Kai Zhang, Yiming Pan, Yunyun Sang, Xuecheng Xu, Fankun Meng
Abstract Due to the prevalent viscosity in the subsurface medium, seismic waves experience amplitude attenuation effects during their propagation in visco-acoustic media. Therefore, it is crucial to develop a method that can compensate for wavelet amplitude attenuation and enhance imaging quality. In this paper, we derive an expression for corrected ray complex travel time by introducing the quality factor Q. Additionally, we modify the classical Gaussian beam propagation operator to an adaptive focus type propagation operator. Our research presents an adaptive focused beam migration imaging method specifically designed for viscous acoustic media, incorporating a combination of traditional Gaussian beam migration imaging methods. In comparison to traditional migration methods, the proposed approach achieves energy focusing along the phase axis and significantly improves imaging quality. The validity and effectiveness of our method are confirmed through the obtained imaging results.
{"title":"Adaptive focus beam migration method in visco-acoustic media","authors":"Kai Zhang, Yiming Pan, Yunyun Sang, Xuecheng Xu, Fankun Meng","doi":"10.1093/jge/gxad086","DOIUrl":"https://doi.org/10.1093/jge/gxad086","url":null,"abstract":"Abstract Due to the prevalent viscosity in the subsurface medium, seismic waves experience amplitude attenuation effects during their propagation in visco-acoustic media. Therefore, it is crucial to develop a method that can compensate for wavelet amplitude attenuation and enhance imaging quality. In this paper, we derive an expression for corrected ray complex travel time by introducing the quality factor Q. Additionally, we modify the classical Gaussian beam propagation operator to an adaptive focus type propagation operator. Our research presents an adaptive focused beam migration imaging method specifically designed for viscous acoustic media, incorporating a combination of traditional Gaussian beam migration imaging methods. In comparison to traditional migration methods, the proposed approach achieves energy focusing along the phase axis and significantly improves imaging quality. The validity and effectiveness of our method are confirmed through the obtained imaging results.","PeriodicalId":54820,"journal":{"name":"Journal of Geophysics and Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135976645","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}
Abstract Petrophysical properties are critical for shale gas reservoir characterization and simulation. The Wufeng-Longmaxi shale, in the southeastern margin of the Sichuan Basin, is identified as a complex reservoir due to its variability in lithification and geological mechanisms. Thus, determining its characteristics is challenging. Based on wireline logs and pressure data analysis, a shale reservoir was identified, and petrophysical properties were described to obtain parameters to build a reservoir simulation model. The properties include shale volume, sand porosity, net reservoir thickness, total and effective porosities, and water saturation. Total and effective porosities were calculated using density method. Shale volume was estimated by applying Clavier equation to gamma-ray responses. Sand porosity and net reservoir thickness were evaluated using Thomas–Stieber model, and Simandoux equation was used to compute water saturation. The results indicate that the reservoir is characterized by a relatively low porosity and high shale content, with shale unequally distributed in its laminated form (approximately 75%), dispersed (about 20%), and structural form (5%). This research workflow can efficiently evaluate shale reservoir parameters and provide a reliable approach for future reservoir development and fracture identification.
