Replaceable antenna sub for logging-while-drilling resistivity measurement

Abstract

A replaceable antenna sub for logging-while-drilling resistivity measurement, comprising a signal transmission module. The signal transmission module comprises a tubular main housing and a signal transmission assembly. The signal transmission assembly comprises signal line through-holes (7, 13, 14) extending in the direction of length within the main housing, a helical mounting hole (11) extending helically around the central axis of the main housing, and an antenna groove (21) formed on an outer surface of the main housing. The helical mounting hole is in communication with the signal line through-holes. A signal line is disposed in the signal wire through-holes, and an antenna in communication connection with the signal line is disposed in the helical mounting hole. The antenna groove is in communication with the helical mounting hole and is filled with a sealing material having no signal shielding effect, so as to form a signal transmission channel. By arranging the antenna in the spiral mounting hole in cooperation with the sealing material, the antenna sub can better protect the antenna, avoid deformation caused by extrusion of the antenna and surrounding structures, reduce wear of the antenna and other structures, and extend the service life of the antenna.

Description

Replaceable Drilling Resistivity Measurement Antenna Subsection

[0001] Cross-reference to related applications

[0002] This application claims the benefit of Chinese Patent Application No. 202411892831.4, filed on December 20, 2024, the contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to the technical field of downhole tools for oil and gas drilling and production, and in particular to a replaceable short section of a drilling resistivity measurement antenna. Background Technology

[0004] As oil exploration and development accelerates, oil and gas resources are gradually evolving into a pattern of "overall dispersion with local enrichment." This is particularly true for complex formations with uncertain reservoir distribution, making geological-guided measurement-while-drilling (MRD) technology crucial. Formation resistivity is an essential geological parameter for MRD. Field application experience shows that resistivity antennas are the most common failure site. This is primarily due to the continuous wear and deformation of the antenna shell caused by highly abrasive formations, leading to drilling fluid intrusion and short-circuit failure. Secondly, in the high-vibration environment at the bottom of the well, the antenna frequently slides up and down within the resistivity body, easily causing breakage and failure.

[0005] Currently, the antenna housing design mainly adopts the form of an antenna protective cover. This requires applying a special fixing adhesive to the resistivity body and the antenna protective cover, heating it to ensure a firm bond, and then fixing it with screws. A drawback is that in the high-frequency vibration and impact environment downhole, the arc-shaped, sheet-like structure of the antenna protective cover has weak deformation resistance and is prone to loosening and deformation, leading to mud intrusion and failure. Another approach integrates the antenna housing with the drill collar body, increasing the wear and impact resistance of the antenna housing. However, this method is more difficult to manufacture overall, and antenna maintenance is challenging and time-consuming. If any one of the six antenna groups suffers severe deformation or damage that is difficult to repair, the entire instrument cluster will be rendered unusable. In addition, existing resistivity instruments have fixed antenna spacing and source distance, resulting in significant differences in measurement accuracy for different blocks. A larger receiving antenna spacing results in a longer formation axial identification section, but it also provides stronger identification capability for high-resistivity formations. A smaller spacing results in higher resolution and is suitable for thin layers. A longer transmitting antenna source distance results in a greater detection depth, which can be used to describe the characteristics of drilling fluid intrusion into the formation. A shorter distance results in a smaller detection depth, which can be used to describe formation characteristics near the wellbore and the absence of drilling fluid intrusion. Existing instruments are insufficient to meet the requirements for accurate measurement of different detection depths, formation resolutions, and high and low resistivity formations. Summary of the Invention

[0006] The technical problem this disclosure aims to solve is: to address the high failure rate of antenna components in conventional antenna-protected resistivity instruments and the difficulty in processing and maintaining integrated resistivity instruments; to improve the overall structural stability of the antenna components; to reduce the overall processing difficulty of the resistivity instrument; and to achieve adjustable antenna spacing and source distance, making it more adaptable to the production needs of different geological features.

