Core resistivity measuring device and coring tool

Abstract

This invention discloses a core resistivity measuring device and a core drilling tool, relating to the field of core drilling technology. The core resistivity measuring device includes an outer tube, a measuring tube, and a measuring component. One end of the outer tube is used to connect to a drill bit, and the other end is used to connect to an outer sleeve. The measuring tube is rotatably connected inside the outer tube. The measuring tube has a first conductive part and a second conductive part, both of which are signal-connected to the measuring component. Both the first and second conductive parts can contact the core material entering the measuring tube. The measuring component can transmit electricity to the core material extending into the measuring tube through the first and second conductive parts to obtain the resistivity of the core. This core resistivity measuring device and core drilling tool can complete the resistivity measurement simultaneously with the core drilling operation, allowing the resistivity data to be compared and calibrated with the actual core material in a timely manner.

Description

Technical Field

[0001] This invention relates to the field of core drilling technology, and in particular to a core resistivity measuring device and a core drilling tool. Background Technology

[0002] Whether for oil and gas resource exploration or earth science research, measuring formation resistivity is essential. Currently, formation resistivity measurements are mostly accomplished through well logging operations. Conventional resistivity logging is typically performed after drilling a section of the well, measuring the resistivity of the wellbore. However, by this time, the wellbore has been eroded by drilling fluid for an extended period and may even have been damaged by the drilling machinery. Relying solely on well logging is insufficient for formation evaluation and identification. In such cases, coring is necessary to obtain physical core samples and compare and calibrate the resistivity data obtained from well logging, a complex process. Although more advanced drilling-while-drilling resistivity measurement technologies have emerged, they can only be used during full-scale drilling after coring, and cannot be performed simultaneously with coring. The resistivity data obtained from coring is thus disconnected in time and space from the core data obtained during core drilling. Once the core data obtained in the early stages is brought to the surface, changes in conditions such as temperature, pressure, or stress can alter the measured resistivity, potentially leading to distortions. This hinders timely comparison and calibration between the core resistivity data and the actual core data. Therefore, there is an urgent need for a core resistivity measurement device and coring tool that can measure resistivity simultaneously with coring operations. This would allow for more timely calibration of resistivity logging data and formation identification models using the core data, eliminating the need for electrical logging operations. Summary of the Invention

[0003] The purpose of this invention is to provide a core resistivity measuring device and a core drilling tool to solve the problems existing in the prior art. It can measure resistivity during core drilling, and use the physical data of the core to calibrate resistivity logging data and formation identification models more timely, eliminating the need for electrical logging operations.

[0004] To achieve the above objectives, the present invention provides the following solution:

[0005] This invention provides a core resistivity measuring device, comprising: an outer tube, a measuring tube, and a measuring component. One end of the outer tube is used to connect to a drill bit, and the other end is used to connect to an outer sleeve. The measuring tube is rotatably connected inside the outer tube. The measuring tube has a first conductive part and a second conductive part inside. Both the first conductive part and the second conductive part are signal-connected to the measuring component. Both the first conductive part and the second conductive part can contact the core material entering the measuring tube. The measuring component can pass electricity through the first conductive part and the second conductive part to the core material extending into the measuring tube and obtain the resistivity of the core material.

[0006] In some embodiments, the measuring tube includes an electron tube and a core tube, one end of the electron tube being threadedly connected to one end of the core tube, and the other end of the core tube being used for connection to the internal suspension of the drill bit.

[0007] In some embodiments, the measuring tube further includes a retaining sleeve and a retaining spring, one end of the retaining sleeve being fixedly connected to the end of the electron tube away from the core tube, and the retaining spring being disposed inside the retaining sleeve, the retaining spring being able to prevent the core from moving when the core has a tendency to move away from the core tube.

[0008] In some embodiments, the electron tube includes a first connecting tube, a first insulating ring, a first electrode ring, an insulating tube, a second electrode ring, a second insulating ring, and a second connecting tube connected in sequence and in communication, wherein the first electrode ring forms the first conductive portion, and the second electrode ring forms the second conductive portion.

