Geophysical Prospecting最新文献

{"title":"Algorithms for extraction of reliable density ratios from pre-stack seismic data—Part 1: Theory","authors":"Ivan Lehocki,&nbsp;Tapan Mukerji,&nbsp;Per Avseth,&nbsp;Erling Hugo Jensen","doi":"10.1111/1365-2478.70029","DOIUrl":"https://doi.org/10.1111/1365-2478.70029","url":null,"abstract":"<p>We have developed two inversion schemes for probabilistic calculation of density ratio across a reflecting interface from P-to-P wave reflectivity by algebraically inverting Zoeppritz's equation. The density ratio is an attribute that can be directly linked to hydrocarbon saturation. The probabilistic approach helps to model uncertainties in the calculated parameter. The methods are free of empiricism. Contrary to conventional wisdom, we show that ultra-far amplitude variation with offset (AVO) data are not required for the inversion of the density ratio parameter. As a matter of fact, with our schemes, it is advisable to restrict the inversion to near-far angle ranges to minimize the impact of the amplitude-distorting phenomena that (strongly) invalidate the assumptions woven into the derivation of the P-to-P Zoeppritz equation. Moreover, we demonstrate that this equation is suitable for density ratio inversion. The first inversion scheme to predict the density ratio involves repeatedly solving a 12th-degree polynomial equation across various incident angles. The most frequent value in the distribution of solutions serves as the best estimate. The second scheme solves a 5th-degree polynomial equation for the squared <i>V</i>_P/<i>V</i>_S ratio of layer 2 (in a two-layered earth model), also at an arbitrary number of incident angles. The range of the angles used in the inversion can, in principle, be freely selected. The most likely density ratio estimate is obtained as a byproduct of the calculation. We tested the methods on a synthetic example. Both schemes predict the density ratio within one standard deviation of the actual value from near-far angle seismic reflection data. Moreover, the two inversion schemes were compared, showing that <i>Loris</i>, which requires repetitive solving of 12th-degree polynomial equations, is computationally more expensive than <i>Lemur</i>, which solves a 5th-degree polynomial equation. Despite both methods achieving accurate density ratio estimates, <i>Lemur</i>’s computational efficiency makes it the preferred choice for large datasets. This paper is the first part of a two-part study on density ratio inversion methods. Here, we focus on the theoretical foundations of the <i>Loris</i> and <i>Lemur</i> inversion approaches and validate them through synthetic tests. In Part 2, we extend this work by applying the methods to real seismic data and evaluating their performance in a practical exploration setting.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144582408","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":"Multiple Reflections on Huygens' Principle","authors":"Kees Wapenaar","doi":"10.1111/1365-2478.70038","DOIUrl":"https://doi.org/10.1111/1365-2478.70038","url":null,"abstract":"<p>According to Huygens' principle, all points on a wave front act as secondary sources emitting spherical waves and the envelope of these spherical waves forms a new wave front. In the mathematical formulation of Huygens' principle, the waves emitted by the secondary sources are represented by Green's functions. In many present-day applications of Huygens' principle, these Green's functions are replaced by their time-reversed versions, thus forming a basis for backpropagation, imaging, inversion, seismic interferometry, etc. However, when the input wave field is available only on a single open boundary, this approach has its limitations. In particular, it does not properly account for multiply reflected waves. This is remedied by a modified form of Huygens' principle, in which the Green's functions are replaced by focusing functions. The modified Huygens' principle forms a basis for imaging, inverse scattering, monitoring of induced sources, etc., thereby properly taking multiply reflected waves into account.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/1365-2478.70038","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144598728","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":"S-Wave Velocity Model of Texas Based On Joint Inversion of Interferometry and P-Wave Receiver Functions","authors":"Galina Lyubomirova Simeonova,&nbsp;Leo Eisner,&nbsp;Umair bin Waheed,&nbsp;Alexandros Savvaidis,&nbsp;Sherif Hanafy","doi":"10.1111/1365-2478.70035","DOIUrl":"https://doi.org/10.1111/1365-2478.70035","url":null,"abstract":"<div>\u0000 \u0000 <p>Velocity models are essential for accurately locating the rapidly increasing seismicity in Texas. The region's limited monitoring infrastructure and extensive sedimentary basins underscore the need for developing both P- and S-wave models, especially for precise depth estimation of seismic events. This study utilizes seismic interferometry and surface wave inversion techniques, along with receiver functions, to construct a three-dimensional velocity model for Western, Central and Southern Texas. Our results indicate that the integration of receiver functions significantly improves the stability of the surface wave inversion process. The resulting inverted model aligns well with known geological structures, revealing lower S-wave velocities in sedimentary basins and higher velocities in areas with bedrock exposure. Notably, the velocity contrasts between the sedimentary basins and bedrock can reach up to 30% at equivalent depths. Furthermore, the S-wave velocities derived from our model are considerably lower than those reported in previous research, suggesting that the use of this revised S-wave model may require a reevaluation of the depths at which seismic events are located.