[0007] To address the aforementioned technical problems, this disclosure provides a replaceable underwater resistivity measurement antenna section, comprising a signal transmission module. The signal transmission module includes a tubular main housing and a signal transmission assembly. The signal transmission assembly includes a signal line through-hole extending along its length within the main housing, a spiral mounting hole extending spirally around the central axis of the main housing, and an antenna slot disposed on the outer surface of the main housing. The spiral mounting hole communicates with the signal line through-hole, a signal line is disposed in the signal line through-hole, and an antenna communicatively connected to the signal line is disposed in the spiral mounting hole. The antenna slot communicates with the spiral mounting hole and is filled with a sealing material that provides no signal shielding to form a signal transmission channel.

[0008] In some embodiments, the antenna slot is configured in a V-shape, and the orientation of the antenna slot is the same as the rotation direction of the main housing, so as to reduce the frictional resistance encountered during rotation.

[0009] In some embodiments, an antenna rib is provided between adjacent antenna slots, the antenna rib being provided with a first recess communicating with the spiral mounting hole, a cover plate being provided in the first recess, the cover plate partially defining the spiral mounting hole and covering the antenna.

[0010] In some embodiments, the outer surface of the main housing is provided with a second recess that communicates with the signal line through hole, and the second recess is provided with a tuning circuit board connected to the signal line and a protective plate covering the tuning circuit board.

[0011] In some embodiments, a plurality of wear-resistant rings spaced axially are provided on the outer periphery of the main housing.

[0012] In some embodiments, the signal transmission module includes three short sections connected in sequence, each of the short sections being provided with at least one of the signal transmission components.

[0013] In some embodiments, at the connection between two adjacent short sections, one short section has an annular groove at its end for receiving the insertion of the end of the other short section, an inner sealing ring is provided on the inner circumferential surface of the end of the other short section, and an outer sealing ring is provided on the outer circumferential surface of the end of the other short section.

[0014] In some embodiments, the three sections include an upper transmitting section, a receiving section, and a lower transmitting section connected in descending order.

[0015] In some embodiments, a circuit module connected to the lower end of the lower launch section is also included.

[0016] In some embodiments, the signal line via includes a first signal line via located in the upper transmitting section, the receiving section, and the lower transmitting section and connected to the circuit module; a second signal line via located in the receiving section and the lower transmitting section and connected to the circuit module; and a third signal line via located in the lower transmitting section and connected to the circuit module.

[0017] In some embodiments, at the junction of two adjacent short sections, the signal line via is formed in a tapered shape at the end face of the short section.

[0018] In some embodiments, the three short sections are provided with wire through holes communicating with the circuit module, and the wire through holes, the first signal line through hole, the second signal line through hole and the third signal line through hole are arranged circumferentially at intervals.

[0019] In some embodiments, at the connection of adjacent short sections, the wire through-hole is formed in a tapered shape at the end face of the short section.

[0020] In some embodiments, the circuit module includes a housing and a circuit board frame disposed inside the housing, and a circuit board disposed on the circuit board frame.

[0021] In some embodiments, each of the short sections is provided with an alignment reference groove aligned in the axial direction.

[0022] The above technical solution, which arranges the antenna through spiral mounting holes and uses sealing materials, can better protect the antenna, prevent the antenna and surrounding structures from being squeezed and deformed, reduce wear on the antenna and other structures, extend service life, and adjust the antenna spacing and source distance, thus reducing processing difficulty. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 is a schematic diagram of the structure of the replaceable drilling resistivity measurement antenna section disclosed in an embodiment of this disclosure;

[0025] Figure 2 is a cross-sectional view of a portion of the replaceable drilling resistivity measurement antenna section disclosed in an embodiment of this disclosure.

[0026] Figure 3 is an enlarged view of part I in Figure 2;

[0027] Figure 4 is a schematic diagram of a portion of the external structure of the replaceable drilling resistivity measurement antenna section disclosed in an embodiment of this disclosure.

[0028] Figure 5 is a cross-sectional view of the upper launch section disclosed in an embodiment of this disclosure;

[0029] Figure 6 is a cross-sectional view of the receiving section disclosed in an embodiment of this disclosure;

[0030] Figure 7 is a cross-sectional view of the lower emission section disclosed in an embodiment of this disclosure;

[0031] Figure 8 is a cross-sectional view of the circuit module disclosed in an embodiment of this disclosure.

