In the CSAMT method, orthogonal electric and magnetic fields are commonly measured to determine the Cagniard apparent resistivity. However, in the near-field zone, the Cagniard resistivity is severely distorted, which is unrelated to underground structures. The Ex and Hz amplitudes in a homogeneous half-space monotonically vary in resistivity, and a numerical algorithm could achieve high-precision apparent resistivity without distortion for all frequencies. On this basis, the main focus of this investigation is on the comparative analysis of the sensitivity for the Ex field, Hz field, and Cagniard apparent resistivity to conductive and resistivity targets via synthetic models. The achieved results confirm that the Ex field could exhibit a more enhanced sensitivity for the resistive objects, while the Hz field could more effectively identify the conductive target. Besides, the static effect often distorts the electromagnetic data, which rigorously influences their application. The influence of the static effect on both the Ex and Hz fields is also examined in detail. The apparent resistivity based on the Ex field and Cagniard apparent resistivity is significantly affected by the static effect, which can mask deep anomalous blocks. However, the apparent resistivity based on the Hz field is almost unaffected by the static effect. Finally, a more efficient observation approach is provided for both the insulating and conductive targets.
在 CSAMT 方法中，通常通过测量正交电场和磁场来确定 Cagniard 视电阻率。然而，在近场区内，Cagniard 表观电阻率严重失真，这与地下结构无关。均质半空间中的 Ex 和 Hz 振幅在电阻率上呈单调变化，数值算法可实现高精度视电阻率，且所有频率都不会失真。在此基础上，本次研究的重点是通过合成模型比较分析 Ex 场、Hz 场和 Cagniard 视电阻率对导电目标和电阻率目标的敏感性。研究结果证实，Ex 场对电阻目标的灵敏度更高，而 Hz 场则能更有效地识别导电目标。此外，静态效应通常会扭曲电磁数据，这严重影响了电磁数据的应用。本文还详细研究了静态效应对 Ex 和 Hz 场的影响。基于 Ex 场和 Cagniard 表观电阻率的表观电阻率受到静电效应的严重影响，会掩盖深部异常块。然而，基于 Hz 场的视电阻率几乎不受静电效应的影响。最后，为绝缘和导电目标提供了一种更有效的观测方法。
{"title":"The comparative analysis of the Ex and Hz fields sensitivity generated by electric dipole sources","authors":"XianXiang Wang, Jiaqi Li, Songda Lei","doi":"10.1093/jge/gxae018","DOIUrl":"https://doi.org/10.1093/jge/gxae018","url":null,"abstract":"\u0000 In the CSAMT method, orthogonal electric and magnetic fields are commonly measured to determine the Cagniard apparent resistivity. However, in the near-field zone, the Cagniard resistivity is severely distorted, which is unrelated to underground structures. The Ex and Hz amplitudes in a homogeneous half-space monotonically vary in resistivity, and a numerical algorithm could achieve high-precision apparent resistivity without distortion for all frequencies. On this basis, the main focus of this investigation is on the comparative analysis of the sensitivity for the Ex field, Hz field, and Cagniard apparent resistivity to conductive and resistivity targets via synthetic models. The achieved results confirm that the Ex field could exhibit a more enhanced sensitivity for the resistive objects, while the Hz field could more effectively identify the conductive target. Besides, the static effect often distorts the electromagnetic data, which rigorously influences their application. The influence of the static effect on both the Ex and Hz fields is also examined in detail. The apparent resistivity based on the Ex field and Cagniard apparent resistivity is significantly affected by the static effect, which can mask deep anomalous blocks. However, the apparent resistivity based on the Hz field is almost unaffected by the static effect. Finally, a more efficient observation approach is provided for both the insulating and conductive targets.","PeriodicalId":54820,"journal":{"name":"Journal of Geophysics and Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139889252","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}
In the CSAMT method, orthogonal electric and magnetic fields are commonly measured to determine the Cagniard apparent resistivity. However, in the near-field zone, the Cagniard resistivity is severely distorted, which is unrelated to underground structures. The Ex and Hz amplitudes in a homogeneous half-space monotonically vary in resistivity, and a numerical algorithm could achieve high-precision apparent resistivity without distortion for all frequencies. On this basis, the main focus of this investigation is on the comparative analysis of the sensitivity for the Ex field, Hz field, and Cagniard apparent resistivity to conductive and resistivity targets via synthetic models. The achieved results confirm that the Ex field could exhibit a more enhanced sensitivity for the resistive objects, while the Hz field could more effectively identify the conductive target. Besides, the static effect often distorts the electromagnetic data, which rigorously influences their application. The influence of the static effect on both the Ex and Hz fields is also examined in detail. The apparent resistivity based on the Ex field and Cagniard apparent resistivity is significantly affected by the static effect, which can mask deep anomalous blocks. However, the apparent resistivity based on the Hz field is almost unaffected by the static effect. Finally, a more efficient observation approach is provided for both the insulating and conductive targets.
