A near-bit measuring device

Abstract

The application discloses a near-bit measuring device, which comprises a short section body connected with a screw rod and a drill bit, respectively, and having a drilling fluid channel formed therein; a resistivity measuring module arranged on the outer wall of the short section body and used for acquiring formation resistivity data at a real-time reaching position of the drill bit in a while-drilling operation under the action of a first control signal; a wireless short transmission module arranged on the outer wall of the short section body and used for receiving the formation resistivity data and sending the formation resistivity data to an external device above the screw rod under the action of a second control signal; and a general control module connected with the resistivity measuring module and the wireless short transmission module, respectively, and used for alternately sending the effective first control signal and the second control signal. The application can fully utilize the space on the near-bit short section, realizes the functions of resistivity measurement with a certain detection depth and wireless cross-screw rod short transmission, and is very favorable for the adjustment of a drilling trajectory and the safety of drilling.

Description

Technical Field

[0001] This invention relates to the field of measurement while drilling in oil exploration and development, and more specifically, to a near-bit measurement device. Background Technology

[0002] With the continuous development of oil and gas, the early conventional oil and gas reservoirs are nearing completion, and the focus is now shifting from shallow to deep development of unconventional and complex reservoirs. Currently, horizontal well drilling techniques are increasingly widely used for these complex reservoirs. During oil and gas well construction, geosteering technology is crucial for improving drilling success rate and drainage area, significantly increasing single-well production. Simultaneously, geosteering places increasingly higher demands on measurement-while-drilling (MWD) instruments, particularly maximizing the proximity of measurement points to the drill bit, ideally below the drill string. Due to the drill string's unique structure, cable routing is difficult; therefore, a wireless short-transmission device across the drill string is typically required near the drill bit to transmit the measurement signal to the top of the drill string, then via a wired connection to the mud pulse generator, and finally to the surface.

[0003] Due to the requirements of drill string assembly and dogleg limitations during drilling, the length of the near-bit sub, installed above the drill bit and below the screw, generally cannot exceed 1 meter. This length is significantly longer than that of conventional drilling instruments, which often exceed 10 meters. This severely restricts the design and installation of measurement sensor structures within the near-bit sub, especially for modules like electromagnetic resistivity measurement, which require multiple coils to form a coil system for formation resistivity measurement. According to the basic principles of electromagnetic resistivity, measurement requires at least one transmitting coil and two receiving coils. The distance from the transmitting coil to the midpoint of the two receiving coils is called the source distance, which is approximately proportional to the detection depth for measuring formation resistivity. Therefore, to ensure a certain detection depth, the source distance must exceed 0.5 meters; otherwise, the signal will not reach a sufficient depth in the formation, resulting in measurement results that only reflect the resistivity of the drilling fluid around the sub.

[0004] A wireless short-transmission coil is essential on the near-bit sub. Due to the low operating frequency of wireless short-transmission, a large inductance in the transmitting coil is required to achieve high-efficiency transmission. A large inductance necessitates a large number of turns in the coil, and a magnetic core must be installed beneath the coil to achieve this. Therefore, the wireless short-transmission coil typically occupies more than 0.4m on the near-bit sub. Thus, how to more effectively utilize the space in the near-bit measurement sub and install as many measurement modules as possible, especially sensors such as electromagnetic resistivity sensors, is a pressing issue that needs to be addressed.

[0005] Existing technologies include directly installing electromagnetic resistivity measurement coils on the near-bit sub to avoid wireless short-transmission coils, or using a current-based lateral resistivity measurement principle, which has very limited resistivity detection depth. Neither of these methods effectively solves the problem of simultaneously achieving near-bit electromagnetic resistivity measurement and wireless short-transmission, while also limiting the length of the near-bit sub to within 1 meter. Summary of the Invention

[0006] The present invention requires the design of an effective device that spatially combines a radio electromagnetic wave short-circuit coil and an electromagnetic wave resistivity coil.

