Seismic Dataset Research Articles

Fluid-driven aseismic fault slip with permeability enhancement and dilatancy

Injection-induced seismicity and aseismic slip often involve the reactivation of long-dormant faults, which may have extremely low permeability prior to slip. In contrast, most previous models of fluid-driven aseismic slip have assumed linear pressure diffusion in a fault zone of constant permeability and porosity. Slip occurs within a frictional shear crack whose edge can either lag or lead pressure diffusion, depending on the dimensionless stress-injection parameter that quantifies the prestress and injection conditions. Here, we extend this foundational work by accounting for permeability enhancement and dilatancy, assumed to occur instantaneously upon the onset of slip. The fault zone ahead of the crack is assumed to be impermeable, so fluid flow and pressure diffusion are confined to the interior, slipped part of the crack. The confinement of flow increases the pressurization rate and reduction of fault strength, facilitating crack growth even for severely understressed faults. Suctions from dilatancy slow crack growth, preventing propagation beyond the hydraulic diffusion length. Our new two-dimensional and three-dimensional solutions can facilitate the interpretation of induced seismicity data sets. They are especially relevant for faults in initially low permeability formations, such as shale layers serving as caprock seals for geologic carbon storage, or for hydraulic stimulation of geothermal reservoirs. This article is part of the theme issue ‘Induced seismicity in coupled subsurface systems’.

Enhancement of CO2 monitoring in the sleipner field (north sea) using seismic inversion based on simulated annealing of time-lapse seismic data

The primary aim of this research is to enhance seismic data interpretation and CO2 monitoring by utilizing seismic inversion techniques based on the simulated annealing method. Simulated annealing is a global optimization technique employed for inverting seismic data and provides better results as compared with local optimization-based inversion. This methodology is implemented in the Utsira Formation, located at a depth of 1000 m within the Sleipner Field, Norway. The study encompasses the analysis of three sets of time-lapse seismic data, first from 1994 (pre-injection), followed by surveys in 1999 and 2001, corresponding to the injection of 2.35 million tonnes and 4.26 million tonnes of CO2, respectively. Firstly, synthetic data is used to check the reliability of the algorithm followed by real data application. This process starts by performing the inversion analysis on the synthetic data which shows a decrease in the impedance values observed at the injection site whereas the seismic amplitude increases. The qualitative as well as quantitative analysis depicts that the algorithm works satisfactorily. The same process is applied to the real data from the Sleipner field. Acoustic impedances are calculated using a simulated annealing-based inversion scheme for the pre-injection case in 1994 and post-injection scenarios in 1999 and 2001. Because of the presence of injected CO2 in the years 1999 and 2001, a low impedance zone that ranged from 2000 m/s*g/cc to 2400 m/s*g/cc appeared at the time interval of 0.85–1.10sec. The interpretation of the inverted impedance section and seismic attribute analysis show no signature of CO2 leakage. The results indicated that the inverted section which is derived from the SA optimization technique shows very clear CO2 information offering a more realistic representation with enhanced resolution of the CO2 plume and its migratory paths.

Interpreting environments of deposition from facies analysis of outcrop versus seismic reflection data: A cautionary tale from the Mount Messenger Formation, Taranaki Basin (New Zealand)

The lower part of the Mount Messenger Formation, which crops out along the North Taranaki coast (North Island, New Zealand), is widely regarded to display classic examples of exhumed basin floor fan strata. This interpretation is supported by numerous publications on the sedimentary facies and depositional environments inferred for these strata, which are exposed in coastal cliff exposures about 20 m high with limited lateral extent. Consequently, for almost three decades, this succession has served as an analogue and training ground for geoscientists investigating the features of basin floor fan deposits and their reservoir characteristics. Here, we bring together seismic stratigraphy and seismic geomorphology of 2D and 3D seismic reflection datasets, as well as photogrammetric models based on images collected using uncrewed aerial vehicle (UAV) drones from selected locations along the outcrop belt to challenge this paradigm. We analyzed seismic reflection data in an area immediately offshore and down-dip of the strata exposed in the coastal outcrop and found no objective criteria for submarine fan depositional elements based on accepted seismic stratigraphic criteria. Furthermore, mapping of seismic reflectors revealed large submarine channel systems (up to 3 km wide and up to 200 m deep) within the lower part of the Mount Messenger Formation. Submarine channel depositional elements (less than 250 m wide and 25 m thick) are also observed to incise through the outcrops, but they are generally below seismic resolution. In the context of the regional geology, we conclude that the lower Mount Messenger Formation accumulated as continental slope sediments cross-cut by channels rather than as basin floor fans. This study issues a cautionary tale about applying facies analysis to outcrop with limited 3D exposure to interpret sedimentary environments. The spatial distribution of facies and architectural elements viewed in seismic data are invaluable for testing the veracity of facies interpretations.