在 CSAMT 方法中，通常通过测量正交电场和磁场来确定 Cagniard 视电阻率。然而，在近场区内，Cagniard 表观电阻率严重失真，这与地下结构无关。均质半空间中的 Ex 和 Hz 振幅在电阻率上呈单调变化，数值算法可实现高精度视电阻率，且所有频率都不会失真。在此基础上，本次研究的重点是通过合成模型比较分析 Ex 场、Hz 场和 Cagniard 视电阻率对导电目标和电阻率目标的敏感性。研究结果证实，Ex 场对电阻目标的灵敏度更高，而 Hz 场则能更有效地识别导电目标。此外，静态效应通常会扭曲电磁数据，这严重影响了电磁数据的应用。本文还详细研究了静态效应对 Ex 和 Hz 场的影响。基于 Ex 场和 Cagniard 表观电阻率的表观电阻率受到静电效应的严重影响，会掩盖深部异常块。然而，基于 Hz 场的视电阻率几乎不受静电效应的影响。最后，为绝缘和导电目标提供了一种更有效的观测方法。
{"title":"The comparative analysis of the Ex and Hz fields sensitivity generated by electric dipole sources","authors":"XianXiang Wang, Jiaqi Li, Songda Lei","doi":"10.1093/jge/gxae018","DOIUrl":"https://doi.org/10.1093/jge/gxae018","url":null,"abstract":"\u0000 In the CSAMT method, orthogonal electric and magnetic fields are commonly measured to determine the Cagniard apparent resistivity. However, in the near-field zone, the Cagniard resistivity is severely distorted, which is unrelated to underground structures. The Ex and Hz amplitudes in a homogeneous half-space monotonically vary in resistivity, and a numerical algorithm could achieve high-precision apparent resistivity without distortion for all frequencies. On this basis, the main focus of this investigation is on the comparative analysis of the sensitivity for the Ex field, Hz field, and Cagniard apparent resistivity to conductive and resistivity targets via synthetic models. The achieved results confirm that the Ex field could exhibit a more enhanced sensitivity for the resistive objects, while the Hz field could more effectively identify the conductive target. Besides, the static effect often distorts the electromagnetic data, which rigorously influences their application. The influence of the static effect on both the Ex and Hz fields is also examined in detail. The apparent resistivity based on the Ex field and Cagniard apparent resistivity is significantly affected by the static effect, which can mask deep anomalous blocks. However, the apparent resistivity based on the Hz field is almost unaffected by the static effect. Finally, a more efficient observation approach is provided for both the insulating and conductive targets.","PeriodicalId":54820,"journal":{"name":"Journal of Geophysics and Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139829257","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}
Zongjie Li, Haiying Li, Jun Liu, Guangxiao Deng, Hanming Gu, Zhe Yan
Accurately predicting the external morphology and internal structure of fractured-vuggy reservoirs is of significant importance for the exploration and development of carbonate oil and gas reservoirs. Conventional seismic prediction methods suffer from serious non-uniqueness and low efficiency, while recent advances in deep learning exhibit strong feature learning capabilities and high generalization. Therefore, this paper proposes an intelligent prediction technique for fault-controlled fracture-vuggy reservoirs based on deep learning methods. The approach involves constructing 3D seismic geological models that conform to the geological characteristics of the study area, simulating seismic wavefield propagation, and combining the interpretation results of fractured-vuggy reservoirs. Training sample datasets are separately established for strike-slip faults, karst caves, and fault-controlled fractured-vuggy reservoir outlines, which are then input into the U-Net model in batches for training. This leads to the creation of a deep learning network model for fault-controlled fractured-vuggy reservoirs. The trained network model is applied to the intelligent identification of fault, karst cave, and fault-controlled fracture-vuggy reservoir outlines using actual seismic data from the Shunbei area. A comparison with traditional methods is conducted, and the experimental results demonstrate that the proposed deep learning approach shows excellent performance in the identification and prediction of fault-controlled fractured-vuggy reservoirs.
