Geophysical Prospecting最新文献

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The potential of a novel gravity research method in geophysics 地球物理学中一种新的重力研究方法的潜力
IF 1.8 3区 地球科学
Geophysical Prospecting Pub Date : 2025-03-05 DOI: 10.1111/1365-2478.70008
Lajos Völgyesi, Gyula Tóth
{"title":"The potential of a novel gravity research method in geophysics","authors":"Lajos Völgyesi,&nbsp;Gyula Tóth","doi":"10.1111/1365-2478.70008","DOIUrl":"https://doi.org/10.1111/1365-2478.70008","url":null,"abstract":"<p>The gravity force, as a vector, has both magnitude (length) and direction. Previously, with the measurement methods employed, only the magnitude (length) of the vector was measured; there was no possibility in geophysical practice to measure the direction of the vector. Previously, the method of astronomic positioning was used to determine the vertical direction. This was extremely time-consuming, taking several months, complex and expensive procedure, used in geodesy at some points to determine the values of vertical deflection. Recently, revolutionary changes have been made in this area, with the development of a new, quick and simple method for determining the local vertical direction, which is more accurate than ever before. In contrast to the previous extremely slow process, with the computer-controlled, fully automated QDaedalus measurement system, a single person can perform multiple high-precision measurements at various locations overnight, making the appropriate quantity and quality of measurement results suitable for geophysical structural research purposes. In this article, we briefly describe the operation of the QDaedalus system and draw attention to the geophysical applicability of the method in terms of detectable mass anomalies and useful station spacing using astrogeodetic field measurements. To demonstrate this, astrogeodetic measurements were also carried out along a 4 km long section, from which the deflection of the vertical values and geoid heights were determined. Our measurements were compared with the normal values calculated with the global gravity model of high resolution (Global Gravity Model plus). As the deflection of the vertical values calculated with this model includes the effect of the surface topographic masses at the resolution of the model, the difference between the measured and the modelled values is practically a function of subsurface density anomalies. At the same time, we performed model calculations showing how density anomalies of different extents assumed at different depths affect the value of the vertical deflections and the geoid anomalies.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 4","pages":"1255-1267"},"PeriodicalIF":1.8,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143846039","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}
引用次数: 0
Resolving key issues of mature Mumbai offshore fields using ocean bottom node seismic interpretation 利用海底节点地震解释解决孟买海上成熟油田的关键问题
IF 1.8 3区 地球科学
Geophysical Prospecting Pub Date : 2025-03-02 DOI: 10.1111/1365-2478.70003
Uday Shanker Mishra, Saumya Kanti Goswami, Souvik Sengupta, Subhankar Basu, Srilata Mohapatra, Anand Prakash
{"title":"Resolving key issues of mature Mumbai offshore fields using ocean bottom node seismic interpretation","authors":"Uday Shanker Mishra,&nbsp;Saumya Kanti Goswami,&nbsp;Souvik Sengupta,&nbsp;Subhankar Basu,&nbsp;Srilata Mohapatra,&nbsp;Anand Prakash","doi":"10.1111/1365-2478.70003","DOIUrl":"https://doi.org/10.1111/1365-2478.70003","url":null,"abstract":"<p>Neelam–Heera fields are located in Mumbai offshore basin and are significant contributors to India's oil and gas production. These mature oil and gas fields are producing mainly from Eocene–Oligocene carbonate reservoirs. Key challenges of Neelam–Heera fields include seismic imaging issues in areas perturbed by shallow gas, discrepancy in time and depth structures caused by lateral and vertical velocity variations and delineation of karst/discontinuities in the Neelam–Bassein formation to improve well planning and avoid mud loss. The seismic interpretation study we conducted used recent ocean bottom node seismic data to provide new insights into these challenges and are discussed in this paper. An integrated study scaling from interpretive processing to high-resolution mapping/attribute analysis was conducted to solve the key challenges of the Neelam–Heera fields. A significant improvement is seen in the imaging of the Neelam–Heera area because of prestack