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<jats:p> The essence of pre-stack inversion is the model inversion, but challenges hinder its accuracy in obtaining precise initial models, particularly in marine environments or regions with limited well-log data. To enhance stability and accuracy in pre-stack seismic inversion in these areas, we propose an elastic parameter estimation approach utilizing sparse envelope inversion with L<jats:sub>0</jats:sub>- L<jats:sub>2</jats:sub> norm regularization. Our method combines signal sparse representation and modulation theories to derive a new formula for sparse envelope extraction at lower frequencies. By applying L<jats:sub>2</jats:sub> norm regularization to the sparse envelope, we obtain parameter inversion results with smoothed trends, augmenting low wave-number information for improved model constraints. Additionally, taking the envelope inversion results obtained by the L<jats:sub>2</jats:sub> norm as the model constraint, the sparsest inversion results with obvious block-like characteristics are obtained by regularizing the inversion equation with the L<jats:sub>0</jats:sub> norm. Notably, our method effectively suppresses wavelet side-lobes, resulting in stable and accurate inversions without the need for initial low-frequency models based on well-logs, as required in traditional methods. We present a synthetic example to illustrate the feasibility and stability of our proposed approach, and further demonstrate its practicality in reservoir parameter estimation through a field case study of gas exploration. </jats:p>

<jats:p> Numerous surface-felt earthquakes have been spatiotemporally correlated with hydraulic fracturing operations. Because large deformations occur close to hydraulic fractures (HFs), any associated fault reactivation and resulting seismicity must be evaluated within the length scale of the fracture stages and based on precise fault location relative to the simulated rock volumes. To evaluate changes in Coulomb failure stress (CFS) with injection, we conducted fully coupled poroelastic finite-element simulations using a pore-pressure cohesive zone model for the fracture and fault core in combination with a fault-fracture intersection model. The simulations quantify the dependence of CFS and fault reactivation potential on host-rock and fault properties, spacing between fault and HF, and fracturing sequence. We find that fracturing in an anisotropic in-situ stress state does not lead to fault tensile opening but rather dominant shear reactivation through a poroelastic stress disturbance over the fault core ahead of the compressed central stabilized zone. In our simulations, poroelastic stress changes significantly affect fault reactivation in all simulated scenarios of fracturing 50-200 m away from an optimally oriented normal fault. Asymmetric HF growth due to the stress-shadowing effect of adjacent HFs leads to 1.) a larger reactivated fault zone following simultaneous and sequential fracturing of multiple clusters compared to single-cluster fracturing; and 2.) larger unstable area (CFSgt;0.1) over the fault core or higher potential of fault slip following sequential fracturing compared to simultaneous fracturing. The fault reactivation area is further increased for a fault with lower conductivity and with a higher opening-mode fracture toughness of the overlying layer. To reduce the risk of fault reactivation by hydraulic fracturing under reservoir characteristics of the Barnett Shale, the Fort Worth Basin, it is recommended to 1.) conduct simultaneous fracturing instead of sequential; and 2.) to maintain a minimum distance of ~ 200 m for HF operations from known faults. </jats:p>

<jats:p> In order to study the structural features and hydrocarbon prospects of the Palawan basin in the South China Sea (SCS), the authors collected and collated the existing gravity and magnetic data, and obtained edge recognition information from potential. Combined with the seismic profile data, this paper analyzed the features of the gravity and magnetic anomalies and the edge recognition information of the potential fields, determined the fault system, and delineated favorable areas for oil and gas exploration in the Palawan basin. The results showed that four main groups of faults with NE, NW, near EW, and near SN trends developed in the Palawan basin and adjacent areas in the SCS. The NE-trending fault was the regional fault, while the NW-trending fault was the main fault. The NW-trending fault often terminated at the NE-trending fault, indicating that the NW-trending fault was formed later. This investigation has characterized two different types (Type I and Type II) of exploration favorable areas based on characteristics observed. The most notable characteristic of these exploration favorable areas was that they were located in the high value zones of the local anomaly of Bouguer gravity anomaly, and their development was obviously controlled by the faults. The amplitude of gravity anomalies was higher and the gradient of the gravity anomalies was steeper, and there were oil and gas wells and fields distributed in Type I favorable areas for exploration. Compared with Type I favorable areas, the amplitude of gravity anomalies was relatively small and the gradient of the gravity anomalies was relatively gentle corresponding to Type II favorable areas. </jats:p>