{"title":"3D seismic intelligent prediction of fault-controlled fractured-vuggy reservoirs in carbonate reservoirs based on deep learning method","authors":"Zongjie Li, Haiying Li, Jun Liu, Guangxiao Deng, Hanming Gu, Zhe Yan","doi":"10.1093/jge/gxae005","DOIUrl":"https://doi.org/10.1093/jge/gxae005","url":null,"abstract":"\u0000 Accurately predicting the external morphology and internal structure of fractured-vuggy reservoirs is of significant importance for the exploration and development of carbonate oil and gas reservoirs. Conventional seismic prediction methods suffer from serious non-uniqueness and low efficiency, while recent advances in deep learning exhibit strong feature learning capabilities and high generalization. Therefore, this paper proposes an intelligent prediction technique for fault-controlled fracture-vuggy reservoirs based on deep learning methods. The approach involves constructing 3D seismic geological models that conform to the geological characteristics of the study area, simulating seismic wavefield propagation, and combining the interpretation results of fractured-vuggy reservoirs. Training sample datasets are separately established for strike-slip faults, karst caves, and fault-controlled fractured-vuggy reservoir outlines, which are then input into the U-Net model in batches for training. This leads to the creation of a deep learning network model for fault-controlled fractured-vuggy reservoirs. The trained network model is applied to the intelligent identification of fault, karst cave, and fault-controlled fracture-vuggy reservoir outlines using actual seismic data from the Shunbei area. A comparison with traditional methods is conducted, and the experimental results demonstrate that the proposed deep learning approach shows excellent performance in the identification and prediction of fault-controlled fractured-vuggy reservoirs.","PeriodicalId":54820,"journal":{"name":"Journal of Geophysics and Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140483080","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}
Hesong Zhu, J. Ba, Lin Zhang, J. Carcione, Xinfei Yan
Temperature and pressure variations during the geologic diagenesis process can lead to the complex pore structures in tight rocks. The effective medium theory, based on the stress-strain relationship in combination with pore structure parameters, can be used to describe the elastic wave responses of rocks. In this work, the differential effective medium (DEM) and self-consistent approximation (SCA) models are combined to invert the pore crack spectrum. The Voigt-Reuss-Hill (VRH) average is used to estimate the elastic moduli of the minerals. Then, based on SCA, the pore structures are incorporated into the rock matrix to create a new host phase. Subsequently, the DEM theory is used to add cracks with different volume fractions and aspect ratios to the host phase. To predict the structure of pores and cracks (crack density and aspect ratio), an objective function is defined as the sum of variances between experimentally measured and predicted wave velocities. The results show that the modeling predictions of P- and S-wave velocities at different temperatures and pressure ratios agree well with the experimental measurements. Variations in pore structure are determined at a zero effective pressure and different temperatures. We analyze the characteristics of how cracks change with variations in temperature and confining pressure, providing a theoretical basis for characterizing the structure of tight rocks.