Temporal and spatial characterization of a thermogenic, fault-controlled gas hydrate system, Woolsey Mound, Gulf of Mexico

Woolsey Mound, located at Mississippi Canyon Lease Block 118 (MC118), is the site of the Gulf of Mexico hydrate research consortium’s seafloor observatory, where gas hydrates outcrop at the seafloor. The presence of gas hydrates in the mound is confirmed directly by coring and indirectly by 3D seismic reflection data. Craters, pockmarks, chemosynthetic communities, and authigenic carbonates populate the seafloor at Woolsey Mound. Each crater is characterized by a network of shallow crestal faults that connect the hydrate mound to the underlying allochthonous salt body. We characterize the temporal and spatial evolution of gas hydrates at Woolsey Mound under natural perturbations using four collocated 3D seismic reflection data sets that span over 14 years. Data acquisition differences embedded in the data sets arising from variation in geometry, sample rate, and phase are minimized using the “cross-equalization” method. Our results indicate that hydrate formation and dissociation vary temporally and spatially in close connection to the shallow crestal faults. Evidence of gas hydrate dissociation is observed over a period of three years (2000–2003), where major dissociation occurred along the southern portion of the crestal fault in the southeast crater. The dissociation is less prominent in the southwest crater. Evidence of methane venting is observed between 2000 and 2010, which is mostly concentrated in the southeast crater. The residual amplitude anomalies observed between 2000 and 2014 in the mound are mostly positive, implying that the methane venting had increased significantly. The positive anomalies are correlated with the methane seepage recorded in 2011. Our results indicate the evolution of a fault-controlled gas hydrate system in the northern Gulf of Mexico, which would aid in assessing its impact on the seafloor.

Quaternary deposition and erosion in the northeastern Sunda Strait: An interplay between sea level, tectonics, and magmatic activity

The northeastern Sunda Strait is a narrow strait separating Java and Sumatra islands. Currently, it forms a seaway between the Java Sea and the Indian Ocean. The geological setting of the region is extremely dynamic, but how the Plio-Pleistocene interplay between sea level oscillations, magmatism, and tectonics, which lead to the current setting, has not been completely understood. We analysed an important set of legacy shallow seismic data from this area to decipher these intricate relationships. Our results indicate that the tectonic extension partly dismantled the Indonesian arc since the Middle Miocene. However, volcanic products formed a barrier between the Sunda Shelf and the Indian Ocean during the Late Pliocene to the Middle Pleistocene. Marine flooding started during the Middle Pleistocene but bypassed the barrier by flooding the NW edge of Java Island. During the Late Pleistocene, high amplitudes and longer periods of the glacial-interglacial cycles ultimately connected the Java Sea with the Indian Ocean. Still, it was only during the Holocene that important erosion made this seaway efficient in transporting seawater between the two reservoirs.

Development of an ANN-Based Technique for Inversion of Seismic Refraction Travel Times

