Method and apparatus for anisotropic vector plane wave decomposition for 3D vertical seismic profile data

A method for decomposition of a seismic vector plane wave for three dimensional vertical seismic profile data comprising the steps of:

• a. providing a surface equipment processor operable to record a plurality of signals, where said processor is further operable to receive said plurality of signals from a downhole logging tool said tool including a seismic receiver array where said signal is representative of vector data of a seismic wavefield sensed by the seismic receiver array;
• b. providing an executable algorithm stored on said surface equipment processor such that when the processor executes the algorithm a method is performed comprising the steps of:
• i. Fourier transforming all waveforms;
• ii. specifying medium properties local to the receiver array;
• iii. specifying plane wave propagation angles for each wave type by specifying an angular aperture and a number of plane waves;
• iv. computing polarization and slowness vectors using the propagation angles and the medium properties;
• v. inputting the polarization and slowness vectors into the polarization moveout matrix and computing an operator;
• vi. applying the operator to the vector data to determine scalar plane wave Fourier coefficients;
• vii. summing the subsets of scalar plane waves into grouped plane waves;
• and
• viii. inverse Fourier transforming the grouped plane waves to decompose the wavefields into its separate components.

A method for decomposition of a seismic plane wave for three dimensional vertical seismic profile data comprising the steps of:

• a. transmitting uphole over a cable a plurality of signals from a downhole logging tool including a seismic receiver array;
• b. rotating data of the plurality of signals to geographical coordinates;
• c. recording the plurality of signals from said downhole logging tool, where said signals comprise seismic wavefields sensed by the seismic receiver array;
• d. Fourier transforming all waveforms;
• e. specifying transverse isotropic medium property moduli local to the detector array;
• f. specifying plane wave propagation angles between the propagation direction and a symmetry axis of the medium relative to vertical for each wave type by specifying an angular aperture and a number of plane waves;
• g. computing the polarization and slowness vectors using the propagation angles and the medium properties;
• h. inputting the polarization and slowness vectors into a polarization moveout matrix and computing an operator;
• i. applying the operator to the data to determine scalar plane wave Fourier coefficients;
• j. summing the subsets of scalar plane waves into grouped plane waves;
• and
• k. inverse Fourier Transforming the grouped plane waves and decomposing the wavefields into its separate components.

A computer program product for decomposition of a seismic plane wave data comprising:

• a. a computer useable medium and computer readable code embodied on said computer useable medium for causing a processor to record a plurality of signalsreceived from a seismic receiver array deployed in a borehole, comprising:
• i. computer readable program code devices configured to cause the surface equipment processor to effect Fourier transforming all waveforms;
• ii. computer readable program code devices configured to cause the surface equipment processor to effect extracting and specifying medium properties local to the detector array;
• iii. computer readable program code devices configured to cause the surface equipment processor to effect specifying plane wave propagation angles for each wave type by specifying an angular aperture and a number of plane waves;
• iv. computer readable program code devices configured to cause the surface equipment processor to effect computing polarization and slowness vectors using the propagation angles and the medium properties;
• v. computer readable program code devices configured to cause the surface equipment processor to effect inputting the polarization and slowness vectors into a polarization moveout matrix and computing an operator;
• vi. computer readable program code devices configured to cause the surface equipment processor to effect applying the operator to the vector data to determine scalar plane wave Fourier coefficients;
• vii. computer readable program code devices configured to cause the surface equipment processor to effect summing subsets of scalar plane waves into grouped plane waves;
• and
• viii. computer readable program code devices configured to cause the surface equipment processor to effect inverse Fourier Transforming the grouped plane waves to decompose the wavefields into its separate components.

A method for decomposition of a seismic plane wave for three dimensional vertical seismic profile data comprising the steps of:

• a. transmitting uphole over a cable a plurality of signals from a downhole logging tool including a seismic receiver array;
• b. rotating the plurality of signals data to geographical coordinates;
• c. recording the plurality of signals received from the downhole logging tool including the seismic detector array;
• d. Fourier transforming all waveforms;
• e. extracting and specifying transverse isotropic medium property moduli local to the detector array;
• f. specifying plane wave propagation to symmetry axis tilt angles and deriving a propagation phase direction and an angle between the propagation direction and a symmetry axis of the medium relative to vertical for each wave type by specifying an angular aperture and a number of plane waves where the tilt angles are the dip angle relative to vertical and the azimuth of the down dip direction;
• g. computing polarization and slowness vectors using the propagation angles and the medium properties;
• h. inputting the polarization and slowness vectors into a polarization moveout matrix and computing an operator;
• i. applying the operator to the data to determine scalar plane wave Fourier coefficients;
• j. summing subsets of scalar plane waves into grouped plane waves by summing the product of the complex amplitude of the plane wave and the polarization moveout matrix;
• and
• k. inverse Fourier Transforming the grouped plane waves to decompose the wavefields into its separated components.

A method for decomposition of a seismic plane wave for data comprising the steps of:

• a. receiving a plurality of signals from a downhole seismic receiver array comprising 3C seismic receivers, where said signal is representative of vector data of a seismic wavefield sensed by the seismic receiver array;
• b. specifying plane wave propagation angles for each wave type by specifying an angular aperture and a number of plane waves;
• c. extracting and specifying medium properties local to the detector array;
• d. computing polarization and slowness vectors using the propagation angles and the medium properties;
• and
• e. inputting the polarization and slowness vectors into a polarization moveout matrix and computing an operator.

A method for decomposition of a seismic vector plane wave for three dimensional vertical seismic profile data comprising the steps of:

• a. recording a plurality of signals received from a downhole logging tool including a seismic receiver array;
• b. specifying plane wave propagation angles for each wave type by specifying an angular aperture and a number of plane waves;
• c. specifying medium properties local to the detector array;
• and
• d. computing polarization and slowness vectors using the propagation angles and the medium properties.