[0007] To address the aforementioned technical problems, the present invention provides a near-bit measurement device, comprising: a short section body having drilling fluid channels formed therein, the short section body being configured to be connected to a screw and a drill bit respectively; a resistivity measurement module disposed on the outer wall of the short section body, the resistivity measurement module being configured to acquire formation resistivity data at the real-time position reached by the drill bit during a measurement-while-drilling operation under the action of a first control signal; a wireless short-transmission module disposed on the outer wall of the short section body, the wireless short-transmission module being configured to receive the formation resistivity data under the action of a second control signal and transmit the formation resistivity data to an external device above the screw; and a central control module connected to the resistivity measurement module and the wireless short-transmission module respectively, the central control module being configured to alternately transmit valid first control signals and second control signals.

[0008] Preferably, the resistivity measurement module includes: a signal generator installed in a second groove adjacent to the drill bit, the signal generator being used to emit a corresponding induced electromagnetic wave signal after an alternating current signal is applied; a first receiver installed in a first groove adjacent to the screw, the first receiver being further disposed near the screw and configured to generate a first induced current signal at a corresponding formation location under the influence of the induced electromagnetic wave signal; a second receiver disposed in the first groove near the signal generator, the second receiver being configured to generate a second induced current signal at a corresponding formation location under the influence of the induced electromagnetic wave signal; and a resistivity measurement controller disposed between the second receiver and the signal generator, the resistivity measurement controller being configured to receive the first induced current signal and the second induced current signal after sending the alternating current signal to the signal generator, and to calculate the formation resistivity data.

[0009] Preferably, the wireless short-transmission module includes: a short-transmission controller connected to the resistivity measurement controller, the short-transmission controller acquiring the formation resistivity data from the resistivity measurement controller; and a short-transmission transmitter disposed between the first receiver and the second receiver, the short-transmission transmitter being further connected to the short-transmission controller, configured to transmit a short-transmission electromagnetic wave signal for transmitting the formation resistivity data in the short-transmission controller to the external device after an alternating current obtained from the short-transmission controller is applied.

[0010] Preferably, the master control module is integrated into the resistivity measurement controller in the resistivity measurement module or the short transmission controller in the wireless short transmission module.

[0011] Preferably, the first groove is formed as an annular groove coaxial with the short section body, and is provided with a plurality of first magnetic cores evenly distributed around the inner wall of the first groove, wherein the first receiver, short transmitter and second receiver in the first groove are arranged around the plurality of first magnetic cores along the axial direction of the short section body.

[0012] Preferably, the second groove is formed as an annular groove coaxial with the short section body, and is provided with a plurality of second magnetic cores evenly distributed around the inner wall of the second groove, wherein the signal generator in the second groove surrounds the plurality of second magnetic cores along the axial direction of the short section body.

[0013] Preferably, the device further includes: a first short section cavity disposed between the first groove and the second groove, the first short section cavity housing the resistivity measurement controller; and a second short section cavity disposed between the first groove and the second groove, the second short section cavity housing the short transmission controller.

[0014] Preferably, the device further includes: a first wiring hole communicating with the first groove and the first short section cavity respectively, the first wiring hole having a built-in signal line for receiving the first induced current signal and the second induced current signal respectively; and a second wiring hole communicating with the second groove and the first short section cavity respectively, the second wiring hole having a built-in signal line for supplying an alternating current signal to the signal generator.

[0015] Preferably, the device further includes a third wiring hole communicating with the first groove and the second short section cavity respectively, the third wiring hole having a built-in signal line for supplying an alternating current signal to the short transmitter.

[0016] Preferably, the device further includes: a first groove protective cover installed outside the first groove, the first groove protective cover having a plurality of first groove gaps uniformly provided and filled by trapezoidal insulating elements; and a second groove protective cover installed outside the second groove, the second groove protective cover having a plurality of second groove gaps uniformly provided and filled by trapezoidal insulating elements.

