Magnetic coupling device for downhole signal transmission

Abstract

The invention discloses a magnetic coupling device for downhole signal transmission, and belongs to the field of downhole transmission. The magnetic coupling device for the downhole signal transmission includes a transmitting module and a receiving module with the same structure; the transmitting module transmits downhole measurement data to the receiving module through a magnetic coupling principle in a wireless mode; the receiving module uploads the downhole measurement data to a surface system; the transmitting module includes a concave tubular body, fan-shaped long strip iron cores, interval coils and palisade type metal shells; a plurality of grooves are evenly formed in the surface of the concave tubular body, the fan-shaped long strip iron cores are fixed into each groove; the outersurface of the concave tubular body is segmentally wound with the interval coils at equal intervals; the interval coils are coated with the palisade type metal shells, a plurality of fan-shaped cut seams are evenly formed in the surfaces of the palisade type metal shells, and each fan-shaped cut seam is filled with non-metallic materials. The magnetic coupling device for the downhole signal transmission can enhance the magnetic field intensity under the same working conditions and greatly reduce the attenuation of signals, so that the downhole high performance and high quality wireless transmission is realized.

Description

technical field [0001] The invention belongs to the technical field of downhole transmission, and more particularly relates to a magnetic coupling device for downhole signal transmission. Background technique [0002] In the petroleum industry, the exploitation of oil fields requires drilling, and after drilling, it is necessary to complete the measurement of downhole temperature, pressure, geological and other information. Due to the harsh downhole environment, the traditional wired transmission method is impossible, and the wireless transmission method has been widely used. application and promotion. To ensure the stable and reliable transmission of measurement data, it is necessary to start from the following two aspects: 1) enhance the strength of the transmission signal; 2) control the loss of the signal during transmission. [0003] The existing wireless transmission methods mainly include the electric field coupling method and the magnetic coupling method. Among them...

AI Technical Summary

Problems solved by technology

The downhole environment is complex and changeable, and the close contact between the launch device and the formation medium cannot be guaranteed, so the transmission efficiency cannot be guaranteed

2) The composition of the formation medium in the oil well is very complex, some components have high conductivity, and the signal will have a large attenuation during the transmission process, thus affecting the transmission quality of the signal

[0004] The magnetic coupling method has the following problems: Since the equipment needs to work downhole, the oil well head is only slightly thicker than the tubing, and the coil needs to go downhole with the tubing, which puts strict requirements on the size of the overall structure of the coil and the installation and recovery of the coil

The existing magnetic coupling coils can generate weak magnetic field strength under the limitation of existing working conditions and device size, which cannot meet the requirements of signal transmission under complex geological conditions

When using the principle of magnetic coupling for signal transmission, choose to use low-frequency signals for transmission, and the large capacitance in the coil will cause signal loss

In addition, the underground is a harsh environment of high temperature and high pressure, so the shell of the coil needs to have high strength. Although the commonly used metal and alloy materials can guarantee the strength, they will produce eddy current effects in the metal shell, which will affect the signal. strength

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