Formation acoustic property measurement with beam-angled transducer array

Methods and apparatus for performing formation evaluation in a borehole intersecting an earth formation. Methods may include exciting at a first borehole depth at least one critical refraction wave by steering an acoustic beam transmitted by at least one ultrasonic transmitter to an interface in the formation to intercept the interface at a critical angle; receiving an acoustic signal comprising critical refraction wave data at a logging tool in the borehole; and obtaining a wave property measurement from the critical refraction wave data. The interface may be the borehole wall in an open-hole well or behind casing. Methods include using ultrasonic transmitter(s) to generate the plurality of acoustic beams, identifying critical refraction wave data within the response signal corresponding to the at least one critical refraction wave, and obtaining the wave property measurement from the critical refraction wave data.