地质成岩过程中的温度和压力变化可导致致密岩石中复杂的孔隙结构。基于应力应变关系的有效介质理论结合孔隙结构参数，可用于描述岩石的弹性波响应。在这项工作中，微分有效介质（DEM）和自一致近似（SCA）模型相结合，反演了孔隙裂缝谱。Voigt-Reuss-Hill (VRH) 平均法用于估算矿物的弹性模量。然后，根据 SCA，将孔隙结构纳入岩石基质，形成新的主相。随后，利用 DEM 理论在主相中加入不同体积分数和长宽比的裂缝。为了预测孔隙和裂缝的结构（裂缝密度和长宽比），将目标函数定义为实验测量波速与预测波速之间的方差之和。结果表明，不同温度和压力比下的 P 波和 S 波速度建模预测结果与实验测量结果非常吻合。孔隙结构的变化是在零有效压力和不同温度下确定的。我们分析了裂缝随温度和约束压力变化而变化的特征，为描述致密岩石的结构特征提供了理论依据。
{"title":"Effect of temperature and fluid on rock microstructure based on an effective medium theory","authors":"Hesong Zhu, J. Ba, Lin Zhang, J. Carcione, Xinfei Yan","doi":"10.1093/jge/gxae014","DOIUrl":"https://doi.org/10.1093/jge/gxae014","url":null,"abstract":"\u0000 Temperature and pressure variations during the geologic diagenesis process can lead to the complex pore structures in tight rocks. The effective medium theory, based on the stress-strain relationship in combination with pore structure parameters, can be used to describe the elastic wave responses of rocks. In this work, the differential effective medium (DEM) and self-consistent approximation (SCA) models are combined to invert the pore crack spectrum. The Voigt-Reuss-Hill (VRH) average is used to estimate the elastic moduli of the minerals. Then, based on SCA, the pore structures are incorporated into the rock matrix to create a new host phase. Subsequently, the DEM theory is used to add cracks with different volume fractions and aspect ratios to the host phase. To predict the structure of pores and cracks (crack density and aspect ratio), an objective function is defined as the sum of variances between experimentally measured and predicted wave velocities. The results show that the modeling predictions of P- and S-wave velocities at different temperatures and pressure ratios agree well with the experimental measurements. Variations in pore structure are determined at a zero effective pressure and different temperatures. We analyze the characteristics of how cracks change with variations in temperature and confining pressure, providing a theoretical basis for characterizing the structure of tight rocks.","PeriodicalId":54820,"journal":{"name":"Journal of Geophysics and Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139592582","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}
Quality factor (Q) is a parameter reflecting the physical properties of reservoirs. Accurate estimation of the quality factor plays an important role in improving the resolution of seismic data. Spectral ratio method is a widely-used traditional method based on the linear least squares fitting to extract the quality factor, but is sensitive to noise. This is the main reason preventing this method from being widely used. Some supervised deep learning methods are proposed to extract Q, in which the construction of training labels is a key link. The proposed method is based on the spectral ratio method to create training labels, avoiding errors in generating them. In contrast to the least squares method, this paper proposes to use a nonlinear regression algorithm based on a fully connected network to fit the spectral logarithmic ratio and frequency. Meanwhile, the empirical equation is applied to constrain prediction results. The proposed method can effectively overcome the influence of noise and improve the accuracy of prediction results. Tests on the synthesized data of vertical seismic profile and common middle profile show that the proposed method has better generalization ability than the spectral ratio method. Applying the method to the field vertical seismic profile data successfully extracts the quality factor, which can provide effective information for dividing stratigraphic layers.
{"title":"An effective Q extraction method via deep learning","authors":"Fang Li, Zhenzhen Yu, Jianwei Ma","doi":"10.1093/jge/gxae011","DOIUrl":"https://doi.org/10.1093/jge/gxae011","url":null,"abstract":"\u0000 Quality factor (Q) is a parameter reflecting the physical properties of reservoirs. Accurate estimation of the quality factor plays an important role in improving the resolution of seismic data. Spectral ratio method is a widely-used traditional method based on the linear least squares fitting to extract the quality factor, but is sensitive to noise. This is the main reason preventing this method from being widely used. Some supervised deep learning methods are proposed to extract Q, in which the construction of training labels is a key link. The proposed method is based on the spectral ratio method to create training labels, avoiding errors in generating them. In contrast to the least squares method, this paper proposes to use a nonlinear regression algorithm based on a fully connected network to fit the spectral logarithmic ratio and frequency. Meanwhile, the empirical equation is applied to constrain prediction results. The proposed method can effectively overcome the influence of noise and improve the accuracy of prediction results. Tests on the synthesized data of vertical seismic profile and common middle profile show that the proposed method has better generalization ability than the spectral ratio method. Applying the method to the field vertical seismic profile data successfully extracts the quality factor, which can provide effective information for dividing stratigraphic layers.","PeriodicalId":54820,"journal":{"name":"Journal of Geophysics and Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139592750","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}