[0032] Explanation of reference numerals in the attached diagram: 1-Upper transmit section, 2-Alignment reference slot, 3-Receive section, 4-Lower transmit section, 5-Circuit module, 6-Wear ring, 7-First signal line through hole, 8-Outer sealing ring, 9-Inner sealing ring, 10-Wire through hole, 11-Spiral ampere hole, 12-Cover plate, 13-Second signal line through hole, 14-Third signal line through hole, 15-Protective plate, 16-Circuit converter connector, 17-Circuit board frame, 18-Antenna rib, 19-Outer shell, 20-Weld seam, 21-Antenna slot. Detailed Implementation

[0033] The embodiments of this disclosure will be further described in detail below with reference to the accompanying drawings and examples. The detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of this disclosure by way of example, but should not be used to limit the scope of this disclosure. This disclosure can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0034] These embodiments are provided to make the disclosure thorough and complete, and to fully express the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, material composition, numerical expressions, and values ​​set forth in these embodiments should be interpreted as exemplary only and not as limiting.

[0035] It should be noted that, in the description of this disclosure, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationship, are only for the convenience of describing this disclosure 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, and therefore should not be construed as a limitation of this disclosure. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0036] Furthermore, the terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. "Vertical" is not strictly vertical, but within the permissible margin of error. "Parallel" is not strictly parallel, but within the permissible margin of error. Terms such as "including" or "contains" mean that the element preceding the word encompasses the element listed after the word, and do not exclude the possibility of encompassing other elements as well.

[0037] It should also be noted that, in the description of this disclosure, unless otherwise expressly 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 direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this disclosure depending on the specific circumstances. When a particular device is described as being located between a first device and a second device, an intermediary device may or may not be present between the particular device and the first or second device.

[0038] All terms used in this disclosure have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and not as idealized or highly formalized, unless expressly defined herein.

[0039] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0040] Referring to Figures 1-8, this solution provides a replaceable antenna section for measuring resistivity while drilling, which includes a signal transmission module. The signal transmission module includes a tubular main housing and a signal transmission assembly. The signal transmission assembly includes a signal line through-hole extending along the length direction within the main housing, a spiral mounting hole 11 extending spirally around the central axis of the main housing, and an antenna slot 21 disposed on the outer surface of the main housing. The spiral mounting hole 11 communicates with the signal line through-hole, and a signal line is disposed in the signal line through-hole. An antenna communicating with the signal line is disposed in the spiral mounting hole 11. The antenna slot 21 communicates with the spiral mounting hole 11 and is filled with a sealing material that does not provide signal shielding to form a signal transmission channel.

[0041] The replaceable drilling resistivity measurement antenna section can receive and transmit signals. It includes a signal transmission module, which consists of a main housing and a signal transmission component. The main housing can be connected to the drill collar, and the signal transmission component is the main component for receiving and transmitting signals.

[0042] The signal transmission assembly includes a signal line through-hole for mounting signal lines, a spiral mounting hole 11 for mounting signal lines, and an antenna slot 21 located in the main housing. The signal line through-hole extends between the spiral mounting hole 11 and the signal receiving and transmitting components to allow the signal line to transmit signals between the signal receiving and transmitting components and the antenna. The spiral mounting hole 11 is a hole that spirally extends around the central axis of the main housing, in which the corresponding antenna spirally extends. The antenna slot 21 is located on the outer peripheral surface of the main housing and extends to the spiral mounting hole 11 to expose the antenna, eliminating signal shielding. The antenna slot 21 is filled with a non-shielding sealing material to prevent external fluids from entering the antenna slot 21 and the spiral mounting hole 11.

[0043] The sealing material that does not shield the signal can be a sealant (high-hardness epoxy resin or silicone). After the sealant is filled, it is cured to seal the antenna slot 21. The sealing material can also be a plastic plate. The plastic plate is sealed to the main housing with sealant. It can be understood that the sealing material can both seal the antenna slot 21 and allow the transmission of wireless signals, that is, it will not shield the signal.

[0044] Regarding the antenna slot 21, since the main housing structure is made of high-strength non-magnetic stainless steel, it is necessary to open the antenna slot 21 to avoid shielding the antenna signal transmission.

