Acoustic Anisotropy and Imaging by Means of High Resolution Azimuthal Sampling

摘要

In an acoustic logging system utilizing one or more acoustic sources, each with a specified radiation pattern around a source orientation, an acoustic signal is transmitted into a formation with a source oriented in a first source orientation. An acoustic waveform is received in response with a receiver oriented in a first direction. The slowness of the formation in the first direction is calculated using the received acoustic waveform.

主权项

1. A method for determining an acoustic anisotropy of a subterranean formation, the method comprising:
(a) rotating an acoustic logging while drilling tool in a borehole, the tool including at least one acoustic transmitter and a linear array of longitudinally spaced acoustic receivers longitudinally spaced apart from the transmitter; (b) measuring an acoustic wave slowness of the formation at three or more toolface angles while rotating the tool in (a); (c) fitting the acoustic wave slownesses measured in (b) to a mathematical model to obtain a maximum slowness and a minimum slowness; and (d) processing the maximum slowness and the minimum slowness obtained in (c) to determine the acoustic anisotropy of the subterranean formation.