depth migration processing of ocean bottom node data, which led to detailed mapping and better understanding of various formations. One of the key challenges was to understand the structural changes in areas masked by shallow gas clouds in the Heera high area. The PP data could not provide clear imaging of areas masked by shallow gas; however, the PS data is not affected by fluid presence and provided imaging below the gas cloud. The gas-bearing Bandra formation in the crestal part of the Heera field is mapped with the help of PS data. The Neelam–Heera area shows prominent trends related to a velocity anomaly at a shallow level (dissolution features), forming the valleys in the time cube that are not seen in the depth cube. The key formations are mapped carefully with the integration of a depth cube. The new depth maps provided insights in areas hindered by previous false structures and are key to future development planning. To gain insights on karstification and mud-loss issues in Neelam field (Bassein formation), various structural attributes were derived and correlated with well data. Most positive/negative curvature attributes at different azimuthal stacks alongside variance maps provided detailed high-resolution insights on faults/lineaments/fractures, and posting of well mud-loss information validated the disturbed-zone-related mud-loss areas. The availability of ocean bottom node data with high-quality processing and imaging and subsequent detailed seismic interpretation using PP and PS data provided new insights to solve the key challenges of Neelam–Heera fields. The key outcome of this study includes an improved understanding of areas perturbed by shallow gas and better depth maps for integration into the future development model in areas with discrepancies caused by significant lateral and vertical velocity variations. In addition, we were better able to delineate karst/discontinuities in the Neelam–Bassein formation, which improved well planning and helped avoid mud loss.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 4","pages":"1204-1211"},"PeriodicalIF":1.8,"publicationDate":"2025-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845792","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}
引用次数: 0
Sensitivity analysis with a 3D mixed-dimensional code for direct current geoelectrical investigations of landfills: synthetic tests 利用三维混合维度代码进行垃圾填埋场直流地质电学调查的敏感性分析:合成试验
IF 1.8 3区 地球科学
Geophysical Prospecting Pub Date : 2025-03-02 DOI: 10.1111/1365-2478.70006
Lorenzo Panzeri, Alessio Fumagalli, Laura Longoni, Monica Papini, Diego Arosio
{"title":"Sensitivity analysis with a 3D mixed-dimensional code for direct current geoelectrical investigations of landfills: synthetic tests","authors":"Lorenzo Panzeri,&nbsp;Alessio Fumagalli,&nbsp;Laura Longoni,&nbsp;Monica Papini,&nbsp;Diego Arosio","doi":"10.1111/1365-2478.70006","DOIUrl":"https://doi.org/10.1111/1365-2478.70006","url":null,"abstract":"<p>Electrical resistivity tomography is a suitable technique for non-invasive monitoring of municipal solid waste landfills, but accurate sensitivity analysis is necessary to evaluate the effectiveness and reliability of geoelectrical investigations and to properly design data acquisition. Typically, a thin high-resistivity membrane is placed underneath the waste to prevent leakage of leachate. In the construction of a numerical framework for sensitivity computation, taking into account the actual dimensions of the electrodes and, in particular, of the membrane, can lead to extremely high computational costs. In this work, we present a novel approach for numerically computing sensitivity effectively by adopting a mixed-dimensional framework, where the membrane is approximated as a two-dimensional object and the electrodes as one-dimensional objects. The code is first validated against analytical expressions for simple four-electrode arrays and a homogeneous medium. Then it is tested in simplified landfill models, where a two-dimensional box-shaped liner separates the landfill body from the surrounding media, and 48 electrodes are used. The results show that electrodes arranged linearly along both sides of the perimeter edges of the box-shaped liner are promising for detecting liner damage, with sensitivity increasing by 2 to 3 orders of magnitude, even for damage as small as one-sixth of the electrode spacing in diameter. Good results are also obtained when simulating an electrical connection between the landfill and the surrounding