Geophysical Prospecting最新文献

{"title":"Observations of Local-Distance P/S Amplitude Ratios from Deep Mine and Natural Seismic Sources: Implications for Seismic-Source Discrimination","authors":"Chanel A. Deane,&nbsp;Charles J. Ammon,&nbsp;Andrew A. Nyblade,&nbsp;Raymond J. Durrheim,&nbsp;Hiroshi Ogasawara","doi":"10.1111/1365-2478.70053","DOIUrl":"https://doi.org/10.1111/1365-2478.70053","url":null,"abstract":"<p>For this investigation, we exploit local-distance P- and S-wave observations generated by mining-related and small-magnitude events in the Klerksdorp, Orkney, Stilfontein and Harteesfontein (KOSH) mining region of South Africa to explore the robustness and variability of low-yield P-to-S-wave amplitude ratios. P/S amplitude ratios are traditionally used in discrimination studies between earthquakes and explosions recorded at regional and teleseismic distances (<span></span><math>\u0000 <semantics>\u0000 <mo>&gt;</mo>\u0000 <annotation>$&gt;$</annotation>\u0000 </semantics></math> 200 km) and for relatively large magnitude events. Few studies have explored the variability of P/S amplitude ratios using data recorded at local distances, distances <span></span><math>\u0000 <semantics>\u0000 <mo>&lt;</mo>\u0000 <annotation>$&lt;$</annotation>\u0000 </semantics></math> 200 km, where more scrutiny of wave propagation, near-surface geology, and source and strain release patterns is required. We took advantage of the dense surface accelerometer cluster network, KOSH, for our variability analysis. Final results show that most of the locally recorded low-magnitude events in the Klerksdorp region have comparable shear wave energy to low-magnitude earthquakes. Consequently, our time-domain rms-based P and S amplitude measurements result in stable event average P/S ratios likely to separate from explosive sources. We demonstrate the expected variability of the ratios with smaller network simulations (three-, five-, seven-station) to show that ratios remain relatively stable between 1 and 30 Hz.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/1365-2478.70053","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144688197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"3D Inversion of Radiomagnetotelluric Data From the Sub-Himalayan Fault Zone, India—Combining Scalar, Tensor and Tipper Transfer Functions","authors":"Burak F. Göçer,&nbsp;Wiebke Mörbe,&nbsp;Bülent Tezkan,&nbsp;Mohammad Israil,&nbsp;Pritam Yogeshwar","doi":"10.1111/1365-2478.70058","DOIUrl":"https://doi.org/10.1111/1365-2478.70058","url":null,"abstract":"<p>Radiomagnetotellurics (RMTs) is an efficient frequency-domain electromagnetic technique for mapping subsurface electrical resistivity, particularly suited for near-surface investigations. This method utilizes commonly available civil and military radio transmitters, broadcasting between 10 kHz and 1 MHz, as sources to measure electric and magnetic field responses at the surface. Modern RMT receiver systems comprise five components (two electrical antennas and three magnetic coils), allowing for the estimation of the full impedance tensor and the tipper transfer function for the vertical magnetic field. In this study, RMT data were acquired to investigate the shallow structure of the Himalayan Frontal Thrust (HFT) fault in the Sub-Himalayan region around Uttarakhand, India. Data were collected at 312 stations along eight profiles over an area of roughly 500 m × 70 m. The dense station distribution enables a 3D inversion of the dataset in the extended frequency range of up to 1 MHz. The observed data were processed using scalar as well as tensor estimations to obtain full impedances and tipper transfer function. We integrated scalar-estimated data from zones with an approximately 2D conductivity distribution in the full-tensor dataset. This approach ensured robust 3D modelling during the initial RMT inversion performed with the ModEM algorithm. To date, a joint 3D interpretation of RMT full impedance tensor and tipper transfer function has not yet been reported. Furthermore, the near-surface manifestations of the HFT have not previously been explored by RMT. The derived 3D model from combined scalar, tensor and tipper data reveals a conductivity contrast zone that aligns well with the HFT fault outcrop and complementary geological information. The derived geo-electrical structure recovers the local sediment thickness and shallow fault inclination.