Non-uniqueness in the inversion of seismic data can be considered the main challenge for the application of such data. Prior information, such as downhole data, can be used to control this problem. However, in most cases, prior information is not available; accordingly, geophysicists/analysts have to suppose a primary model for the observed data and then find the final adequate layered earth model through trial and error. In this study, a new technique was developed based on the artificial neural network (ANN) for the inversion of seismic refraction data in the absence of prior information. In this regard, a sequential multilayer perceptron (SMLP) was proposed, which integrates the sequential information of the model parameters to predict a reasonable layered earth model. In fact, at first, a multilayer perceptron (MLP) (First-MLP) was trained by synthetic data; then, a layered earth model, i.e., the primary model, was predicted for the observed data. Next, using the primary model, a range for each of the model parameters, i.e., thickness and P-wave velocity, for each layer was defined. Subsequently, new synthetic samples were generated based on the determined ranges. Finally, using another MLP (Second-MLP), which was trained by the new synthetic samples, the final model for the observed data was estimated. The proposed method was also tested by employing different synthetic data with and without noise. Moreover, the SMLP inversion technique was used to analyze the experimental seismic refraction dataset at a dam construction site. The results for both synthetic and experimental data confirmed the reliability of the proposed SMLP inversion technique.

Application of 9-component S-wave 3D seismic data to study sedimentary facies and reservoirs in a biogas-bearing area: A case study on the Pleistocene Qigequan Formation in Taidong area, Sanhu Depression, Qaidam Basin, NW China

To solve the problems in restoring sedimentary facies and predicting reservoirs in loose gas-bearing sediment, based on seismic sedimentologic analysis of the first 9-component S-wave 3D seismic dataset of China, a fourth-order isochronous stratigraphic framework was set up and then sedimentary facies and reservoirs in the Pleistocene Qigequan Formation in Taidong area of Qaidam Basin were studied by seismic geomorphology and seismic lithology. The study method and thought are as following. Firstly, techniques of phase rotation, frequency decomposition and fusion, and stratal slicing were applied to the 9-component S-wave seismic data to restore sedimentary facies of major marker beds based on sedimentary models reflected by satellite images. Then, techniques of seismic attribute extraction, principal component analysis, and random fitting were applied to calculate the reservoir thickness and physical parameters of a key sandbody, and the results are satisfactory and confirmed by blind testing wells. Study results reveal that the dominant sedimentary facies in the Qigequan Formation within the study area are delta front and shallow lake. The RGB fused slices indicate that there are two cycles with three sets of underwater distributary channel systems in one period. Among them, sandstones in the distributary channels of middle-low Qigequan Formation are thick and broad with superior physical properties, which are favorable reservoirs. The reservoir permeability is also affected by diagenesis. Distributary channel sandstone reservoirs extend further to the west of Sebei-1 gas field, which provides a basis to expand exploration to the western peripheral area.

Quantifying anisotropy parameters in weakly anisotropic media through diffraction traveltime parameter clusters

The seismic response datasets obtained from anisotropic media present several challenges for established seismic processing methods. To determine whether wavefront interference stems from anisotropic effects, velocity model heterogeneity, or both remains a key challenge. While reflection signatures may be insufficient for distinguishing these attributes, diffraction information in seismic datasets often provides richer insights into subsurface structures. In response to these challenges, we propose a framework that explores the feasibility of using diffraction traveltime parameters as indicators of anisotropy. By introducing an average measurement velocity derived from a cluster of diffraction traveltime responses, defined as a function of the traveltime slopes estimated from the dataset, we aim to discern the prevalence of anisotropy, heterogeneity, or both within a target region. Experiments conducted with synthetic data designed to simulate realistic scenarios have yielded promising results.

A High-Resolution subtle fault mapping in Marlin oilfield, Brazil

Discriminating geological discontinuities is important for reservoir management because they influence storage capacity and fluid flow. Structural heterogeneities, such as faults and fractures, significantly impact the compartmentalization of the reservoir’s facies and affect the flow of hydrocarbons. These structures can act as the pore space for fluid storage, flow-control conduits, or barriers that allow the accumulation of exploitable volumes of oil and gas. Understanding these structures’ spatial and temporal development can significantly impact hydrocarbon exploration. Reservoir characterization is a critical process in the oil and gas industry that aims to comprehensively understand reservoir rocks and their fluid content and distribution. It is a multidisciplinary approach that combines geological, geophysical, and engineering datasets through statistical and deterministic mathematical models. Seismic datasets play a crucial role in reservoir characterization. Interpreters can use seismic data processing and imaging to interpret geological horizons and map faults, building complex geological models. Seismic inversion is also employed to estimate acoustic impedance and other petrophysical properties. Faults and fractures mapping are highly relevant themes in reservoir characterization. Identifying subtle faults and fractures is essential in specifying hydrocarbon migration paths and identifying bypassed oil accumulations. However, traditional seismic amplitude data interpretation should consider these structures more. In this study, we apply a high-resolution fault mapping workflow to map the subtle faults system at the Marlim field in the offshore portion of the Campos Basin. As an outcome, we imaged two separate fault trends inside and outside the Marlim reservoir.

