Near-bit antenna device

Abstract

The invention relates to the field of measurement while drilling in petroleum and natural gas drilling engineering, in particular to a near-bit antenna device which mainly solves the problems that an original device is too large in signal attenuation rate, complex in shielding structure process, low in signal transmission stability and low in resistivity measurement precision. The near-bit device comprises a near-bit body (1), an annular groove is formed in the outer wall of the near-bit body (1), a receiving antenna shell (2) is arranged outside the annular groove, a short-pass antenna protection cover (4) is arranged in the receiving antenna shell (2), a receiving antenna (9) is annularly wound between the short-pass antenna protection cover (4) and the receiving antenna shell (2), and a short-pass antenna structure is arranged in the short-pass antenna protection cover (4). The device can greatly reduce the signal attenuation rate of the antenna, simplify the installation process of the shielding structure, improve the installation efficiency, and improve the signal transmission stability and the resistivity measurement precision of a near-bit instrument under the complex formation condition.

Description

Technical Field

[0001] This invention relates to the field of measurement while drilling in oil and gas drilling engineering, and in particular to a near-bit antenna device. Background Technology

[0002] Currently, the industry commonly uses a loop antenna layout for drilling electromagnetic resistivity instruments, employing an axially symmetrical antenna array to calculate formation resistivity through phase difference or amplitude ratio. However, mutual interference exists between the short-pass transmitting antenna and the resistivity signal receiving antenna, leading to excessive signal attenuation, and there is a lack of shielding technology or related design solutions. Conventional resistivity measurement instruments do not consider the collaborative operation requirements of the short-pass antenna and the resistivity receiving antenna. Electromagnetic field coupling between the two easily leads to signal interference, affecting the stability of short-pass communication. Simultaneously, the short-pass antenna also affects the signal-to-noise ratio of the resistivity receiving antenna. The root cause of this problem lies in the overlapping operating frequency bands of the short-pass antenna and the resistivity receiving antenna, coupled with limited axial spacing, resulting in electromagnetic field coupling, low signal transmission stability, and low resistivity measurement accuracy. Traditional antenna devices cannot simultaneously address the conflicting requirements of high-frequency signal transmission and low-frequency interference suppression. To address these shortcomings, a near-drill bit antenna device is proposed. Summary of the Invention

[0003] To address the problems of excessive signal attenuation, overly complex shielding structure installation, low signal transmission stability, and low resistivity measurement accuracy of existing near-bit antenna devices, this invention provides a near-bit antenna device that significantly reduces antenna signal attenuation, simplifies shielding structure installation, improves installation efficiency, and enhances signal transmission stability and resistivity measurement accuracy of near-bit instruments under complex geological conditions.

[0004] The technical solution of the present invention is: a near-drill bit antenna device, comprising: a near-drill bit body, characterized in that: an annular groove is formed on the outer wall of the near-drill bit body, a receiving antenna shell is provided outside the annular groove, a short-transmission antenna protective cover is provided inside the receiving antenna shell, a receiving antenna is annularly wound between the short-transmission antenna protective cover and the receiving antenna shell, and a short-transmission antenna structure is provided inside the short-transmission antenna protective cover.

[0005] Preferably, the receiving antenna housing contains a receiving antenna core, which is disposed between the receiving antenna and the short-pass antenna protective cover.

[0006] Preferably, the short-transmission antenna structure includes a short-transmission antenna core, which is fitted into the bottom of an annular groove near the drill bit body. The short-transmission antenna is wound around the outer wall of the short-transmission antenna core in an annular shape. A short-transmission antenna shield is provided on the outer wall of the short-transmission antenna. The short-transmission antenna shield is installed between the short-transmission antenna protective cover and the short-transmission antenna to prevent wear on the short-transmission antenna.

[0007] Preferably, the short-pass antenna core comprises several individual core units, each core unit being cylindrical, and the material of the short-pass antenna core is a ferrite core.

[0008] Preferably, the short-transmission antenna shield is a hollow cylinder composed of two semi-circular rings joined together. The two ends of the short-transmission antenna shield are connected to the drill bit body. The middle part of the short-transmission antenna shield protrudes outward, and the protruding part is on the side wall. The short-transmission antenna shield has several hollow holes for isolating the short-transmission signal from the received signal.

[0009] Preferably, the short-pass antenna protective cover is composed of several circumferentially distributed short-pass antenna protective cover units, and each short-pass antenna protective cover unit is arc-shaped.

[0010] Preferably, the short-pass antenna is wound around the outer surface of the short-pass antenna core, with 3-10 winding layers, and the wire diameter of the short-pass antenna is 0.5mm < ɓ < 1.5mm.

