Geophysical Prospecting最新文献

{"title":"Velocity model building via combining seismic slope tomography and supervised deep learning","authors":"Yao Huang,&nbsp;Huachen Yang,&nbsp;Jianzhong Zhang","doi":"10.1111/1365-2478.13652","DOIUrl":"https://doi.org/10.1111/1365-2478.13652","url":null,"abstract":"<p>Seismic slope tomography is an effective method to build macro velocity model. In order to improve the accuracy and resolution of the slope tomography, we proposed a novel approach that combines slope tomography with supervised deep learning. First, the slope tomography is used to obtain the macro velocity model and the positions of reflection points. Subsequently, the slope tomographic model, positions of reflection points and the corresponding observed traveltimes are used as inputs simultaneously for a neural network, whereas the actual velocity models are used as the labels. Through training the neural network with sufficient samples, the mapping from the inputs to the real velocity model is established. The neural network learns the background velocity of the real model from the smooth tomographic model, the velocity details from the traveltimes and the formation interface information from the positions of reflection points. Consequently, a high-accuracy and high-resolution velocity model is obtained on the basis of the slope tomographic model. Both tests on synthetic seismic data and applications to field seismic data demonstrate the effectiveness of the proposed method.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 1","pages":"67-79"},"PeriodicalIF":1.8,"publicationDate":"2024-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143113394","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 novel strategy for simultaneous super-resolution reconstruction and denoising of post-stack seismic profile","authors":"Wenshuo Yu,&nbsp;Shiqi Dong,&nbsp;Shaoping Lu,&nbsp;Xintong Dong","doi":"10.1111/1365-2478.13646","DOIUrl":"https://doi.org/10.1111/1365-2478.13646","url":null,"abstract":"<p>Post-stack seismic profiles are images reflecting geological structures which provide a critical foundation for understanding the distribution of oil and gas resources. However, due to the limitations of seismic acquisition equipment and data collecting geometry, the post-stack profiles suffer from low resolution and strong noise issues, which severely affects subsequent seismic interpretation. To better enhance the spatial resolution and signal-to-noise ratio of post-seismic profiles, a multi-scale attention encoder–decoder network based on generative adversarial network is proposed. This method improves the resolution of post-stack profiles and effectively suppresses noises and recovers weak signals as well. A multi-scale residual module is proposed to extract geological features under different receptive fields. At the same time, an attention module is designed to further guide the network to focus on important feature information. Additionally, to better recover the global and local information of post-stack profiles, an adversarial network based on a Markov discriminator is proposed. Finally, by introducing an edge information preservation loss function, the conventional loss function of the Generative Adversarial Network is improved, which enables better recovery of the edge information of the original post-stack profiles. Experimental results on simulated and field post-stack profiles demonstrate that the proposed multi-scale attention encoder–decoder network based on generative adversarial network method outperforms two advanced convolutional neural network-based methods in noise suppression and weak signal recovery. Furthermore, the profiles reconstructed by the multi-scale attention encoder–decoder network based on generative adversarial network method preserve more geological structures.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 1","pages":"96-112"},"PeriodicalIF":1.8,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143120248","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":"Broadband seismic data acquisition and processing of iron oxide deposits in Blötberget, Sweden","authors":"Lea Gyger,&nbsp;Alireza Malehmir,&nbsp;Musa Manzi,&nbsp;Lilas Vivin,&nbsp;Jean Lépine,&nbsp;Ayse Kaslilar,&nbsp;Oleg Valishin,&nbsp;Paul Marsden,&nbsp;Ronne Hamerslag","doi":"10.1111/1365-2478.13648","DOIUrl":"https://doi.org/10.1111/1365-2478.13648","url":null,"abstract":"<p>In June 2022, an innovative seismic survey was conducted in Blötberget, central Sweden, to evaluate the effectiveness of employing both a broadband seismic source and broadband receivers for mineral exploration in a challenging hardrock setting. The Blötberget mine hosts high-quality iron oxides, predominantly magnetite and hematite, sometimes enriched with apatite. These deposits comprise 10–50 m thick sheet-like horizons with a moderate eastward dip (<span></span><math>\u0000 <semantics>\u0000 <mo>∼</mo>\u0000 <annotation>$sim$</annotation>\u0000 </semantics></math>45°) along an NNE-trending zone. The survey employed a combination of co-located micro-electromechanical sensors, three-component