{"title":"Petrophysical properties identification and estimation of the Wufeng-Longmaxi shale gas reservoirs: A case study from South-West China","authors":"Or Aimon Brou Koffi Kablan, Tongjun Chen","doi":"10.1093/jge/gxad088","DOIUrl":"https://doi.org/10.1093/jge/gxad088","url":null,"abstract":"Abstract Petrophysical properties are critical for shale gas reservoir characterization and simulation. The Wufeng-Longmaxi shale, in the southeastern margin of the Sichuan Basin, is identified as a complex reservoir due to its variability in lithification and geological mechanisms. Thus, determining its characteristics is challenging. Based on wireline logs and pressure data analysis, a shale reservoir was identified, and petrophysical properties were described to obtain parameters to build a reservoir simulation model. The properties include shale volume, sand porosity, net reservoir thickness, total and effective porosities, and water saturation. Total and effective porosities were calculated using density method. Shale volume was estimated by applying Clavier equation to gamma-ray responses. Sand porosity and net reservoir thickness were evaluated using Thomas–Stieber model, and Simandoux equation was used to compute water saturation. The results indicate that the reservoir is characterized by a relatively low porosity and high shale content, with shale unequally distributed in its laminated form (approximately 75%), dispersed (about 20%), and structural form (5%). This research workflow can efficiently evaluate shale reservoir parameters and provide a reliable approach for future reservoir development and fracture identification.","PeriodicalId":54820,"journal":{"name":"Journal of Geophysics and Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134909126","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}
Abstract The diffusive-viscous wave (DVW) equation is used to characterize the relationship between frequency-dependent seismic responses and saturated fluids by incorporating the frictional dissipation and viscous damping to the scalar wave equation. Simultaneous inversion of three model parameters in DVW equation is essential for seismic interpretations. Traditional inversion methods require continuous forward modeling updates, resulting in low computational efficiency. Moreover, the traditional methods have limitations in simultaneously inverting multi-parameters of wave equations such as DVW equation, usually fixing one parameter to invert the other two parameters. Gaussian process regression (GPR) is a kernel-based non-parametric probabilistic model that introduces prior variables through Gaussian processes (GP). We present a method for the inversion of the three parameters (velocity, diffusive and viscous attenuation coefficients) of the DVW equation based on GPR. The procedure consists of initially implementing the central finite difference approximation to discretize the DVW equation in the time domain. Subsequently, a Gaussian prior is provided on two snapshots of the DVW equation to obtain the corresponding kernel functions. Furthermore, the hyperparameters in kernel functions and the three model parameters are simultaneously trained by minimizing the negative logarithmic marginal likelihood with few training samples while incorporating the underlying physics in terms of encoding the DVW equation into the kernel functions. It is worth noting that it is the first time to implement three-parameter simultaneous inversion based on DVW equation. The numerical examples in homogeneous, layered and heterogeneous media demonstrate the effectiveness of this method.
{"title":"Parameter inversion of the diffusive-viscous wave equation based on Gaussian process regression","authors":"Zhaowei Bai, Haixia Zhao, Shaoru Wang","doi":"10.1093/jge/gxad085","DOIUrl":"https://doi.org/10.1093/jge/gxad085","url":null,"abstract":"Abstract The diffusive-viscous wave (DVW) equation is used to characterize the relationship between frequency-dependent seismic responses and saturated fluids by incorporating the frictional dissipation and viscous damping to the scalar wave equation. Simultaneous inversion of three model parameters in DVW equation is essential for seismic interpretations. Traditional inversion methods require continuous forward modeling updates, resulting in low computational efficiency. Moreover, the traditional methods have limitations in simultaneously inverting multi-parameters of wave equations such as DVW equation, usually fixing one parameter to invert the other two parameters. Gaussian process regression (GPR) is a kernel-based non-parametric probabilistic model that introduces prior variables through Gaussian processes (GP). We present a method for the inversion of the three parameters (velocity, diffusive and viscous attenuation coefficients) of the DVW equation based on GPR. The procedure consists of initially implementing the central finite difference approximation to discretize the DVW equation in the time domain. Subsequently, a Gaussian prior is provided on two snapshots of the DVW equation to obtain the corresponding kernel functions. Furthermore, the hyperparameters in kernel functions and the three model parameters are simultaneously trained by minimizing the negative logarithmic marginal likelihood with few training samples while incorporating the underlying physics in terms of encoding the DVW equation into the kernel functions. It is worth noting that it is the first time to implement three-parameter simultaneous inversion based on DVW equation. The numerical examples in homogeneous, layered and heterogeneous media demonstrate the effectiveness of this method.","PeriodicalId":54820,"journal":{"name":"Journal of Geophysics and Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135779519","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}
Abstract Ultrasonic waves are capable of helping characterize pores of rocks. A model of viscous squirt is used to simulate phase velocity and the quality factor of ultrasonic P-wave measured in water-saturated Spergen limestone, thus determining pore parameters of the limestone. The measured P-wave had a centroid frequency of ∼0.75 MHz, and two simulations are conducted in this paper. The first simulation yields a dispersion curve with a dipping spike followed by a rising spike. However, it cannot yield the measured quality factor. Another drawback is that one of the pore parameters violates rock physics. The second simulation yields a dispersion curve with a small velocity depression followed by an upward velocity concave; the measured phase velocity and quality factor are simultaneously predicted. The resulting dimensions of the rock unit are 0.3 by 0.333 mm, which is consistent with the mean grain diameter of 0.3 mm. The relative first and second porosities are ascertained to be 0.97 and 0.03, respectively. The aperture distance at contact of grains is inverted as 1.8 µm. Remarkably, the minimum phase velocity of the water-saturated limestone is lower than the Gassmann velocity.