[0017] Compared with the prior art, one or more embodiments of the above solutions may have the following advantages or beneficial effects:

[0018] This invention can make full use of the space on the near-bit sub to achieve near-bit electromagnetic resistivity measurement with a certain detection depth. It also has the function of wireless cross-screw short transmission, which is very beneficial for drilling trajectory adjustment and drilling safety, and is of great significance for cost reduction and efficiency improvement.

[0019] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained by means of the structures particularly pointed out in the following description, claims, and drawings. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with the embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0021] Figure 1 This is a schematic diagram of the overall structure of the near-drill bit measuring device according to an embodiment of this application.

[0022] Figure 2 This is a schematic diagram of the cross-sectional structure of the first groove A in the near-drill bit measuring device of this application embodiment.

[0023] Figure 3 This is a schematic diagram of the appearance of the near-drill bit measuring device according to an embodiment of this application.

[0024] Figure 4 This is a schematic cross-sectional view of the first groove protective cover B in the near-drill bit measuring device of this application embodiment.

[0025] In this application, all drawings are schematic and are used only to illustrate the principles of the invention, and are not drawn to scale.

[0026] The list of reference numerals in the attached figures is as follows:

[0027] 100: Puppet body

[0028] 110: Drilling fluid channel

[0029] 120: Inner wall of pup body

[0030] 130: Short section male buckle

[0031] 140: Short-section female buckle

[0032] 200: First groove

[0033] 210: First Receiver

[0034] 220: Inner wall of the first groove

[0035] 230: Short-range transmitter

[0036] 240: First magnetic core

[0037] 250: First fixed magnetic core housing

[0038] 260: Second receiver

[0039] 270: First recessed protective cover

[0040] 271: First groove gap

[0041] 280: First wiring hole

[0042] 281: First Connector

[0043] 290: Third wiring hole

[0044] 291: Third Connector

[0045] 300: First short segment cavity

[0046] 310: Measuring circuit board

[0047] 320: Second wiring hole

[0048] 321: Second Connector

[0049] 330: Short section cavity protective cover

[0050] 400: Second short segment cavity

[0051] 410: Wireless transmission circuit board

[0052] 500: Second groove

[0053] 510: Signal Generator

[0054] 520: Inner wall of the second groove

[0055] 530: Second magnetic core

[0056] 540: First fixed magnetic core housing

[0057] 550: Second recessed protective cover

[0058] 551: Second groove gap Detailed Implementation

[0059] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples, so that the process of how the present invention uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly. It should be noted that, as long as there is no conflict, the various embodiments and features in the various embodiments of the present invention can be combined with each other, and the resulting technical solutions are all within the protection scope of the present invention.

[0060] Due to the requirements of drill string assembly and dogleg limitations during drilling directional drilling operations, the length of the near-bit sub, installed above the drill bit and below the screw, generally cannot exceed 1 meter. This length is significantly longer than that of conventional drilling instruments, which often exceed 10 meters. This severely restricts the design and installation of measurement sensor structures within the near-bit sub, especially for modules like electromagnetic resistivity measurement, which require multiple coils to form a coil system for formation resistivity measurement. According to the basic principles of electromagnetic resistivity, measurement requires at least one transmitting coil and two receiving coils. The distance from the transmitting coil to the midpoint of the two receiving coils is called the source distance, which is approximately proportional to the detection depth for measuring formation resistivity. Therefore, to ensure a certain detection depth, the source distance must exceed 0.5 meters; otherwise, the signal will not reach a sufficient depth in the formation, resulting in measurement results that only reflect the resistivity of the drilling fluid around the sub.

