships indicated by up, down, front, back, left, right, etc. are based on the orientations or positional relationships shown in the accompanying drawings. This is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present application.

[0049] In the description of the present application, if words such as several, greater than, less than, exceeding, above, below, within, etc. appear, where the meaning of several is one or more, the meaning of multiple is two or more, greater than, less than, exceeding, etc. are understood as not including the present number, and above, below, within, etc. are understood as including the present number.

[0050] In the description of the present application, if words such as first, second, etc. appear, they are only used for the purpose of distinguishing technical features and should not be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0051] In the description of the present application, unless otherwise clearly defined, words such as setting, installing, connecting, etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in the present application in combination with the specific content of the technical solution.

[0052] Referring to Figures 1 to 14 , according to the drill string structure of the embodiment of the present application, it includes a drill pipe 100 and a core sampling mechanism.

[0053] Specifically, the number of the drill pipes 100 is at least two sections, and the drill pipes 100 are connected in sequence. An internal core sampling mechanism is provided in at least two sections of the drill pipes 100. The core sampling mechanism includes a driving assembly, a transmission assembly, and a core grabbing assembly that can extend to the outside of the drill pipe 100. The driving assembly can drive the core grabbing assembly to rotate through the transmission assembly and drive the core grabbing assembly to extend to the outside of the drill pipe 100, so that the core grabbing assembly can drill into the wellbore to collect core samples.

[0054] After the drill bit of the drill string structure stops drilling to end the drilling operation, the part of the drill string structure located inside the wellbore can be driven to move up and down, so that the drill pipe 100 with a core sampling mechanism installed inside can be moved to the target formation. Subsequently, the drive assembly is activated, so that the drive assembly drives the core grabbing assembly to rotate through the transmission assembly and drives the core grabbing assembly to extend outside the drill pipe 100, so that the core grabbing assembly drills into the wellbore wall of the target formation to collect core samples. Subsequently, the core grabbing assembly with the collected core samples is retracted into the drill pipe 100, and finally the drill string structure is retracted to obtain the collected core samples. Among them, at least two drill pipes 100 are provided with a core sampling mechanism inside. When collecting core samples, all the drill pipes 100 provided with a core sampling mechanism inside can be driven to move to different target formations one by one to collect core samples. Compared with the traditional core sampling tool that uses rotary coring to collect core samples, the drill string structure of the embodiment of the present application can perform sampling while drilling, and can collect core samples from multiple different target formations in one drilling operation, which is beneficial to improving the collection efficiency of core samples.

[0055] It should be noted that the conventional drill string structure not only includes the above-mentioned drill pipe 100, but also includes a drill bit provided at the end for drilling.

[0056] Refer to Figure 1 、 Figure 3 and Figures 5 to 10 In some of the embodiments, a first channel 110 for accommodating the core sampling mechanism is provided inside the corresponding drill pipe 100. The first channel 110 has a first channel inlet end 110a and a first channel outlet end 110b. The first channel inlet end 110a is used for pumping drilling fluid, and the first channel outlet end 110b penetrates the outer wall of the drill pipe 100. The drive assembly includes a positive displacement motor stator 210 and a positive displacement motor rotor 220. The positive displacement motor stator 210 is slidably arranged in the first channel 110, and the positive displacement motor rotor 220 is rotatably arranged in the positive displacement motor stator 210 and acts on the transmission assembly. The positive displacement motor rotor 220 can rotate relative to the positive displacement motor stator 210 under the drive of the drilling fluid and drive the positive displacement motor stator 210 to slide along the first channel 110, so that the positive displacement motor rotor 220 can drive the core grabbing assembly to rotate through the transmission assembly and drive the core grabbing assembly to extend outside the drill pipe 100. When it is necessary to drive the core sampling mechanism to collect core samples, pumping drilling fluid into the first channel 110 is sufficient, and its structure is simple and easy to operate.

