Generating subterranean imaging data based on vertical seismic profile data and ocean bottom sensor data

A non-transitory computer-readable medium storing instructions executable by a computer system to perform operations comprising:

• receiving vertical seismic profile (VSP) data of a subterranean region, the VSP data comprising reflection ray paths of incident rays from a surface source to a reflector and from the reflector to a borehole receiver, and comprising locations of the surface source, the reflector and the borehole receiver;
• computing angle attributes for primary reflection and free surface multiples for each image point of a plurality of image points based on the received VSP data and one or both of an initial isotropic model or an anisotropic velocity model;
• generating angle-domain common-image gathers (ADCIG) according to a ray-equation method, based on the angle attributes computed based on the received VSP data;
• migrating mode-converted energy PS-data of the received VSP data in a depth or a vertical time domain;
• wherein the migrating mode-converted energy PS-data of the received VSP data in a time domain comprises migrating mode-converted energy PS-data of the received VSP data in a depth or a vertical domain by:
• storing a first multi-parameter table for the surface source for a P-wave velocity model for PS-data of the received VSP data in a first file;
• storing a second multi-parameter table for the borehole receiver for an S-wave velocity model for the PS-data of the received VSP data in a second file;
• summing the first multi-parameter table for the surface source for the P-wave velocity model for the PS-data of the received VSP data and the second multi-parameter table for the borehole receiver for an S-wave velocity model for the PS-data of the received VSP data;
• and
• migrating each sample of the PS-data of the received VSP data for every sample of the ADCIG via an associated total-time-imaging-condition;
• and
• computing a multi-parameter Green's function based on ray-tracing for a composited velocity model containing both a regular and its mirror-image component for handling primary reflection and free surface multiples simultaneously.

A system comprising one or more computers that include:

• memory operable to store vertical seismic profile (VSP) data of a subterranean region;
• and
• data processing apparatus operable to:
• receive VSP data of the subterranean region, the VSP data comprising reflection ray paths of incident rays from a surface source to a reflector and from the reflector to a borehole receiver, and comprising locations of the surface source, the reflector and the borehole receiver;
• compute angle attributes for primary reflection and free surface multiples for each image point of a plurality of image points based on the received VSP data and one or both of an initial isotropic model or an anisotropic velocity model;
• generate angle-domain common-image gathers (ADCIG) according to a ray-equation method, based on the angle attributes computed based on the received VSP data;
• migrate mode-converted energy PS-data of the received VSP data in a depth or a vertical time domain;
• wherein the migrating mode-converted energy PS-data of the received VSP data in a time domain comprises migrating mode-converted energy PS-data of the received VSP data in a depth or a vertical domain by:
• storing a first multi-parameter table for the surface source for a P-wave velocity model for PS-data of the received VSP data in a first file;
• storing a second multi-parameter table for the borehole receiver for an S-wave velocity model for the PS-data of the received VSP data in a second file;
• summing the first multi-parameter table for the surface source for the P-wave velocity model for the PS-data of the received VSP data and the second multi-parameter table for the borehole receiver for an S-wave velocity model for the PS-data of the received VSP data;
• and
• migrating each sample of the PS-data of the received VSP data for every sample of the ADCIG via an associated total-time-imaging-condition;
• and
• compute a multi-parameter Green's function based on ray-tracing for a composited velocity model containing both a regular and its mirror-image component for handling primary reflection and free surface multiples simultaneously.