Stephen E. Ekwok, Ahmed M Eldosuoky, Edward A Thompson, Romeo A Ojong, Anthony M. George, Saad S. Alarifi, S. Kharbish, Peter Andráš, A. E. Akpan
In this study, geologic structures as well as attendant orientations, and sediment thickness in the Nigerian Obudu Complex, were delineated using the Centre for Exploration Targeting (CET), and depth determination methods like source parameter imaging (SPI) and standard Euler deconvolution (SED). The CET, SPI and SED procedures were applied on the total magnetic intensity (TMI) data. Also, the enhanced TMI data using analytic signal (ASIG), first-vertical derivative (FVD), total-horizontal derivative (THD), and tilt-angle derivative (TDR) filters were further subjected to CET operation, with the aim of mapping both subtle and prominent lineaments. In general, mapped geologic structures trends in the NE-SW, NNE-SSW, E-W, and N-S directions. Overall, the dominant geologic structural orientations of NE-SW and NNE-SSW reflect the regional strike orientation. The regional striking of the lineation, which is caused by the Pan-African orogeny and subsequent post-orogenic processes, has an impact on these orientations. The N-S and E-W structural deviations from the main NE-SW and NNE-SSW trends are initiated by the YGS of the post-orogenic events. Overall, these complex geologic structures are probable sites for metallogenic minerals.
在这项研究中，利用勘探定位中心（CET）以及源参数成像（SPI）和标准欧拉解卷积（SED）等深度测定方法，对尼日利亚奥布杜复合体的地质结构及其相关方向和沉积厚度进行了划分。CET、SPI 和 SED 程序适用于总磁强 (TMI) 数据。此外，使用分析信号 (ASIG)、第一垂直导数 (FVD)、总水平导数 (THD) 和倾斜角导数 (TDR) 滤波器的增强 TMI 数据也进一步进行了 CET 操作，目的是绘制细微和突出的线状结构图。总体而言，绘制的地质结构呈东北-西南、东北-西南、东西和南北走向。总体而言，NE-SW 和 NNE-SSW 的主要地质构造走向反映了区域走向。泛非造山运动及其后的造山过程所造成的区域走向对这些走向产生了影响。N-S和E-W构造偏离主要的NNE-SW和NNE-SW走向是由后成因事件的YGS引起的。总体而言，这些复杂的地质结构可能是成矿矿物的产地。
{"title":"Mapping of geological structures and sediment thickness from analysis of aeromagnetic data over the Obudu Basement Complex of Nigeria","authors":"Stephen E. Ekwok, Ahmed M Eldosuoky, Edward A Thompson, Romeo A Ojong, Anthony M. George, Saad S. Alarifi, S. Kharbish, Peter Andráš, A. E. Akpan","doi":"10.1093/jge/gxae012","DOIUrl":"https://doi.org/10.1093/jge/gxae012","url":null,"abstract":"\u0000 In this study, geologic structures as well as attendant orientations, and sediment thickness in the Nigerian Obudu Complex, were delineated using the Centre for Exploration Targeting (CET), and depth determination methods like source parameter imaging (SPI) and standard Euler deconvolution (SED). The CET, SPI and SED procedures were applied on the total magnetic intensity (TMI) data. Also, the enhanced TMI data using analytic signal (ASIG), first-vertical derivative (FVD), total-horizontal derivative (THD), and tilt-angle derivative (TDR) filters were further subjected to CET operation, with the aim of mapping both subtle and prominent lineaments. In general, mapped geologic structures trends in the NE-SW, NNE-SSW, E-W, and N-S directions. Overall, the dominant geologic structural orientations of NE-SW and NNE-SSW reflect the regional strike orientation. The regional striking of the lineation, which is caused by the Pan-African orogeny and subsequent post-orogenic processes, has an impact on these orientations. The N-S and E-W structural deviations from the main NE-SW and NNE-SSW trends are initiated by the YGS of the post-orogenic events. Overall, these complex geologic structures are probable sites for metallogenic minerals.","PeriodicalId":54820,"journal":{"name":"Journal of Geophysics and Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139592705","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}
Suzhen Shi, Weixu Gao, Teng Long, Dongshan Xie, Li Li, Jinbo Pei, Jianchao Cai