[0045] The spiral mounting hole 11 can accommodate a single antenna, providing support to a certain extent. Furthermore, when combined with sealing material, it can achieve a dual fixation effect on the antenna, reducing the exposed area of ​​the antenna, lowering the risk of short circuits when drilling fluid enters, and increasing the support strength around the antenna. This makes it less susceptible to deformation under external forces, reducing wear on the surrounding structure and extending its service life.

[0046] Among them, the replaceable underwater resistivity measurement antenna sub-section of this solution can be used to measure resistivity. Different models of sub-sections can be set. Different models of sub-sections have different overall lengths, antenna positions, and distances between antennas on the sub-sections. By selecting different sub-sections and connecting them together, the spacing and source distance of the resistivity measurement tools can be adjusted.

[0047] In addition, compared with the small-diameter, long-distance gun drilling of integral resistivity tools, multi-segment antenna sections have obvious advantages and reduce the difficulty of processing.

[0048] In this solution, the antenna is arranged through spiral mounting holes, and with the help of sealing materials, the antenna can be better protected, avoiding compression and deformation of the antenna and surrounding structures, reducing wear on the antenna and other structures, extending service life, and allowing adjustment of the antenna spacing and source distance, thus reducing manufacturing difficulty.

[0049] In some embodiments, the antenna slot 21 is formed in a V-shape, and the orientation of the antenna slot 21 is the same as the rotation direction of the main housing to reduce the frictional resistance during rotation. Referring to Figure 4, each antenna slot 21 includes two segments forming an angle, forming a V-shaped structure, with the corners facing the same direction as the rotation of the main housing. When the main housing rotates, the circumferential frictional force on the antenna slot 21 and the portion between adjacent antenna slots 21 (antenna ribs 18) can be partially converted into axial force under the guidance of the antenna slot 21, thus weakening the frictional force and reducing the friction on the antenna slot 21 and the portion between it.

[0050] In some embodiments, referring to Figures 3 and 4, an antenna rib 18 is provided between adjacent antenna slots 21. The antenna rib 18 has a first recess that communicates with the spiral mounting hole 11. A cover plate 12 is provided in the first recess, which partially defines the spiral mounting hole 11 and covers the antenna. The depth of the first recess can be substantially the same as the depth of the antenna slot 21. The spiral mounting hole 11 is formed between the cover plate 12 and the main housing to allow the antenna to pass through. The cover plate 12 can be connected to the antenna rib 18 by a weld 20. During installation, the antenna slot 21 can be machined on the main housing first, and the first recess can be machined on the antenna rib 18. The antenna is wound around the main housing, and then the cover plate 12 is welded and fixed to the main housing to stably support the antenna. Finally, the antenna slot 21 is filled with a sealing material (e.g., sealant).

[0051] In some embodiments, the outer surface of the main housing is provided with a second recess communicating with the signal line through-hole. A tuning circuit board connected to the signal line and a protective plate 15 covering the tuning circuit board are disposed in the second recess. Referring to FIG2, the signal line in the first signal line through-hole 7 can extend into the second recess to connect to the tuning circuit board therein. The tuning circuit board is connected to the antenna to transmit the tuned signal to the antenna or to transmit the received signal from the antenna after tuning. The protective plate 15 can be disposed in the second recess to seal the second recess and protect the structure therein. Additionally, a sealing ring can be provided between the protective plate 15 and the inner circumference of the second recess to improve sealing.

[0052] In some embodiments, a plurality of axially spaced wear-resistant rings 6 are provided on the outer periphery of the main housing. The wear-resistant rings 6 have a larger outer diameter and protrude from the main housing to contact external structures, reducing the contact between external structures and the main housing and reducing friction on the main housing, thereby better protecting structures such as the antenna slot 21 and the antenna rib 18. The main housing may include a multi-segment structure, namely, a plurality of short sections as described below, each of which may be provided with a plurality of wear-resistant rings 6.

[0053] In some embodiments, the signal transmission module includes three short sections connected in sequence, each short section having at least one signal transmission component. In other embodiments, one, two, four, five, or other numbers of short sections may be provided, each used for transmitting signals. Some of these short sections may be used for transmitting signals, while others may be used for receiving signals.