[0057] Refer to Figures 1 to 10, in some of these embodiments, a second channel 120 penetrating the drill pipe 100 axially is provided inside each drill pipe 100. The second channel 120 is used for pumping drilling fluid. An installation channel 130 is provided at the head end of the drill pipe 100 with a core sampling mechanism inside. The second channel 120 has a second channel inlet end 120a and a second channel outlet end 120b. The first channel inlet end 110a and the second channel inlet end 120a are both connected to the installation channel 130. A sealing ring 310 is fixedly provided in the installation channel 130. A diversion pipe 320 is inserted through the sealing ring 310. One end of the diversion pipe 320 is inserted into the second channel inlet end 120a. The other end of the diversion pipe 320 is provided with an annular blocking portion 321 for blocking the drilling fluid from flowing towards the first channel inlet end 110a. A pin 330 for fixing the two is provided between the annular blocking portion 321 and the sealing ring 310. The diversion pipe 320 can break the pin 330 and slide relative to the sealing ring 310 when subjected to an external force to release the block of the annular blocking portion 321 on the drilling fluid. When the drilling tool structure is performing a drilling operation, the annular blocking portion 321 can block the drilling fluid from flowing towards the first channel inlet end 110a, that is, the drilling fluid can only flow through the second channel 120 to the drill bit of the drilling tool structure. When it is necessary to drive the core sampling mechanism to collect a core sample, a sphere M is put into the second channel 120. Among them, the diameter of the sphere M is larger than the inner diameter of the diversion pipe 320, and at the same time, the diameter of the sphere M is smaller than the inner diameter of the second channel 120, so that the sphere M can block the corresponding diversion pipe 320. After the diversion pipe 320 is blocked by the sphere M, it will be subjected to the pressure of the drilling fluid pumped into the second channel 120, so that the diversion pipe 320 breaks the pin 330 and slides relative to the sealing ring 310 to release the block of the annular blocking portion 321 on the drilling fluid. At this time, the drilling fluid can be pumped into the first channel 110 to drive the screw motor rotor 220 to rotate relative to the screw motor stator 210 and drive the screw motor stator 210 to slide along the first channel 110.

[0058] Refer to Figure 1 , Figure 5 , Figure 9 and Figure 10 , in some of these embodiments, at least two non-interfering first channels 110 are provided inside the corresponding drill pipe 100, and a core sampling mechanism is provided in each first channel 110. So that the same drill pipe 100 with a core sampling mechanism inside can collect at least two core samples after the drilling stops.

[0059] Refer to Figure 1 , Figure 3 , Figure 5 , Figure 9 , Figure 10 and Figure 14, in some of these embodiments, when at least two non-interfering first channels 110 are provided inside the corresponding drill pipe 100, a flow splitting joint 400 fixedly arranged in the installation channel 130 is sleeved on the diversion pipe 320. At least two flow splitting holes 410 corresponding to the first channel inlet ends 110a of the respective first channels 110 are provided on the flow splitting joint 400. When the annular blocking portion 321 releases the blockage of the drilling fluid, the flow splitting joint 400 can specifically split the drilling fluid into each first channel 110, thereby facilitating the improvement of the directivity of the drilling fluid flow and enabling the drilling fluid to quickly and efficiently flow into the first channel 110.

[0060] In some of these embodiments, among the drill pipes 100 each internally provided with a core sampling mechanism, the inner diameters of the respective diversion pipes 320 decrease one by one, so that the inner diameter of the diversion pipe 320 closer to the drill bit among any two diversion pipes 320 is smaller than the inner diameter of the diversion pipe 320 farther from the drill bit. When it is necessary to collect a core sample from the first target formation, first move the drill pipe 100 corresponding to the diversion pipe 320 closest to the drill bit (hereinafter referred to as the first diversion pipe 320) to the first target formation, and then put a sphere M with a diameter only larger than the inner diameter of the first diversion pipe 320 into the second channel 120. At this time, the sphere M can only block the first diversion pipe 320, so that the drilling fluid can only specifically drive the corresponding core sampling mechanism to collect the core sample at the first target formation. When it is necessary to collect a core sample from the second target formation, first move the drill pipe 100 corresponding to the diversion pipe 320 closest to the first diversion pipe 320 (hereinafter referred to as the second diversion pipe 320) to the second target formation, and then put a sphere M with a diameter only larger than the inner diameters of the first diversion pipe 320 and the second diversion pipe 320 into the second channel 120. At this time, the sphere M can only block the second diversion pipe 320, so that the drilling fluid can only specifically drive the corresponding core sampling mechanism to collect the core sample at the second target formation. According to the above method, by successively putting spheres M with increasing diameters, the core sampling mechanisms arranged in different drill pipes 100 can be successively driven to collect core samples from different target formations respectively, thereby realizing the function of collecting core samples from multiple different target formations in one drilling operation.

[0061] Specifically, the drill pipes 100 each provided with a core sampling mechanism may be adjacent or not adjacent to each other, which is not limited herein.