{"title":"Ultrasonic P-wave to determine pore parameters of Spergen limestone","authors":"Guangquan Li, Zhongyuan Liu, Bohua Li","doi":"10.1093/jge/gxad084","DOIUrl":"https://doi.org/10.1093/jge/gxad084","url":null,"abstract":"Abstract Ultrasonic waves are capable of helping characterize pores of rocks. A model of viscous squirt is used to simulate phase velocity and the quality factor of ultrasonic P-wave measured in water-saturated Spergen limestone, thus determining pore parameters of the limestone. The measured P-wave had a centroid frequency of ∼0.75 MHz, and two simulations are conducted in this paper. The first simulation yields a dispersion curve with a dipping spike followed by a rising spike. However, it cannot yield the measured quality factor. Another drawback is that one of the pore parameters violates rock physics. The second simulation yields a dispersion curve with a small velocity depression followed by an upward velocity concave; the measured phase velocity and quality factor are simultaneously predicted. The resulting dimensions of the rock unit are 0.3 by 0.333 mm, which is consistent with the mean grain diameter of 0.3 mm. The relative first and second porosities are ascertained to be 0.97 and 0.03, respectively. The aperture distance at contact of grains is inverted as 1.8 µm. Remarkably, the minimum phase velocity of the water-saturated limestone is lower than the Gassmann velocity.","PeriodicalId":54820,"journal":{"name":"Journal of Geophysics and Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135823580","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}
Abstract Crosswell seismic technique can provide high-resolution imaging and monitoring of the subsurface. However, compared to the surface seismic, crosswell data contain more complex wave components, which increases the difficulty of seismic processing and migrations. Conventional acoustic reverse time migration (RTM) mainly uses the cross-correlation of the source forward and the receiver backward wavefields. The redundant information generated by cross-correlation may undermine the imaging reliability in the crosswell models. Thus, we develope a novel wavefield decomposition imaging condition and only used cross-correlation information of incident and reflection waves in the same propagation directions, which eliminate the artifacts generated from the cross-correlation of wave information unrelated to reflections in the crosswell image. We perform RTM in the frequency domain to maintain efficiency in multi-shot problems. A mono-frequency wavefield decomposition method is applied to separate and process the seismic data. The forward and backward wavefields are reclassified into the up-and-down- propagating components. And the L1 norm is introduced to enhance the robustness of the proposed imaging method. We then use this method to synthesized data from layering models and analyse the imaging results generated from each pair of cross-correlations using source and receiver wavefields. Results show that the cross-correlation information belonging to the same propagation contributes most to the crosswell image, and the other information always generates migration noises. Moreover, we apply the proposed method to a real field dataset. Processing results validate the effectiveness of the proposed means for eliminating false events in the crosswell models and improving image quality.