Application of Convolutional Networks for Localization and Prediction of Scalar Parameters of Fractured Geological Inclusion

Seismic inversion is an important part of the modern geological exploration process. Novel applications of deep learning are capable of handling heterogeneous media, but require too much data for training. In this paper, we focus on the prediction of fracture inclusion location and its parameters in rock media and approach the problem in the multi-task manner. For this, several multi-task convolutional neural network (CNN) architectures are proposed and compared. The direct seismic problem is considered in the heterogeneous fractured geological model based on the well-known Marmousi2 model in a two-dimensional case. The model of the deformable solid medium containing slip planes with nonlinear slip conditions on them and explicit–implicit numerical method is applied to obtain the synthetic seismic dataset for CNN training and validation.

Quantifying fault interpretation uncertainties and their impact on fault seal and seismic hazard analysis

Fault-horizon cut-off data extracted from seismic reflection datasets are used to study normal fault geometry, displacement distribution, and growth history. We assess the influence of three seismic interpretation factors (repeatability, measurement obliquity, and fault cut-off type) on fault parameter uncertainty. Two repeat interpretations resulted in mean differences of 5–15% for throw, 11–42% for heave, 9–31% for displacement, and 7–27% for dip across faults. Measurement obliquity, where faults are interpreted using non-perpendicular transects to fault strike, show increasing uncertainty with increasing obliquity. Uncertainty in throw is 14–24% at obliquities >20° and 6–13% where obliquities <20°. Continuous cut-offs, including non-discrete deformation, generally exhibit greater uncertainties compared to discontinuous (discrete) cut-offs. We consider the effect of interpretation factors on fault parameters used in seismic hazard assessment (SHA) and fault seal, using the established Shale Gouge Ratio (SGR). Even modest measurement obliquities and repeatability errors can affect inputs for SHA, causing large differences in throw- or slip-rate and inferred fault length. Measurement obliquity and repeatability have a variable impact on SGR calculations, highlighting the additional importance of sedimentary layer thickness and distribution. Our findings raise questions about the optimum workflow used to interpret faults and how uncertainties in fault interpretation are constrained and reported.

Exploration potential of Papua New Guinea – latest multiclient 3D provides new insight into the underexplored Papuan Basin over the Papuan and Eastern Plateaus

The Gulf of Papua, part of the regional Papuan Basin, is characterised by extensional to passive margin tectonics from the Triassic to Late Oligocene and collisional tectonics from the Late Oligocene until the present day. The basin has experienced rapid clastic deposition in the late Neogene which covers an underlying extensive Miocene carbonate shelf with local bioherms and associated carbonate facies. Underlying the carbonates, an array of deformed and complex rift basins are present, with potential petroleum plays in undifferentiated Mesozoic sediments which onlap basement highs. The Miocene carbonates are the primary exploration targets, along with Pliocene clastic turbidite sediments in the Fly River Delta, Western Gulf of Papua. It is postulated that these were charged by Mesozoic marine–deltaic/terrestrial source rocks that were deposited during the opening of the Coral Sea. The offshore Papuan Basin is underexplored and the Gulf of Papua play types seen in the onshore Aure Fold Belt and offshore Fly River Platform could potentially extend offshore into the Coral Sea area. New broadband Pre‐Stack Depth Migration seismic data covering a part of the Eastern and Papuan Plateaus reveals new insights into the structural development of the region, rift basin geometries, configuration, and association of rift clastics and post-rift carbonates. Internal carbonate features can be observed on the new seismic data set, and new plays in the yet undifferentiated rift sediments of Mesozoic age are proposed in this study.

