A method for estimating the depth-domain seismic wavelets from depth-domain seismic data and synthesizing depth-domain seismic records. The method includes: obtaining depth coordinates and P-wave velocity v and density from well log, calculating a corresponding reflectivity series r; performing constant-velocity depth conversion for a seismic trace S and a reflectivity series r by using a velocity v, as a reference velocity to obtain the converted seismic trace S.sub.1 and the converted reflectivity series r.sub.1; and estimating a depth-domain seismic wavelet w based on the Gibbs sampling method; synthesizing depth-domain seismic record by using the P-wave v, the reflectivity series r and the estimated depth-domain seismic wavelet w.

A vibration while drilling acquisition and signal processing system include a sensor assembly affixable to a drill string in a drilling unit and a sensor for detecting vibrations in the drill string. A first processor is in signal communication with the sensor and is programmed to digitally sample signals from the sensor. A transmitter in signal communication with the first processor communicates the digitized signals to a device disposed apart from the drill string. The first processor is programmed to operate the signal. An electric power source to provides power to the sensor, the first processor and transmitter. Either or both the first processor and a second processor associated with the device is programmed to calculate properties of rock formations using only detected vibration signals from the drill string.

A method is described for seismic imaging of complex subsurface volumes using prismatic seismic energy. The method receives a seismic dataset and an earth model. The earth model is perturbed such that prismatic reflections will generate perturbed seismic amplitudes in a target area and seismic imaging is performed using the perturbed model. A second seismic image is generated using a second earth model; the second earth model may be the original earth model or a second perturbed model wherein the perturbation generates different seismic amplitudes in the target area. The two seismic images are differenced to generate a prismatic seismic image that can be used to identify geologic features that are poorly illuminated in conventional imaging. The method may be executed by a computer system.

Techniques involve obtaining acoustic data (including waves reflected from the casing, the annular fill material, the formation, and/or interfaces between any of the mud, the casing, and the annular fill material) from an acoustic logging tool. Techniques include normalizing the acoustic wave to result in a normalized wave having a comparable spectral shape with a reference wave, and comparing the normalized wave with the reference wave. The reference wave may be generated or modeled or produced from a look-up table or database, and may be estimated based on initial estimates of wellbore parameters. Based on the comparison of the normalized wave with the reference wave, a best-fit reference wave substantially matching the normalized wave may be identified. The best-fit reference wave may correspond with a thickness of the casing, an acoustic impedance of the annular fill material, and an acoustic impedance of mud.

An Earth model of a subsurface is created from acquired seismic data by migrating at least one of the incident wavefields and reflected wavefields to generate angle gathers for the seismic data and identifying for the subsurface an elastic Earth model equation for the incident wavefields and the reflected wavefields in the acquired seismic data. The elastic Earth model is a function of reflection angle between the incident wavefields and reflected wavefields and elastic parameters and is fit to the generated angle gathers through perturbation in the elastic parameters. The generated perturbations are used to create the Earth model of the subsurface.

Embodiments of the subject technology provide for predicting seismic impedance. The subject technology generates a corridor stack based on vertical seismic profile (VSP) data of a wellbore in a subterranean formation. The subject technology generates an initial estimate of a velocity model for the subterranean formation below the wellbore. The subject technology generating a density model for the subterranean formation below the wellbore based on information from nearby wells. The subject technology inverts, based on a global inversion algorithm and the initial estimate of the velocity model, the generated corridor stack to determine a set of velocity models. The subject technology generates impedance models in a depth domain based on the generated density model and the set of velocity models. Further, the subject technology stores the generated impedance models.

Methods for seismic imaging of a subterranean geological formation include receiving first acoustic impedance data, having a first resolution, associated with wells in a subsurface region. A system receives seismic data including second acoustic impedance data having a second resolution. The system performs a quality control process configured to identify a mismatch between the first acoustic impedance data and the second acoustic impedance data. The system resamples the second acoustic impedance data into a three-dimensional (3D) grid model. The system scales up the first acoustic impedance data into the 3D grid model. The system downscales the second acoustic impedance data controlled by the first acoustic impedance data in the 3D grid model. The system generates third acoustic impedance data representing fine-scale impedance data. The system extrapolates the fine-scale impedance into areas or regions having no seismic data coverage or poor seismic data coverage.

The disclosure relates to a method of determining at least a property of a material situated behind a casing of a borehole, wherein an image of a imaging parameter of the material, such as acoustic impedance, has been obtained. The method comprising identifying zones of the image corresponding to disturbance zones, based in particular on values of the imaging parameters or other measured parameters, deleting the data of the imaging parameter in each of the disturbance zones, reconstructing for each zone, data of the imaging parameter from the data of imaging parameter at the neighboring zones, and determining at least a property of the material based on the reconstructed image.

Embodiments of the subject technology provide for predicting seismic impedance. The subject technology generates a corridor stack based on vertical seismic profile (VSP) data of a wellbore in a subterranean formation. The subject technology generates an initial estimate of a velocity model for the subterranean formation below the wellbore. The subject technology generating a density model for the subterranean formation below the wellbore based on information from nearby wells. The subject technology inverts, based on a global inversion algorithm and the initial estimate of the velocity model, the generated corridor stack to determine a set of velocity models. The subject technology generates impedance models in a depth domain based on the generated density model and the set of velocity models. Further, the subject technology stores the generated impedance models.

A combining mechanism for borehole logging tool data that uses density data from a logging tool to inform the geometry of an acoustic-based or ultrasound-based data inversion is provided, comprising: at least one mechanism for converting three-dimensional density data into a three-dimensional density model; at least one mechanism for converting three-dimensional density model into a three-dimensional acoustic impedance model; and, at least one mechanism for processing acoustic data using said three-dimensional acoustic impedance model to produce an interpretable data log. A method of using density data from a logging tool to inform the geometry of an acoustic-based or ultrasound-based data inversion is also provided, comprising: converting three-dimensional density data into a three-dimensional density model; converting three-dimensional density model into a three-dimensional acoustic impedance model; and, processing acoustic data using said three-dimensional acoustic impedance model to produce an interpretable data log.