Disclosed is a method of characterising a subsurface volume. The method comprises: extracting a geobody from seismic data arranged within a discretised volume comprising a plurality of cells, the geobody comprising a subset of the plurality of cells, each cell of the subset having one or more properties indicative of a particular fluid phase. The extraction of the geobody comprises: determining a propagation probability value for each cell indicative of the probability that a front will propagate through the cell; beginning from a source within the discretised volume, using the propagation probability value to calculate a travel-time for each cell, the travel time describing the time the front takes to travel from the source point to the cell; and using the traveltimes to extract the geobody from the seismic data.

Synthetic survey data is generated using a two-way or one-way wave propagator based on a current model of a target structure. The current model is modified to reduce a difference between the synthetic survey data and observed survey data, while maintaining unchanged a velocity component of the current model, where the modifying of the current model produces a modified model. The modified model is used to reduce an adverse effect of multiples in the target structure, or to promote a favorable effect of multiples in the target structure.

A seismic modeling system is provided which may include a seismic model data storage device, and a processor cooperating with the seismic model data storage device to identify an obstruction within a seismic model spatial domain data set having a lateral boundary, and define a suspect area including spatial domain data within the lateral boundary and directly below the obstruction. The processor may further inpaint the suspect area in the seismic model spatial domain data set based upon an exemplar inpainting algorithm.

A method and system for prospecting for gas hydrates and gas hydrates over free gas is disclosed. The method includes using well log data to form a rock physics model to generate synthetic seismic representing hydrate and hydrate-over-gas models. Spectral decomposition is applied to the synthetic seismic and to field seismic from the prospecting area, forming low frequency narrow band data sets. From mapped potential sands in the field data, compare positive amplitude dominated event in the narrow band field data to the narrow band synthetics for gas hydrates. Compare negative amplitude dominated event in the narrow band field data to the narrow band synthetics for gas or gas hydrate-over gas. From these comparisons, perform modeling to determine saturation and thickness for hydrates and hydrates-over-gas.

A method includes receiving, via a processor, input data based upon received seismic data, migrating, via the processor, the input data via a pre-stack depth migration technique to generate migrated input data, encoding, via the processor, the input data via an encoding function as a migration attribute to generate encoded input data having a migration function that is non-monotonic versus an attribute related to the input data, migrating, via the processor, the encoded input data via the pre-stack depth migration technique to generate migrated encoded input data, and generating an estimated common image gather based upon the migrated input data and the migrated encoded input data. The method also includes generating a seismic image utilizing the estimated common image gather, wherein the seismic image represents hydrocarbons in a subsurface region of the Earth or subsurface drilling hazards.

Hydrocarbon exploration and extraction can be facilitated using machine-learning models. For example, a system described herein can receive seismic data indicating locations of geological bodies in a target area of a subterranean formation. The system can provide the seismic data as input to a trained machine-learning model for determining whether the target area of the subterranean formation includes one or more types of geological bodies. The system can receive an output from the trained machine-learning model indicating whether or not the target area of the subterranean formation includes the one or more types of geological bodies. The system can then execute one or more processing operations for facilitating hydrocarbon exploration or extraction based on the seismic data and the output from the trained machine-learning model.

Limitations in accuracy and computing power requirements impeding conventional Kirchhoff migration and reverse time migration are overcome by using the wave-equation Kirchhoff, WEK, technique with Kirchhoff migration. WEK technique includes forward-propagating a low-frequency wavefield from a shot location among pre-defined source locations, calculating an arrival traveltime of a maximum amplitude of the low-frequency wavefield, and applying Kirchhoff migration using the arrival traveltime and the maximum amplitude.

Systems, devices, and methods are disclosed for identifying subsurface features as a function of position in a subsurface volume of interest. A computer-implemented method may include obtaining training subsurface data and corresponding training subsurface feature data; obtaining an initial subsurface feature model including tiers of elements; generating a conditioned subsurface feature model by training the initial subsurface feature model using the training subsurface data and the corresponding training subsurface feature data; and storing the conditioned subsurface feature model in the non-transient electronic storage.

The present disclosure describes methods and systems, including computer-implemented methods, computer program products, and computer systems, for smoothing seismic data. One computer-implemented method includes obtaining, by a hardware data processing apparatus, a plurality of seismic data samples; forming, by the hardware data processing apparatus, guiding vectors using the plurality of seismic data samples and a plurality of guiding structure attributes; generating, by the hardware data processing apparatus, a structure guided directional weighted vector filter using the guiding vectors and a plurality of weighting factors; filtering, by the hardware data processing apparatus, the seismic data samples using the structure guided directional weighted vector filter to generate smoothed seismic data; and initiating output of the smoothed seismic data.

A system can output a graphical user interface for use in planning or performing a wellbore operation. The system can receive a location of a geological point location of interest for subterranean exploration and a geological time-frame for the geological point location of interest. The system can determine present-day data about the geological point location of interest from the received location. The system can generate a pseudo-well and reconstruct geological-historical parameters in separate time-intervals based on the received location, plate-tectonic models, and paleo-geographic datasets. The system can generate a graphical user interface including present-day data, paleo-geographic data, plate-tectonic data, and plate-interaction data. The system can output the graphical user interface for use in planning or performing a wellbore operation to extract hydrocarbon fluid.