[0061] A wireless short-transmission coil is essential on the near-bit sub. Due to the low operating frequency of wireless short-transmission, a large inductance in the transmitting coil is required to achieve high-efficiency transmission. A large inductance necessitates a large number of turns in the coil, and a magnetic core must be installed beneath the coil to achieve this. Therefore, the wireless short-transmission coil typically occupies more than 0.4m on the near-bit sub. Thus, how to more effectively utilize the space in the near-bit measurement sub and install as many measurement modules as possible, especially sensors such as electromagnetic resistivity sensors, is a pressing issue that needs to be addressed.

[0062] Existing technologies include directly installing electromagnetic resistivity measurement coils on the near-bit sub to avoid wireless short-transmission coils, or using a current-based lateral resistivity measurement principle, which has very limited resistivity detection depth. Neither of these methods effectively solves the problem of simultaneously achieving near-bit electromagnetic resistivity measurement and wireless short-transmission, while also limiting the length of the near-bit sub to within 1 meter.

[0063] Therefore, this invention overcomes the shortcomings of the prior art and designs a near-bit measurement device. This device effectively combines a radio electromagnetic wave short-transmission coil and an electromagnetic wave resistivity coil in space, reusing the magnetic core to improve coil performance, thus achieving a compact coil system structure. This device fully utilizes the space on the near-bit short section, enabling near-bit electromagnetic wave resistivity measurement with a certain detection depth, while also possessing the function of wireless cross-screw short-transmission.

[0064] Figure 1 This is a schematic diagram of the overall structure of the near-drill bit measuring device according to an embodiment of this application. Figure 1 As shown, the device includes a sub-body 100, a resistivity measurement module (not shown), a wireless short-transmission module (not shown), and a central control module (not shown). The sub-body 100 has male and female threads 130 at its front and rear positions for connecting the drill bit and screw, respectively. A drilling fluid channel 110 is formed in the hollow portion of the sub-body 100 (i.e., the inner wall 120 of the sub-body). A first groove 200, coaxial with the sub-body 100, is provided immediately adjacent to the screw end of the sub-body 100. A second groove 500, coaxial with the sub-body 100, is also provided immediately adjacent to the drill bit end of the sub-body 100.

[0065] Furthermore, a first short section cavity 300 and a second short section cavity 400 are provided on the outer wall of the short section body 100 between the first groove 200 and the second groove 500.

[0066] Furthermore, the aforementioned resistivity measurement module is mounted on the outer wall of the sub body 100. Under the action of the first control signal, the resistivity measurement module can acquire formation resistivity data at the real-time location reached by the drill bit during the measurement-while-drilling operation. The resistivity measurement module includes a signal generator 510, a first receiver 210, a second receiver 260, and a resistivity measurement controller (not shown).

[0067] Specifically, the signal generator 510, the first receiver 210, and the second receiver 260 all employ coil devices. The signal generator 510 is installed within the second groove 500, and the coil device within it winds axially around the short section body 100. The first receiver 210 and the second receiver 260 are respectively installed within the first groove 200 near the screw and the signal generator 510. The coil device in the first receiver 210 winds axially around the short section body 100, and similarly, the coil device in the second receiver 260 winds axially around the short section body 100. A measurement circuit board 310 is disposed within the first short section cavity 300 between the second receiver 260 in the first groove 200 and the signal generator 510 in the second groove 500. The resistivity measurement controller is integrated onto the measurement circuit board 310 and is connected to the signal generator 510, the first receiver 210, and the second receiver 260, respectively.

[0068] Under the control of a first control signal, the resistivity measurement controller sends an alternating current signal to the signal generator 510. Upon receiving the alternating current signal from the resistivity measurement controller, the signal generator 510 emits a corresponding induced electromagnetic wave signal. Subsequently, the first receiver 210 and the second receiver 260, under the influence of the induced electromagnetic wave signal, respectively generate a first induced current signal and a second induced current signal at the corresponding formation location. Further, the resistivity measurement module receives the first and second induced current signals and calculates the formation resistivity data based on them.