{"title":"Crosswell frequency-domain reverse time migration imaging with wavefield decomposition","authors":"Jixin Yang, Xiao He, Hao Chen","doi":"10.1093/jge/gxad083","DOIUrl":"https://doi.org/10.1093/jge/gxad083","url":null,"abstract":"Abstract Crosswell seismic technique can provide high-resolution imaging and monitoring of the subsurface. However, compared to the surface seismic, crosswell data contain more complex wave components, which increases the difficulty of seismic processing and migrations. Conventional acoustic reverse time migration (RTM) mainly uses the cross-correlation of the source forward and the receiver backward wavefields. The redundant information generated by cross-correlation may undermine the imaging reliability in the crosswell models. Thus, we develope a novel wavefield decomposition imaging condition and only used cross-correlation information of incident and reflection waves in the same propagation directions, which eliminate the artifacts generated from the cross-correlation of wave information unrelated to reflections in the crosswell image. We perform RTM in the frequency domain to maintain efficiency in multi-shot problems. A mono-frequency wavefield decomposition method is applied to separate and process the seismic data. The forward and backward wavefields are reclassified into the up-and-down- propagating components. And the L1 norm is introduced to enhance the robustness of the proposed imaging method. We then use this method to synthesized data from layering models and analyse the imaging results generated from each pair of cross-correlations using source and receiver wavefields. Results show that the cross-correlation information belonging to the same propagation contributes most to the crosswell image, and the other information always generates migration noises. Moreover, we apply the proposed method to a real field dataset. Processing results validate the effectiveness of the proposed means for eliminating false events in the crosswell models and improving image quality.","PeriodicalId":54820,"journal":{"name":"Journal of Geophysics and Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135888003","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}
Abstract Induction Magnetometers (IM) are commonly used in Magnetotelluric Method for exploration. 1/f noise in the low frequency band of the preamplifier reduce the signal-to-noise ratio of IM, thus affecting the exploration results. We designed a low noise chopper amplifier with equivalent input voltage noise of 9.8 nV/√Hz at 1 mHz, 2.1 nV/√Hz at 0.01 Hz, 1.9 nV/√Hz at 0.1 Hz, 1/f noise corner frequency of 8 mHz, and equivalent input current noise of 200 fA/√Hz at 1 mHz, 100 fA/√Hz at 0.01 Hz, 60 fA/√Hz at 0.1 Hz. The IM using this chopper amplifier is 85.5 cm long, 6.0 cm in diameter and has a total weight of 4.8 kg. Its sensitivity is 300 mV/nT during 20 Hz and 1 kHz, with a theoretical equivalent input magnetic field noise of 0.3 pT/√Hz at 1 Hz and a measurement frequency range of 1 mHz to 1 kHz.
{"title":"Low noise chopper amplifier design for low frequency Induction Magnetometers","authors":"Yao Tang, Zhenzhu Xi, Xingpeng Chen, Xia Long","doi":"10.1093/jge/gxad082","DOIUrl":"https://doi.org/10.1093/jge/gxad082","url":null,"abstract":"Abstract Induction Magnetometers (IM) are commonly used in Magnetotelluric Method for exploration. 1/f noise in the low frequency band of the preamplifier reduce the signal-to-noise ratio of IM, thus affecting the exploration results. We designed a low noise chopper amplifier with equivalent input voltage noise of 9.8 nV/√Hz at 1 mHz, 2.1 nV/√Hz at 0.01 Hz, 1.9 nV/√Hz at 0.1 Hz, 1/f noise corner frequency of 8 mHz, and equivalent input current noise of 200 fA/√Hz at 1 mHz, 100 fA/√Hz at 0.01 Hz, 60 fA/√Hz at 0.1 Hz. The IM using this chopper amplifier is 85.5 cm long, 6.0 cm in diameter and has a total weight of 4.8 kg. Its sensitivity is 300 mV/nT during 20 Hz and 1 kHz, with a theoretical equivalent input magnetic field noise of 0.3 pT/√Hz at 1 Hz and a measurement frequency range of 1 mHz to 1 kHz.","PeriodicalId":54820,"journal":{"name":"Journal of Geophysics and Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135823205","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}
Da ZHANG, Yinghan QI, Tingdong XING, Zhiqi GUO, Lei CAO
Abstract The Songnan fault basin contains a significant distribution of basaltic volcanics, which serve as one of the primary types of reservoirs in the area. Volcanic formations exhibit notable distinctions when compared to conventional oil and gas reservoirs, and the precise seismic response mechanism of these formations remains uncertain. Hence, it is imperative to investigate the seismic response mechanism of volcanic formations to enhance the geophysical characterization capability of oil and gas reservoirs composed of igneous rock. The seismic physical simulation model method is utilised to obtain dependable data for investigating the seismic response mechanisms of volcanic structures. This is achieved by constructing intricate physical models of rocks and volcanic structures.Our team focused on the development of materials and processes for accurately modelling various rock and volcanic structures, and we successfully designed and produced a three-dimensional physical model representing volcanic structures in the Chaganhua area. Furthermore, we conducted thorough data acquisition and analysis to examine the seismic response characteristics and sensitive properties of different geological bodies. We can improve the accuracy of identifying different lithofacies of volcanic rocks by extracting different seismic attributes. This study presents a reliable approach for elucidating the seismic response mechanism of intricate rock and volcanic formations. It can also serve as a valuable resource for processing and interpreting seismic data in the specific study region. The conclusion that weak seismic reflection signals in volcanic rocks are effective signals rather than noise can be more conducive to accurate analysis and description of volcanic structures.