[0011] Preferably, the receiving antenna housing has several perforated holes, and a gap is left between the receiving antenna housing and the receiving antenna. Anaerobic adhesive is injected into the perforated holes of the receiving antenna housing to prevent wear on the receiving antenna during operation.

[0012] Preferably, the diameter of the receiving antenna is 0.25mm < α < 1.0mm.

[0013] Preferably, the outer wall of the receiving antenna is provided with a receiving antenna protective sleeve, and the end of the receiving antenna protective sleeve has an opening so that both ends of the receiving antenna can pass through it.

[0014] Preferably, the protective cover of the short-pass antenna is made of polyetheretherketone (PEEK), and the protective sleeve of the receiving antenna is made of PEEK.

[0015] The present invention has the following beneficial effects: The near-drill bit antenna device provided by the present invention adopts the above-mentioned scheme. The near-drill bit device adopts a layered composite shielding structure, which greatly reduces the antenna signal attenuation rate. Under the same magnetic core and coil conditions, it effectively improves the actual transmission distance. The use of an integrated receiving antenna and its short-transmission antenna shielding structure greatly shortens the antenna impedance matching time. The shielding design improves the signal transmission stability and resistivity measurement accuracy of the near-drill bit instrument under complex geological conditions. Therefore, it solves the problems of excessive antenna signal attenuation rate, overly complicated shielding structure installation process, low signal transmission stability and low resistivity measurement accuracy of the original near-drill bit antenna device under complex geological conditions. Attached Figure Description

[0016] Figure 1 This is a cross-sectional view of the present invention; Figure 2 These are cross-sectional views of the present invention from different angles; Figure 3 This is a schematic diagram of the receiving antenna and the protective sleeve for the receiving antenna of the present invention; Figure 4 This is a schematic diagram of the short-pass antenna shield of the present invention; Figure 5 This is a schematic diagram of the receiving antenna housing of the present invention; Figure 6 This is a schematic diagram of the receiving antenna protective sleeve of the present invention; Legend: 1-Near the drill bit body; 2-Receiving antenna shell; 3-Receiving antenna core; 4-Short-pass antenna protective cover; 5-Short-pass antenna; 6-Short-pass antenna shield; 7-Short-pass antenna core; 8-Receiving antenna protective sleeve; 9-Receiving antenna. Detailed Implementation

[0017] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. The technical solutions in the embodiments of the present invention will be clearly and completely described. 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.

[0018] In the description of this invention, it is necessary to understand that the orientations or positional relationships indicated by terms such as "upper," "lower," "left," "right," "inner," "outer," "top," and "bottom" are based on the orientations or positional relationships shown in the accompanying drawings. They are intended only to facilitate the description of this invention and to simplify the description, and are not intended to indicate or imply that the components referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0019] In this description, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0020] Figure 1 This is a cross-sectional view of the present invention; Figure 2 These are cross-sectional views of the present invention from different angles; Figure 3 This is a schematic diagram of the receiving antenna and the protective sleeve for the receiving antenna of the present invention; Figure 4 This is a schematic diagram of the short-pass antenna shield of the present invention; Figure 5This is a schematic diagram of the receiving antenna housing of the present invention; Figure 6 This is a schematic diagram of the receiving antenna protective sleeve of the present invention; as shown. Figures 1 to 6 As shown, the present invention provides a near-drill bit antenna device, comprising: a near-drill bit body 1, an annular groove on the outer wall of the near-drill bit body 1, a receiving antenna housing 2 outside the annular groove, a short-transmission antenna protective cover 4 inside the receiving antenna housing 2, a receiving antenna 9 annularly wound between the short-transmission antenna protective cover 4 and the receiving antenna housing 2, the receiving antenna 9 being connected to a circuit board, and a short-transmission antenna structure inside the short-transmission antenna protective cover 4.

[0021] The receiving antenna housing 2 is provided with a receiving antenna core 3 inside, and the receiving antenna core 3 is disposed between the receiving antenna 9 and the short-pass antenna protective cover 4.

[0022] The receiving antenna 9 has a receiving antenna core 3 at its bottom. The receiving antenna core 3 is made of ferrite and is cylindrical or elongated in shape. It is used for the transmission of short-range signals.

[0023] The outer wall of the receiving antenna 9 is provided with a receiving antenna protective sleeve 8. The end of the receiving antenna protective sleeve 8 is opened so that both ends of the receiving antenna 9 can pass through it. The receiving antenna protective sleeve 8 is made of polyetheretherketone and has an outer diameter between 3mm and 5mm.

