Chinese Academy of Sciences

Beijing Didi Infinity Technology and Development Co., Ltd.

Jing Ou

Wenxiu Zhang

Xinzhen He

Jiansheng Du

Yuliang Wang

Xiaolong Li

Qihui Zhen

Hui Wu

Jiwen Xiao

Baoming Qu

A method of encoding and decoding downlink instructions based on mud flow rate includes an encoding method and a decoding method. The encoding method and the decoding method are configured to transmit and receive instructions by controlling the mud flow rate during drilling process. The method of encoding and decoding downlink instructions based on mud flow rate does not require a fixed threshold of voltage as a judgement standard for '0' and “1” symbols, but uses voltage change rate as a standard for judging the level transition, avoiding decoding failure caused by the inability of voltage sampling values to reach the fixed threshold after well depth is increased.

Method of encoding and decoding downlink instructions based on mud flow rate

A service table for polling data of downhole transmission devices in MWD includes a frame number, a number of data items of a data frame, a number of cycles of the data frame in a polling process, a device address of each of the data items, a measurement parameter, a valid bit number, a valid byte number of the data frame, a total frame number, a total polling frame number H and a total polling frame number L, an error polling frame number H and an error polling frame number L, and a transmission status bit flag. The service table architecture for polling data of a downhole transmission device in MWD has been used in actual drilling devices and has completed field operations for multiple wells. Compared to the simplified service tables in the past, the service table can support multiple downhole transmission devices working simultaneously, which has improved drilling efficiency and saved drilling costs.

Service table for polling data of downhole transmission device in measurement-while-drilling

The present application discloses a carrier wave distortion compensation method for an MWD mud continuous wave system, comprising: in the downhole, modulating the carrier wave according to the transmission data to obtain a mud continuous wave signal to be transmitted; transmitting the mud continuous wave signal to the ground via a mud channel; denoising the received pressure signal on the ground to obtain a denoised mud continuous wave signal; performing subsequent processing on the denoised mud continuous wave signal to obtain the final transmission data; and performing downhole distortion compensation before modulating the carrier wave or performing ground distortion compensation on the denoised mud continuous wave signal before performing subsequent processing. The present application reduces the bit error rate of the MWD mud continuous wave system by performing waveform distortion compensation prior to downhole modulation or during performing signal processing on the ground.

Method for carrier distortion compensation in MWD mud pulse telemetry

Disclosed is a synchronization method for an MWD mud pulse telemetry system. The method comprises: determining a synchronous training sequence on the basis of a frame structure of downhole sent data; constructing a correlation between the down-hole sending synchronous training sequence waveform and the uphole synchronous training sequence local waveform by means of the irrelevance of the trigonometric function; and performing correlation calculation on the synchronous training codeword waveform, which is received uphole and is subjected to the first modulation, and the synchronous training sequence local waveform, which is subjected to the second modulation, so as to obtain a correlation curve, and finding a synchronous position by means of the correlation curve.

Synchronization method for an MWD mud pulse telemetry system

The present disclosure relates to a system and a method for displaying a prompt message. The method includes displaying a first prompt message in an entry box on a user interface of an electronic terminal; determining there is an input instruction in the entry box; replacing the first prompt message with a second prompt message; and changing display status of the first prompt message.

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Beijing, China

Jing Ou