全尺寸实验井井下多点多参数测量数据传输系统

DATA TRANSMISSION FOR MULTI-POINT MULTI-PARAMETER MEASUREMENT IN FULL-SCALE EXPERIMENTAL WELL

沿井眼不同位置设置测量点.每一测量点可以测量若干参数.选用8芯测井电缆作为井下各测量点的公共电源线及信号线.设计了脉冲编码调制(PCM)线路.利用模数转换芯片的外部时钟输入及串行数据输出。大大减少了井下线路板的规模.降低了功耗.采用计数式译码方法.可以方便地选择某测量点的某个参数的数据转换及传输.并减化了井下线路结构.应用双极性脉冲传输信号.避免了因远距离电缆充、放电带来的波形畸变.

Measuring devices for a number of parameters were set up in different positions all along the well bore. A eight-core log cable was taken as the common cable of power supply and signal transmission for all measuring devices in the well bore. A pulse decoded modulation (PCM) circuit was designed by the use of external clock input of serial data output of analog-to-digital converter. The circuit size in the well bore was reduced greatly and power consumption cut down. The method of counting and decoding is suitable for data conversion, and transmission in any measuring device, and the downhole circuit construction can be simplified. Application of bipolar pulse in transmitting signal can avoid distorted wave caused by charge or discharge in a long cable.