</p>\u0000 </div>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144582390","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":"Connect Geophysical Data Interpretation and Geology Through Inversion for Anisotropic Magnetic Susceptibility","authors":"Zhuo Liu,&nbsp;Yaoguo Li","doi":"10.1111/1365-2478.70037","DOIUrl":"https://doi.org/10.1111/1365-2478.70037","url":null,"abstract":"<div>\u0000 \u0000 <p>Anisotropic magnetic susceptibility, as an intrinsic property that records the strain history a rock formation experienced, has been widely used in structural geological studies based on direct specimen measurements. By comparing measurements of anisotropic parameters on drill samples from different locations, rock formations can be differentiated into different or the same groups. However, the applications of anisotropic magnetic susceptibility in geophysical data interpretation are rare due to its complexity in inverse problems, despite its long-recognized influence on induced magnetization. In this work, we present a one-dimensional inversion algorithm that simultaneously recovers two principal susceptibility components. To connect geophysical data with geology differentiation through different anisotropies, the inversion is constrained by fuzzy C-means clustering to enforce coherency in the parameter space for model values within the same rock formation. Under the assumption of a sedimentary scenario, the synthetic tests show that, when the data are influenced by anisotropy, the inversion for an isotropic model could fail to reproduce the data, while inverting for an anisotropic model with clustering can lead to better data recovery and produce valuable information about different formations. We also test our method with field data published by the United States Geological Survey over the Wyoming Salient. The inversion results and their comparison against geochronological records reveal connections between airborne magnetic data and geology, including structures and rock formations originating from different geologic ages.</p></div>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144581786","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":"Simultaneous P- and S-wave seismic traveltime tomography using physics-informed neural networks","authors":"Chao Song,&nbsp;Hang Geng,&nbsp;Yufeng Wang,&nbsp;Umair Bin Waheed,&nbsp;Cai Liu","doi":"10.1111/1365-2478.70034","DOIUrl":"https://doi.org/10.1111/1365-2478.70034","url":null,"abstract":"<div>\u0000 \u0000 <p>Seismic tomography has long been an effective tool for constructing reliable subsurface structures. However, simultaneous inversion of P- and S-wave velocities presents a significant challenge for conventional seismic tomography methods, which depend on numerical algorithms to calculate traveltimes. A physics-informed neural network—based seismic tomography method (PINNtomo) has been proposed to solve the eikonal equation and construct the velocity model. We propose extending PINNtomo to perform multiparameter inversion of P- and S-wave velocities jointly, which we refer to as PINNPStomo. In PINNPStomo, we employ two neural networks: one for the P- and S-wave traveltimes and another for the P- and S-wave velocities. By optimizing the misfits of P- and S-wave first-arrival traveltimes calculated from the eikonal equations, we can obtain the predicted P- and S-wave velocities that determine these traveltimes. Recognizing that the original PINNtomo utilizes a multiplicative factored eikonal equation, which depends on background traveltimes corresponding to a homogeneous velocity at the source location, we propose to use an effective-slowness-based factored eikonal equation for PINNPStomo to eliminate this dependency. The proposed PINNPStomo, incorporating the effective-slowness-based factored eikonal equation, demonstrates superior convergence speed and multiparameter inversion accuracy. We validate these improvements using two-dimensional Marmousi, two-dimensional Overthrust and three-dimensional foothill elastic velocity models across three different seismic data acquisition geometries.