Atlantic Richfield Company

Other

Charles C Mosher

Lonnie J Smith

David D Thompson

David A Chapin

Iain M Mason

David S Campbell

Chander M Ahuja

Ronnie B Darnell

Delman Lee

Aaron L Janssen

Geoffrey M Jackson

Ali Tura

Michael Davidson

Roman Kazinnik

A method and system for interactively applying wavelet transform and filter operations to digital data corresponding to geological measurements is disclosed. The disclosed system and method provides the capability of applying sequences of wavelet transform filter operations to input signal datasets representative of the measurements, where the wavelet transforms can utilize different scale-wavelet function pairs within the sequence. Interactive filtering is available within each wavelet transform-filter operation, allowing either manual filtering of selected level and bands, or automatic filtering through application of a filter function. Multiple wavelet transform-filter operations may be applied to the same filtered datasets, to facilitate comparison of the various analysis techniques.

Method and apparatus for analyzing geological data using wavelet analysis

A method of analyzing geological survey data of the potential field measurement type is disclosed. According to the disclosed method, discrete measurement values of the potential field, either the gravitational or magnetic field, are retrieved from memory, corresponding to either a one-dimensional or two-dimensional survey region of the earth. The discrete values are first preconditioned by the application of a noise-reduction digital filter, preferably of the Weiner type. The disclosed method then performs decomposition of the filtered discrete values using the Daubechies scale function and wavelet function of length 2. According to the preferred method, the second level low-frequency component of the first level high-frequency component is generated, and expanded by a factor of four to correspond to the range of the input discrete values. Interpolation is performed to fill in values between adjacent coefficients of this component. As a result of the disclosed method, resolution of geological structures is much improved, enabling detection and discrimination of complex and interfering structures at increased depths.

Method and apparatus for identifying geological structures using wavelet

A method of seismic surveying uses seismic waveguides in the earth. Seismic energy is transmitted from outside the waveguide and detected within the waveguide or vice-versa. Coupling of energy between the outside and the inside of the waveguide is effected by energy leakage at coupling sites where the waveguide departs from planarity. The method analyzes seismic signals to determine the position and nature of coupling sites and the propagation characteristics of the waveguide.

Seismic surveying

A method and apparatus for deriving a three-dimensional seismic image from an irregular grid of two-dimensional seismic data is provided. The two-dimensional seismic data incldue a plurality of shot lines. For each of the shot lines, a two-dimensional migration is performed therealong (22) to create a plurality of migrated shot lines. For each of a plurality of three-dimensional image points, the following substeps are performed. A migrated trace (X) is selected from each of the migrated shot lines that is closest to the image point (I). A further migration (30) is performed on each selected migrated trace (28) with respect to the image point (I). A three-dimensional migrated image (30) comprising the image points is thereby obtained. The invention allows the use of historical, irregular two-dimensional grids of seismic data to be efficiently used for the three-dimensional imaging of subsurface features.

3-dimensional migration of irregular grids of 2-dimensional seismic data

Multiple downhole seismic signals are generated by an apparatus comprising one or more elongated rod segments insertable in a borehole and provide with spaced-apart predetermined lengths of Primacord explosive charge helically wrapped on the exterior of the rod segment and spaced apart by circumferential baffles supported on the rod segment. The charges are selectively fired through a motor actuated selector switch and a switch stepping and firing circuit including only two conductors and blocking diodes for imposing signals of opposite polarity on the selector switch and its actuating motor.

Apparatus for generating multiple seismic signals in a wellbore

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Plano, TX, United States of America

Charles C Mosher