[0009] In some embodiments, the outer tube includes a tube body, a first electrode contact ring, and a second electrode contact ring. Both the first and second electrode contact rings are fixedly connected to the tube body and are coaxially arranged with the tube body. The first electrode contact ring contacts the first electrode ring, and the second electrode contact ring contacts the second electrode ring. Both the first and second electrode contact rings are signal-connected to the measuring component, and the measuring tube is rotatably connected to the tube body.

[0010] In some embodiments, the tube body has a mounting cavity in its side wall, and the measuring component is fixedly connected in the mounting cavity.

[0011] In some embodiments, the measurement component includes a power supply and an integrated circuit, the power supply being signal-connected to the integrated circuit, and the integrated circuit being signal-connected to the first electrode contact ring and the second electrode contact ring, respectively.

[0012] In some embodiments, the integrated circuit includes a processing module, a storage module, and a transmission module. The processing module is signal-connected to the storage module and the transmission module, respectively. The processing module is capable of obtaining the current passing through the core and the voltage across the core and calculating the resistivity of the core. The storage module is capable of storing the resistivity calculated by the processing module. The transmission module is used for signal connection with external devices and is capable of transmitting the resistivity calculated by the processing module to the external devices.

[0013] In some embodiments, the inner wall of the tube is provided with an annular first fixing groove and a second fixing groove. The inner walls of the first fixing groove and the second fixing groove are both covered with an insulating layer. The first electrode contact ring and the second electrode contact ring are respectively fixedly connected to the insulating layer in the first fixing groove and the insulating layer in the second fixing groove.

[0014] The present invention also provides a core drilling tool, including a drill bit, an outer sleeve, an inner suspension and the aforementioned core resistivity measuring device, wherein one end of the outer sleeve is detachably fixedly connected to the drill bit and the other end is detachably fixedly connected to the outer sleeve, the inner suspension is rotatably connected inside the outer sleeve, and the inner suspension is detachably fixedly connected to one end of the measuring tube.

[0015] The present invention achieves the following technical effects compared to the prior art:

[0016] The core resistivity measuring device provided by this invention allows for the measurement of core resistivity during core sampling. After the core enters the measuring tube, it contacts the first and second conductive parts. The measuring component can then supply electricity to the core through these parts. Based on the magnitude of the current flowing through the core, the voltage across the core, and Ohm's law, the measuring component can calculate the core resistivity. This allows for simultaneous core sampling and resistivity measurement, preventing temporal and spatial discrepancies between the core resistivity data and the acquired core material. It also enables timely comparison and calibration between the core material and resistivity data. Furthermore, when calculating the core resistivity, the resistance of other components besides the core itself can be ignored, and the output voltage of the measuring component can be directly equated to the voltage across the core. Alternatively, a voltage detection device can be connected in parallel with the core to detect the voltage across its terminals. Attached Figure Description

[0017] 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.

[0018] Figure 1 This is a cross-sectional view of the core resistivity measuring device in some embodiments of the present invention;

[0019] Figure 2 This is a cross-sectional view of an electron tube in some embodiments of the present invention;

[0020] Figure 3 This is a cross-sectional view of the outer tube and the drill bit in some embodiments of the present invention;

[0021] In the diagram: 1. Outer tube; 11. Tube body; 12. First electrode contact ring; 13. Second electrode contact ring; 14. Mounting cavity; 15. First fixing groove; 16. Second fixing groove; 17. Insulating layer; 2. Measuring tube; 21. Electron tube; 211. First connecting tube; 212. First insulating ring; 213. First electrode ring; 214. Insulating tube; 215. Second electrode ring; 216. Second insulating ring; 217. Second connecting tube; 22. Core tube; 23. Snap ring sleeve; 24. Snap ring; 3. Power supply; 4. Integrated circuit; 5. Core; 6. Drill bit. Detailed Implementation

[0022] 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.

[0023] The purpose of this invention is to provide a core resistivity measuring device and a core drilling tool to solve the problems existing in the prior art. It can measure resistivity during core drilling, and use the physical data of the core to calibrate resistivity logging data and formation identification models more timely, eliminating the need for electrical logging operations.

