Article

SV-P: A potential viable alternative to mode-converted P-SV seismic data for reservoir characterization

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Abstract

P-SV seismic acquisition requires 3C geophones and thus more cost compared to conventional P-P data. However, some companies justify this added cost because P-SV data provide an independent set of shear-wave measurements, which can increase the reliability of subsurface property estimation. This study investigates SV-P data generated by vertical vibrator and recorded by vertical geophones as a cost-effective alternative to traditional P-SV data. To evaluate the efficacy of the SV-P mode relative to P-P and P-SV modes, multi-component seismic data from Wellington Field, Kansas were interpreted. P-P AVO gathers and stacked SV-P seismic data were jointly inverted to estimate elastic properties, which were compared with the estimates obtained from joint-inversion of P-P AVO gathers and stacked P-SV seismic data, and inversion of P-P AVO gathers data. All inversions provide identical P-impedance characteristics. However, a significant improvement in S-impedance estimates is observed when P-P and converted wave data (either SV-P or P-SV) are inverted jointly, compared to P-P inversion results alone. In the Arbuckle interval, which is being considered for CO2 injection, use of converted-wave data clearly demarcates Middle Arbuckle baffle zone and the Lower Arbuckle injection zone, with the latter having low P- and S-impedances. These observations, while consistent with other well-based geological evidence, are absent on P-P only inversion results. No major difference in the inversion results is seen when SV-P data are used instead of P-SV data. Moreover, we demonstrate for the first time by comparing the SV-P image obtained from vertical-vibrator data and the SV-P image obtained from horizontal-vibrator data establishes that both data image subsurface geology equivalently, except for the important distinction that former contains valuable higher frequencies than latter. Because legacy P-wave data can be reprocessed to extract the SV-P mode, using SV-P data can provide a unique way to perform multi-component seismic analysis. © 2017 Society of Exploration Geophysicists and American Association of Petroleum Geologists.

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Typescript (photocopy) Thesis (Ph. D.)--Colorado School of Mines, 1996. Bibliography: leaves 140-147. Thesis advisor: Ilya Tsvankin, Dept. of Geophysics.
Small scale field test demonstrating CO2 sequestration in Arbuckle Saline Aquifer and by CO2-EOR at Wellington Field
  • W L Watney
  • J Rush
  • Liu E.