Owing to the increasing challenges associated with coal mine exploration and development, extremely precise surveys with high-resolution images are required to support production. Conventional inversion methods cannot provide sufficiently precise images of the complex lithologies in coal measure strata. Accordingly, this study performed the research in Qiyuan mining area, Shanxi Province, China, and predicted the complex lithology on the bases of facies control using waveform indication inversion and waveform indication simulation. Horizontal changes in seismic waveforms were used to reflect lithologic assemblage characteristics for facies-controlled constraints, and the vertical mapping the connection between seismic waveform and logging curves was shown. Moreover, high-resolution inversions of wave impedance and natural gamma parameters were conducted. Combined with lithologic shielding and accurate time-depth conversion, the inversions enabled the precise characterisation of the lithological assemblage distribution in the study area. Our results showed that waveform indication inversion could distinguish between coal seams and limestone while waveform indication simulation based on natural gamma could effectively distinguish between sandstone and mudstone. Furthermore, the horizontal resolution was improved while the vertical resolution extended to a thickness of 2–3 m. In addition, the inversion results were highly consistent with drilling results, with an error less than 0.1 m. Therefore, waveform indication inversion and simulation could be applied to coal mines for safe and efficient production.
{"title":"Fine characterization of interbedding sand-mudstone based on waveform indication inversion","authors":"Suzhen Shi, Weixu Gao, Teng Long, Dongshan Xie, Li Li, Jinbo Pei, Jianchao Cai","doi":"10.1093/jge/gxae010","DOIUrl":"https://doi.org/10.1093/jge/gxae010","url":null,"abstract":"\u0000 Owing to the increasing challenges associated with coal mine exploration and development, extremely precise surveys with high-resolution images are required to support production. Conventional inversion methods cannot provide sufficiently precise images of the complex lithologies in coal measure strata. Accordingly, this study performed the research in Qiyuan mining area, Shanxi Province, China, and predicted the complex lithology on the bases of facies control using waveform indication inversion and waveform indication simulation. Horizontal changes in seismic waveforms were used to reflect lithologic assemblage characteristics for facies-controlled constraints, and the vertical mapping the connection between seismic waveform and logging curves was shown. Moreover, high-resolution inversions of wave impedance and natural gamma parameters were conducted. Combined with lithologic shielding and accurate time-depth conversion, the inversions enabled the precise characterisation of the lithological assemblage distribution in the study area. Our results showed that waveform indication inversion could distinguish between coal seams and limestone while waveform indication simulation based on natural gamma could effectively distinguish between sandstone and mudstone. Furthermore, the horizontal resolution was improved while the vertical resolution extended to a thickness of 2–3 m. In addition, the inversion results were highly consistent with drilling results, with an error less than 0.1 m. Therefore, waveform indication inversion and simulation could be applied to coal mines for safe and efficient production.","PeriodicalId":54820,"journal":{"name":"Journal of Geophysics and Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139602445","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}
Time-frequency decomposition technology is an effective tool to analyze non-stationary signals. Improving resolution of spectral decomposition techniques is important to extract more useful information from the received signal. Wigner-Ville distribution (WVD) has been widely applied in seismic signal analysis, it can better analyzes seismic signals due to many excellent mathematical properties, but this method has a drawback that cross terms interference exists in the analyzing of multi-component signals, which severely limits its application. The combination of the complex domain matching-pursuit (CDMP) with this approach effectively solves this problem. However, the conventional CDMP-WVD does not take the influence of the scale parameter on the Morlet wavelet waveform into account, which reduces the time-frequency resolution of CDMP-WVD. Therefore, in order to correct the defect that the atomic waveforms change only with the frequency parameter, we propose an improved spectral decomposition method ICDMP-WVD that considers the scale parameter. In this study, we first analyze influences of the scale parameter on Morlet wavelet waveform and make the scale parameter as search parameter, that improves the computational efficiency and time-frequency resolution of the traditional CDMP-WVD method. Accordingly, the seismic dispersion-dependent attributes are calculated via combing the improved CDMP-WVD algorithm and the frequency-dependent AVO inversion. We adopt a two-step frequency-dependent AVO inversion method to improve the stability of the conventional frequency-dependent AVO inversion. Theoretical data and real data application show that the approach in this study can identify gas reservoirs efficiently and accurately.