Structural framework of the Caswell Sub-basin, North West Shelf, Australia

The Caswell Sub-basin, situated within the Browse Basin in the North West Shelf constitutes one of Australia’s primary hydrocarbon producing regions, with notable gas-condensate producing fields including Ichthys and Prelude. Jurassic syn-rift sandstones are extensively distributed across the basin and serve as one of the major reservoirs. However, reservoir sequences are typically intensely faulted and exhibit heterogeneity in thickness and lithofacies, with some areas experiencing localised erosion on uplifted fault blocks (e.g. Northern Caswell Sub-basin). Hence, understanding the nature of the 3D fault patterns and their growth history is crucial for evaluating the reservoir characteristics for field development and additional exploration activities. This study, therefore, aims to evaluate the structural framework and the tectonic evolution of the Caswell Sub-basin. Detailed structural interpretation of Paleozoic and younger sequences was conducted using multiple 3D seismic datasets extending over Ichthys, Prelude, Lasseter, and Crown fields. Our study focuses mainly on Mesozoic faulting patterns and kinematics evaluated from interpreted structural maps, thickness changes of each stratigraphic interval and fault throw profiles of major bounding faults. The extensional phase during the Early–Middle Jurassic triggered the development of NE–SW trending faults and the deepening of the Brewster Graben. While, from the Late Jurassic to the Early Cretaceous, the development of E–W trending faults in the north of the Crown and Lasseter fields indicate a shift in the regional stress regime. We highlight the importance of evaluating the structural linkage from basement to cover sequences to achieve a comprehensive understanding of reservoirs and associated petroleum systems.

The influence of salt tectonics on the distribution of the Triassic Skagerrak Formation in the Ula Field, Norwegian North Sea

Distribution of the Triassic succession in the North Sea is poorly understood because of structural complexities associated with halokinesis and limited stratigraphic control. This study uses a seismic and well-based dataset to improve understanding of development of the Triassic succession in the Ula Field Area, in the Norwegian North Sea. Core interpretation revealed a fluvial-dominated depositional environment in the Ula Field Area. Palynological studies allowed dating of cored intervals, revealing Ladinian and Carnian sections, time-equivalent to the Julius and Joanne members of the Skagerrak Formation. Well-log interpretation provided insight into the intra-Triassic stratigraphy of the Ula Field Area. A section considered to be equivalent to and extending from the Smith Bank Formation to the Jonathan Member of the Skagerrak Formation was interpreted and correlated across the area. In the proposed correlation, the Julius Member thins towards the Ula Field Area and is replaced by a time equivalent sandstone unit. The Jonathan Member displays a sandier composition compared to the equivalent section in the UK sector. Seismic facies-based interpretation of Triassic stratigraphy within salt minibasins allowed recognition and mapping of intra-Triassic units and showed that mudstone members thin towards the NE. Interpreted internal geometries within minibasins allowed determination of the timing of halokinesis. Integration of different datasets allowed palaeogeographic reconstructions for the Anisian, early Ladinian, Carnian and Norian to be constructed. To conclude, the distribution of stacked fluvial channel deposits indicates that they occur both within minibasins and across salt highs such that ongoing halokinesis had no topographic expression and that channels were free to migrate across the area.

Stacking pattern transition caused by submarine channel inception and internal levée development

ABSTRACTThe shift from highly amalgamated and laterally offset to aggradational and vertically stacked submarine channels is a pattern that has been widely recognized in seismic reflection datasets as well as in outcropping successions worldwide. However, the sedimentary and stratigraphic details of such an important part of channel evolution and its implications have not been discussed extensively. That gap is addressed here by characterizing a previously undocumented, seismic‐scale outcrop of the Tres Pasos Formation (Magallanes Basin, Chile) that records the transition from a laterally offset/low‐aggradational channel complex to a vertically stacked aggradational complex associated with the development of an internal levée that enhanced channel aggradation. The boundary between the two complexes is defined by a composite erosional surface (up to ca 35 m relief) with two adjacent element‐scale channelized incisions with contrasting sedimentary infills that provide unprecedented insight into this key phase of submarine channel evolution. Observations indicate that, in between these two depositional architecture styles, there is a significant phase of deep incision and bypass. The relief achieved via this deep incision of one or multiple simultaneously active conduits is interpreted to be necessary to set up the conditions for flow stripping and, subsequently, overbank deposition. Finally, the siltstone‐rich intra‐channel lithofacies association observed directly overlying part of the incision is interpreted to represent the stratigraphic expression of the earliest deposits of an active submarine channel preserved due to the abrupt abandonment of this pathway and the development of an adjacent conduit, which resulted in the former being covered with fine‐grained overbank deposits.

