Determining anisotropy for a build section of a wellbore

A method of determining anisotropy for a build section of a wellbore, the method comprising:

• receiving seismic data from a plurality of seismic sensors located proximate to a build section of a wellbore that is drilled into a subsurface, wherein the seismic data is recorded for a plurality of seismic waves, at different angles, sent from a plurality of seismic sources towards the plurality of seismic sensors, and wherein locations of the plurality of seismic sources relative to locations of the plurality of seismic sensors are such that the plurality of seismic waves are essentially planar at the plurality of seismic sensors, and wherein the subsurface is essentially homogenous proximate to the build section;
• for at least a portion of the plurality of seismic waves, determining a slowness vector for each seismic wave, wherein each slowness vector comprises a horizontal slowness component value and a vertical slowness component value, and determining a phase velocity and a phase angle for each seismic wave;
• determining at least one anisotropic parameter value for the build section based on fitting a model to at least a portion of the determined slowness vectors;
• determining a vertical velocity value based on fitting the model to at least a portion of the determined phase velocities;
• and
• using the at least one anisotropic parameter value and the determined vertical velocity value to generate a digital seismic image, a stress model, or any combination thereof.

A system, comprising:

• a processor;
• and
• a memory operatively connected to the processor, the memory storing instructions that, when executed by the processor, cause the system to:
• receive seismic data from a plurality of seismic sensors located proximate to a build section of a wellbore that is drilled into a subsurface, wherein the seismic data is recorded for a plurality of seismic waves, at different angles, sent from a plurality of seismic sources towards the plurality of seismic sensors, and wherein locations of the plurality of seismic sources relative to locations of the plurality of seismic sensors are such that the plurality of seismic waves are essentially planar at the plurality of seismic sensors, and wherein the subsurface is essentially homogenous proximate to the build section;
• for at least a portion of the plurality of seismic waves, determine a slowness vector for each seismic wave, wherein each slowness vector comprises a horizontal slowness component value and a vertical slowness component value, and determine a phase velocity and a phase angle for each seismic wave;
• determine at least one anisotropic parameter value for the build section based on fitting a model to at least a portion of the determined slowness vectors;
• determine a vertical velocity value based on fitting the model to at least a portion of the determined phase velocities;
• and
• use the at least one anisotropic parameter value and the determined vertical velocity value to generate a digital seismic image, a stress model, or any combination thereof.