</p></div>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144581787","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":"An Integrated Geophysical Approach to Unveil Alteration Zones and Geologic Structures for Sulphide–Uranium Mineralization in Singhbhum Shear Zone, India","authors":"Anurag Tripathi,&nbsp;Afaque Karim,&nbsp;Chandrai Murmu,&nbsp;Sandeep Kumar,&nbsp;Shailendra Singh","doi":"10.1111/1365-2478.70036","DOIUrl":"https://doi.org/10.1111/1365-2478.70036","url":null,"abstract":"&lt;div&gt;\u0000 \u0000 &lt;p&gt;Singhbhum Shear Zone (SSZ) also referred as Copper Belt Thrust (CBT), located at the southern margin of North Singhbhum Fold Belt (NSFB) is well-known for highly mineralized copper, uranium and other sulphide minerals deposits. In order to the identify favourable structures that could host the sulphide–uranium mineralization in Gurulpada area of SSZ, an integrated geophysical study was conducted using magnetic, self-potential (SP), electrical resistivity tomography (ERT) and induced polarization (IP) surveys. The present study identifies pronounced magnetic anomalies in the central part due to presence of magnetite mineral along the shear planes of quartz-chlorite-schist (±sericite) and basic dykes, exhibiting an ENE–WSW orientation, which follows the geological strike and the trend of the shear zone within the area. Low magnetic intensity in the southern part of area suggests demagnetization caused by hydrothermal alteration, indicate mineralized zones. SP anomaly map has identified six zones exhibiting negative anomalies. Tilt derivative (TDR) and Euler deconvolution (ED) technique were applied on magnetic and SP data to depict geological structures that control mineralization and its depth. Magnetic and SP anomalies along the profile are plotted with a 2D inverted resistivity and chargeability section for comparative analysis. The inverted resistivity and chargeability model, illustrated as 2D cross sectional view and a 3D fence diagram, has delineated several anomalous zones at varying depths. The high magnetic anomaly, corroborated with negative SP values, is associated with low resistivity and high chargeability zones, indicating the disseminated sulphide ore bodies with quartz and magnetite mineral along the shear planes. Conversely, positive SP, high chargeability and high resistivity zones signify disseminated sulphide deposits that infilled quartz veins and intense silicification in the fractured zones. The 3D pseudo iso-surface chargeability models indicate high chargeability values (&lt;i&gt;M&lt;/i&gt; ≥ 15 mV/V) oriented in an ENE–WSW direction. The integration of geophysical (magnetic, SP, ERT and IP) anomalies and geological (bedrock and trench sampling) data, in conjunction with borehole analysis, confirms the presence of sulphide–uranium mineralization in the study area. The present study reaffirms the presence of ENE–WSW trending ductile-brittle intense shear and hydrothermal alteration zones, which are key indicators of sulphide–uranium mineralization in the study area. The findings revealed that the mineralization accommodated within the quartz-chlorite-schist (±sericite) of the Chaibasa Formation of the Singhbhum Group, appearing as dissemination and fracture filling in association with quartz and magnetite in certain locations. Thus, these integrated geophysical studies are essential for understanding and delineating the complex structural and mineralogical framework of the SSZ. They provide a foundation for","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144581788","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":"Interpretation of seismic inversion using ternary diagram: Seismic lithology identification","authors":"Javad Sharifi","doi":"10.1111/1365-2478.70033","DOIUrl":"https://doi.org/10.1111/1365-2478.70033","url":null,"abstract":"<p>Considering the demand for lithology identification in quantitative seismic interpretation, I introduced ternary diagrams based on rock physics modelling to derive lithology from seismic data. For this purpose, physical and acoustic parameters of minerals were utilized to reconstruct the most common rocks in hydrocarbon reservoirs, including source, reservoir and caprock. Subsequently, the generated rocks were input into a ternary diagram based on easily obtained parameters from seismic data, including acoustic impedance, <i>V</i>_P/<i>V</i>_S ratio and lambda–mu–rho parameters. Next, two ternary diagrams were implemented according to the elastic parameters for reservoir (and source) and caprock identification. The theoretical results indicated that the proposed ternary diagrams can be applied for interpreting seismic inversion data to discriminate limestone from sandstone and shale using lambda–rho. Additionally, mu–rho can serve as a criterion to differentiate dolomite from limestone and anhydrite (or sandstone from shale and limestone). The obtained ternary diagram was validated using ultrasonic and well-log data from blind wells and subsequently used to interpret 3D seismic data. For this purpose, acoustic impedance was calculated using a simultaneous inversion method from pre-stack data and converted to elastic parameters, which were then input into the ternary diagrams. The validation procedures yielded promising results and demonstrated that ternary diagrams can effectively identify different lithologies compared to conventional binary cross-plots. The advantage of the proposed diagrams lies in their comprehensiveness and generality, making them compatible with seismic limitations and applicable to a wide range of sedimentary rocks. The findings of this research can enhance the interpretation of seismic inversion results when mineral fraction or petrophysical interpretation is unavailable. Finally, the advantages and limitations of the methodology were discussed, and the impact of reservoir heterogeneities and fluid types on ternary diagrams was analysed. It was concluded that the proposed diagrams are not restricted to specific depositional settings and can be developed for the seismic interpretation of unconventional reservoirs and igneous rocks through the implementation of the mentioned methodology.