[0024] 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.

[0025] Example 1

[0026] This embodiment provides a core resistivity measuring device, such as... Figure 1-3 As shown, it includes: an outer tube 1, a measuring tube 2, and a measuring assembly. One end of the outer tube 1 is used to connect to the drill bit 6, and the other end is used to connect to the outer sleeve. The measuring tube 2 is rotatably connected inside the outer tube 1. The measuring tube 2 has a first conductive part and a second conductive part. Both the first conductive part and the second conductive part are signal connected to the measuring assembly. Both the first conductive part and the second conductive part can contact the rock core 5 that enters the measuring tube 2. The measuring assembly can pass electricity to the rock core 5 that extends into the measuring tube 2 through the first conductive part and the second conductive part and obtain the resistivity of the rock core 5.

[0027] The core resistivity measuring device provided in this embodiment, during the core sampling operation, the power system drives the outer casing to rotate, which in turn drives the outer tube to rotate and the drill bit to rotate for core sampling. After the core 5 enters the measuring tube 2, it contacts the first and second conductive parts. The measuring component can supply electricity to the core 5 through the first and second conductive parts. Then, the measuring component can calculate the resistivity of the core 5 based on the magnitude of the current passing through the core 5, the magnitude of the voltage across the core 5, and Ohm's law. Thus, the resistivity of the core 5 is measured simultaneously with the core sampling operation, avoiding the time and space separation between the obtained core 5 resistivity data and the obtained core 5 physical data. It also allows the core 5 resistivity data to be compared with the core physical data in a timely manner, calibrating the resistivity and formation identification model, and eliminating the need for electrical logging operations. When calculating the resistivity of core 5, the influence of the resistance of other components besides the resistance of core 5 itself can be ignored. The output voltage of the measuring component can be directly equated to the voltage across core 5. Alternatively, a voltage detection device can be connected in parallel to core 5 to detect the voltage across core 5.

[0028] In this first embodiment, the measuring tube 2 includes an electron tube 21 and a core tube 22. One end of the electron tube 21 is threadedly connected to one end of the core tube 22, and the other end of the core tube 22 is used for connection to the internal suspension of the drill bit. The threaded connection between the core tube 22 and the electron tube 21 ensures a high degree of reliability, and allows for disassembly when maintenance is required on either the electron tube 21 or the core tube 22.

[0029] In this embodiment, the measuring tube 2 further includes a retaining sleeve 23 and a retaining spring 24. One end of the retaining sleeve 23 is fixedly connected to the end of the electron tube 21 away from the core tube 22. The retaining spring 24 is disposed inside the retaining sleeve 23. After the core 5 enters the electron tube 21, the retaining spring 24 can prevent the core 5 from moving away from the core tube 22. After the core 5 extends into the measuring tube 2 to a certain depth, it stops extending. At this time, the core has a tendency to move away from the core tube 22 due to gravity. The retaining spring 24 can tighten and lock the core 5, and then the core 5 can be taken out from the well by drilling.

[0030] In this first embodiment, the electron tube 21 includes a first connecting tube 211, a first insulating ring 212, a first electrode ring 213, an insulating tube 214, a second electrode ring 215, a second insulating ring 216, and a second connecting tube 217 connected in sequence. The first electrode ring 213 forms a first conductive part, and the second electrode ring 215 forms a second conductive part. Both the first electrode ring 213 and the second electrode ring 215 are annular, which allows for a large contact area with the core 5 in the circumferential direction, avoiding poor contact caused by an insufficient contact area. In addition, to improve strength, the first connecting tube 211, the second connecting tube 217, and the outer tube 1 are mostly made of metal. To prevent short circuits between the first electrode ring 213 and the second electrode ring 215, the first insulating ring 212, the insulating tube 214, and the second insulating ring 216 are used to separate the first electrode ring 213 and the second electrode ring 215 separately.