Giant sediment wave fields adjacent to debris-flow filled deep sea valleys: New evidence of cohesive flows transforming into dilute turbidity currents

Sediment waves are subaqueous sedimentary figures belonging to the supercritical flow domain and are of growing interest to the scientific community and industry. They are ubiquitously observed on the seafloor of world's oceans, as well as in the stratigraphic record imaged by marine seismic datasets. In this study we focus on the Cenozoic strata offshore Ivory Coast, where giant sediment waves developed at the base of slope range in height and wavelength: 10–100 m and 1–6 km, respectively. Sediment waves fields in this study developed simultaneously and adjacent to wide, rectilinear valleys, filled by mass-transport deposits. Thus, sediment waves serve as a rare example of large-scale deep-water cyclic steps formed through phase transformation (water entrainment and dilution) of laminar debris flows.The lithological nature of sediment waves can be estimated through the observation of polygonal faulting affecting the sediment waves fields, which suggest a dominant abundance of fine-grained material (clay and silt-prone). This study also shows that wide submarine valleys flanked by sediment waves do not necessarily correspond to sand-prone depositional systems, and that their potential to hold reservoir units for hydrocarbon exploration or CO2 storage should be evaluated with caution when in lower resolution datasets are used.

Seaway restriction, sea level drop and erosion in the Alboran Basin from a paleotopographic reconstruction for the Messinian Salinity Crisis

The Messinian Salinity Crisis (MSC) resulted from changes in the Atlantic-Mediterranean connectivity in the Alboran Basin, a region with a complex and debated geodynamic configuration. Since the MSC, this basin's topography and its record of the Messinian Erosional Surface have been subject to vertical motions due to sediment accumulation, tectonic deformation, isostasy, and latent effects of thermal cooling after extension and magmatic arc formation. The objective of this work is to restore these contributions to post-Messinian subsidence in order to quantify the original depth of formation of the MSC features. We do this by performing a pseudo-3D planform flexural isostatic reconstruction of the Messinian Erosion Surface mapped from an extensive set of seismic reflection data. We focus on identifying the most likely position of the gateway between Atlantic and Mediterranean, the effect of a drawdown on gateway topography and connectivity, and the depth of proposed erosional features related to the Messinian lowstand. The results indicate that the depth of the Alboran Basin by the end of the Messinian was about 500 m shallower than nowadays, but over 500 m deep on average, reaching depths of >1000 m in most subbasins, even when accounting for the possible ∼300 m isostatic rebound caused by water unloading in a largely desiccated Alboran Sea during the MSC. Although these results are compatible with volcanic cones locally emerging above sea level at the East Alboran Volcanic Arc during the Messinian, several lows remaining in the reconstruction suggest that that region is unlikely to have been the sill between Atlantic and Mediterranean at that time, unless the basin saw unconstrained dynamic topography contributions of over −500 m. Full desiccation of the Alboran Basin implies an uplift of up to 100 m at the Strait of Gibraltar, and uplift rates too high to be counteracted by erosion, suggesting that full disconnection and the main corresponding evaporative drawdown took place only once. The terraces and canyons in the West Alboran are restored to depths between 250 and 550 m (shallowest terrace) and 750–1500 m (deepest terrace), and cannot be clearly linked to a single, stable water level during the MSC, pointing to climate-controlled variations in the water level during the isolation phase.

