Use of an effective tool model in sonic logging data processing

摘要

Methods and apparatus facilitating radial profiling of shear slowness are disclosed. According to some aspects of the invention, acoustic tool bias is accounted for in the calculation of radial profiles. According so some aspects, acoustic tool bias is accounted for by replacing acoustic tool structure with a resonance-impedance model. The resonance-impedance modeling according to principles of the present invention is applicable to vertical, deviated, and horizontal boreholes.

主权项

1. An acoustic logging system for radial profiling of horizontal shear slowness of a formation surrounding a borehole, the system comprising:
an acoustic logging tool comprising:
at least one acoustic transmitter configured to excite acoustic waves within the formation;a plurality of acoustic receivers configured to detect the acoustic waves and acquire acoustic data having dispersive characteristics; and at least one processor configured to (i) account for acoustic logging tool effects at multiple frequencies on the acoustic data by modeling the acoustic logging tool with a resonance-impedance model, (ii) identify the presence of near-borehole alteration effects outside the borehole and within the formation by comparing a measured Stoneley dispersion with a reference Stoneley dispersion without any near-borehole alteration effects, and (iii) account for near-borehole alteration effects outside the borehole and within the formation on horizontal shear slowness.