[0031] It should be noted that if the first connecting pipe 211 and the second connecting pipe 217 are made of insulating material, the first insulating ring 212 and the second insulating ring 216 may not be provided.

[0032] To facilitate the connection between the first electrode ring 213 and the second electrode ring 215 and the measuring component, in this embodiment, the outer tube 1 includes a tube body 11, a first electrode contact ring 12, and a second electrode contact ring 13. The first electrode contact ring 12 and the second electrode contact ring 13 are both fixedly connected inside the tube body 11. The first electrode contact ring 12 and the second electrode contact ring 13 are both coaxially arranged with the tube body 11. The first electrode contact ring 12 is in contact with the first electrode ring 213, and the second electrode contact ring 13 is in contact with the second electrode ring 215. The first electrode contact ring 12 and the second electrode contact ring 13 are both signal connected to the measuring component. The measuring tube is rotatably connected inside the tube body 11.

[0033] In this first embodiment, the side wall of the tube body 11 has a mounting cavity 14, and the measuring component is fixedly connected in the mounting cavity 14. By placing the measuring component in the mounting cavity 14, the tube wall of the outer tube 1 protects the measuring component and prevents it from being damaged by collision with the outside.

[0034] In this first embodiment, the measuring component includes a power supply 3 and an integrated circuit 4. The power supply 3 is signal-connected to the integrated circuit 4, and the integrated circuit 4 is signal-connected to the first electrode contact ring 12 and the second electrode contact ring 13, respectively. The power supply 3 can supply power to the integrated circuit 4, and the integrated circuit 4 can guide current into the first electrode contact ring 12 and the second electrode contact ring 13. The integrated circuit 4 can also calculate the resistivity of the core 5 based on the magnitude of the current passing through the core 5 and the magnitude of the voltage across the core 5.

[0035] In this first embodiment, the integrated circuit 4 includes a processing module, a storage module, and a transmission module connected together. The processing module is signal-connected to both the storage module and the transmission module. The processing module can obtain the current passing through the core 5 and the voltage across the core 5, and calculate the resistivity of the core 5. The storage module can store the resistivity calculated by the processing module. The transmission module is used for signal connection with external devices, and can transmit the resistivity calculated by the processing module to the external devices. The processing module can obtain the resistivity of the core 5, the storage module can store the resistivity value for easy retrieval by staff, and the transmission module can connect to external devices, such as the staff's computer, to transmit data, allowing staff to access the data at any time.

[0036] In this first embodiment, the inner wall of the tube 11 is provided with an annular first fixing groove 15 and a second fixing groove 16. Both the inner walls of the first fixing groove 15 and the inner walls of the second fixing groove 16 are covered with an insulating layer 17. The first electrode contact ring 12 and the second electrode contact ring 13 are respectively fixedly connected to the insulating layer 17 in the first fixing groove 15 and the insulating layer 17 in the second fixing groove 16. To ensure the strength of the tube 11, the tube 11 is mostly made of metal. The insulating layer 17 can prevent the first electrode contact ring 12 and the second electrode contact ring 13 from conducting through the tube 11 and causing a short circuit.

[0037] It should be noted that when the pipe body 11 uses insulating material, the insulating layer 17 may not be provided.

[0038] Example 2

[0039] This embodiment provides a core drilling tool, including a drill bit 6, an outer sleeve, an inner suspension, and the core resistivity measuring device in Embodiment 1. One end of the outer sleeve 1 is detachably fixedly connected to the drill bit 6, and the other end is detachably fixedly connected to one end of the outer sleeve. The other end of the outer sleeve is used to connect the drill rod. The inner suspension is rotatably connected inside the outer sleeve and is detachably fixedly connected to one end of the measuring tube 2.

[0040] The coring tool provided in this embodiment, by using the core resistivity measuring device in Embodiment 1, avoids the time and space disconnect between the acquired core resistivity data and the acquired core physical data. This allows the acquired core physical data to be used to promptly calibrate the resistivity data and formation identification model, eliminating the need for electrical logging operations. The output end of the power system is connected to the drill pipe, which rotates under the drive of the power system, thereby rotating the outer casing, outer casing 1, and drill bit 6 to achieve coring operations.