[0069] A first wiring hole 280 is provided between the side of the first groove 200 and the side of the first short section cavity 300 to connect the two. The first wiring hole 280 contains signal lines for receiving the first induced current signal and the second induced current signal, namely the coils of the first receiver 210 and the second receiver 260, and these signal lines are respectively connected to the corresponding signal connection points of the resistivity measurement controller in the measurement circuit board 310. Furthermore, a first connector 281 is installed in the first wiring hole 280. The connector 281 is a high-pressure sealed connector, one end of which is connected to the coils of the first receiver 210 and the second receiver 260 in the first groove 200, and the other end is connected to the corresponding signal connection points in the measurement circuit board 310 (the signal receiving points of the first induced current signal and the second induced current signal on the circuit board).

[0070] Furthermore, a second wiring hole 320 is provided between the side of the second groove 500 and the side of the first short section cavity 300 to connect the two. The second wiring hole 320 contains a signal line for supplying an alternating current signal to the signal generator 510, i.e., the coil of the signal generator 510, and this signal line is connected to the corresponding signal connection point of the resistivity measurement controller in the measurement circuit board 310. Furthermore, a second connector 321 is installed in the second wiring hole 320. This connector 321 is a high-pressure sealed connector, one end of which is connected to the coil of the signal generator 510 in the second groove 500, and the other end is connected to the corresponding signal connection point in the measurement circuit board 310 (the signal emission point of the alternating current signal on the circuit board).

[0071] The first connector 281 and the second connector 321 serve a sealing function to ensure that drilling fluid does not enter the first short section cavity 300 where the measuring circuit board 310 is installed, thus avoiding damage to the circuit board, battery, and other equipment.

[0072] Furthermore, the aforementioned wireless short-transmission module is disposed on the outer wall of the short section body 100. Under the action of the second control signal, the wireless short-transmission module can receive the aforementioned formation resistivity data and transmit the formation resistivity data to external equipment above the screw or ground equipment. The wireless short-transmission module includes a short-transmission transmitter 230 and a short-transmission controller (not shown).

[0073] Specifically, the aforementioned short-transmission transmitter 230 employs a coil device. The short-transmission transmitter 230 is installed between the first receiver 210 and the second receiver 260 within the first groove, and the coil device in the short-transmission transmitter 230 surrounds the short section body 100 axially. A wireless transmission circuit board 410 is disposed within the second short section cavity 400 between the first groove 200 and the second groove 500. The aforementioned short-transmission controller is integrated onto the wireless transmission circuit board 410 and is connected to the short-transmission transmitter and the resistivity measurement controller.

[0074] Under the control of the second control signal, the short-transmission controller can send an alternating current signal to the short-transmission transmitter 230. After receiving the alternating current signal obtained from the short-transmission controller, the short-transmission transmitter 230 transmits a short-transmission electromagnetic wave signal containing the formation resistivity data in the short-transmission controller to an external device or a formation device, so that the wireless short-transmission receiving device in the external device or the formation device can obtain the corresponding formation resistivity data.

[0075] Furthermore, a third wiring hole 290 is provided between the side of the first groove 200 and the side of the second short section cavity 400 to connect the two. The third wiring hole 290 houses a signal line for transmitting alternating current signals to the short-transmission transmitter, i.e., the coil of the short-transmission transmitter 230, and this signal line is connected to the corresponding signal connection point of the short-transmission controller within the wireless transmission circuit board 410. Furthermore, a third connector 291 is installed within the third wiring hole 290. This connector 291 is a high-pressure sealed connector, with one end connected to the coil of the short-transmission transmitter 230 within the first groove 200, and the other end connected to the corresponding signal connection point within the wireless transmission circuit board 410 (the signal transmission point of the alternating current signal on the circuit board). The third connector 291 serves a sealing function, ensuring that drilling fluid does not enter the second short section cavity 400 where the wireless transmission circuit board 410 is installed, thus preventing damage to the circuit board and battery, etc.