[0062] Refer to Figures 1 to 3 and Figure 5 、 Figure 8 and Figure 9 , in some of these embodiments, one end of the diversion pipe 320 provided with the annular blocking portion 321 is flared, so that the sphere M put into the second channel 120 can quickly and accurately block the corresponding diversion pipe 320.

[0063] It should be noted that in some other embodiments, channels for conveying drilling fluid independent of the second channel 120 may be respectively provided for different first channels 110. In this case, there is no need to drive the drilling fluid to flow into the first channel 110 by inserting the sphere M to block the diversion pipe 320, that is, there is no need to provide structures such as the above-mentioned sealing ring 310 and diversion pipe 320.

[0064] Referring to Figure 1 、 Figure 5 and Figure 8 , in some of these embodiments, the first channel 110 has a first section 111 and a second section 112. The driving assembly is arranged in the first section 111, and the transmission assembly and the core grabbing assembly are arranged in the second section 112. The second section 112 is inclined or bent so that the core grabbing assembly can extend out of the drill pipe 100 in a posture inclined to the axis of the drill pipe 100. Compared with the situation where the core grabbing assembly extends out of the drill pipe 100 in a posture perpendicular to the axis of the drill pipe 100, during the process of retracting the core grabbing assembly that extends out of the drill pipe 100, it is beneficial to prevent jamming, so as to facilitate the smooth retraction of the core grabbing assembly that extends out of the drill pipe 100.

[0065] Referring to Figure 1 、 Figure 5 and Figure 8 , in some of these embodiments, the first section 111 is parallel to the second channel 120, which is beneficial to reducing the processing difficulty of the first section 111.

[0066] Referring to Figure 3 、 Figure 5 、 Figure 6 and Figure 8 , in some of these embodiments, on the outer sidewall of the drill pipe 100 with a core sampling mechanism arranged inside, there is a groove 140 that is inclined or bent. A pressing plate 500 fixedly connected to the drill pipe 100 is provided at the groove 140. The pressing plate 500 and the groove 140 enclose at least part of the second section 112. In this way, the processing difficulty of the second section 112 can be reduced.

[0067] Referring to Figure 4 as well as Figures 9 to 11 , in some of these embodiments, the transmission assembly includes a flexible transmission shaft 610 and a flexible housing 620 sleeved outside the flexible transmission shaft 610. The screw motor rotor 220 acts on the flexible transmission shaft 610 and the flexible housing 620. The flexible transmission shaft 610 can be bent and deformed and is used for transmitting torque, and the flexible housing 620 can be bent and deformed and is used for transmitting thrust and tension. In this way, the transmission assembly can adapt to the inclined or bent second section 112.

[0068] Referring to Figure 4and Figures 9 to 11 In some embodiments, the flexible transmission shaft 610 includes a transmission shaft main body 611 which is a steel wire rope, enabling the flexible transmission shaft 610 to bend and deform. One end of the transmission shaft main body 611 is provided with a first connection portion 612 for inputting power, and the other end of the transmission shaft main body 611 is provided with a second connection portion 613 for outputting power. Its structure is simple and easy to implement.

[0069] Referring to Figure 4 、 Figure 11 and Figure 13 In some embodiments, the flexible housing 620 includes a plurality of sequentially connected housing units. The housing unit includes a first sub-unit 621, a second sub-unit 622, and a spherical joint 623. The spherical joint 623 is disposed between the first sub-unit 621 and the second sub-unit 622, enabling the flexible housing 620 to bend and deform. One end of the flexible housing 620 is provided with a third connection portion 624 for inputting power, and the other end of the flexible housing 620 is provided with a fourth connection portion 625 for outputting power. Its structure is simple and easy to implement.

[0070] Specifically, since the flexible housing 620 is provided with the spherical joint 623, the flexible housing 620 cannot transmit torque. To improve the torque transmission efficiency, the third connection portion 624 is rotatably connected to the adjacent housing unit, and the fourth connection portion 625 is rotatably connected to the adjacent housing unit. When the screw motor rotor 220 drives the flexible transmission shaft 610 to rotate, the housing units of the flexible housing 620 will not rotate accordingly, so that the torque generated when the screw motor rotor 220 rotates is mainly transmitted to the flexible transmission shaft 610.

