Communications – electrical: acoustic wave systems and devices – Seismic prospecting – Land-reflection type
Patent
1996-06-18
1998-06-30
Lobo, Ian J.
Communications, electrical: acoustic wave systems and devices
Seismic prospecting
Land-reflection type
340690, 364421, 367 36, G01V 128
Patent
active
057744190
ABSTRACT:
A high speed microseismic event detector constructed in accordance with the present invention uses a point derivative comb to quickly and accurately detect microseismic events. Compressional and shear waves impinging upon microseismic receiver stations disposed to collect waves are converted into digital data and analyzed using a point derivative comb including assurance of quiet periods prior to declaration of microseismic events. If a sufficient number of quiet periods have passed, the square of a two point derivative of the incoming digital signal is compared to a trip level threshold exceeding the determined noise level to declare a valid trial event. The squaring of the derivative emphasizes the differences between noise and signal, and the valid event is preferably declared when the trip threshold has been exceeded over a temporal comb width to realize a comb over a given time period. Once a trial event has been declared, the event is verified through a spatial comb, which applies the temporal event comb to additional stations. The detector according to the present invention quickly and accurately detects initial compressional waves indicative of a microseismic event which typically exceed the ambient cultural noise level by a small amount, and distinguishes the waves from subsequent larger amplitude shear waves.
REFERENCES:
patent: 3930145 (1975-12-01), Fort et al.
patent: 3949353 (1976-04-01), Waters et al.
patent: 3992672 (1976-11-01), Fasching
patent: 4066992 (1978-01-01), Buller et al.
patent: 4314347 (1982-02-01), Stokely
patent: 4516206 (1985-05-01), McEvilly
patent: 4566083 (1986-01-01), Thigpen
patent: 4611312 (1986-09-01), Ikeda
patent: 4635238 (1987-01-01), Gallagher et al.
patent: 4648039 (1987-03-01), Devaney et al.
patent: 4686657 (1987-08-01), Dellinger et al.
patent: 4701891 (1987-10-01), Castagna et al.
patent: 4759636 (1988-07-01), Ahern et al.
patent: 4870580 (1989-09-01), Lang et al.
patent: 4885711 (1989-12-01), Neff
"ASP: An Automated Seismic Processor For Microearthquake Networks", T.V. McEvilly and E.L. Majer, Bulletin of the Seismological Society of America, vol. 72, No. 1. pp. 303-325, Feb. 1982.
"A New Event Detector Designed for the Seismic Research Observatories", James N. Murdock and Charles R. Hutt, United States Department of the Interior Geological Survey, Report 33-785, Oct. 1983.
"Influence of the Bandpass Filtering and Model Order on the Autoregressive Seismic Detection in the Real-Time Domain", T.H. Burghardt and I. Savin, Computers and Geosciences, vol. 19, No. 2., pp. 111-115, 1993.
Uhl James Eugene
Warpinski Norman Raymond
Whetten Ernest Blayne
Gas Research Institute
Lobo Ian J.
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