Acoustic well logging method.

摘要

An acoustic logging method for detecting mechanical anisotropy of a hydrocarbon bearing formation (28) transversed by a well (14) comprises transmitting acoustic signals at different azimuths about a longitudinal axis of the well (14); and receiving from the different azimuths in the well respective signals responsive to different waves produced in the hydrocarbon bearing formation (28) in response to the transmitted signals and tectonic stress in the hydrocarbon bearing formation. Suitably, the received azimuthal signals have waveforms responsive to compression, shear and Stonely waves. From the data so obtained, elastic moduli and Poisson's ratio can be determined to show variations in horizontal stress and strain in the formation about the well bore. This information can be used to predict the orientation of hydraulic fractures and other directional properties of the formation (28). <IMAGE>