Synchronization method of measure while drilling (MWD) system
A technology of measuring while drilling and synchronizing position, which is applied in the directions of surveying, earthwork drilling and production, wellbore/well components, etc. It can solve the problems of shallow transmission depth, poor anti-noise ability, and poor synchronization accuracy, so as to improve synchronization accuracy and reliability sexual effect
Active Publication Date: 2021-05-07
INST OF GEOLOGY & GEOPHYSICS CHINESE ACAD OF SCI
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Problems solved by technology
[0005] In practical applications, due to the poor correlation of the synchronization training codewords of FSK modulation, it leads to problems such as poor synchronization accuracy, high bit error rate, poor anti-noise ability, and shallow transmission depth of the system. Application and Development of Drilling MWD Mud Continuous Wave System
Currently, there is no effective solution to this problem
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[0039] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is illustrative only, and in no way restricts the disclosure, its application or uses. The present disclosure can be implemented in many different forms and is not limited to the embodiments described here. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. It should be noted that relative arrangements of parts and steps, compositions of materials, numerical expressions and numerical values set forth in these embodiments should be interpreted as illustrative only and not as limiting, unless specifically stated otherwise.
[0040] "First", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distin...
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The invention discloses a synchronization method of a measure while drilling (MWD) system. The synchronization method comprises the steps that a synchronous training sequence is determined based on a frame structure of underground transmission data; by utilizing irrelevance of a trigonometric function, a corresponding relation between an underground sending synchronous training sequence waveform and a ground synchronous training sequence local waveform is constructed; and correlation calculation is conducted on a synchronous training code word waveform which is received on the ground and is subjected to first modulation and the synchronous training sequence local waveform which is subjected to second modulation to obtain a correlation curve, and a synchronous position is found through the correlation curve. According to the synchronization method of the MWD system, the synchronous training sequence is constructed, and the improvement of a synchronization method of an FSK system is provided based on the synchronous sequence; the ground and underground synchronization of the FSK system is completed, so that a correlation peak value of the correlation curve is increased, and the difference between a main peak value and a secondary peak value is increased; and on the premise that the motor control complexity of the MWD system is not increased, the synchronization precision and reliability of the MWD system are improved.
Description
technical field [0001] The invention relates to the technical field of measurement-while-drilling, in particular to a synchronization method of a measurement-while-drilling system. Background technique [0002] In recent years, in order to further improve the drilling efficiency, the real-time logging information such as orientation, formation characteristics and drilling parameters that the MWD (Measure While Drilling) system needs to transmit has shown explosive growth. The traditional positive and negative pulse transmission system has low Transmission rate has become a bottleneck restricting the development of MWD while drilling. In order to meet the demand for increasing information volume, the technology of using shear valve to realize mud continuous wave has emerged, which improves the data transmission rate of MWD system and gradually becomes a promising technology. [0003] The MWD mud continuous wave system achieves the interception effect on the mud through the c...
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IPC IPC(8): E21B47/12
CPCE21B47/12E21B47/18E21B47/20
Inventor 欧晶杜建生洪林峰何新振李小龙
Owner INST OF GEOLOGY & GEOPHYSICS CHINESE ACAD OF SCI