[0071] In some embodiments, an elastic reset structure is provided between the screw motor rotor 220 and the transmission assembly. The elastic reset structure is used to drive the core grabbing assembly extending to the outside of the drill pipe 100 to retract into the drill pipe 100, that is, to drive the core grabbing assembly extending to the outside of the drill pipe 100 to retract into the second section 112. After a certain core grabbing assembly completes the collection of the core sample, the pumping of the drilling fluid is stopped, and this core grabbing assembly can automatically retract into the drill pipe 100 under the action of the elastic reset structure.

[0072] Referring to Figure 3 、 Figure 4 、 Figure 6 、 Figure 7 、 Figure 9 and Figure 10, in some of these embodiments, the elastic reset structure includes a connecting shaft 710 and a helical spring 720. One end of the connecting shaft 710 is connected to the screw motor rotor 220, and the other end of the connecting shaft 710 is connected to the transmission assembly. The helical spring 720 is sleeved on the connecting shaft 710. A limiting portion 711 is provided at one end of the connecting shaft 710 close to the screw motor rotor 220. One end of the helical spring 720 abuts against the limiting portion 711, and a limiting step 113 is provided in the first channel 110 corresponding to the other end of the helical spring 720. When the screw motor rotor 220 rotates relative to the screw motor stator 210 under the drive of the drilling fluid and drives the screw motor stator 210 to slide along the first channel 110, it can drive the connecting shaft 710 to rotate and slide along the first channel 110, so as to drive the core grabbing assembly to rotate and extend out of the drill pipe 100 through the transmission assembly. Among them, when the connecting shaft 710 rotates and slides along the first channel 110 under the drive of the screw motor rotor 220, since the other end of the helical spring 720 away from the limiting portion 711 is restricted by the limiting step 113, the limiting portion 711 can compress the helical spring 720. When the pumping of the drilling fluid stops, the helical spring 720 resets, so as to drive the core grabbing assembly to retract into the drill pipe 100.

[0073] Refer to Figure 4 , in some of these embodiments, a washer 730 is sleeved on the connecting shaft 710 between the helical spring 720 and the limiting step 113, and the other end of the helical spring 720 away from the limiting portion 711 abuts against the washer 730.

[0074] It should be noted that, in some other embodiments, the other end of the helical spring 720 away from the limiting portion 711 can also directly abut against the limiting step 113, which is not limited herein.

[0075] Refer to Figure 4 , in some of these embodiments, the other end of the connecting shaft 710 away from the screw motor rotor 220 is connected to the flexible transmission shaft 610 and the flexible housing 620. Specifically, the other end of the connecting shaft 710 away from the screw motor rotor 220 is connected to the first connecting portion 612 and the third connecting portion 624.

[0076] Refer to Figure 7 、 Figure 9 and Figure 10 , in some of these embodiments, a pressure relief hole 150 communicating with the first channel 110 is provided on the side wall of the drill pipe 100 with a core sampling mechanism inside. During the process of the helical spring 720 driving the core grabbing assembly to retract into the drill pipe 100, the drilling fluid in the first channel 110 can be discharged through the pressure relief hole 150 to reduce the reset pressure of the helical spring 720, so that the core grabbing assembly can retract into the drill pipe 100 more stably after the pumping of the drilling fluid stops.

[0077] Referring to Figure 7 、 Figure 9 and Figure 10 , in some of these embodiments, the pressure relief hole 150 is located on the side of the limiting portion 711 facing away from the screw motor rotor 220. Among them, the pressure relief hole 150 is configured to be located on the side of the limiting portion 711 facing the screw motor rotor 220 when the core grabbing assembly extends out of the drill pipe 100. When the core grabbing assembly completely extends out of the drill pipe 100, the limiting portion 711 has a certain blocking effect on the drilling fluid. At this time, the pressure in the first channel 110 is relatively large. When the core grabbing assembly completely extends out of the drill pipe 100, the position of the limiting portion 711 changes, so that the pressure relief hole 150 is located on the side of the limiting portion 711 facing the screw motor rotor 220. At this time, the flow path of the drilling fluid between the screw motor rotor 220 and the pressure relief hole 150 is no longer blocked by the limiting portion 711, enhancing the pressure relief effect of the pressure relief hole 150, thereby suddenly reducing the pressure in the first channel 110. Therefore, by detecting the change in the pressure in the first channel 110, the timing when the core grabbing assembly completely extends out of the drill pipe 100 can be determined, and thus the pumping of the drilling fluid can be stopped in a timely manner.

[0078] Specifically, the pressure relief hole 150 communicates with the first section 111.