recorders, surface and borehole distributed acoustic sensing, along with a 77-kN broadband seismic vibrator operating with 2–200 Hz linear sweeps. A tailored processing workflow was applied to preserve the broadband nature of the recorded data, and a one-dimensional velocity model was derived from the borehole distributed acoustic sensing data for migration and time-to-depth conversion purposes. Compared to the previous seismic surveys, the resulting seismic cross section reveals several well-defined reflections with improved resolution. Notably, a reflection intersecting the main deposits at a depth of approximately 1200 m exhibits a distinct polarity reversal relative to the reflection from the mineralization, providing further evidence for its interpretation as originating from a fault zone. Shallow reflections align with geological boundaries and partially coincide with weak magnetic anomalies. Additional reflections were revealed underneath the known mineralization on both sides of the fault zone and may suggest the presence of potential additional resources. The delineation of these reflections and the fault zone is critical for future mine planning and development in the region. This case study underscores the potential of broadband data in achieving high-resolution subsurface imaging in hardrock environment and its pivotal role in mineral resource assessment processes.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 1","pages":"80-95"},"PeriodicalIF":1.8,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/1365-2478.13648","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143120245","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":"High-resolution velocity model building with fault control: Methods and applications","authors":"Hua Xue,&nbsp;Min Du,&nbsp;Wenbin Jiang,&nbsp;Bin Liu,&nbsp;Xi Chen,&nbsp;Li Yang,&nbsp;Yan Li,&nbsp;Baojin Zhang,&nbsp;Ruwei Zhang,&nbsp;Yuan Gu,&nbsp;Yong Yang,&nbsp;Gaowen He,&nbsp;Xiaoming Sun","doi":"10.1111/1365-2478.13645","DOIUrl":"https://doi.org/10.1111/1365-2478.13645","url":null,"abstract":"<p>In seismic exploration, particularly within the domain of oil and gas reservoirs, the accurate imaging of complex fault blocks and the identification of structural traps are important. Geological risk factors, including the implementation of structural traps, reservoir delineation, and precise target drilling, require immediate attention in practical exploration. Addressing these factors involves two primary challenges: ensuring imaging accuracy and minimizing structural distortions. This study introduces a high-resolution velocity modelling technique with fault control, specifically developed to mitigate misties between seismic image and well-log data and improve the accuracy of seismic depth imaging and well depth correlation. The method offers a targeted solution to the challenges of implementing structural traps, delineating reservoirs and executing precise drilling operations. By incorporating fault control, it accounts for the structural complexity of subsurface media, enabling an accurate inversion of velocity variations across fault blocks. This approach ensures that velocity models, constrained by geological and structural models, exhibit a high degree of consistency. Utilizing fault-controlled travel time inversion, the method resolves mistier between seismic imaging and well-log data, guaranteeing the precision of velocity models and imaging. The methodology provides reliable seismic data for target evaluation, effectively reducing exploration risks and improving the accuracy of velocity modelling.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 4","pages":"1027-1036"},"PeriodicalIF":1.8,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143846152","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":"Deep learning-based inversion with discrete cosine transform discretization for two-dimensional basement relief imaging of sedimentary basins from observed gravity anomalies","authors":"Arka Roy,&nbsp;Yunus Levent Ekinci,&nbsp;Çağlayan Balkaya,&nbsp;Hanbing Ai","doi":"10.1111/1365-2478.13647","DOIUrl":"https://doi.org/10.1111/1365-2478.13647","url":null,"abstract":"<p>Sedimentary basins, integral to Earth's geological history and energy resource exploration, undergo complex changes driven by sedimentation, subsidence and geological processes. Gravity anomaly inversion is a crucial technique offering insights into subsurface structures and density variations. Our study addresses the challenge of complex subsurface structure assessment by leveraging deep neural networks to invert observed gravity anomalies. Optimization approaches traditionally incorporate known density distributions obtained from borehole data or geological logging for inverting basement depth in sedimentary basins using observed gravity anomalies. Our study explores the application of deep neural networks in accurate architectural assessment of sedimentary basins and demonstrates their significance in mineral and hydrocarbon exploration. Recent years have witnessed a surge in the use of machine learning in geophysics, with