Numerical modeling and interpretation of drillstring waves

Drill-bit seismic and pilot seismograms contain drillstring periodicities from signal and environmental noise sources. These coherent components are similar in seismic-while-drilling correlations, and their joint contribution may cause distortions in signal processing. Numeric modeling of the drillstring transmission line is used to correctly interpret the axial and torsional events with similar propagating modes of signal and noise. The reflection coefficients are computed for drillstrings of arbitrary materials, and their average mechanical features are related to the axial and torsional group velocities obtained by the dispersion equations. Fitting of the periodical components in the real seismograms is used to automatically correct the drill-bit pilot delays and to estimate the surface and downhole boundary conditions.

[1]  Luca Bertelli,et al.  Drill-bit signal separation for RVSP using statistical independence , 2000 .

[2]  Douglas S. Drumheller.  Extensional stress waves in one‐dimensional elastic waveguides , 1992 .

[3]  Jean Raynal,et al.  Instantaneous Logging Based on a Dynamic Theory of Drilling , 1972 .

[4]  Herbert Kolsky,et al.  Stress Waves in Solids , 2003 .

[5]  D. Drumheller.  Acoustical properties of drill strings , 1989 .

[6]  Bob A. Hardage,et al.  Radiation pattern and seismic waves generated by a working roller-cone drill bit , 1992 .

[7]  L. Aleotti,et al.  Seismic while-drilling technology: use and analysis of the drill-bit seismic source in a cross-hole survey , 1999 .

[8]  P. Schultz,et al.  Fundamentals of geophysical data processing , 1979 .

[9]  F. Poletto,et al.  SWD Interpretation by Modelling of Pilot and Seismic Signals , 1998 .

[10]  Douglas E. Miller,et al.  Walk-away VSP using drill noise as a source , 1995 .

[11]  A. K. Booer,et al.  Drillstring Imaging: An Interpretation of Surface Drilling Vibrations , 1993 .

[12]  Douglas S. Drumheller,et al.  The propagation of sound waves in drill strings , 1995 .

[13]  Mark Hutchinson,et al.  An MWD Downhole Assistant Driller , 1995 .

[14]  Carcione,et al.  Simulation of stress waves in attenuating drill strings, including piezoelectric sources and sensors , 2000, The Journal of the Acoustical Society of America.

[15]  J. Rector,et al.  The use of drill‐bit energy as a downhole seismic source , 1991 .

[16]  Fabio Rocca,et al.  Impact of the seismic 'While Drilling' technique on exploration wells , 1996 .

[17]  Age Kyllingstad,et al.  Propagation of Coupled Pressure Waves in Borehole with Drillstring , 1996 .

[18]  T. G. Barnes,et al.  Passbands for Acoustic Transmission in an Idealized Drill String , 1972 .

[19]  D. Drumheller.  Attenuation of sound waves in drill strings , 1993 .