| 摘要 |
<p>The present invention relates to a method for diagnosing the area that is close to the bottom of a well, wherein said method comprises generating an acoustic field and correcting the emission mode parameters according to the results provided by a feedback link. This method is characterised in that the acoustic action is applied step by step using a vertical acoustic field as well as a horizontal and circular acoustic field. The first step comprises generating a standing wave in the space closed by a tube, while the second step comprises generating a travelling wave having a frequency which is close to the resonance frequency of the structure of the fluid-bearing bed. The feedback link consists in the frequency-dependence of the amplitude of the acoustic signal which is dispersed in the return direction. The device of the present invention comprises a well instrument (10) in the shape of two sections (11, 12) connected by a cable (13). The upper section (11) includes a generator, while the lower section (12) communicates with the surrounding medium and contains a feedback link sensor (3) and at least one acoustic emitter (1, 14, 15). The acoustic emitter comprises at least one acoustic wave reflector (16) which is arranged coaxially with said emitter at a fixed distance a from the end thereof. The reflector has a conical surface whose summit is directed towards the emitter at an angle of 90° at said summit. The distance a between the emitter and the reflector is selected according to the standing-wave generation conditions in the space of the well defined by the tubes, and the lower portion of the well instrument ends up in an acoustic concentrator (18) or in an echometer.</p> |
