Time-frequency processing and analysis of seismic data using very short-time fourier transforms

In a digital computer wherein seismic traces obtained over a pre-determined volume of the earth are read into memory, wherein a plurality of spatially related seismic traces are selected from said seismic traces, and wherein said digital computer is used to filter said plurality of spatially related seismic traces, a digital computer programmed to perform a process comprising the steps of:

• (a) transforming at least a portion of said plurality of spatially related seismic traces using a very short time discrete orthonormal transformation, said very short time discrete orthonormal transformation producing transform coefficients;
• (b) organizing said transform coefficients into a plurality of sub-band traces;
• (c) modifying one or more of said transform coefficients within one or more of said sub-band traces;
• and,
• (d) inverting said sub-band traces using a very short time discrete orthonormal transform inverse, thereby producing a filtered version of said transformed portion of said plurality of spatially related seismic traces.

A method for the generation of seismic attributes for use in the exploration of hydrocarbons, comprising the steps of:

• (a) obtaining a representation of a set of seismic traces distributed over a pre-determined volume of the earth, said seismic traces containing samples, said samples being characterized by a travel time, a position, and an amplitude;
• (b) selecting a part of said volume and the seismic traces contained therein to define a region of interest within said volume;
• (c) transforming at least a portion of said seismic traces within said region of interest using a very short time discrete orthonormal transformation, said very short time discrete orthonormal transformation producing transform coefficients;
• (d) organizing said transform coefficients into sub-band traces;
• and,
• (e) forming, from said sub-band traces, a seismic attribute display.

In a digital computer wherein seismic traces obtained over a pre-determined volume of the earth are read into memory, wherein a plurality of spatially related seismic traces are selected from said seismic traces, and wherein said digital computer is used to form a seismic attribute display from said plurality of spatially related seismic traces, a digital computer programmed to perform a process comprising the steps of:

• (a) transforming at least a portion of said spatially related seismic traces using a very short time discrete orthonormal transformation, said very short time discrete orthonormal transformation producing transform coefficients;
• (b) organizing said transform coefficients into sub-band traces;
• and,
• (c) forming, from said sub-band traces, a seismic attribute display.

In the exploration for hydrocarbons, a seismic attribute map prepared by a process, said process comprising the steps of:

• (a) accessing by means of a computer, a dataset comprising seismic traces distributed over a pre-determined volume of the earth, said seismic traces containing digital samples, said digital samples being characterized by a travel time, a position, and an amplitude;
• (b) selecting a plurality of spatially related seismic traces from said seismic signal trace dataset;
• (c) calculating for at least a portion of each spatially related seismic trace so selected a very short time discrete orthonormal transform, said very short time discrete orthonormal transform producing a plurality of transform coefficients;
• (d) organizing said transform coefficients into a plurality of sub-band traces;
• (e) calculating a plurality of seismic attribute values from said transform coefficients;
• (f) determining a position for each calculated seismic attribute value;
• and,
• (g) displaying said seismic attribute values at locations representative of said positions.

A computer based method of seismic exploration, wherein the claimed method is applied to a plurality of spatially related seismic traces containing at least one seismic reflector of interest, said spatially related seismic traces containing digital samples, said digital samples being characterized by a travel time, a position, and an amplitude, and said seismic reflector of interest being characterized by spatial variations, comprising the steps of:

• (a) transforming at least a portion of said spatially related seismic traces using a very short time discrete orthonormal transformation, said very short time discrete orthonormal transformation producing transform coefficients, and a plurality of said transform coefficients corresponding to a same seismic reflector of interest;
• (b) locating at least two of said transform coefficients corresponding to said same seismic reflector of interest;
• and,
• (c) analyzing for spatial variations said located transform coefficients corresponding to said same seismic reflector of interest.

A computer based method of interpolating a geophysical time series from a plurality of spatially related geophysical time series containing digital samples, comprising the steps of:

• (a) obtaining a plurality of spatially related geophysical time series distributed over a pre-determined volume of the earth, said geophysical time series containing digital samples, said digital samples being characterized by a travel time, a position, and an amplitude;
• and,
• (b) selecting a part of said volume and the geophysical time series contained therein to define a region of interest within said volume;
• (c) transforming at least a portion of said geophysical time series within said region of interest using a very short time discrete orthonormal transformation, said very short time discrete orthonormal transformation producing transform coefficients;
• (d) organizing said transform coefficients into a plurality of sub-band traces;
• (e) calculating a plurality of interpolated sub-band traces from said plurality of sub-band traces;
• and,
• (f) inverting said plurality of interpolated sub-band traces using a very short time discrete orthonormal transform inverse.

A computer based method of identifying aberrant seismic traces, comprising the steps of:

• (a) obtaining a plurality of spatially related seismic traces distributed over a pre-determined volume of the earth, said seismic traces containing digital samples, said digital samples being characterized by a travel time, a position, and an amplitude;
• (b) selecting a part of said volume and the seismic traces contained therein to define a region of interest within said volume;
• (c) transforming at least a portion of said seismic traces within said region of interest using a very short time discrete orthonormal transformation, said very short time discrete orthonormal transformation producing transform coefficients;
• (d) organizing said transform coefficients into a plurality of sub-band traces;
• and,
• (e) determining, from said plurality of sub-band traces, if a spatially related seismic trace within said region of interest is aberrant.