deep learning models playing a pivotal role. Integrating deep neural networks, such as the feedforward neural networks, has revolutionized subsurface density distribution and basement depth estimation. This study introduces a deep neural network specifically tailored for inverting observed gravity anomalies to estimate two-dimensional basement relief topographies in sedimentary basins. To enhance computational efficiency, a one-dimensional discrete cosine transform based discretization approach is employed. Synthetic data, generated using non-Gaussian fractals, compensates for the scarcity of true datasets for training the deep neural network model. The algorithm's robustness is validated through noise introduction with comparisons against an efficient and traditional global optimization-based approach. Gravity anomalies of real sedimentary basins further validate the algorithm's efficacy, establishing it as a promising methodology for accurate and efficient subsurface imaging in geological exploration.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 1","pages":"113-129"},"PeriodicalIF":1.8,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143119200","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":"Amplitude versus offset attribute inversion method for characterizing gas hydrate: Insights from high resolution seismic imaging and drilling results in the Shenhu area, South China Sea","authors":"Xudong Zhang,&nbsp;Fanxiang Zeng,&nbsp;Wenbin Jiang,&nbsp;Dajiang Meng,&nbsp;Sheng Yan","doi":"10.1111/1365-2478.13641","DOIUrl":"https://doi.org/10.1111/1365-2478.13641","url":null,"abstract":"<p>Amplitude versus offset attribute inversion primarily utilizes the change in amplitude with offset to extract lithologic information of the reservoir. We performed high resolution imaging using three-dimensional seismic data and simulated four different models of gas hydrate and free gas to optimize the selection of sensitive attributes for gas hydrate characterization. We optimized the selection of sensitive attributes for gas hydrate characterization. Our research identified the gradient parameter <i>G</i> as a highly sensitive attribute for characterizing gas hydrate reservoirs. By comparing theoretical models with drilling site data, we predicted the saturation variations of gas hydrate based on the amplitude of <i>G</i> and summarized the amplitude versus offset characteristics and sensitive attributes of gas hydrate at different saturation levels. The results offer valuable insights for identification of gas hydrate in seismic data and provide a reference for their characterization.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 4","pages":"1008-1026"},"PeriodicalIF":1.8,"publicationDate":"2024-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143846084","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":"Analytical formulas for geometrical factor and sensitivity for long electrodes","authors":"S. L. Butler","doi":"10.1111/1365-2478.13644","DOIUrl":"https://doi.org/10.1111/1365-2478.13644","url":null,"abstract":"<p>In the electrical resistivity method, electrodes are usually modelled as point current sources and point voltage measurements. If the burial depth of the electrode is significant compared with the spacing between electrodes, this point approximation may not be accurate. Common situations employing long electrodes include the use of metal-cased boreholes as electrodes and small-scale, high-resolution environmental, engineering and archaeological surveys where electrode spacings may be very small. In this contribution, I present analytical expressions for the mutual resistance between long electrodes modelled as line current sources. Mutual resistances are then used to calculate geometrical factors. Additionally, I present an expression for the current density and use it to derive an analytical expression for the sensitivity of electrode arrays with long electrodes. The sensitivity is, in turn, used to calculate the mean depth and position which can be used as estimates of depth and position of investigation and as pseudosection plot points. Example calculations using the geometrical factor, sensitivity and mean depth are shown, and comparisons are made with simulations and lab-scale experiments.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 1","pages":"130-141"},"PeriodicalIF":1.8,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143118151","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 novel Fourier domain scheme for three-dimensional magnetotelluric modelling in anisotropic media","authors":"Shikun Dai,&nbsp;Qingrui Chen,&nbsp;Kun Li,&nbsp;Jiaxuan Ling,&nbsp;Dongdong Zhao","doi":"10.1111/1365-2478.13643","DOIUrl":"https://doi.org/10.1111/1365-2478.13643","url":null,"abstract":"<div>\u0000 \u0000 <p>This study presents a novel algorithm that combines the Lorenz gauge equations with the Fourier domain technique to simulate magnetotelluric responses in three-dimensional conductivity structures with general anisotropy. The method initially converts the Helmholtz equations governing vector potentials into one-dimensional