{"title":"Physical modeling of complex lithofacies volcanic edifices and seismic characteristics","authors":"Da ZHANG, Yinghan QI, Tingdong XING, Zhiqi GUO, Lei CAO","doi":"10.1093/jge/gxad081","DOIUrl":"https://doi.org/10.1093/jge/gxad081","url":null,"abstract":"Abstract The Songnan fault basin contains a significant distribution of basaltic volcanics, which serve as one of the primary types of reservoirs in the area. Volcanic formations exhibit notable distinctions when compared to conventional oil and gas reservoirs, and the precise seismic response mechanism of these formations remains uncertain. Hence, it is imperative to investigate the seismic response mechanism of volcanic formations to enhance the geophysical characterization capability of oil and gas reservoirs composed of igneous rock. The seismic physical simulation model method is utilised to obtain dependable data for investigating the seismic response mechanisms of volcanic structures. This is achieved by constructing intricate physical models of rocks and volcanic structures.Our team focused on the development of materials and processes for accurately modelling various rock and volcanic structures, and we successfully designed and produced a three-dimensional physical model representing volcanic structures in the Chaganhua area. Furthermore, we conducted thorough data acquisition and analysis to examine the seismic response characteristics and sensitive properties of different geological bodies. We can improve the accuracy of identifying different lithofacies of volcanic rocks by extracting different seismic attributes. This study presents a reliable approach for elucidating the seismic response mechanism of intricate rock and volcanic formations. It can also serve as a valuable resource for processing and interpreting seismic data in the specific study region. The conclusion that weak seismic reflection signals in volcanic rocks are effective signals rather than noise can be more conducive to accurate analysis and description of volcanic structures.","PeriodicalId":54820,"journal":{"name":"Journal of Geophysics and Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135045588","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}
Abstract Seismic wave velocity estimation is critical for understanding Earth's internal structure. Traditional rock physics models require careful physical assumptions and mathematical derivations, often facing challenges when applied to complex field data. Empirical formulas, while simple, lack a solid physical foundation. To address these limitations, we propose a data-driven approach using rational function neural networks (RafNN) for rock physics modelling. By analysing logging data, RafNN establishes a rational equation capturing the interdependencies among rock modulus, matrix stiffness, porosity, and fluid. The results show that RafNN accurately extracts the Gassmann's equation when the training data adheres to its constraints. Moreover, RafNN can derive general models from logging data that deviate from the Gassmann's equation. These data-driven models exhibit lower prediction errors while maintaining consistency with Gassmann's model. RafNN's adaptability to field data variability is a key advantage, facilitating better comprehension of the underlying mathematical and physical principles. Additionally, we explore the relationship between modulus, porosity, and compressibility, shedding light on the physical interpretation of RafNN models. Notably, RafNN derives analytical models directly from field data, reducing reliance on mathematical derivations and physical assumptions. Although further research is needed to understand the convergence theory of RafNN, this study presents a promising approach for data-driven rock physics modelling. It contributes to the exploration of Earth's heterogeneous structure and advances the field of seismic wave velocity estimation.