media that is not due to liner damage. The configurations with the highest sensitivity directly beneath the liner are quadrupoles in which both the current and voltage dipoles have one electrode inside the liner and one electrode outside, and a two-dimensional arrangement of the electrodes. The modelled sensitivity values beneath the liner are close to a minimum sensitivity threshold derived from arbitrary and simplified assumptions. We believe that direct current surveys have the potential to detect liner damage using electrode spreads positioned along the liner perimeter, both inside and outside the landfill. However, down-scaled laboratory tests will be necessary to validate the modelling results and confirm whether the computed sensitivity values are sufficiently high to reliably detect liner damage.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 4","pages":"1212-1227"},"PeriodicalIF":1.8,"publicationDate":"2025-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/1365-2478.70006","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845794","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}
引用次数: 0
The effect of lamination on elastic anisotropy of primary coals under confining pressure: Experiment and theoretical modelling 层压对约束压力下原生煤弹性各向异性的影响:实验与理论建模
IF 1.8 3区 地球科学
Geophysical Prospecting Pub Date : 2025-03-02 DOI: 10.1111/1365-2478.70009
Fei Gong, Jiwei Cheng, Guowei Wang, Suping Peng, Zhaoji Zhang
{"title":"The effect of lamination on elastic anisotropy of primary coals under confining pressure: Experiment and theoretical modelling","authors":"Fei Gong,&nbsp;Jiwei Cheng,&nbsp;Guowei Wang,&nbsp;Suping Peng,&nbsp;Zhaoji Zhang","doi":"10.1111/1365-2478.70009","DOIUrl":"https://doi.org/10.1111/1365-2478.70009","url":null,"abstract":"<p>The deep coalbed methane development is in its initial stage, with limited research on elastic anisotropy of coals in deep coalbed methane reservoirs. To study the elastic anisotropy of coals in deep coalbed methane reservoirs, three sets of cylindrical primary coals are collected from the relatively shallow area of the Taiyuan 8<sup>#</sup> coal formation, a key site for deep coalbed methane extraction. The microscopic observation, basic physical property test, ultrasonic velocity measurement and theoretical modelling are constructed to study the pressure sensitivity of elastic properties and the factors affecting the elastic anisotropy of coal samples. The velocity increases rapidly with confining pressure increasing at confining pressures below 13 MPa but relatively stabilizes at higher pressures. The velocity perpendicular to the bedding plane is more sensitive to pressure than that parallel to the bedding plane. As confining pressure increases, the velocity anisotropy decreases but remains noticeable at the highest pressure. Based on the microstructure and ultrasonic experiment results, an anisotropic rock physics model for the deep coalbed methane reservoir is constructed to quantitatively analyse the effects of the clay and organic matter and pore structure on the elastic anisotropy of coals. The modelling analysis indicates that P- and S-wave velocity anisotropies decrease as the degree of preferred orientation of organic matter and clay decreases, which increases with the increase of organic matter and clay content. The equivalent pore aspect ratio and lamination index of studied coals are obtained from a practical inversion scheme based on the proposed model. The results can support the anisotropic rock physics inversion of deep coalbed methane reservoirs and the accurate prediction of engineering sweet spot parameters.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 4","pages":"1228-1242"},"PeriodicalIF":1.8,"publicationDate":"2025-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845793","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}
引用次数: 0
On signal contribution functions and sensitivity for frequency-domain electromagnetic and direct current electrical resistivity methods 频域电磁电阻率法和直流电阻率法的信号贡献函数和灵敏度
IF 1.8 3区 地球科学
Geophysical Prospecting Pub Date : 2025-03-02 DOI: 10.1111/1365-2478.70011
S. L. Butler
