Crosshole elastic WTW inversion of the McElroy data

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:80171

Zhou, C; Schuster, G T ^[1]; Hassanzadeh, S ^[2]; Harris, J M ^[3]

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1. Univ. of Utah, Salt Lake City, UT (United States)
2. Fijitsu America, Inc., San Jose, CA (United States)
3. Stanford Univ., CA (United States)

The authors apply the elastic wave equation traveltime and waveform inversion (elastic WTW) method to the McElroy crosshole data. These data are characterized by a well offset of 184 ft and a wide-band source wavelet (250--2,000 Hz). Numerical tests indicate that the following processing steps are necessary, but not sufficient, for successful waveform inversion: FK filtering of the upgoing and downgoing waves, FK-fan filter extraction of the PP and SS reflections, and balancing the amplitudes of the upgoing and downgoing reflections. To reduce the complexity of the data they use a divide and conquer strategy, i.e., extract the PP reflections and SS reflections, then invert each wave mode separately. Numerical results show that vertical spatial resolution of the WTW P-wave and S-wave tomograms are approximately 7--10 feet and 4 feet, respectively. This compares favorably to the 40--50 feet vertical resolution of the P-velocity tomogram obtained from the first arrival traveltime data. there is good to very good agreement between the sonic logs and the velocity from the WTW tomogram. These results demonstrate the high resolution Poisson ratio, S-velocity, and P-velocity tomograms can be extracted from crosshole data, and therefore can be used for lithological interpretation.

• OSTI ID: 80171
• Report Number(s): CONF-941015--
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
03 NATURAL GAS
58 GEOSCIENCES
ATTENUATION
CORRECTIONS
DATA PROCESSING
GEOLOGIC DEPOSITS
NATURAL GAS INDUSTRY
PETROLEUM INDUSTRY
REFLECTION
RESOLUTION
RESPONSE FUNCTIONS
SEISMIC SURVEYS
SEISMIC WAVES
TEXAS
WAVE PROPAGATION