SONIC DATA LOGGING SYSTEM

摘要

In its widest form the present invention proposes a sonic logging method which involves the pre-processing of the detection signal by the downhole processing device (8) thereby to determine simply an arrival time of the sonic wave at its receiver (R1, R2) and then transmitting to the surface the arrival time only. The invention also provides a suitable sonic logging downhole tool (1) and a logging system using the tool - which includes a control device (8) (for controlling the generation and reception of the sonic wave) which comprises: an A-D converter for digitising the detection signal at a predetermined sampling interval; a first memory for storing a waveform thus digitised; a second memory for storing the program for processing the thus stored digitised waveform; and a microprocessor capable of executing the program stored in the second memory, thereby in operation processing the digitised waveform stored in the first memory to determine an arrival time of sonic wave generated from the generator (T) and arriving at the receiver (R1, R2).