{"title":"On signal contribution functions and sensitivity for frequency-domain electromagnetic and direct current electrical resistivity methods","authors":"S. L. Butler","doi":"10.1111/1365-2478.70011","DOIUrl":"https://doi.org/10.1111/1365-2478.70011","url":null,"abstract":"<p>Signal contribution functions can be integrated over space to calculate the response of an electrical or electromagnetic technique to a given resistivity distribution. On the other hand, sensitivity functions show how the measured signal changes with a change in resistivity in a region of the ground. Signal contribution functions and sensitivity have been previously presented for the direct current resistivity technique. While useful forms of both the signal contribution function and sensitivity are proportional to the correlation of the current densities from the normal and reciprocal configurations, it has not previously been shown how sensitivity can be derived directly from the signal contribution. For frequency-domain electromagnetic techniques, there are existing expressions for sensitivity but not for the signal contribution. In this contribution, I show how the direct current signal contribution can be differentiated to obtain the sensitivity. I also derive an expression for the signal contribution function for frequency-domain electromagnetics and show how it can be differentiated to obtain the sensitivity. The new signal contribution function has a term that, like the sensitivity, is proportional to the electrical current densities from the normal and reciprocal configurations and an additional term that is proportional to the correlation of the magnetic fields from the normal and reciprocal configurations. I show plots of these two terms and investigate their magnitudes as a function of the induction number. This new expression will be useful for testing numerical models and aids in understanding the measured results in frequency-domain electromagnetics.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 4","pages":"979-993"},"PeriodicalIF":1.8,"publicationDate":"2025-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/1365-2478.70011","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845795","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}
引用次数: 0
Towards deep learning for seismic demultiple 面向地震解乘的深度学习
IF 1.8 3区 地球科学
Geophysical Prospecting Pub Date : 2025-02-26 DOI: 10.1111/1365-2478.13672
Mario R. Fernandez, Norman Ettrich, Matthias Delescluse, Alain Rabaute, Janis Keuper
{"title":"Towards deep learning for seismic demultiple","authors":"Mario R. Fernandez,&nbsp;Norman Ettrich,&nbsp;Matthias Delescluse,&nbsp;Alain Rabaute,&nbsp;Janis Keuper","doi":"10.1111/1365-2478.13672","DOIUrl":"https://doi.org/10.1111/1365-2478.13672","url":null,"abstract":"<p>Multiple attenuation is an important step in seismic data processing, leading to improved imaging and interpretation. Radon-based algorithms are commonly used for discriminating primaries and multiples in common depth point seismic gathers. This process implies a large number of parameters that need to be optimized for a satisfactory result. Moreover, Radon-based approaches sometimes present challenges in discriminating primaries and multiples with similar moveouts. Deep learning, based on convolutional neural networks, has recently shown promising results in seismic processing tasks that could mitigate the challenges of conventional methods. In this work, we detail how to train convolutional neural networks with only synthetic seismic data for assessing the demultiple problem in field datasets. We compare different training strategies for multiples removal based on different loss functions. We evaluate the performance of the different strategies on 400 clean and noisy synthetic data. We found that training a convolutional neural network to predict the multiples and then subtracting them from the input image is the most effective strategy for demultiple, especially for noisy data. Finally, we test our model to predict multiples on an elastic synthetic dataset and four distinctive field datasets. Our proposed approach reports successful generalization capabilities predicting and eliminating internal and surface-related multiples before and after migration while mitigating Radon challenges and relieving the user from any manual tasks. As a result, our effectively trained models bring a new valuable tool for seismic demultiple to consider in existing processing workflows.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 4","pages":"1185-1203"},"PeriodicalIF":1.8,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/1365-2478.13672","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143846203","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}
引用次数: 0
Joint event location and 3D Poisson's ratio tomography for downhole microseismic monitoring 联合事件定位和三维泊松比层析成像技术用于井下微地震监测