{"title":"Rational function neural networks for learning rock physics models from field data","authors":"Weitao Sun, Zhifang Yang","doi":"10.1093/jge/gxad079","DOIUrl":"https://doi.org/10.1093/jge/gxad079","url":null,"abstract":"Abstract Seismic wave velocity estimation is critical for understanding Earth's internal structure. Traditional rock physics models require careful physical assumptions and mathematical derivations, often facing challenges when applied to complex field data. Empirical formulas, while simple, lack a solid physical foundation. To address these limitations, we propose a data-driven approach using rational function neural networks (RafNN) for rock physics modelling. By analysing logging data, RafNN establishes a rational equation capturing the interdependencies among rock modulus, matrix stiffness, porosity, and fluid. The results show that RafNN accurately extracts the Gassmann's equation when the training data adheres to its constraints. Moreover, RafNN can derive general models from logging data that deviate from the Gassmann's equation. These data-driven models exhibit lower prediction errors while maintaining consistency with Gassmann's model. RafNN's adaptability to field data variability is a key advantage, facilitating better comprehension of the underlying mathematical and physical principles. Additionally, we explore the relationship between modulus, porosity, and compressibility, shedding light on the physical interpretation of RafNN models. Notably, RafNN derives analytical models directly from field data, reducing reliance on mathematical derivations and physical assumptions. Although further research is needed to understand the convergence theory of RafNN, this study presents a promising approach for data-driven rock physics modelling. It contributes to the exploration of Earth's heterogeneous structure and advances the field of seismic wave velocity estimation.","PeriodicalId":54820,"journal":{"name":"Journal of Geophysics and Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135425442","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}
Yao Bai, Peng Sun, Haoyu Dou, Tiancheng Ma, Yujing Wang, Pengqian Liu
Abstract The mechanical behavior of fractured rock in tensile stress environment is a hot topic in underground mining engineering. Here, real surrounding rock of coal mine roadway was simulated by using rock-like materials and the tensile failure behavior of Brazilian discs with intermittent double fissures was investigated experimentally. The deformation response, fracture evolution, and failure mode of rock were analyzed. The fissured disc specimen's discrete element model was proposed in particle flow code (PFC2D). The microforce field, crack, and energy evolution processes of model specimens were discussed. The results showed that the load-displacement curves exhibit single-peak and double-peak types, corresponding to the splitting penetration and wing crack penetration damage modes of the specimen. The fissure angle or rock bridge angle showed a great influence on the evolution of main cracks and secondary cracks. The double-fissured Brazilian disc failed due to the initiation and transfer of microcracks in the stress concentration zone, combined with the continuous propagation and convergence of those microcracks. The splitting failure of the Brazilian disc is a continuous process of strain energy accumulation from the early stage of loading and instantaneous release of strain energy after obtaining the peak strength as the dissipative energy sharply rises.
{"title":"Experiment and particle flow simulation on mechanical properties and crack evolution mechanism of Brazilian discs containing two flaws","authors":"Yao Bai, Peng Sun, Haoyu Dou, Tiancheng Ma, Yujing Wang, Pengqian Liu","doi":"10.1093/jge/gxad080","DOIUrl":"https://doi.org/10.1093/jge/gxad080","url":null,"abstract":"Abstract The mechanical behavior of fractured rock in tensile stress environment is a hot topic in underground mining engineering. Here, real surrounding rock of coal mine roadway was simulated by using rock-like materials and the tensile failure behavior of Brazilian discs with intermittent double fissures was investigated experimentally. The deformation response, fracture evolution, and failure mode of rock were analyzed. The fissured disc specimen's discrete element model was proposed in particle flow code (PFC2D). The microforce field, crack, and energy evolution processes of model specimens were discussed. The results showed that the load-displacement curves exhibit single-peak and double-peak types, corresponding to the splitting penetration and wing crack penetration damage modes of the specimen. The fissure angle or rock bridge angle showed a great influence on the evolution of main cracks and secondary cracks. The double-fissured Brazilian disc failed due to the initiation and transfer of microcracks in the stress concentration zone, combined with the continuous propagation and convergence of those microcracks. The splitting failure of the Brazilian disc is a continuous process of strain energy accumulation from the early stage of loading and instantaneous release of strain energy after obtaining the peak strength as the dissipative energy sharply rises.","PeriodicalId":54820,"journal":{"name":"Journal of Geophysics and Engineering","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135579809","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：