differential equations in the wave number domain via the horizontal two-dimensional Fourier transform. Subsequently, a one-dimensional finite element method employing quadratic interpolation is applied to obtain three five-diagonal linear equation systems. Upon solving these equations, the spatial domain fields are obtained via the inverse Fourier transform. This process guarantees the computational efficiency, memory efficiency and high parallelization of the algorithm. Moreover, an anisotropic medium iteration operator guarantees stable convergence of the method. The correctness, competence and applicability of the algorithm are verified using some synthetic models. The results demonstrate that the new method is efficient and performs well in anisotropic undulating terrain and complex structures. Compared to other Fourier domain methods and the latest edge-based finite element algorithm, the proposed method exhibits superior computing performance. Finally, the impact of the Euler angles on the magnetotelluric responses is analysed.</p>\u0000 </div>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 1","pages":"142-159"},"PeriodicalIF":1.8,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143116417","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":"Variable gauge length: Processing theory and applications to distributed acoustic sensing","authors":"Theo Cuny,&nbsp;Pierre Bettinelli,&nbsp;Joël Le Calvez","doi":"10.1111/1365-2478.13640","DOIUrl":"https://doi.org/10.1111/1365-2478.13640","url":null,"abstract":"<p>Most distributed acoustic sensing systems will only process acoustic data with a fixed gauge length for the entire well depth. However, it has been shown that the gauge length is a critical parameter to improve the signal-to-noise ratio when used as a function of certain geophysical parameters, such as the apparent velocity. It can also be responsible for significant distortions if tuned incorrectly. In this paper, we first aim to reintroduce the concept of gauge length and derive a robust method to optimize its value based on the geophysical parameters whilst ensuring no distortion to the original signal. We then present a novel method of processing the distributed acoustic sensing data using the concept of a variable gauge length. We finish by showing applications of these techniques on synthetic vertical seismic profiling data and some of the results obtained on actual field datasets.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 1","pages":"160-187"},"PeriodicalIF":1.8,"publicationDate":"2024-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143116418","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 rock physics modelling approach for time-lapse monitoring and characterization of fluid–rock interactions in hydrocarbon reservoirs","authors":"Moumita Sengupta,&nbsp;Ranjana Ghosh","doi":"10.1111/1365-2478.13642","DOIUrl":"https://doi.org/10.1111/1365-2478.13642","url":null,"abstract":"<p>One of the research gaps is to understand the development of seismic characteristics of gas-saturated rock along with the change in rock properties because of chemical reactions. We suggest a method to explain the change in elastic properties brought on by CO₂ injection in a rock by capturing the physico-chemical interactions observed in the laboratory in a theory of rock physics. To explain the laboratory-measured physical characteristics and velocity of a dynamic rock–fluid system, we include a time-dependent component in the existing cemented-sand model. We demonstrate theoretically the rate of change of elastic moduli of the dry frame by incorporating the measured rate of change of cement due to chemical dissolution. We adapt the theory such that it can be applied to the field data and calibrate the theory using water-saturated well log data from the Ankleshwar field, an established oil field in the Cambay basin, western India. Theoretical time-lapse logs of velocity and density are then produced using the theory over a range of CO₂ saturations, assuming cementing material in grain contacts and geochemical interactions comparable to those observed in the laboratory rock. Then, using theoretical logs, corresponding time-lapse synthetic seismic data are produced for different saturation. These data clearly demonstrate that, for a uniform model, velocity decreases by up to 18% as CO₂ saturation increases from 0% to 20% (ignoring the chemical effect), and that, for a specific saturation, say 20%, chemical effects result in a 17% decrease in velocity from the present to the end of 60 years. However, for the patchy model, velocity decreases maximum by 14% and 16% due to varying saturation and chemical reaction. Moreover, for a particular saturation of CO₂, say 20%, velocity differs by 16% for different types of models. This research contributes to making strategy for CO₂-sequestration in a designated field.</p>","PeriodicalId":12793,"journal":{"name":"Geophysical Prospecting","volume":"73 4","pages":"994-1007"},"PeriodicalIF":1.8,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845942","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}