| 摘要 |
A method and tool used for determining the orientation of a downhole object, comprising providing the downhole object with a high frequency highly directional sound source 36 fixed in known relation to the object; operating the high frequency directional sound source; rotating the downhole object; and detecting the high frequency directional sound source using an optical fiber 56 acoustic sensing system 58 deployed downhole when the high frequency directional sound source is pointing at the optical fiber; wherein the rotational orientation of the downhole object with respect to the optical fiber is determined based on the detection of the sound source and the known fixed relation between the sound source and the object and the tool comprises an optical interferometer 58, which may be described as a DAS or distributed acoustic sensing system, arranged to detect optical backscatter signals from the optical fiber. In preferred embodiments the sound source is an ultrasonic source 36 operating at in excess of 100 kHz, and the optical fiber acoustic sensing system operates in a continuous wave mode of operation to be able to detect the high frequencies. The object being detected may be a perforating gun 32. |
