Patent ID: 8625390

Claim:
A method for making acoustic logging while drilling measurements in a subterranean formation, the method comprising: (a) rotating an acoustic logging while drilling tool in a borehole, the borehole having a borehole wall, the tool including at least one acoustic transmitter configured to transmit an acoustic pulse into the borehole, at least one linear array of longitudinally spaced acoustic receivers, and at least one sensor configured to measure a borehole condition, wherein the borehole condition comprises an azimuth angle; (b) causing the transmitter to transmit a plurality of sequential pulses of acoustic energy into the subterranean formation; (c) causing the receivers to receive corresponding acoustic waveforms; (d) causing the sensor to measure borehole conditions corresponding to at least one of said transmitting in (b) or said receiving in (c); (e) sorting the waveforms received in (c) into a plurality of groups, each group representative of a range of values of the borehole condition; and (f) stacking the waveforms from at least one of the groups to acquire average waveforms; wherein a time shift is applied to at least one of the waveforms prior to stacking in (f), the time shift based on the borehole conditions measured in (d).