[0054] In some embodiments, at the connection between two adjacent short sections, one short section has an annular groove at its end to accommodate the insertion of the end of the other short section. An inner sealing ring 9 is provided on the inner circumferential surface of the end of the other short section, and an outer sealing ring 8 is provided on its outer circumferential surface. Referring to Figure 2, two short sections, left and right, are provided. The right end (male end) of the left short section is inserted into the annular groove at the left end (female end) of the right short section. The outer and inner circumferential surfaces of the right end of the left short section are respectively provided with an outer sealing ring 8 and an inner sealing ring 9 to improve the sealing performance between the two short sections. Multiple outer sealing rings 8 and inner sealing rings 9 can be provided with axial spacing. Any two adjacent short sections can use the same connection structure to facilitate the selection of appropriate short sections for combination as needed, and to allow for the selection of an appropriate number of short sections.

[0055] In some embodiments, the three segments include an upper transmitting segment 1, a receiving segment 3, and a lower transmitting segment 4 connected sequentially from top to bottom. The upper transmitting segment 1 and the lower transmitting segment 4 can be used to transmit signals, and the receiving segment 3 can be used to receive signals. In other embodiments, other similar segment combinations can be used, such as one receiving segment + one transmitting segment, two receiving segments + one transmitting segment, etc., and the segment selection and combination can be made according to specific needs.

[0056] Additionally, in some embodiments, the replaceable drilling resistivity measurement antenna section further includes a circuit module 5 connected to the lower end of the lower transmitting section 4. The circuit module 5 can be used to detect and process signals, such as resistivity detection, to transmit signals to be transmitted, and to process received signals.

[0057] In some embodiments, the signal line vias include a first signal line via 7 located in the upper transmitting section 1, the receiving section 3, and the lower transmitting section 4 and connected to the circuit module 5; a second signal line via 13 located in the receiving section 3 and the lower transmitting section 4 and connected to the circuit module 5; and a third signal line via 14 located in the lower transmitting section 4 and connected to the circuit module 5. Referring to Figures 5, 6, and 7, the upper transmitting section 1 is provided with a first signal line through-hole 7, the receiving section 3 is provided with a first signal line through-hole 7 and a second signal line through-hole 13, and the lower transmitting section 4 is provided with a first signal line through-hole 7, a second signal line through-hole 13, and a third signal line through-hole 14. The first signal line through-holes 7 in the three sections are aligned and connected to each other, and the signal lines contained therein connect the circuit module 5 to the antenna in the upper transmitting section 1. The second signal line through-holes 13 in the two sections are aligned and connected to each other, and the signal lines contained therein connect the circuit module 5 to the antenna in the receiving section 3. The signal lines in the third signal line through-hole in the lower transmitting section 4 connect the circuit module 5 to the antenna in the lower transmitting section 4.

[0058] Referring to Figure 1, each of the upper transmitting section 1, the receiving section 3, and the lower transmitting section 4 is provided with two sets of signal transmission components. Each section is provided with two levels of circumferentially spaced antenna slots 21 and spiral mounting holes 11 that communicate with the antenna slots 21. The signal line through holes can communicate with the two spiral mounting holes 11 to connect the signal line to the antenna therein.

[0059] In some embodiments, at the junction of two adjacent short sections, the signal wire through-hole is formed in a tapered shape at the end face of the short section. The tapered horn shape of the signal wire through-hole at the end face of the short section facilitates signal insertion and passage, simplifying installation. At the junction of two short sections, the signal wire through-hole in only one short section may be formed in a tapered horn shape.

[0060] In some embodiments, the three short sections are provided with wire through-holes 10 communicating with the circuit module 5. The wire through-holes 10, the first signal line through-hole 7, the second signal line through-hole 13, and the third signal line through-hole 14 are arranged circumferentially at intervals. The upper transmitting short section 1, the receiving short section 3, and the lower transmitting short section 4 are all provided with wire through-holes 10, which house wires that can connect the circuit module 5 to other structures connected to the replaceable drilling resistivity measurement antenna short section, allowing power transfer. The wire through-holes 10, the first signal line through-hole 7, the second signal line through-hole 13, and the third signal line through-hole 14 are arranged circumferentially around the main housing to avoid mutual interference.

