| 摘要 |
The present invention relates to a logging tool for logging formational changes in a borehole, the logging tool having a longitudinal axis. The logging tool comprises a radiating source (5) for emitting an interaction signal, a detector (6) for detecting a reaction signal, and a screen (7) for limiting a volume (53) investigated by the radiating source and the detector, wherein the tool comprises a first part ( 8 ) and a second part ( 9 ), the second part being able to rotate around the longitudinal axis relative to the first part during use, and the second part comprising the screen (7), and wherein a speed of rotation of the second part is controlled by the rotation unit to be proportional to an output signal of the detector. Furthermore, the present invention relates to a method of characterising a geological formation surrounding a borehole by a logging tool according to the present invention. |