IF 1.8 3区 地球科学
Geophysical Prospecting Pub Date : 2025-02-23 DOI: 10.1111/1365-2478.13673
Congcong Yuan, Jie Zhang
{"title":"Joint event location and 3D Poisson's ratio tomography for downhole microseismic monitoring","authors":"Congcong Yuan,&nbsp;Jie Zhang","doi":"10.1111/1365-2478.13673","DOIUrl":"https://doi.org/10.1111/1365-2478.13673","url":null,"abstract":"<p>Passive seismic tomography plays a significant role in monitoring subsurface structures and properties during hydraulic fracturing. In this study, we develop a new passive seismic tomography approach to jointly invert for event locations, 3D P-wave velocity (<i>V</i><sub>p</sub>) and Poisson's ratio models, for downhole microseismic monitoring. The method enables to directly obtain the 3D Poisson's ratio or <i>V</i><sub>p</sub>/<i>V</i><sub>s</sub> ratio without the assumption of identical P- and S-wave raypaths. The back azimuths of passive seismic events are incorporated into the proposed method to better constrain the event locations. The 3D cross gradients are further applied to the proposed method to assimilate the P-wave velocity model with Poisson's ratio model in the same geological structure. The synthetic experiment demonstrates that the proposed tomographic method can recover the event locations and their adjacent 3D P-wave velocity as well as Poisson's ratio models effectively. In the field experiment, microseismic events are relocated reasonably well compared with the grid search solutions in a calibrated layer model. The area with low Poisson's ratios may be utilized to estimate the stimulated reservoir volume and indicate a potential area associated with highly saturated hydrocarbon.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 4","pages":"1171-1184"},"PeriodicalIF":1.8,"publicationDate":"2025-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143846087","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}
引用次数: 0
The application of frequency-modulated continuous wave modulated thermoacoustic imaging in geological media 调频连续波调制热声成像在地质介质中的应用
IF 1.8 3区 地球科学
Geophysical Prospecting Pub Date : 2025-02-15 DOI: 10.1111/1365-2478.13663
Chang Liu, Chang Wang, Xu Mao, Weite Zhang, Raquel Isabel Martínez-López, Juan Heredia-Juesas, Jose Martinez-Lorenzo
{"title":"The application of frequency-modulated continuous wave modulated thermoacoustic imaging in geological media","authors":"Chang Liu,&nbsp;Chang Wang,&nbsp;Xu Mao,&nbsp;Weite Zhang,&nbsp;Raquel Isabel Martínez-López,&nbsp;Juan Heredia-Juesas,&nbsp;Jose Martinez-Lorenzo","doi":"10.1111/1365-2478.13663","DOIUrl":"https://doi.org/10.1111/1365-2478.13663","url":null,"abstract":"<p>A thermoacoustics imaging system is investigated in this paper to enhance conventional imaging modalities in geological subsurface situational awareness applications. While thermoacoustics imaging has traditionally been used in biological scenarios like breast cancer detection, this work aims to extend thermoacoustics imaging to geophysical applications by demonstrating that water-saturated sand can be distinguished from dry and oil-saturated sand based on their amplitude differences. This breakthrough enables the feasibility of monitoring water distribution in these media. Moreover, to compensate for the low conversion efficiency from electromagnetic power to thermoacoustics amplitude, the signal modulation method is used by applying the frequency-modulated continuous wave techniques. The experiment results show that the frequency-modulated continuous wave can enhance the signal-to-noise ratio while maintaining a similar resolution as the pulse-excited thermoacoustics wave. These findings pave the way for the future use of thermoacousticsimaging in subsurface sensing and imaging of fluid flow and transport in porous media.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 4","pages":"1154-1170"},"PeriodicalIF":1.8,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/1365-2478.13663","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845989","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}
引用次数: 0
Unified model for microscopic and mesoscopic wave-induced fluid flow in a fluid-saturated porous periodically layered medium 饱和多孔周期性层状介质中微观和介观波致流体流动的统一模型
IF 1.8 3区 地球科学
Geophysical Prospecting Pub Date : 2025-02-07 DOI: 10.1111/1365-2478.13671
Jianping Liao, Junxin Guo, Hexiu Liu, Yanbin He, Anyu Li, Liang Cheng, Lin Zhou