Seismic deconvolution based on SNR-weighted stacking

We propose a seismic deconvolution algorithm based on signal-to-noise ratio (SNR)-weighted stacking. First, we applied the time-frequency analysis to decompose the common midpoint (CMP) or common reflection point (CRP) gather. It is considered that there are differences in noise between different traces in the frequency domain profile. Then, we employ an SNR-weighted stacking strategy in each frequency-domain profile. Finally, we construct the resolution-enhancement amplitude spectrum, apply a linear inversion approach to calculate the overall weights of each frequency-domain profile, perform weighted stacking between the frequency-domain profiles, and obtain the resolution-enhancement post-stack data. The frequency decomposition of the pre-stack gather is efficiently utilized for the primary data of the proposed method. The SNR-weighted stacking adaptively selects the components with high SNR at each frequency. In addition, the resolution-oriented stacking weights are determined by the linear inversion approach. This algorithm can be adaptively weighted by considering the SNR of each frequency component, which can effectively overcome the problem of low SNR in spectral simulation and obtain high-resolution seismic data. The algorithm does not include wavelet extraction and regularization; thus, the resolution-enhancement data is more reliable. Applications to synthetic and field seismic datasets demonstrate that the proposed resolution-enhancement methodology is of great benefit to the succeeding structural interpretation and thin-bed identification.

Seismic Anisotropy and Deep Crustal Deformation Across Alaska

AbstractBased on a new seismic surface wave data set, we present a model of Alaskan crustal seismic anisotropy that provides new insight into Alaska's geographically diverse deformation history. We use both Rayleigh and Love wave isotropic phase speed and Rayleigh wave azimuthal anisotropy to estimate crustal anisotropy. Unlike traditional seismic tomography, which focuses on apparent seismic anisotropy in which the symmetry axis of anisotropy is assumed to be known, we resolve the spatial variation of inherent anisotropy by inferring the depth‐dependent tilt of the hexagonally symmetric elastic tensor. The amplitude of inherent anisotropy is typically stronger in the lower than the upper crust. We principally interpret the dip angle (plunge of the symmetry axis) or the tilt of the anisotropy foliation plane, which reflects the influence of vertically and/or horizontally oriented structures or deformation. The depth variation of crustal anisotropy appears in four principal motifs that partition Alaska into six distinct geographical regions, which display characteristic dip angle patterns in the upper and lower crust. By considering geological context, we discuss how each region reflects active or historical crustal deformation.

ENHANCING OIL AND GAS EXPLORATION EFFICIENCY THROUGH AI-DRIVEN SEISMIC IMAGING AND DATA ANALYSIS

This paper delves into the advancements in AI-driven seismic imaging and data analysis techniques aimed at augmenting the efficiency of oil and gas exploration. We explore various AI algorithms and machine learning models that have been deployed to interpret seismic data, predict subsurface structures, and identify potential hydrocarbon reservoirs with unprecedented precision. Furthermore, we discuss the integration of big data analytics and high-performance computing in handling vast volumes of seismic data, thereby facilitating rapid decision-making in exploration projects. Through case studies and empirical evidence, we highlight the tangible benefits and potential challenges associated with the adoption of AI-driven seismic imaging and data analysis in the oil and gas industry. Ultimately, this paper underscores the transformative impact of AI technologies in optimizing exploration workflows and maximizing resource discovery while mitigating risks and reducing operational costs. In the pursuit of optimizing oil and gas exploration, the integration of artificial intelligence (AI) methodologies has emerged as a transformative force. This paper examines the evolving landscape of AI-driven seismic imaging and data analysis techniques, aimed at enhancing efficiency within the exploration domain. By harnessing AI algorithms and machine learning models, seismic data interpretation is propelled to unprecedented levels of accuracy, enabling the prediction of subsurface structures and the identification of potential hydrocarbon reservoirs with enhanced precision. Moreover, the synergistic fusion of big data analytics and high-performance computing facilitates the processing of vast seismic datasets, expediting decision-making processes in exploration endeavors. Through a synthesis of case studies and empirical evidence, this paper elucidates the tangible benefits and potential challenges associated with AI adoption in the oil and gas sector. By amplifying exploration workflows, mitigating risks, and curbing operational costs, AI-driven seismic imaging and data analysis stand poised to revolutionize the landscape of oil and gas exploration, catalyzing sustainable resource discovery in an evolving energy paradigm. Keywords: AI-Driven Seismic Imaging, Oil And Gas Exploration, Data Analysis, Efficiency Optimization, Geophysical Insights, Seismic Interpretation.