[0024] The receiving antenna housing 2 has several perforated holes, which are trapezoidal or serrated in shape. This prevents the anaerobic adhesive from falling into the drill bit device due to excessive downhole pressure during operation, and also prevents the anaerobic adhesive from falling out of the drill bit device due to excessive internal pressure. A gap is left between the receiving antenna housing 2 and the receiving antenna 9. Anaerobic adhesive is injected into the perforated holes of the receiving antenna housing 2 to prevent wear on the receiving antenna 9 during operation.

[0025] In this embodiment, the receiving antenna 9 consists of two antennas installed at equal intervals inside the receiving antenna housing 2, with an antenna wire diameter between 0.25mm and 1.0mm.

[0026] The short-transmission antenna structure includes a short-transmission antenna core 7, which is fitted at the bottom of the annular groove near the drill bit body 1. The short-transmission antenna 5 is wound around the outer wall of the short-transmission antenna core 7 in annular shape. The short-transmission antenna 5 is provided with a short-transmission antenna shield 6 on the outer wall of the short-transmission antenna 5. The short-transmission antenna shield 6 is installed between the short-transmission antenna protective cover 4 and the short-transmission antenna 5.

[0027] The short-pass antenna core 7 comprises several individual cores, each of which is cylindrical or an integrated core. The material of the short-pass antenna core 7 is a ferrite core.

[0028] The short-transmission antenna shield 6 is composed of two semicircles joined together, and its material is aluminum or copper. The short-transmission antenna shield 6 is a hollow cylinder. Both ends of the short-transmission antenna shield 6 are connected to the drill bit body 1. The middle part of the short-transmission antenna shield 6 protrudes. Several hollow holes are opened on the short-transmission antenna shield 6 to isolate the short-transmission signal from the received signal.

[0029] The short-transmission antenna protective cover 4 is composed of several circumferentially distributed individual short-transmission antenna protective covers 4. Each individual short-transmission antenna protective cover 4 is arc-shaped and can be divided into 2, 4, or an even number of segments for transmission by the short-transmission antenna. The strip-shaped opening method is optimal, which can increase the transmission distance of the short-transmission antenna by more than 100%.

[0030] The short-pass antenna protective cover 4 is made of polyetheretherketone.

[0031] The short-pass antenna 5 is wound around the outer surface of the short-pass antenna core 7, with 3-10 layers. The diameter of the short-pass antenna wire is 0.5mm < ɓ < 1.5mm.

[0032] During the winding process of the short-transmission antenna 5, to ensure a sufficiently tight connection, the last turn of each layer needs to be secured at the end of the winding process. Simultaneously, to guarantee a tight connection, the starting position of each subsequent layer should be shifted one to two times the wire diameter towards the center of the short-transmission antenna 5 compared to the previous layer. After the receiving antenna housing 2, the short-transmission antenna protective cover 4, and the short-transmission antenna magnetic core 7 are installed, the inductance of the short-transmission antenna is between 100μH and 500μH.

[0033] In practice, when the near-bit device starts working, the device collects geodetic parameters. After the receiving antenna 9 collects the geodetic data, it transmits it to the near-bit circuit for data processing. The near-bit circuit transmits the processed geodetic parameters to the receiving short section above the screw, and then uploads them to the surface platform through the downhole mud pulser. The function of the short transmission antenna is to communicate across the screw.

[0034] This invention provides a near-drill bit antenna device. The device has a simple structure and includes a near-drill bit body 1. An annular groove is formed on the outer wall of the near-drill bit body 1. A receiving antenna housing 2 is disposed outside the annular groove. A short-pass antenna protective cover 4 is disposed inside the receiving antenna housing 2. A set of receiving antennas 9 is disposed inside the receiving antenna housing 2. In this embodiment, the set of antennas consists of two antennas, annularly wound around the short-pass antenna protective cover 4. A receiving antenna core 3 is disposed at the bottom of each receiving antenna 9. The receiving antenna core 3 is made of ferrite. A receiving antenna is disposed on the outer wall of the receiving antenna 9. The antenna protective sleeve 8 is made of polyetheretherketone (PEEK). The short-transmission antenna structure includes a short-transmission antenna core 7, which is fitted into the bottom of an annular groove near the drill bit body 1. A short-transmission antenna 5 is wound annularly around the outer wall of the short-transmission antenna core 7. A short-transmission antenna shield 6 is provided on the outer wall of the short-transmission antenna 5. The short-transmission antenna shield 6 is installed between the short-transmission antenna protective sleeve 4 and the short-transmission antenna 5. In this embodiment, the short-transmission antenna 5 is a thin wire uniformly wound annularly around the short-transmission antenna core 7, with 3-10 layers. The inductance range after winding is 5. 0-500μH, the short-transmission antenna 5 is externally equipped with a short-transmission antenna shield 6, which is connected to the drill bit body 1. The short-transmission antenna shield 6 is made of conductive metal and is a hollow cylinder. The inner diameter of the central cylinder of the short-transmission antenna shield 6 is higher than the inner diameters of the cylinders on both sides. Several uniform or non-uniform strip-shaped or other shaped perforations are opened on the outer wall of the central cylinder. The perforations on the outer wall of the receiving antenna housing 2 are consistent with those of the short-transmission antenna shield 6. In practice, the strip-shaped holes of the receiving antenna housing 2 are used for injection. Anaerobic adhesive is used to prevent wear on the receiving antenna 9 during operation. Due to the above-mentioned solutions, the near-drill bit device adopts a layered composite shielding structure, significantly reducing the antenna signal attenuation rate. Under the same magnetic core and coil conditions, this effectively increases the actual transmission distance. The integrated receiving antenna and its short-transmission antenna shielding structure significantly shorten the antenna impedance matching time. The shielding design improves the signal transmission stability and resistivity measurement accuracy of the near-drill bit instrument under complex geological conditions. In practice, both the short-transmission antenna protective cover 4 and the short-transmission antenna 5 are fixed with adhesive to prevent them from falling off during operation.