{"title":"Unified model for microscopic and mesoscopic wave-induced fluid flow in a fluid-saturated porous periodically layered medium","authors":"Jianping Liao,&nbsp;Junxin Guo,&nbsp;Hexiu Liu,&nbsp;Yanbin He,&nbsp;Anyu Li,&nbsp;Liang Cheng,&nbsp;Lin Zhou","doi":"10.1111/1365-2478.13671","DOIUrl":"https://doi.org/10.1111/1365-2478.13671","url":null,"abstract":"<p>The interlayer mesoscopic wave-induced fluid flow and the squirt flow are two important mechanisms for seismic attenuation and dispersion in the fluid-saturated porous layered rock. Although numerous studies have been conducted on these two mechanisms, their combined effects (especially the resulting frequency-dependent anisotropy features) have not been sufficiently investigated. Hence, we propose a concise and rigorous theoretical model to quantify the combined effects of these two mechanisms. We first quantify the squirt flow effects through a wet rock frame for each layer that has frequency-dependent and complex-valued elastic properties. Then, we apply Biot's quasi-static poroelasticity theory to derive the analytical solutions for the effective stiffness coefficients of the periodically layered rock. Using the derived rock stiffness coefficients, we calculate the seismic attenuation and dispersion, as well as the frequency-dependent anisotropy. Two cases are studied, one with alternating water- and gas-saturated layers (constant rock frame properties) and the other with periodically distributed fracture layers (constant saturating fluid properties). The P-waves in these two cases are both influenced by the mesoscopic interlayer wave-induced fluid flow and the squirt flow. However, the SV-wave is solely affected by the squirt flow in the first case and primarily influenced by the mesoscopic interlayer wave-induced fluid flow in the second case, respectively. The wave velocity and attenuation in the first case are isotropic, whereas those in the second case exhibit frequency-dependent anisotropy (induced by the mesoscopic interlayer wave-induced fluid flow). To validate our model, we compare our model to the measured extensional attenuation in a partially saturated sandstone sample under different effective pressures. The joint effects of the mesoscopic interlayer wave-induced fluid flow and the squirt flow observed in the experiments are well predicted by our model. Our model has potential applications in the seismic characterization of reservoirs composed of layered rocks, such as shale reservoirs.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 4","pages":"1125-1140"},"PeriodicalIF":1.8,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845882","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}
引用次数: 0
Improving Resolution of Near Surface Structure Imaging Based on Elastic Full Waveform Inversion 基于弹性全波形反演提高近地表结构成像分辨率
IF 1.8 3区 地球科学
Geophysical Prospecting Pub Date : 2025-02-07 DOI: 10.1111/1365-2478.70000
Yihao Wang, Zhiwen Xue, John Bradford, Andrew Gase
{"title":"Improving Resolution of Near Surface Structure Imaging Based on Elastic Full Waveform Inversion","authors":"Yihao Wang,&nbsp;Zhiwen Xue,&nbsp;John Bradford,&nbsp;Andrew Gase","doi":"10.1111/1365-2478.70000","DOIUrl":"https://doi.org/10.1111/1365-2478.70000","url":null,"abstract":"<p>Estimating structure of pyroclastic deposits plays an important role in the interpretation of volcanic geology and evaluation of potential hazard. We aim to invert near surface seismic data to produce high-resolution images of pyroclastic density current deposits resulting from the 18 May 1980 volcanic eruption at Mount St. Helens, Washington, USA. Elastic full waveform inversion is a popular data fitting method used to estimate seismic properties of the earth. Due to the great challenges in the convergence of elastic full waveform inversion when inverting high-frequency and complex near-surface land seismic data, we develop a specific workflow to improve the resolution of velocity models that progress from traveltime inversion and surface wave inversion to full elastic full waveform inversion. The final inverted models include fine-scale feature structures that compare favourably to an adjacent outcrop. The final data fitting shows significant improvement with normalized waveform misfit decreasing from 1 to 0.4.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 4","pages":"1141-1153"},"PeriodicalIF":1.8,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845883","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}
引用次数: 0
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