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/1365-2478.70058","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144705533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the Normal Compliance of Individual Fractures: Comparing Wave-Propagation and Local Displacement-Jump Estimations on Rock Cores","authors":"Federico Riveiro Cicchini,&nbsp;Emilio Camilión,&nbsp;Santiago G. Solazzi,&nbsp;Nicolás D. Barbosa,&nbsp;Martín Sanchez","doi":"10.1111/1365-2478.70050","DOIUrl":"https://doi.org/10.1111/1365-2478.70050","url":null,"abstract":"<div>\u0000 \u0000 <p>Fractures are omnipresent features in the shallower regions of the Earth's crust. In the context of rock physics, fracture characterization techniques rely largely on the determination of normal fracture compliances. Despite being thoroughly investigated through wave propagation experiments, this parameter is seldom estimated locally. In this work, we measure and compare local displacement-jump- and transmission-related fracture compliances using forced oscillations and ultrasonic propagation techniques, respectively. The experiments are carried out on an aluminium standard and on four different sandstone samples that contain a single planar fracture, considering a range of axial stresses. The results show that, for most rocks, both transmission-related and locally measured dry normal compliances are of the same order and also present similar tendencies with axial loads. However, transmission methods predict larger dry normal fracture compliances than those retrieved from local strain estimations. The results of this study may help to assess the validity of linear slip theory, which is widely used in fracture characterization efforts in the specific literature.</p>\u0000 </div>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144681096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A New Fracture Characterization Method Using Petrophysical Model With Inherent Anisotropy and Borehole Data","authors":"Yongping Wang,&nbsp;Jingye Li,&nbsp;Weiheng Geng,&nbsp;Qiyu Yang,&nbsp;Lei Han,&nbsp;Yuning Zhang","doi":"10.1111/1365-2478.70054","DOIUrl":"https://doi.org/10.1111/1365-2478.70054","url":null,"abstract":"<div>\u0000 \u0000 <p>Fractures represent a critical structural feature in unconventional reservoirs, as they create essential pathways for the migration and accumulation of oil and gas. Therefore, fracture characterization is a fundamental task in the exploration of unconventional hydrocarbon resources. Conventional fracture characterization methods typically do not account for the inherent anisotropy of the formation, which arises from the sedimentary environment and fluid distribution, often leading to inaccurate fracture predictions. To address this challenge, we propose a petrophysical model that incorporates inherent anisotropy, employing rock physics modelling to accurately characterize fracture distribution. Furthermore, to reduce the substantial workload involved in manually calibrating the petrophysical model, we introduce a one-dimensional convolutional neural network combined with an attention mechanism. By leveraging the advanced nonlinear learning capabilities of the convolutional neural network, we aim to fit the petrophysical model and extend its application across all exploration wells and the entire field. The effectiveness and feasibility of the proposed method are demonstrated through experiments using actual borehole data from a fracture-dominated reservoir.</p>\u0000 </div>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144672638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Intriguing 4D Seismic Signature of Reservoir Pore Collapse in Weakly Cemented Sandstones","authors":"Gustavo Côrte,&nbsp;Colin MacBeth","doi":"10.1111/1365-2478.70057","DOIUrl":"https://doi.org/10.1111/1365-2478.70057","url":null,"abstract":"<p>Time-lapse seismic signals and their relation to variations in reservoir pore pressure and fluid saturations are, in general, well understood. Occasionally time-lapse (4D) seismic data do present some intriguing anomalies that cannot be properly explained by our general well stablished expectations, forcing us to consider less conventional hypotheses. We present one such case, occurring in a weakly cemented sandstone reservoir in the North Sea. This reservoir presents a few 4D seismic softening signals occurring as a response to pore pressure decrease, where no saturation changes are expected. With a detailed multidisciplinary analysis, we assess all possible explanations for this type of signal and show that conventional explanations in terms of fluid saturation changes and/or elastic stress variations fail to explain the full characteristic of the observed anomalies. As an alternative hypothesis, we propose the possibility of pore collapse, an inelastic rock damage process, as an unconventional explanation to the observed anomalies. We show that this hypothesis is the only one that explains all the characteristics of the observed anomalies in terms of their lateral and vertical extents, as well as their magnitude and temporal evolution behaviour. We then conduct a theoretical