{"title":"A novel fluid identification method based on a high-precision spectral decomposition method","authors":"Fawei Miao, Yanxiao He, Shangxu Wang, Handong Huang","doi":"10.1093/jge/gxae007","DOIUrl":"https://doi.org/10.1093/jge/gxae007","url":null,"abstract":"\u0000 Time-frequency decomposition technology is an effective tool to analyze non-stationary signals. Improving resolution of spectral decomposition techniques is important to extract more useful information from the received signal. Wigner-Ville distribution (WVD) has been widely applied in seismic signal analysis, it can better analyzes seismic signals due to many excellent mathematical properties, but this method has a drawback that cross terms interference exists in the analyzing of multi-component signals, which severely limits its application. The combination of the complex domain matching-pursuit (CDMP) with this approach effectively solves this problem. However, the conventional CDMP-WVD does not take the influence of the scale parameter on the Morlet wavelet waveform into account, which reduces the time-frequency resolution of CDMP-WVD. Therefore, in order to correct the defect that the atomic waveforms change only with the frequency parameter, we propose an improved spectral decomposition method ICDMP-WVD that considers the scale parameter. In this study, we first analyze influences of the scale parameter on Morlet wavelet waveform and make the scale parameter as search parameter, that improves the computational efficiency and time-frequency resolution of the traditional CDMP-WVD method. Accordingly, the seismic dispersion-dependent attributes are calculated via combing the improved CDMP-WVD algorithm and the frequency-dependent AVO inversion. We adopt a two-step frequency-dependent AVO inversion method to improve the stability of the conventional frequency-dependent AVO inversion. Theoretical data and real data application show that the approach in this study can identify gas reservoirs efficiently and accurately.","PeriodicalId":54820,"journal":{"name":"Journal of Geophysics and Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139602114","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}
The southern part of the Lower Yangtze, located in the area bounded by the Jiangnan and Dabie orogenic belts, is characterised by a complex fault structure and unique magmatism, and is one of the key areas in regional tectonic evolution and magmatism. In this study the authors used a 45-km-long deep reflection seismic profile to study the crustal structure of the southern Lower Yangtze. The results show that the crust in the study area is about 31.5∼33.6 km thick, with the Huaining Basin as the thinnest part. A detachment surface at a depth of around 12 km divides the crust into the upper and lower crust, act as a key tectonic decoupling layer. Two sets of thrust nappe faults with opposite tendencies have horizontally developed above the detachment surface, with the Huaining Basin as the centre. A typical wedge-shaped structure has developed below the Qianshan Basin, suggesting that two sets of thrust nappe faults may have formed in the same dynamic system. The reflection patterns of the lower crust on both sides of the profile exhibit a monoclinic feature with opposite tendencies, while the lower part of the Huaining Basin exhibits an arcuate upward-arch feature. A prominent ductile shear zone in the lower crust has developed on the west side of the Huaining Basin, which can provide a favourable channel for magma migration. The results of this study deepen our understanding of the deep structure of the Lower Yangtze Region, and provide important constraint data for research on dynamic mechanisms.