[0076] Furthermore, the aforementioned master control module is integrated into the resistivity measurement controller in the resistivity measurement module or the short-transmission controller in the wireless short-transmission module. The master control module, connected to both the resistivity measurement controller in the resistivity measurement module and the short-transmission controller in the wireless short-transmission module, can alternately transmit valid first and second control signals. In this way, by connecting the short-transmission transmitter and the resistivity measurement controller through the master control module, the operating timing of various coils can be controlled, avoiding interference between resistivity measurement and wireless short-transmission. This ensures that wireless short-transmission is not performed during resistivity measurement, and vice versa.

[0077] A fourth wiring hole (not shown) is provided between the side of the first short section cavity 300 and the side of the second short section cavity 400, connecting the two. This hole is located within the side wall of the short section body 10 and houses a signal line for transmitting a first or second control signal. Furthermore, a fourth connector (not shown) is installed within the fourth wiring hole. This connector is a high-pressure sealed connector, with one end connected to the main control module integrated into the resistivity measurement controller or the short-transmission controller, and the other end connected to the signal connection point of the first control signal in the resistivity measurement controller or the signal connection point of the second control signal in the short-transmission controller. The fourth connector acts as a seal, ensuring that drilling fluid does not enter the wireless short-transmission transmitting circuit board 410 and the measuring circuit board 310, thus preventing damage to the circuit boards and batteries.

[0078] In addition, a plurality of uniformly distributed cylindrical first magnetic cores 240 are provided around the outer periphery of the inner wall 220 of the first groove (the central axis of the first magnetic core 240 is parallel to the axial direction of the short section body 100). The length of the first magnetic core 240 needs to reach or exceed the sum of the axial winding lengths of the various coils (the combination of the first receiver 210 coil, the second receiver 260 coil, and the short transmitter 230 coil) within the first groove 200, to ensure that there is a magnetic core under each of the three types of coils, thereby effectively improving the performance of each type of coil. Furthermore, a first magnetic core housing 250 for fixing the plurality of first magnetic cores 240 is provided between the inner wall 220 of the first groove and the various coils within the first groove 200, wherein the plurality of first magnetic cores 240 are uniformly distributed within the first magnetic core housing 250. The first magnetic core housing 250 is a cylindrical cavity. For ease of installation, the housing 250 can be divided into two or more segments, that is, two or more segments form a complete hollow cylinder that wraps around the inner wall 220 of the first groove. Various coils in the first groove 200 are wound around the outer surface of the first magnetic core housing 250.

[0079] A plurality of uniformly distributed cylindrical second magnetic cores 530 are disposed around the outer periphery of the inner wall 520 of the second groove (the central axis of the second magnetic core 530 is parallel to the axial direction of the short section body 100). The length of the second magnetic core 530 needs to reach or exceed the axial winding length of the short transmitter 230 coil within the second groove 500 to ensure that there are magnetic cores below the coil of the short transmitter 230, thereby effectively improving the performance of the coil. Furthermore, a second magnetic core housing 540 for fixing the plurality of second magnetic cores 530 is disposed between the inner wall 520 of the second groove and the coil of the short transmitter 230 within the second groove 500, wherein the plurality of second magnetic cores 530 are uniformly distributed within the second magnetic core housing 540. Similarly, the second magnetic core housing 540 is a cylindrical cavity. For ease of installation, the housing 540 can be divided into two or more segments, that is, two or more segments form a complete hollow cylinder that wraps around the inner wall 520 of the second groove. The short-transmitter 230 coil in the second groove 500 is wound around the outer surface of the second magnetic core housing 540.

[0080] Furthermore, a first groove protective cover 270 and a second groove protective cover 550 are respectively installed on the outer surfaces of the first groove 200 and the second groove 500. The bodies of the first groove protective cover 270 and the second groove protective cover 550 are made of metal material, which respectively protects the various coils inside the first groove 200 and the second groove 500, and prevents the various coils inside the grooves from being eroded by drilling fluid and rock cuttings in the wellbore.