modelling feasibility study to estimate the critical pressure for initiation of rock damage and estimate the amount of rock damage needed to produce the observed 4D seismic signals. This feasibility study suggests that the reservoir effective pressure achieved during field production is likely not enough to crush grains and cause reservoir compaction. However, they may be enough to cause cement and weak grain cracking, which we estimate through rock physics modelling to be a sufficient mechanism for producing the observed softening anomalies. This makes weakly cemented sandstones more prone to this type of counterintuitive signal, as cement damage occurs at lower effective pressures, more commonly achieved during reservoir production. We also highlight important considerations regarding plans of CO₂ storage into depleted reservoirs, as the possibility of rock damage during production would complicate the monitorability of the injected CO₂ plume.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-07-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/1365-2478.70057","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144671983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exact Equation for Seismic Response of Viscous Non-Welded Interface in Saturated Orthotropic Media Under the In Situ Stress","authors":"Zihang Fan,&nbsp;Zhaoyun Zong","doi":"10.1111/1365-2478.70052","DOIUrl":"https://doi.org/10.1111/1365-2478.70052","url":null,"abstract":"<div>\u0000 \u0000 <p>Deep-strata high-pressure reservoirs are a key research area in subsurface resource exploration. The complex mix of in situ pressure, anisotropy and fluid saturation in rocks leads to unclear seismic responses and uncertainties in wave propagation. Using acoustoelasticity theory and assuming weak anisotropy, we derived equations for the elastic parameters of stressed orthotropic media. These equations use anisotropic parameters to describe the unstressed elastic properties of orthotropic media. Then, using the Gassmann equation and low-frequency poro-elasticity, we found elastic parameters for single fluid-saturated orthotropic media. Non-welded interfaces serve as a reasonable approximation for tiny fractures and are ubiquitous in subsurface formations, and the viscous fluid present within these interfaces contributes to the observable attenuation of seismic waves. Using elastic parameters of stressed, fluid-saturated orthotropic media, we formulated reflection and transmission coefficient equations for these interfaces based on linear-slip theory. Using these equations, we analysed how stress, fluid saturation and interface changes affect seismic response and wave propagation. We then analysed how frequency, porosity, viscosity, fracture weakness and other physical properties affect seismic behaviour within and at the medium's interface. By constructing exact equations, we have achieved a more realistic simulation of subsurface seismic response. This enhancement in simulation accuracy facilitates a deeper understanding of the seismic response patterns observed in deep and complex subsurface reservoirs. Furthermore, it provides a solid theoretical foundation for fluid identification and reservoir prediction in actual subsurface reservoir scenarios.</p>\u0000 </div>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144635150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Elastic Impedance Inversion With Gramian Constraint for Simultaneously Inverting Multiple Partial Angle Stack Seismic Data","authors":"Ronghuo Dai,&nbsp;Cheng Yin","doi":"10.1111/1365-2478.70056","DOIUrl":"https://doi.org/10.1111/1365-2478.70056","url":null,"abstract":"<div>\u0000 \u0000 <p>The transformation of elastic impedance (EI) from partial-angle-stacked seismic data is a crucial technique in the domains of reservoir modelling. Conventionally, EI inversion is performed on a per-angle basis, leading to significant discrepancies in EI values across different angles, which may not accurately represent actual conditions. When the signal-to-noise ratio (SNR) of seismic data is low, the inverted EI tends to be unstable, resulting in poor-quality inversion outcomes. This research proposes a novel method that allows for enabling the derivation of EI for various angles simultaneously inverted from multiple partial angle-stack seismic datasets in one process. The aim of simultaneous inversion is to potentially ensure consistent EI results. To obtain this aim, we utilize an advanced regularization method called the Gramian constraint. Consequently, the objective function for the simultaneous inversion of multiple EIs is developed. Results from both synthetic and field data demonstrate improved stability in EI inversion, especially for the case of low SNR.