[0079] It should be noted that in some other embodiments, the core grabbing assembly extending out of the drill pipe 100 can also be retracted into the drill pipe 100 by the traction of a steel wire rope, which is not limited herein.

[0080] Referring to Figure 11 and Figure 12 , in some of these embodiments, the core grabbing assembly includes a sampling cylinder 810 and cutting teeth 820. One end of the sampling cylinder 810 is an open end, and the other end of the sampling cylinder 810 is connected to the transmission assembly. The cutting teeth 820 are arranged at the open end of the sampling cylinder 810, and its structure is simple and easy to implement. Among them, by arranging the cutting teeth 820 at the open end of the sampling cylinder 810, the sampling cylinder 810 can drill into the wellbore of the target formation to collect core samples.

[0081] Specifically, the cutting teeth 820 are annular to avoid the core, so that the core can enter the sampling cylinder 810.

[0082] Specifically, both the second connecting portion 613 and the fourth connecting portion 625 are connected to the sampling cylinder 810.

[0083] In some of these embodiments, the core grabbing assembly further includes a clamping structure for clamping the collected core sample, which helps to reduce the risk of the core sample collected in the sampling cylinder 810 detaching from the sampling cylinder 810, thereby helping to improve the integrity of the collected core sample.

[0084] In some of these embodiments, the clamping structure includes an elastic flexible bushing disposed on the inner wall of the sampling cylinder 810. During use, the core sample collected in the sampling cylinder 810 will squeeze the flexible bushing, causing the flexible bushing to elastically deform, so that the flexible bushing can provide an elastic force for clamping the collected core sample.

[0085] Specifically, the flexible bushing can be a silicone part or a rubber part, and is not limited herein.

[0086] Refer to Figure 12 , in some of these embodiments, the clamping structure includes a snap ring 830. An annular mounting groove 821 is provided on the inner wall of the cutting teeth 820, and the snap ring 830 is disposed in the annular mounting groove 821. An elastic portion 831 protruding from the inner wall of the sampling cylinder 810 is provided on the inner ring of the snap ring 830. A guiding inclined surface 8311 for facilitating the core to enter the sampling cylinder 810 is provided on the side of the elastic portion 831 facing away from the transmission assembly. During use, the core sample collected in the sampling cylinder 810 will squeeze the elastic portion 831, causing the elastic portion 831 to elastically deform, so that the elastic portion 831 can provide an elastic force for clamping the collected core sample. Among them, if the core sample collected in the sampling cylinder 810 is a relatively soft (i.e., low hardness) core sample, for example, the core sample collected during the exploration of natural gas hydrates, at this time, the core sample collected in the sampling cylinder 810 can break on the side of the elastic portion 831 facing the transmission assembly under the action of the elastic portion 831 to form an end face, so that the elastic portion 831 can protrude from the inner wall of the sampling cylinder 810 again and be limited to the end face of the core sample collected in the sampling cylinder 810 to prevent the core sample collected in the sampling cylinder 810 from detaching from the sampling cylinder 810.

[0087] It should be noted that in some other embodiments, the annular mounting groove 821 can also be provided on the inner wall of the sampling cylinder 810, and is not limited herein.

[0088] It should be noted that in some other embodiments, the above guiding inclined surface 8311 can also be replaced by a guiding arc surface, and is not limited herein.

[0089] It should be noted that in some other embodiments, the clamping structure can also be a claw spring or a crown spring disposed in the sampling cylinder 810, and is not limited herein.

[0090] In some of these embodiments, the cutting tooth 820 is detachably connected to the open end of the sampling cylinder 810 to facilitate replacement of the cutting tooth 820.

[0091] Specifically, the cutting tooth 820 is threadedly connected to the open end of the sampling cylinder 810.

[0092] It should be noted that, in some other embodiments, the cutting tooth 820 can also be detachably connected to the open end of the sampling cylinder 810 by screws or snap-fit structures, which are not limited herein.

[0093] Specifically, the cutting tooth 820 is made of wear-resistant alloy.

[0094] The drilling equipment according to the embodiments of the present application includes the above-mentioned drill string structure.

[0095] It should be noted that, since the drilling equipment according to the embodiments of the present application includes the above-mentioned drill string structure, therefore, the drilling equipment according to the embodiments of the present application includes all the technical effects of the above-mentioned drill string structure.