[0035] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A near-drill bit antenna device, comprising: The near-drill bit body (1) is characterized in that: the near-drill bit body (1) has an annular groove on its outer wall, a receiving antenna shell (2) is provided outside the annular groove, a short-transmission antenna protective cover (4) is provided inside the receiving antenna shell (2), a receiving antenna (9) is annularly wound between the short-transmission antenna protective cover (4) and the receiving antenna shell (2), and a short-transmission antenna structure is provided inside the short-transmission antenna protective cover (4).

2. The near-drill bit antenna device according to claim 1, characterized in that: The receiving antenna housing (2) is provided with a receiving antenna core (3) inside, and the receiving antenna core (3) is located between the receiving antenna (9) and the short-pass antenna protective cover (4).

3. The near-drill bit antenna device according to claim 1, characterized in that: The short-transmission antenna structure includes a short-transmission antenna core (7), which is fitted into the bottom of the annular groove near the drill bit body (1). The short-transmission antenna (5) is wound around the outer wall of the short-transmission antenna core (7). The short-transmission antenna (5) is provided with a short-transmission antenna shield (6) on the outer wall of the short-transmission antenna (5). The short-transmission antenna shield (6) is installed between the short-transmission antenna protective cover (4) and the short-transmission antenna (5) to prevent wear on the short-transmission antenna (5).

4. The near-drill bit antenna device according to claim 3, characterized in that: The short-pass antenna core (7) includes several core units, each core unit being cylindrical, and the material of the short-pass antenna core (7) is a ferrite core.

5. The near-drill bit antenna device according to claim 4, characterized in that: The short-transmission antenna shield (6) is a hollow cylinder composed of two semi-circular rings joined together. Both ends of the short-transmission antenna shield (6) are connected to the drill bit body (1). The middle part of the short-transmission antenna shield (6) protrudes outward, and the protruding part is on the side wall. The short-transmission antenna shield (6) has several hollow holes for isolating the short-transmission signal from the received signal.

6. The near-drill bit antenna device according to claim 5, characterized in that: The short-pass antenna protective cover (4) is composed of several circumferentially distributed short-pass antenna protective cover units, each of which is arc-shaped.

7. The near-drill bit antenna device according to claim 3, characterized in that: The short-pass antenna (5) is wound around the outer surface of the short-pass antenna core (7) with 3-10 layers, and the wire diameter of the short-pass antenna is 0.5mm < ɓ < 1.5mm.

8. The near-drill bit antenna device according to claim 2, characterized in that: The receiving antenna housing (2) has several hollow holes, and there is a gap between the receiving antenna housing (2) and the receiving antenna (9). Anaerobic glue is injected into the hollow holes of the receiving antenna housing (2) to prevent wear on the receiving antenna (9) during operation.

9. The near-drill bit antenna device according to claim 8, characterized in that: The diameter of the receiving antenna (9) is 0.25mm < α < 1.0mm.

10. The near-drill bit antenna device according to claim 9, characterized in that: The outer wall of the receiving antenna (9) is provided with a receiving antenna protective sleeve (8), and the end of the receiving antenna protective sleeve (8) is opened so that both ends of the receiving antenna (9) can pass through it.

11. The near-drill bit antenna device according to any one of claims 1-10, characterized in that: The short-pass antenna protective cover (4) is made of polyetheretherketone (PEEK), and the receiving antenna protective cover (8) is made of PEEK.

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