Position Detecting of the Interface out of a Borehole in Single Well Imaging

The prime shortcoming of traditional single well imaging technique is that in the radial direction the azimuth ambiguity of the interface out of a borehole is unable to be eliminated. In this paper, a new method is proposed to deal with it. An important character about the reflected waves is used here, which is the reflection coefficient of normal stress is opposite to that of displacement in radial direction. Compared the reflected waveforms of pressure and displacement with their own reference waveforms on phase, the incident direction is defined in a certain quadrant in the radial plane. This means the azimuth ambiguity has been cleared up. Some significant details about this kind of method are given in this paper, such as how to acquire the reference waveforms, how to use the compare results and etc. With numerical simulation, an example about position determination of an interface out of a borehole was finished. The result indicates this method can identified the interface position accurately with the data received in borehole alone.