| 摘要 |
<p>A method of vertical seismic profiling of formations in a drilling operation utilizes the drill bit as a source of seismic energy without any break in drilling operations. The sound of the drill bit and reflections of the sound in the formation are recorded by a geometrically extended array of separate receiver elements which are provided in a predetermined matrix group. The received signals are analysed, for instance according to principles known per se, on the basis of differences in reception times, by which the noise signature of the drill bit can be determined at any desired location during drilling operations. The remaining received signal frequencies and signal amplitudes are analysed in relation to their deviation in time, the signals being grouped according to time differences corresponding to focusing on certain areas in the formation.</p> |
