Communications – electrical: acoustic wave systems and devices – Seismic prospecting – Land-reflection type
Patent
1996-05-28
1999-01-19
Lobo, Ian J.
Communications, electrical: acoustic wave systems and devices
Seismic prospecting
Land-reflection type
367 47, 367 68, 364421, G01V 130, G01V 128
Patent
active
058621008
ABSTRACT:
A method and system for producing an indicator for amplitude-versus-offset (AVO) analysis of seismic survey data is disclosed. According to the disclosed method and system, a raw AVO indicator is generated for each of multiple depth points, from the AVO intercept and gradient coefficient values. The indicator is generally a positive amplitude number for those locations having petrophysical importance, while the background neighboring points will have a zero or negative value for the raw indicator. Statistics are derived for a group of depth points that surround the depth point under analysis, in time and in space, from which a probability function may be evaluated, assuming a distribution of values in the background trend of AVO intercept and gradient values, and based upon which the raw AVO indicator will be modified. In one embodiment, the probability function is evaluated to determine the loci of points that are within the background to a certain statistical confidence. The modified AVO indicator is set to zero for points within the loci, so that a depth point having a positive raw AVO indicator but within the statistical spread of points in the survey will not be falsely identified as petrophysically important. According to a second embodiment, the probability function for the depth point under analysis is evaluated, and the result combined with the raw AVO indicator to produce the modified indicator; points within the statistical spread of the background have greatly devalued modified AVO indicators according to this embodiment.
REFERENCES:
patent: 4995007 (1991-02-01), Corcoran et al.
patent: 5001677 (1991-03-01), Masters
patent: 5257242 (1993-10-01), Clawson
patent: 5258960 (1993-11-01), Swan
patent: 5515335 (1996-05-01), Swan
Swan, "Properties of direct AVO hydrocarbon indicators", Offset-dependent reflectivity --Theory and Practice of AVO Analysis (Castagna, J.P. & Backus, M.M., eds., Soc. Expl. Geophys., 1993), pp. 78-92.
Taner, et al., "Complex Seismic Trace Analysis", Geophysics, vol. 44, No. 6 (Jun., 1979), pp. 1041-1063.
Abramowitz and Stegun, ed., Handbook of Mathematical Functions (Dover Publications, 1965), pp. 936, 940.
Castagna et al., "Comparison of AVO indicators: A modeling study", Geophysics, vol. 59, No. 12, Dec. 1994.
Atlantic Richfield Company
Lobo Ian J.
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