[0041] The steps for measuring using the coring drill tool in Embodiment 2 of the present invention are as follows:

[0042] Before drilling, a measurement trigger switch is installed on the ground surface. The measurement trigger switch is connected to the measurement component, and the receiving end of the measurement trigger switch is located inside the measurement tube.

[0043] During drilling, after the core 5 enters the designated position of the measuring tube 2, the measurement trigger switch is triggered, and the core resistivity is measured using the measuring device; then the drill is pulled out and the core is brought back to the surface, completing the core sampling and core resistivity measurement operations at the same time.

[0044] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A core resistivity measuring device, characterized in that: include: The system comprises an outer tube, a measuring tube, and a measuring assembly. One end of the outer tube is connected to a drill bit, and the other end is connected to an outer sleeve. The measuring tube is rotatably connected inside the outer tube and has a first conductive part and a second conductive part. Both the first and second conductive parts are signal-connected to the measuring assembly and can contact the rock core inserted into the measuring tube. The measuring assembly can transmit electricity to the rock core inserted into the measuring tube through the first and second conductive parts to obtain the resistivity of the rock core. The measuring tube includes an electron tube, a core tube, a retaining sleeve, and a retaining spring. One end of the electron tube is threaded to one end of the core tube, and the other end of the core tube is used for internal suspension connection with the drill bit. One end of the snap ring sleeve is fixedly connected to the end of the electron tube away from the core tube. The snap ring is disposed in the snap ring sleeve and can prevent the core from moving when the core has a tendency to move away from the core tube. The electron tube includes a first connecting tube, a first insulating ring, a first electrode ring, an insulating tube, a second electrode ring, a second insulating ring, and a second connecting tube connected in sequence. The first electrode ring forms the first conductive part, and the second electrode ring forms the second conductive part.

2. The core resistivity measuring device according to claim 1, characterized in that: The outer tube includes a tube body, a first electrode contact ring, and a second electrode contact ring. Both the first electrode contact ring and the second electrode contact ring are fixedly connected to the tube body and are coaxially arranged with the tube body. The first electrode contact ring contacts the first electrode ring, and the second electrode contact ring contacts the second electrode ring. Both the first electrode contact ring and the second electrode contact ring are signal connected to the measuring component. The measuring tube is rotatably connected to the tube body.

3. The core resistivity measuring device according to claim 2, characterized in that: The tube body has a mounting cavity in its side wall, and the measuring component is fixedly connected in the mounting cavity.

4. The core resistivity measuring device according to claim 3, characterized in that: The measurement component includes a power supply and an integrated circuit. The power supply is signal-connected to the integrated circuit, and the integrated circuit is signal-connected to the first electrode contact ring and the second electrode contact ring, respectively.

5. The core resistivity measuring device according to claim 4, characterized in that: The integrated circuit includes a processing module, a storage module, and a transmission module. The processing module is signal-connected to the storage module and the transmission module, respectively. The processing module can obtain the current passing through the core and the voltage across the core and calculate the resistivity of the core. The storage module can store the resistivity calculated by the processing module. The transmission module is used for signal connection with external devices and can transmit the resistivity calculated by the processing module to the external devices.

6. The core resistivity measuring device according to claim 2, characterized in that: The inner wall of the tube is provided with an annular first fixing groove and a second fixing groove. The inner walls of the first fixing groove and the second fixing groove are both covered with an insulating layer. The first electrode contact ring and the second electrode contact ring are respectively fixedly connected to the insulating layer in the first fixing groove and the insulating layer in the second fixing groove.

7. A coring tool, characterized in that: The device includes a drill bit, an outer casing, an inner suspension, and a core resistivity measuring device according to any one of claims 1-6. One end of the outer casing is detachably and fixedly connected to the drill bit, and the other end is detachably and fixedly connected to the outer casing. The inner suspension is rotatably connected inside the outer casing, and the inner suspension is detachably and fixedly connected to one end of the measuring tube.

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