In an example implementation, first seismic energy is generated using first seismic sources positioned on an earth's surface. First data including measurements of the first seismic energy is obtained from first geophones positioned at a first depth below the earth's surface. Second data including measurements of the first seismic energy is obtained from second geophones positioned on the earth's surface. Second seismic energy is generated using second seismic sources positioned on an earth's surface and proximal to the second geophones. Third data including measurements of the second seismic energy is obtained from third geophones positioned at the first depth below the earth's surface. A propagation of the first seismic energy along a first path is estimated based on the first, second and third data. One or more characteristics of the target are determined based on the estimate.

Downhole tools and method for a well. At least some of the example embodiments are methods of imaging a formation around a first borehole, including: focusing first outbound acoustic energy, launched from a tool with the first borehole, on a volume within the formation spaced away from the first borehole, the focusing creates a first virtual point source (VPS) that creates a first return acoustic energy; receiving the first return acoustic energy from the first VPS at a plurality of seismic sensors; and determining a parameter of the formation between the first VPS and a location of the seismic sensors using the first return acoustic energy.

Method and device for generating an induced source shot point gather. The method includes receiving seismic data at least partially generated by an unintentional seismic source; calculating plural reconstructed receiver traces (RG.sub.i) based on pairing traces from the seismic data; and generating the induced source shot point gather based on the plural reconstructed receiver traces (RG.sub.i).

A system and method of processing seismic data obtained using a plurality of towed single-component receivers in a marine environment is described, the towed single-component receivers configured to measure compressional P waves. The method comprises retrieving seismic data from a storage device, the seismic data comprising P-P data and shear mode data, wherein the P-P data and shear mode data were both received at the towed single-component receivers configured to measure compressional P waves to generate the seismic data. The method further comprises processing the seismic data to extract SV-P shear mode data and generating shear mode image data based on the extracted shear mode data.

This disclosure describes a system and method for generating images and location data of a subsurface object using existing infrastructure as a source. Many infrastructure objects (e.g., pipes, cables, conduits, wells, foundation structures) are constructed of rigid materials and have a known shape and location. Additionally these infrastructure objects can have exposed portions that are above or near the surface and readily accessible. A signal generator can be affixed to the exposed portion of the infrastructure object, which induces acoustic energy, or vibrations in the object. The object with affixed signal generator can then be used as a source in performing a subsurface imaging of subsurface objects, which are not exposed.

Provided is elastic reverse-time migration system and method using an absolute value function for improving the quality of subsurface structure images, and more particularly, elastic reverse-time migration system and method using an absolute value function for improving the quality of subsurface structure images capable of minimizing waveform changing by separating wavefields using stress-displacement relationships and improving accuracy of the subsurface structure images by applying the absolute value function to migration images.

Embodiments of super-virtual borehole sonic interferometry include machines, systems, and methods that can increase the signal-to-noise ratio of sonic log waveforms. Embodiments include performing a common shot gather and recording traces with a sonic tool, repositioning the tool and performing another common-shot gather; cross-correlating each trace with neighboring corresponding traces for each common shot gather, which leads to creating the virtual trace response due to a redatumed virtual source; stacking the common virtual traces with common ray paths for different common shot gathers; convolving the virtual traces with an actual trace that travels from the source through the virtual source to a receiver on the tool; and stacking the traces having common ray paths. The resulting waveforms can have a signal-to-noise ratio significantly greater than the signal-to-noise ratio of the original waveforms, due to the two stacking operations following each redatuming step.

Provided is elastic reverse-time migration system and method using an absolute value function for improving the quality of subsurface structure images, and more particularly, elastic reverse-time migration system and method using an absolute value function for improving the quality of subsurface structure images capable of minimizing waveform changing by separating wavefields using stress-displacement relationships and improving accuracy of the subsurface structure images by applying the absolute value function to migration images.