<jats:p> The crustal structures of the continent-ocean transition (COT) zone and oceanic domain are key to revealing the tectono-magmatic evolution from rift to drift and the following seafloor spreading. We develop a comprehensive study of the deep seismic reflection imaging and tomographic inversion of a wide-angle seismic line that runs across the COT and extinct spreading center of the Southwest Subbasin (SWSB) in the South China Sea. We reveal a low-velocity (&lt;3 km/s) region in the shallow upper crust of the Longmen Seamount, which may represent serpentinized mud or volcanoclastic. The mature oceanic crust is approximately 4–6 km thick with high-velocity bodies (7.2–7.5 km/s) overlapping the Moho, reflecting relatively rich magmatic additions during seafloor spreading. The northern and southern COT segments exhibit a prominent long-wavelength high magnetic anomaly and synbreakup volcano, indicating magmatic additions in the lower crust and lava flows with magma ascending along faults to the surfaces. However, the COT in the south is wider than that in the north. In addition, the southern COT is characterized by limited PmP reflections, well-developed rotated fault blocks and ocean-ward synrifting faults, and a low-velocity (7.5–7.8 km/s) upper mantle, suggesting that the southern COT is probably underlain by a local serpentinized mantle during continental lithosphere breakup. The differences between the southern and northern COTs on the origin of high-velocity lower crustal layers and faulting styles imply asymmetric continental breakup processes in the SWSB. </jats:p>

<jats:p> The Mula River Basin is in an active tectonic region of the Kirthar fold fault belt in the Western Himalayas. The presence of numerous major faults like Chaman Fault, Kirthar Frontal Fault, and Bannh Fault near the study suggests complex tectonic processes in the region. The seismic record of the study area also indicates that this area is tectonically active. This makes the study area an ideal site to measure tectonic activity through geomorphic indices like hypsometric integrals (HI). For tectonic analysis of the Mula River Basin, we divided the study area into 309 subbasins. The results obtained from the HI calculations for the subbasins led us to the classification of the study area into three classes, i.e., class 1 (0.51–0.78), class 2 (0.37–0.50), and class 3 ([Formula: see text]), where class 1 is for the highest tectonic activity, class 2 responds to moderate, and class 3 is for the lowest tectonic activity. We calculated the hypsometric curves to understand the geomorphological cycle of the Mula River Basin. We quantified the subbasins of the Mula River Basin inside the highly active tectonic zone of Kirthar fold and fault zone as per their tectonic activity and found that a major portion of the study area indicates low tectonic activity (44.33%), medium tectonically active, and high tectonically active subbasins are 37.86% and 17.79%, respectively. These findings are supported by the presence of high-relief areas and known faults in the study area. </jats:p>

<jats:p> Causal factors of induced seismicity in the Permian Basin are investigated by collecting and processing data on reported earthquakes, hydraulic fracture operations, and salt water disposal (SWD). Data are collected from five online sources: (1) the TexNet Earthquake Catalog, which provides earthquake data for Texas; (2) the TexNet Injection Volume Reporting Tool, which provides daily SWD data for select Texas wells; (3) the FracFocus Chemical Disclosure Registry, which provides hydraulic fracture data to the public; and (4) B3 Insight and (5) IHS Enerdeq Browser, which are proprietary database services that provide current and historical well data through paid subscriptions. TexNet makes their data available to the public at dynamic map websites. We automate data processing and data management using Python and ArcGIS Pro tools. The workflow produces quick, reliable, consistent, and reproducible output. We developed a Python script for each collected data table to filter, select fields, and write a new table. We created ArcGIS Pro Model Builder models for each new table to control format properties at import to the geodatabase. Further models contain customized ArcToolbox tools arranged to run geospatial, quality assurance, and quality control processing steps. In addition to discussing the source data and general workflow, we also review the results of the automated data processing. To illustrate our method, we create areas of investigation around the 5.4 magnitude Coalson earthquake to collect and process available data to create maps, charts, and data products for use in subsequent analysis. We make our Python scripts available on GitHub. </jats:p>