[0061] In some embodiments, at the connection between adjacent short sections, the wire through-hole 10 is formed in a tapered shape at the end face of the short section. Similar to the signal wire through-hole, the wire through-hole 10 is also formed in a tapered flared shape at the end face of the short section, which facilitates the insertion and passage of wires through the short section, simplifying the installation operation. For two adjacent short sections, only the wire through-hole 10 of one of the short sections can be formed in a flared shape.

[0062] In some embodiments, the circuit module 5 includes a housing 19, a circuit board frame 17 disposed inside the housing 19, and a circuit board disposed on the circuit board frame 17. The housing 19 is generally tubular and can support and protect the internal structure. The circuit board frame 17 is also generally tubular and is located inside the housing 19, forming a space between the circuit board frame 17 and the housing 19 to accommodate the circuit board. The lower end of the circuit board frame 17 engages with the inner circumferential surface of the housing 19 to form a seal. The upper end of the circuit board frame 17 is provided with a circuit conversion connector 16, which is connected to the lower launch sub 4.

[0063] In some embodiments, each of the short sections is provided with an axially aligned alignment reference groove 2. During installation, the alignment reference grooves 2 on multiple short sections can be aligned axially, thereby aligning the internal wire through holes and signal wire through holes, allowing the wires and signal wires to pass through the corresponding short sections.

[0064] The replaceable underwater resistivity measurement antenna section of this design has the following advantages:

[0065] (1) The antenna slot is designed as a V-shaped structure, pointing in the clockwise direction (the same as the rotation direction), which can offset some of the circumferential friction or impact force when the drill string rotates clockwise. The antenna housing is designed as an integral unit, with the two ends and the lower side of the antenna rib integrated with the body. The rib is thickened to improve its resistance to extrusion deformation.

[0066] (2) It consists of three parts: upper transmitting section, receiving section and lower transmitting section. The modular design facilitates the replacement of antenna sections and avoids serious damage to the antenna housing, which would render the whole device unusable. It can be disassembled and replaced with spare antenna sections for individual maintenance and repair, shortening maintenance time and ensuring the availability of spare tools on site. Compared with the integral structure, its deep hole and gun drill hole length is reduced by two-thirds, reducing the processing difficulty.

[0067] (3) Provide receiving sections with different receiving antenna spacing and different lengths, which can replace the corresponding receiving sections according to different formation resolutions and detection depths, reducing the cost of equipping a whole string of instruments of different specifications.

[0068] (4) A single antenna is arranged through a spiral wire hole and sealed with sealant to achieve the function of dual antenna fixation. This can greatly reduce the exposed area of ​​the antenna, reduce the risk of short circuit when drilling fluid invades, and increase the circumferential support strength of the antenna so that it is not easily damaged.

[0069] (5) The center of each wire hole (signal wire hole and wire hole) on the end face of the short section is located on the same circle centered on the central axis of the short section. The hole is set as a funnel-shaped wire groove. The upper clamping torque is fixed. The wire reference groove is set to intuitively judge whether the internal holes are misaligned, which helps to ensure that the connection holes of each short section are in a connected state and facilitates the subsequent wiring.

[0070] (6) The resistivity module circuits are integrated on the circuit board skeleton inside the circuit shell. The circuits are connected to the lower transmitter section through the circuit conversion connector, avoiding the need to dig grooves on the outer wall of the body for traditional circuit cover type, which may cause stress concentration cracking and tool scrap.

[0071] (7) Two sealing rings are provided on the outer end face of the male thread and the inner end face of the female thread at each short section connection, which can effectively prevent drilling fluid from entering the circuit and causing failure. The wear-resistant rings are designed to reduce the contact area between the antenna strip and the well wall, thereby improving the wear resistance of the antenna part.

[0072] The embodiments of this disclosure have now been described in detail. To avoid obscuring the concept of this disclosure, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0073] While specific embodiments of this disclosure have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of this disclosure. In particular, as long as there is no structural conflict, the technical features mentioned in the various embodiments can be combined in any manner.

