Method for depth imaging multicomponent seismic data

A method of imaging multicomponent seismic data to obtain depth images of the earth's subsurface geological structures, comprising the steps of:

• (a) beam forming the multicomponent seismic data into sets of plane wave seismograms;
• (b) partitioning the plane wave seismograms into sets of compressional and shear wavefield seismograms;
• (c) forming time-dependent reflectivity functions from the sets of compressional and shear wavefield seismograms;
• and
• (d) migrating the time-dependent reflectivity functions to obtain depth images of the earth's subsurface geological structures.

A method for imaging the earth's subsurface geological structures, comprising the steps of:

• (a) collecting a set of multicomponent seismic data with seismic sources having at least one linearly independent line of action and receivers having at least two linearly independent lines of action;
• (b) sorting the set of multicomponent seismic data into incident angle ordered gathers;
• (c) partitioning the incident angle ordered gathers of the set of multicomponent seismic data into compressional and shear wavefields;
• and
• (d) migrating the compressional and shear wavefields to obtain a depth image of the earth's subsurface geological structures.

A method for imaging the earth's subsurface geological structures, comprising the steps of:

• (a) collecting a set of multicomponent seismic data;
• (b) partitioning the set of multicomponent seismic data so as to separate and decouple compressional and shear wavefield potentials in the set of multicomponent seismic data;
• (c) iteratively migrating the separated and decoupled compressional and shear wavefields for a plurality of assumed compressional and shear interval velocities;
• and
• (d) selecting from the plurality of assumed compressional and shear wave and shear interval velocities, the compressional interval velocities which produce coherent migrated wavefields.

A method of geophysical exploration to obtain depth images of the earth's subsurface geological structures from multicomponent seismic data U.sub.ij, wherein seismic energy is imparted into the earth with seismic sources having at least one linearly independent line of action i and the earth's response thereto is recorded by receivers having at least two linearly independent lines of action j, comprising steps of:

• (a) obtaining separate measures of compressional and shear wavefields generated by the seismic energy imparted into the earth which are incident on reflecting interfaces in the earth's subsurface;
• (b) obtaining separate measures of compressional and shear wavefields scattered from reflecting interfaces in the earth's subsurface from the multicomponent seismic data U.sub.ij ;
• and
• (c) migrating the incident and scattered compressional and shear wavefields to obtain depth images of the earth's subsurface geological structures.

A method of imaging multicomponent seismic data U.sub.ij, wherein seismic energy is imparted into the earth with seismic sources having at least one linearly independent line of action i and the earth's response thereto is recorded by receivers having at least two linearly independent lines of action j, comprising the steps of:

• (a) radon transforming the multicomponent seismic data U.sub.ij ;
• (b) partitioning the radon transform multicomponent seismic data U.sub.ij to separate and decouple measures of compressional and shear wavefields scattered from reflecting interfaces in the earth's subsurface;
• (c) partitioning the seismic energy imparted into the earth to separate the decouple measures of compressional and shear wavefields incident on the reflecting interfaces in the earth's subsurface;
• and
• (d) migrating the compressional and shear wavefields incident on reflecting interfaces and the compressional and shear wavefields scattered from the reflecting interfaces to obtain depth images of the earth's subsurface geological structures.

A method for imaging the earth's subsurface geological structures with multicomponent seismic data U.sub.ij, wherein the multicomponent seismic data U.sub.ij is obtained by imparting seismic energy into the earth with seismic sources having at least one linearly independent line of action i and recording the earth's response thereto with receivers having at least two linearly independent lines of action j, comprising the steps of:

• (a) radon transforming the multicomponent seismic data U.sub.ij to obtain sets of plane wave seismograms, wherein each set of plane wave seismograms includes plane wave seismograms for a plurality of incident angles;
• (b) partitioning each set of plane wave seismograms to separate and decouple compressional and shear wavefields scattered from reflecting interfaces in the earth's subsurface;
• (c) partitioning the seismic energy imparted into the earth to separate and decouple measures of compressional and shear wavefields incident on reflecting interfaces in the earth's subsurface
• (d) cross correlating the incident and reflecting compressional and shear wavefields to obtain a plurality of time-dependent reflectivity functions;
• and
• (e) iteratively migrating the plurality of time-dependent reflectivity functions for a plurality of compressional and shear wavefield interval velocities to determine the compressional and shear wavefield interval velocities which produce spatially consistent depth images.