{"title":"Crustal structure of the southern Lower Yangtze region and its geological implications: a deep reflection seismic profile","authors":"Penghui Zhang, Tong Wang, Guangcai Li, Jianxun Liu, Hui Fang, Pei Li, Hongkui Li","doi":"10.1093/jge/gxae006","DOIUrl":"https://doi.org/10.1093/jge/gxae006","url":null,"abstract":"\u0000 The southern part of the Lower Yangtze, located in the area bounded by the Jiangnan and Dabie orogenic belts, is characterised by a complex fault structure and unique magmatism, and is one of the key areas in regional tectonic evolution and magmatism. In this study the authors used a 45-km-long deep reflection seismic profile to study the crustal structure of the southern Lower Yangtze. The results show that the crust in the study area is about 31.5∼33.6 km thick, with the Huaining Basin as the thinnest part. A detachment surface at a depth of around 12 km divides the crust into the upper and lower crust, act as a key tectonic decoupling layer. Two sets of thrust nappe faults with opposite tendencies have horizontally developed above the detachment surface, with the Huaining Basin as the centre. A typical wedge-shaped structure has developed below the Qianshan Basin, suggesting that two sets of thrust nappe faults may have formed in the same dynamic system. The reflection patterns of the lower crust on both sides of the profile exhibit a monoclinic feature with opposite tendencies, while the lower part of the Huaining Basin exhibits an arcuate upward-arch feature. A prominent ductile shear zone in the lower crust has developed on the west side of the Huaining Basin, which can provide a favourable channel for magma migration. The results of this study deepen our understanding of the deep structure of the Lower Yangtze Region, and provide important constraint data for research on dynamic mechanisms.","PeriodicalId":54820,"journal":{"name":"Journal of Geophysics and Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139606250","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}
The mining of coal mines in western China needs to focus on protecting groundwater. A non-hydrophilic similar material for simulating the development and hydraulic conductivity of weakly cemented overlying strata fractures was developed. Fine sand, coarse sand, and gypsum are used as aggregates. Paraffin and vaseline are used as binders. The non-hydrophilic material ratios of weakly cemented sandy mudstone and medium-grained sandstone were determined by orthogonal experiments, and used for similar simulation tests. The results show that the non-hydrophilicity of rock-like materials can be adjusted to prevent them from softening and collapsing under the action of water. Non-hydrophilic materials of higher strength and brittleness of rocks can be achieved by adjusting the content of paraffin, fine sand, and gypsum. The non-hydrophilic materials of soft and large particle rocks can be achieved by adjusting the content of paraffin, fine sand, and gypsum. After the coal seam in the similar simulation experiment was extracted, the large area of weakly cemented rock above it undergoes overall settlement and fracture. Although this part is located within the failure zone, there is no macroscopic water conducting cracks generated. The height of the water conducting fracture zone was lower than the height of the fracture zone classified by the traditional ‘three zone’ theory, which is consistent with the on-site measurements. This indicates that the prepared non-hydrophilic material is reliable. The similarity simulation method based on non-hydrophilic materials can enrich the means for studying the fracture and permeability of weakly cemented overlying rocks in coal mines.
{"title":"Development of non-hydrophilic similar materials for weakly cemented rocks and its experimental application in water conservation mining","authors":"Qingheng Gu, Minjie Qi, Guangming Zhao, Qing Ma, Weiyao Guo, Wenlong Lu","doi":"10.1093/jge/gxae009","DOIUrl":"https://doi.org/10.1093/jge/gxae009","url":null,"abstract":"\u0000 The mining of coal mines in western China needs to focus on protecting groundwater. A non-hydrophilic similar material for simulating the development and hydraulic conductivity of weakly cemented overlying strata fractures was developed. Fine sand, coarse sand, and gypsum are used as aggregates. Paraffin and vaseline are used as binders. The non-hydrophilic material ratios of weakly cemented sandy mudstone and medium-grained sandstone were determined by orthogonal experiments, and used for similar simulation tests. The results show that the non-hydrophilicity of rock-like materials can be adjusted to prevent them from softening and collapsing under the action of water. Non-hydrophilic materials of higher strength and brittleness of rocks can be achieved by adjusting the content of paraffin, fine sand, and gypsum. The non-hydrophilic materials of soft and large particle rocks can be achieved by adjusting the content of paraffin, fine sand, and gypsum. After the coal seam in the similar simulation experiment was extracted, the large area of weakly cemented rock above it undergoes overall settlement and fracture. Although this part is located within the failure zone, there is no macroscopic water conducting cracks generated. The height of the water conducting fracture zone was lower than the height of the fracture zone classified by the traditional ‘three zone’ theory, which is consistent with the on-site measurements. This indicates that the prepared non-hydrophilic material is reliable. The similarity simulation method based on non-hydrophilic materials can enrich the means for studying the fracture and permeability of weakly cemented overlying rocks in coal mines.","PeriodicalId":54820,"journal":{"name":"Journal of Geophysics and Engineering","volume":null,"pages":null},"PeriodicalIF":1.4,"publicationDate":"2024-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139527890","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：