Claims

1. A replaceable antenna section for measuring resistivity while drilling, characterized in that, The system includes a signal transmission module comprising a tubular main housing and a signal transmission assembly. The signal transmission assembly includes a signal line through-hole extending along the length direction within the main housing, a spiral mounting hole (11) spirally extending around the central axis of the main housing, and an antenna slot (21) disposed on the outer surface of the main housing. The spiral mounting hole (11) communicates with the signal line through-hole, a signal line is disposed in the signal line through-hole, and an antenna communicating with the signal line is disposed in the spiral mounting hole (11). The antenna slot (21) communicates with the spiral mounting hole (11) and is filled with a sealing material that does not provide signal shielding to form a signal transmission channel.

2. The replaceable drilling resistivity measurement antenna section according to claim 1, characterized in that, The antenna slot (21) is configured in a V-shape, and the orientation of the antenna slot (21) is the same as the rotation direction of the main housing, so as to reduce the frictional resistance encountered during rotation.

3. The replaceable drilling resistivity measurement antenna section according to claim 1, characterized in that, An antenna rib (18) is provided between adjacent antenna slots (21). The antenna rib (18) is provided with a first recess that communicates with the spiral mounting hole (11). A cover plate (12) is provided in the first recess. The cover plate (12) partially defines the spiral mounting hole (11) and covers the antenna.

4. The replaceable drilling resistivity measurement antenna section according to claim 1, characterized in that, The outer surface of the main housing is provided with a second recess that communicates with the signal line through hole. The second recess is provided with a tuning circuit board connected to the signal line and a protective plate (15) covering the tuning circuit board.

5. The replaceable drilling resistivity measurement antenna section according to claim 1, characterized in that, Multiple wear-resistant rings (6) spaced axially are provided on the outer periphery of the main housing.

6. The replaceable drilling resistivity measurement antenna section according to claim 1, characterized in that, The signal transmission module includes three short sections connected in sequence, and each short section is provided with at least one of the signal transmission components.

7. The replaceable drilling resistivity measurement antenna section according to claim 6, characterized in that, At the connection between two adjacent short sections, one of the short sections has an annular groove at its end to accommodate the insertion of the end of the other short section, an inner sealing ring (9) is provided on the inner circumferential surface of the end of the other short section, and an outer sealing ring (8) is provided on the outer circumferential surface of the end of the other short section.

8. The replaceable drilling resistivity measurement antenna section according to claim 7, characterized in that, The three sections comprise an upper transmitting section (1), a receiving section (3), and a lower transmitting section (4) connected sequentially from top to bottom.

9. The replaceable drilling resistivity measurement antenna section according to claim 8, characterized in that, It also includes a circuit module (5) connected to the lower end of the lower transmitter section (4).

10. The replaceable drilling resistivity measurement antenna section according to claim 9, characterized in that, The signal line vias include a first signal line via (7) located in the upper transmitting section (1), the receiving section (3), and the lower transmitting section (4) and connected to the circuit module (5), a second signal line via (13) located in the receiving section (3) and the lower transmitting section (4) and connected to the circuit module (5), and a third signal line via (14) located in the lower transmitting section (4) and connected to the circuit module (5).

11. The replaceable drilling resistivity measurement antenna section according to claim 10, characterized in that, At the junction of two adjacent short sections, the signal line through-hole is formed in a tapered shape at the end face of the short section.

12. The replaceable drilling resistivity measurement antenna section according to claim 10, characterized in that, Each of the three short sections is provided with a wire through hole (10) communicating with the circuit module (5), and the wire through hole (10), the first signal line through hole (7), the second signal line through hole (13) and the third signal line through hole (14) are arranged circumferentially at intervals.

13. The replaceable drilling resistivity measurement antenna section according to claim 12, characterized in that, At the connection between adjacent short sections, the wire through-hole (10) is formed in a tapered shape at the end face of the short section.

14. The replaceable drilling resistivity measurement antenna section according to claim 9, characterized in that, The circuit module (5) includes a housing (19) and a circuit board frame (17) disposed inside the housing (19), and a circuit board disposed on the circuit board frame (17).

15. The replaceable drilling resistivity measurement antenna section according to claim 7, characterized in that, Each of the short sections is provided with an alignment reference groove (2) aligned in the axial direction.

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