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 6","pages":""},"PeriodicalIF":1.8,"publicationDate":"2025-05-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144582400","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":"Correction to “Elastic properties of unconsolidated sandstones of interest for carbon storage”","authors":"","doi":"10.1111/1365-2478.70028","DOIUrl":"https://doi.org/10.1111/1365-2478.70028","url":null,"abstract":"<p>Sayers, C. M., &amp; Dasgupta, S. (2024). Elastic properties of unconsolidated sandstones of interest for carbon storage. <i>Geophysical Prospecting</i>, 72(2), 617–632.</p><p>On line 17 of the abstract, “low shear compliance” should read “low shear stiffness.”</p><p>We apologize for this error.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 5","pages":"1667"},"PeriodicalIF":1.8,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/1365-2478.70028","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143949862","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":"The Cu–Au–Mo deposit mineralization dynamics at the northern margin of the North China Craton and the southeastern margin of the Central Asian Orogenic Belt based on crustal oxide content","authors":"Baochun Li,&nbsp;Gaofeng Ye,&nbsp;Xiangguo Guo,&nbsp;Baoqiang Tai,&nbsp;Sheng Jin,&nbsp;Kuo Zhang,&nbsp;Shaohuai Sun,&nbsp;Cheng Gao,&nbsp;Jien Dong","doi":"10.1111/1365-2478.70031","DOIUrl":"https://doi.org/10.1111/1365-2478.70031","url":null,"abstract":"<p>The study of the mineralization dynamics of the Cu–Au–Mo deposit at the northern margin of the North China Craton and the southeastern margin of the Central Asian Orogenic Belt is important for understanding metallogenic settings. We calculated the crustal oxide content in heterogeneous systems using crustal temperature, seismic wave velocity (<i>V</i>_p), pressure and 1 wt.% water content. The oxide contents of SiO₂, MgO, K₂O and Na₂O in the crust from 10 to 40 km depth were obtained. The Bohai Bay Basin, Yanshan Block and Songliao Basin in the eastern study area exhibit an upper mantle lithology characterized by low SiO₂ and high MgO at 40 km, suggesting that the lithosphere in this area has been thinned. The destruction of the lithosphere was accompanied by the upwelling of the asthenosphere and upper mantle and the underplating of the lower crust by thermal material. Eventually, the crust formed mineralized fluids rich in volatiles, metallic elements and high oxygen fugacity. There is a good correspondence between the mineralization, the medium acidic, high alkali and low Mg–Fe regions in the lower crust and the extensional settings. This suggests that extensional settings provided conditions for the circulation and deposition of metallogenic fluids. The dynamics of Cu–Au–Mo mineralization at the northern margin of the North China Craton are subduction and retreat of the Paleo–Pacific Plate, and the mode of mineralization is ‘Decratonic deposits’. Unlike the northern margin of the North China Craton, the Erguna and Xing'an blocks have a more basal and ancient lower crust, and their mineralization was not only influenced by the Okhotsk, Paleo-Asian and Paleo–Pacific plates but also related to later modifications.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 5","pages":"1651-1666"},"PeriodicalIF":1.8,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/1365-2478.70031","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143950545","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":"Scalable Bayesian seismic wavelet estimation","authors":"Guillermina Senn,&nbsp;Matthew Walker,&nbsp;Håkon Tjelmeland","doi":"10.1111/1365-2478.70026","DOIUrl":"https://doi.org/10.1111/1365-2478.70026","url":null,"abstract":"<div>\u0000 \u0000 <p>In seismic amplitude-versus-angle data, the forward model connecting the elastic properties with the data involves the convolution of seismic reflection coefficients with a wavelet. If the wavelet is erroneously specified, the modelled seismic will be biased and associated seismic inversion results will be difficult to trust. Therefore, it is of interest to estimate the wavelet from the observations, prior to the seismic inversion. An existing Bayesian estimation procedure proposes a Bayesian model for the problem and explores the posterior distribution with a Gibbs sampler algorithm. However, the algorithmic complexity scales non-linearly with the number of observations, thus limiting input data to elastic well-log data and seismic data at the well. We adopt a similar hierarchical Bayesian model but introduce a computationally efficient Gibbs sampler to allow estimation from large two-dimensional seismic images. The efficiency is obtained by embedding the seismic image in an extended cyclic lattice so that large matrices acquire circulant properties and expensive matrix operations can be done with the fast Fourier transform. We include results for simulated datasets and a real dataset from an offshore gas reservoir in Egypt.</p></div>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 5","pages":"1635-1650"},"PeriodicalIF":1.8,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143950546","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}