Method and device for receiving and detecting mud pressure pulse signal
A technology of mud pressure and pulse signal, which is applied in measurement, earthwork drilling, wellbore/well components, etc. It can solve problems such as incompatibility of ground systems, difficulty in receiving and detecting signals, inconvenient use and maintenance of field engineers, etc., to achieve The effects of increasing the maximum measured well depth, improving detection and identification capabilities, and enhancing ease of use and maintenance
Inactive Publication Date: 2008-08-13
CNPC DRILLING RES INST
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However, regardless of the positive pulse or the negative pulse, with the increase of the measured well depth, due to the continuous attenuation of the mud pressure pulse signal in the transmission process, coupled with the interference of noise and echo and other factors, it becomes difficult to receive and detect the signal on the ground , especially in the case of harsh noise environments, the existing methods cannot detect useful signals at all, which limits the use of such MWD instruments. In addition, the ground systems of different types of instruments are incompatible with each other, making the on-site Inconvenient for engineers to use and maintain
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[0054]① Establish a more effective signal detection method. Aiming at the general mud pulse code modulation principle, that is, the synchronous word plus code bit or combined code bit modulation principle, the present invention provides a more effective mud pressure pulse signal detection method. The method's The core is to perform a low-pass filter on the received signal, remove the DC component, and then perform two correlation operations (one for the sync word, one for the code bit) and one adaptive filter to complete the signal detection. In practical applications, the signal with coded information is degraded by the channel. It can be considered that the input signal of the source is convolved with the channel transfer function to cause inter-symbol interference. Using adaptive filtering to equalize the source is to convert the original code from These are recovered from the interference signal, so the essence of its processing is the deconvolution (De-Convolution) operati...
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The invention relates to a method and device for receiving and testing pulse signal of mud pressure receiving the signal of coding information containing the mud pressure transmitted from signal channel; filtering the signal received; clearing the direct current component of the signal; building noise evaluation to the noise in the signal; relative operation of simultaneous word detection systematically to the signal without direct current component; self-adopted filtering to the signal without direct current component; using relative operation of code to decide code and demodulate the data from the signal received according to the coding protocol. Even in the seriously noisy environment, the useful signal can also be abstracted out; meanwhile, the method can is compatible several measuring instrument.
Description
technical field [0001] The invention relates to measurement-while-drilling instruments used in geological resource exploration and development drilling, especially measurement-while-drilling instruments (MWD), logging-while-drilling instruments (LWD), etc., which use drilling fluid pressure pulse sequences to transmit information while drilling measuring instrument. Specifically, it is a method and device for receiving and detecting mud pressure pulse signals. Background technique [0002] At present, for MWD (Measurement While Drilling), LWD (Logging While Drilling) and other measurement instruments while drilling, most of them use mud (drilling fluid) pressure pulse as the signal transmission mode, that is, the downhole measurement data is transmitted according to a certain sequence. The pulse code is modulated, and a series of pressure pulses are generated in the mud fluid inside the hollow drill string through the mud pressure pulse generator. demodulate out. However,...
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IPC IPC(8): E21B47/06E21B47/12E21B47/20
Inventor 苏义脑盛利民王家进张润香窦修荣邓乐李林张晓丽戴越彭英
Owner CNPC DRILLING RES INST