Detection of high incident reflective boundaries using near-field shear waves

摘要

Systems, devices and methods for evaluating an earth formation intersected by a borehole. Method include detecting a reflective boundary in the earth formation by: generating a multipole acoustic signal with a logging tool in the borehole; identifying a shear wave signal resulting from shear body waves reflected in the formation in a near-field region of the formation around the borehole responsive to the generated multipole acoustic signal; and estimating at least a depth along the borehole of the boundary based on the shear wave signal. The boundary may have an angle of incidence with respect to the borehole of greater than 70 degrees. The boundary may be at least one of i) a fracture; and ii) a fault. The method may include evaluating the boundary using at least one attribute of the shear wave signal and the estimated depth.