Application of a New Data-Driven Processing Method to LWD and Wireline Dispersive Compressional and Shear Waveform Data

摘要

A challenge for acoustic logging data processing, especially LWD (logging while drilling) data, is how to realistically handle the dispersion effects of the waveform data. Significant dispersion is often encountered in the LWD compressional wave data acquired in an unconsolidated slow formation and in the quadrupole shear wave data with a heavy drilling mud. In the presence of dispersion, formation slowness computed from the waveform data is generally higher than the true slowness value. Correction for the dispersion effect usually uses an idealized theoretical model that may not be adequate to handle the actual wave dispersion in the varying LWD environments. To accurately handle the dispersion effect, a new data-driven method has recently been developed. The process is based on the actual dispersion computed from the data. The dispersion data are also used for quality control of the computed wave slowness. This new method is applied to extract compressional and shear slowness from the dispersive LWD and wireline acoustic waveform data from several wells. The results show that the new method realistically accounts for the dispersion effect in the waveform data and obtains more accurate estimates of formation slowness.