[0096] In the description of this specification, if descriptions involving reference terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", and "some examples" are involved, it means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0097] Although the embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and purposes of the present application. The scope of the present application is defined by the claims and their equivalents.

Claims

1. A drilling tool structure, characterized in that: include: At least two sections of drill pipe, each of which is connected in sequence; A core sampling mechanism is provided inside at least two sections of the drill pipe, and the core sampling mechanism includes a driving assembly, a transmission assembly, and a core grabbing assembly that can be extended to the outside of the drill pipe. The driving assembly can drive the core grabbing assembly to rotate through the transmission assembly and drive the core grabbing assembly to extend to the outside of the drill pipe, so that the core grabbing assembly can drill into the well wall to collect core samples.

2. The drilling tool structure according to claim 1, characterized in that: Correspondingly, a first channel for accommodating the core sampling mechanism is provided inside the drill rod, the first channel having a first channel inlet end and a first channel outlet end, the first channel inlet end is used to pump drilling fluid, the first channel outlet end passes through the outer wall of the drill rod, the driving assembly includes a screw motor stator and a screw motor rotor, the screw motor stator is slidably disposed in the first channel, the screw motor rotor is rotatably disposed in the screw motor stator and acts on the transmission assembly.

3. The drilling tool structure according to claim 2, characterized in that: A second channel penetrating the drill pipe along the axial direction of the drill pipe is arranged inside each section of the drill pipe, and the second channel is used to pump drilling fluid. The head end of the drill pipe in which the core sampling mechanism is arranged is provided with an installation channel, and the second channel has a second channel inlet end and a second channel outlet end. The first channel inlet end and the second channel inlet end are both connected to the installation channel. A sealing ring is fixedly arranged in the installation channel, and a flow guide tube is passed through the sealing ring. One end of the flow guide tube is inserted into the inlet end of the second channel. The other end of the tube is provided with an annular blocking portion for blocking the drilling fluid from flowing toward the inlet end of the first channel, and a pin for fixing the annular blocking portion and the sealing ring is provided between the annular blocking portion and the sealing ring. The flow guide tube can destroy the pin and slide relative to the sealing ring when subjected to external force to release the blocking of the drilling fluid by the annular blocking portion. In each of the drill rods having the core sampling mechanism arranged therein, the inner diameter of each of the flow guide tubes decreases one by one, so that the inner diameter of the flow guide tube close to the drill bit of any two of the flow guide tubes is smaller than the inner diameter of the flow guide tube far away from the drill bit.

4. The drilling tool structure according to claim 2 or 3, characterized in that: The first channel has a first section and a second section, the drive assembly is arranged in the first section, the transmission assembly and the core grabbing assembly are arranged in the second section, and the second section is inclined or curved so that the core grabbing assembly can extend to the outside of the drill rod in a posture inclined to the axis of the drill rod.

5. The drilling tool structure according to claim 4, characterized in that: An inclined or curved groove is provided on the outer wall of the drill rod in which the core sampling mechanism is arranged. The groove is covered with a pressure plate fixedly connected to the drill rod. The pressure plate and the groove enclose at least part of the second section.

6. The drilling tool structure according to claim 5, characterized in that: The transmission assembly includes a flexible transmission shaft and a flexible shell sleeved outside the flexible transmission shaft, the screw motor rotor acts on the flexible transmission shaft and the flexible shell, the flexible transmission shaft can be bent and deformed and used to transmit torque, and the flexible shell can be bent and deformed and used to transmit thrust and tension.

7. The drilling tool structure according to claim 2 or 3, characterized in that: An elastic reset structure is provided between the screw motor rotor and the transmission assembly, and the elastic reset structure is used to drive the core grabbing assembly extending outside the drill rod to be retracted into the inside of the drill rod.

8. The drilling tool structure according to claim 7, characterized in that: A pressure relief hole connected to the first channel is arranged on the side wall of the drill rod in which the core sampling mechanism is arranged.

9. The drilling tool structure according to any one of claims 1 to 3, characterized in that: The core grabbing assembly comprises a sampling barrel and cutting teeth, one end of the sampling barrel is an open end, the other end of the sampling barrel is connected to the transmission assembly, and the cutting teeth are arranged at the open end of the sampling barrel.

10. The drilling tool structure according to claim 9, characterized in that: The core grab assembly also includes a clamping structure for clamping the collected core sample.

11. A drilling equipment, characterized in that: The invention comprises a drilling tool structure as claimed in any one of claims 1 to 10.

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