Chinese Academy of Sciences

Jiwen Xiao

Wenxiu Zhang

Xinzhen He

Jiansheng Du

Yuliang Wang

Qihui Zhen

Hui Wu

Jing Ou

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

Growing community of inventors

Beijing, China

Jiwen Xiao