CN-122000692-A - 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 of overlarge signal attenuation rate, complex shielding structure process, low signal transmission stability and low resistivity measurement precision in the original device. The invention comprises a near-bit body (1), wherein 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-transmission antenna protection cover (4) is arranged inside the receiving antenna shell (2), a receiving antenna (9) is wound between the short-transmission antenna protection cover (4) and the receiving antenna shell (2) in an annular mode, and a short-transmission antenna structure is arranged inside the short-transmission antenna protection cover (4). The device can greatly reduce the attenuation rate of antenna signals, simplify the installation process of a shielding structure, improve the installation efficiency, and improve the signal transmission stability and the resistivity measurement precision of near-bit instruments under the condition of complex stratum.

Inventors

• ZHANG WEIWEI
• ZOU HONG
• WANG QIURAN
• WANG HAIQI
• YIN XUESONG
• LIANG HAITAO

Assignees

• 大庆钻探工程有限公司
• 中国石油天然气集团有限公司

Dates

Publication Date

20260508

Application Date

20251023

Claims (11)

1. 1. A near-bit antenna device comprises a near-bit body (1) and is characterized in that 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-transmission antenna protection cover (4) is arranged inside the receiving antenna shell (2), a receiving antenna (9) is wound between the short-transmission antenna protection cover (4) and the receiving antenna shell (2) in an annular mode, and a short-transmission antenna structure is arranged inside the short-transmission antenna protection cover (4).
2. 2. The near-bit antenna device of claim 1, wherein a receiving antenna core (3) is disposed inside the receiving antenna housing (2), and the receiving antenna core (3) is disposed between a receiving antenna (9) and a short-transmitting antenna protection cover (4).
3. 3. The near-bit antenna device of claim 1, wherein the short-transmission antenna structure comprises a short-transmission antenna magnetic core (7), the short-transmission antenna magnetic core (7) is sleeved at the bottom of an annular groove near the bit body (1), the short-transmission antenna (5) is wound on the outer wall of the short-transmission antenna magnetic core (7) in an annular mode, a short-transmission antenna shielding cover (6) is arranged on the outer wall of the short-transmission antenna (5), and the short-transmission antenna shielding cover (6) is arranged between the short-transmission antenna shielding cover (4) and the short-transmission antenna (5) to prevent the short-transmission antenna (5) from being worn.
4. 4. The near-bit antenna device of claim 3, wherein the short-transmission antenna core (7) comprises a plurality of core units, each core unit is cylindrical, and the short-transmission antenna core (7) is made of ferrite.
5. 5. The near-bit antenna device of claim 4, wherein the short-transmission antenna shielding cover (6) is a hollow cylinder and is formed by butt joint of two semicircular rings, two ends of the short-transmission antenna shielding cover (6) are connected with the near-bit body (1), the middle part of the short-transmission antenna shielding cover (6) protrudes outwards, the protruding part is arranged on the side wall, and a plurality of hollowed-out holes are formed in the short-transmission antenna shielding cover (6) and used for isolating short-transmission signals and receiving signals.
6. 6. The near-bit antenna device of claim 5, wherein the short-transmission antenna protection cover (4) is composed of a plurality of short-transmission antenna protection cover monomers which are uniformly distributed in the circumferential direction, and each short-transmission antenna protection cover monomer is arc-shaped.
7. 7. The near-bit antenna device of claim 3, wherein the short-transmission antenna (5) is wound on the outer surface of the short-transmission antenna magnetic core (7), the number of winding layers is 3-10, and the line diameter of the short-transmission antenna is 0.5mm < ɓ <1.5mm.
8. 8. The near-bit antenna device of claim 2, wherein the receiving antenna housing (2) is provided with a plurality of hollow holes, a gap is reserved between the receiving antenna housing (2) and the receiving antenna (9), and anaerobic adhesive is injected into the hollow holes of the receiving antenna housing (2) to prevent the receiving antenna (9) from being worn in the operation process.
9. 9. The near-bit antenna device of claim 8, wherein the receiving antenna (9) has a wire diameter of 0.25mm < alpha <1.0mm.
10. 10. The near-bit antenna device of claim 9, wherein a receiving antenna protective sleeve (8) is arranged on the outer wall of the receiving antenna (9), and an end of the receiving antenna protective sleeve (8) is provided with an opening, so that two ends of the receiving antenna (9) penetrate out.
11. 11. The near-bit antenna device of any one of claims 1-10, wherein the short-transmission antenna protection cover (4) is made of polyether-ether-ketone, and the receiving antenna protection cover (8) is made of polyether-ether-ketone.