[0081] Furthermore, Figure 3This is a schematic diagram of the near-drill bit measuring device according to an embodiment of this application. Since the bodies of the first groove protective cover 270 and the second groove protective cover 550 are made of metal, the metal material shields the electromagnetic wave signals of various coils inside the first groove 200 and the second groove 500 from penetration and transmission. Therefore, as... Figure 3 As shown, a plurality of first groove slits 271 are uniformly arranged on the first groove protective cover 270, and a plurality of second groove slits 551 are also uniformly arranged on the second groove protective cover 550.

[0082] The protective cover 270 of the first groove 200, installed outside the first groove 200, is uniformly provided with a plurality of first groove gaps 271 filled with trapezoidal insulating elements. Specifically, each first groove gap 271 is formed into a trapezoid with a larger inner surface and a smaller outer surface. In order to ensure that electromagnetic wave signals can penetrate and transmit through the aforementioned plurality of first groove gaps 271 and reach the wellbore and formation, trapezoidal insulating elements are used to fill each first groove gap 271. Figure 4 This is a schematic cross-sectional view of the protective cover B of the first groove in the near-drill bit measuring device according to an embodiment of this application. The shape and distribution of the plurality of first groove gaps 271 and the plurality of trapezoidal insulating elements within the first groove 200 are shown below. Figure 4 As shown.

[0083] Similarly, the second groove protective cover 550 installed outside the second groove 500 is uniformly provided with a plurality of second groove gaps 551 filled with trapezoidal insulating elements. Specifically, each second groove gap 551 is formed into a trapezoid with a larger inner surface and a smaller outer surface. In order to ensure that electromagnetic wave signals can penetrate and transmit through the aforementioned plurality of second groove gaps 551 to reach the wellbore and formation, trapezoidal insulating elements are also required to fill each second groove gap 551.

[0084] Thus, through the structural design of the first groove protective cover 270 and the second groove protective cover 550, it is further ensured that each insulating component will not fall off the main body of the first groove protective cover 270 and the second groove protective cover 550. Furthermore, the corresponding grooves on the inner surfaces of the first groove protective cover 270 and the second groove protective cover 550 are also filled with insulating material, and the first groove protective cover 270 and the second groove protective cover 550 are tightly attached to this insulating material. Therefore, the insulating components in the gaps of the first groove protective cover 270 and the second groove protective cover 550 will not fall off the inner or outer surfaces of the first groove protective cover 270 and the second groove protective cover 550.

[0085] Furthermore, Figure 2This is a schematic cross-sectional view of the first groove A in the near-drill bit measuring device according to an embodiment of this application. Taking the first groove 200 as an example, the distribution of the plurality of first magnetic cores 240, first magnetic core housings 250, first groove gaps 271, and first groove protective covers 270 is as follows. Figure 2 As shown.

[0086] Refer again Figure 3 Both the first short section cavity 300 and the second short section cavity 400 are provided with a short section cavity protective cover 330. The short section cavity protective cover 330 seals the first short section cavity 300 and the second short section cavity 400 inside the short section body 100, thereby protecting the measurement circuit board 310 and the wireless transmission and transmitting circuit board 410.

[0087] This invention proposes a near-bit measurement device. The system involved in this device can fully optimize the structure of near-bit measurement instruments, achieving a very compact near-bit electromagnetic resistivity measurement sub with wireless short-transmission capabilities. For example, it can achieve resistivity measurement at a depth of 0.5m while keeping the length of the entire sub within 1 meter, meeting the dogleg requirements of the drill string assembly. These advantages are highly beneficial for adjusting the drilling trajectory and ensuring drilling safety, and also have significant implications for reducing equipment costs and improving measurement-while-drilling accuracy.

