Systems and methods for modelling complex geological sequences representing new actual surfaces within a gross interval thickness using geologic rules based on facies data and paleographic maps represented by MRS shoreline facies.

A method for seismic geological lineation mapping, wherein a seismic dataset is collected, with information about minor lineations generated by Seismic dataset subtle structural geological features in an underground earth formation. Seismic attribute volumes are identified in the seismic dataset, relating to trace continuity, amplitude, frequency and phase. The attribute volumes may have an insufficient resolution to display the minor lineations. A seismic multivolume lithological lineation map is generated, in which single attribute 92d lineation maps generated for each of the identified seismic attribute volumes are combined to accurately display the minor lineations generated by the subtle geological features.

Methods and systems, including computer programs encoded on a computer storage medium can be used to preserve edges while performing Gaussian grid smoothing of noise components in subsurface grids to generate geological maps. A subsurface grid is generated from data indicating properties of subsurface formations. A weighting grid is generated by: i) receiving seismic data representing the subsurface formations; ii) generating seismic attributes associated with discontinuities in the subsurface formations; and iii) assigning a particular weight value to weighting grid points that the seismic attributes associated with discontinuities in the subsurface formations indicate the presence of a discontinuity. The subsurface grid is processed by iteratively computing local averages of grid points in the subsurface grid using a compact Gaussian filter weighted by values in the weighting grid. A geological map of subsurface formations is generated based on the filtered subsurface grid.

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 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.

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.

Simulated wells may be selected from a subsurface representation to serve as representation of the corresponding simulated subsurface region. Spatial coverage of a simulated well for the simulated subsurface region may be determined based on extent of similarity between the simulated well and other simulated wells in the subsurface representation. The simulated wells may be selected to achieve desired spatial coverage for the simulated subsurface region and to achieve desired representation of properties of interest for the simulated subsurface region.