Description

Near-bit antenna device Technical Field 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. Background At present, a ring antenna layout scheme is generally adopted in the electromagnetic wave resistivity instrument while drilling industry, an antenna array which is axially and symmetrically distributed is adopted, the stratum resistivity is calculated through a phase difference or an amplitude ratio, and a phenomenon of mutual interference exists between a short-term transmitting antenna and a resistivity signal receiving antenna, so that the signal attenuation rate is overlarge, and a shielding technology or a related design scheme is not adopted. The antenna layout of the conventional resistivity measuring instrument does not consider the cooperative work requirement of the short-circuit antenna and the resistivity receiving antenna, electromagnetic field coupling of the short-circuit antenna and the resistivity receiving antenna easily causes signal interference to influence the stability of short-circuit communication, meanwhile, the short-circuit antenna also influences the signal to noise ratio of the resistivity receiving antenna, the problem is fundamentally sourced from the overlapping of working frequency bands of the short-circuit antenna and the resistivity receiving antenna, the axial distance between the short-circuit antenna and the resistivity receiving antenna is limited, the electromagnetic field is mutually coupled, the stability of signal transmission is low, the measurement precision of the resistivity is low, the contradiction requirement of high-frequency signal transmission and low-frequency interference suppression cannot be considered by the conventional antenna device, and the near-bit antenna device is provided for the defects. Disclosure of Invention In order to solve the problems that the antenna transmission signal attenuation rate of the original near-bit antenna device is too large, the installation process of a shielding structure is too complex, and the near-bit instrument has low signal transmission stability and low resistivity measurement accuracy under the complex stratum condition, the invention provides the near-bit antenna device which greatly reduces the antenna signal attenuation rate, simplifies the installation process of the shielding structure, improves the installation efficiency, and improves the signal transmission stability and the resistivity measurement accuracy of the near-bit instrument under the complex stratum condition. The technical scheme is that the near-bit antenna device comprises a near-bit body and is characterized in that an annular groove is formed in the outer wall of the near-bit body, a receiving antenna shell is arranged outside the annular groove, a short-transmission antenna protection cover is arranged inside the receiving antenna shell, a receiving antenna is wound between the short-transmission antenna protection cover and the receiving antenna shell in an annular mode, and a short-transmission antenna structure is arranged inside the short-transmission antenna protection cover. Preferably, a receiving antenna magnetic core is arranged in the receiving antenna shell, and the receiving antenna magnetic core is arranged between the receiving antenna and the short-transmission antenna protection cover. Preferably, the short-transmission antenna structure comprises a short-transmission antenna magnetic core, the short-transmission antenna magnetic core is sleeved at the bottom of the annular groove near the drill bit body, the short-transmission antenna is wound on the outer wall of the short-transmission antenna magnetic core in an annular mode, a short-transmission antenna shielding cover is arranged on the outer wall of the short-transmission antenna, and the short-transmission antenna shielding cover is arranged between the short-transmission antenna shielding cover and the short-transmission antenna to prevent the short-transmission antenna from being worn. Preferably, the short transmission antenna magnetic core comprises a plurality of magnetic core monomers, each magnetic core monomer is cylindrical, and the material of the short transmission antenna magnetic core is ferrite magnetic core. Preferably, the short-transmission antenna shielding cover is a hollow cylinder and is formed by butt joint of two semicircular rings, two ends of the short-transmission antenna shielding cover are connected with the near-bit body, the middle part of the short-transmission antenna shielding cover protrudes outwards, the protruding part is arranged on the side wall, and a plurality of hollowed-out holes are formed in the short-transmission antenna shielding cover and used for isolating short-transmission signals and receiving signals. Preferably, the short-transmission antenna protection cover is composed of a plurality of short-transmi