</p>\u0000 </div>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144635151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transient Electromagnetic Nonlinear Inversion Method Based On Improved Bat Algorithm","authors":"Ruiyou Li,&nbsp;Long Zhang,&nbsp;Yong Zhang,&nbsp;Min Li,&nbsp;Pengshan Li","doi":"10.1111/1365-2478.70051","DOIUrl":"https://doi.org/10.1111/1365-2478.70051","url":null,"abstract":"<div>\u0000 \u0000 <p>The transient electromagnetic method (TEM) is a prominent geophysical technique, and the TEM inversion for resistivity models is a crucial aspect of physical exploration. However, TEM inversion faces challenges such as nonlinearity, multiple solutions and ill-conditioning, which can lead to inaccurate results. In response to these challenges, metaheuristic algorithms have been extensively studied for their innovative approaches to solving inverse problems. Despite this, many existing metaheuristic inversion algorithms exhibit limitations, including premature convergence, slow convergence speed and inadequate computational accuracy. To address these issues, an improved bat algorithm (IBA) that incorporates logistic chaotic mapping and a spiral flight strategy (Logistic Chaotic Mapping and Spiral Flight Strategy-Based Bat Algorithm, LSBA) has been proposed. The logistic chaotic mapping strategy is utilized to initialize the population of the bat algorithm to enhance the initial convergence rate. Moreover, the spiral flight strategy facilitates the bats’ escape from local optima, thereby improving the algorithm's local exploration capabilities and solution accuracy. Numerical simulations, synthetic models and field experiments have demonstrated that the LSBA significantly enhances solution precision (the degree of closeness between the algorithm's inverted parameters and the true values), convergence speed and anti-noise performance. The LSBA effectively retrieves the stratigraphic parameters of the true model and accurately represents the geological information of actual mining areas, thereby validating the efficacy and feasibility of the proposed approach in TEM inversion.</p>\u0000 </div>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144635152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dimensionality Reduction in Full-Waveform Inversion Uncertainty Analysis","authors":"W. A. Mulder,&nbsp;B. N. Kuvshinov","doi":"10.1111/1365-2478.70044","DOIUrl":"https://doi.org/10.1111/1365-2478.70044","url":null,"abstract":"<p>The uncertainty of model parameters obtained by full-waveform inversion can be determined from the Hessian of the least-squares error functional. A description of uncertainty characterisation is presented that takes the null space of the Hessian into account and does not rely on the Bayesian formulation. Because the Hessian is generally too costly to compute and too large to be stored, a segmented representation of perturbations of the reconstructed subsurface model in the form of geological units is proposed. This enables the computation of the Hessian and the related covariance matrix on a larger length scale. Synthetic two-dimensional isotropic elastic examples illustrate how conditional and marginal uncertainties can be estimated for the properties per geological unit by themselves and in relation to other units.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/1365-2478.70044","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144582291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seismic Monitoring for CO2 Sequestration—A New Advanced Strategy","authors":"Leo Eisner,&nbsp;James P. Verdon,&nbsp;Sherilyn C. Williams-Stroud,&nbsp;Zuzana Jechumtálová,&nbsp;Umair bin Waheed,&nbsp;Thomas Finkbeiner","doi":"10.1111/1365-2478.70042","DOIUrl":"https://doi.org/10.1111/1365-2478.70042","url":null,"abstract":"<div>\u0000 \u0000 <p>Advanced seismicity monitoring is needed for CO₂ sequestration monitoring. Current regulator practices (so-called traffic light systems—TLS) are limited to mitigate public hazards and associated risks caused by induced seismicity. Such seismicity is often associated with slip on larger faults below the reservoir. We propose an advanced seismic monitoring strategy that not only accounts for felt seismicity but also targets seismicity in the seal and reservoir. This novel concept of tiered seismicity criteria for an advanced seismic monitoring strategy is governed by a storage site's specific geological properties (underburden, reservoir and seal). These observed seismicity criteria can be set by the regulator or operator to develop a corresponding and fit for purpose system that further manages induced seismicity to ensure seal integrity and storage longevity.</p>\u0000 </div>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144582216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}