[0088] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A near-drill bit measuring device, comprising: The short section body having drilling fluid channels is configured to be connected to the screw and the drill bit respectively; The resistivity measurement module is installed on the outer wall of the short section body. The resistivity measurement module is configured to acquire formation resistivity data at the real-time position reached by the drill bit during the drilling measurement operation under the action of the first control signal. The wireless short transmission module is installed on the outer wall of the short section body. The wireless short transmission module is configured to receive the formation resistivity data under the action of the second control signal and send the formation resistivity data to an external device above the screw. and A central control module is connected to both the resistivity measurement module and the wireless short-transmission module. The central control module is configured to alternately transmit valid first and second control signals. The resistivity measurement module includes: A signal generator is installed in the second groove adjacent to the drill bit. The signal generator is used to emit a corresponding induced electromagnetic wave signal after an alternating current signal is applied. A first receiver is installed in a first groove adjacent to the screw, and the first receiver is further disposed near the screw, configured to generate a first induced current signal at a corresponding stratum location under the influence of the induced electromagnetic wave signal; A second receiver, disposed within the first groove near the signal generator, is configured to generate a second induced current signal at a corresponding formation location under the influence of the induced electromagnetic wave signal; and A resistivity measurement controller is disposed between the second receiver and the signal generator. The resistivity measurement controller is configured to receive the first induced current signal and the second induced current signal after sending the alternating current signal to the signal generator, and calculate the formation resistivity data. The wireless short-transmission module includes: A short-transmission controller connected to the resistivity measurement controller, the short-transmission controller acquiring the formation resistivity data from the resistivity measurement controller; and A short-transmission transmitter is disposed between the first receiver and the second receiver, and the short-transmission transmitter is further connected to the short-transmission controller. The transmitter is configured to, upon application of an alternating current obtained from the short-transmission controller, transmit a short-transmission electromagnetic wave signal for transmitting formation resistivity data from the short-transmission controller to the external device. The first groove is formed as an annular groove coaxial with the short section body, and is provided with a plurality of first magnetic cores evenly distributed around the inner wall of the first groove. The first receiver, short transmitter and second receiver in the first groove are arranged around the plurality of first magnetic cores along the axial direction of the short section body.

2. The apparatus according to claim 1, characterized in that, The master control module is integrated into the resistivity measurement controller in the resistivity measurement module or the short transmission controller in the wireless short transmission module.

3. The apparatus according to claim 1, characterized in that, The second groove is formed as an annular groove coaxial with the short section body, and is provided with a plurality of second magnetic cores evenly distributed around the inner wall of the second groove. The signal generator in the second groove surrounds the plurality of second magnetic cores along the axial direction of the short section body.

4. The apparatus according to claim 1 or 3, characterized in that, The device further includes: A first short section cavity is disposed between the first groove and the second groove, and the resistivity measurement controller is built into the first short section cavity; A second short section cavity is disposed between the first groove and the second groove, and the short transmission controller is built into the second short section cavity.

5. The apparatus according to claim 4, characterized in that, The device further includes: A first wiring hole communicates with both the first groove and the first short section cavity, and the first wiring hole contains signal lines for receiving the first induced current signal and the second induced current signal, respectively; and A second wiring hole is connected to the second groove and the first short section cavity respectively, and the second wiring hole has a built-in signal line for supplying an alternating current signal to the signal generator.

6. The apparatus according to claim 4, characterized in that, The device further includes: A third wiring hole is connected to the first groove and the second short section cavity respectively, and the third wiring hole has a built-in signal line for transmitting alternating current signals to the short transmitter.

7. The apparatus according to claim 6, characterized in that, The device further includes: A first groove protective cover is installed outside the first groove, and the first groove protective cover is evenly provided with a plurality of first groove gaps filled by trapezoidal insulating elements; and A second groove protective cover is installed outside the second groove, and the second groove protective cover is evenly provided with a number of second groove gaps filled by trapezoidal insulating parts.

Images