Article
Energy & Fuels
Zi-Zhen Wang, Gautier Njiekak, Douglas R. Schmitt, Rui-He Wang
Summary: Laboratory tests were conducted to analyze the ultrasonic velocity response to pressure changes in dry carbonate rocks from the Weyburn oilfield in Canada. Results showed that P- and S-wave velocities in these samples follow a linear relation regardless of pressure changes, with the Vp/Vs ratio being more sensitive to pressure changes. The pressure dependence of velocities (PDV) of Weyburn carbonate rocks varied widely, even for samples from the same formation, and an empirical model for elastic wave velocity was found to fit well for most samples.
Article
Geochemistry & Geophysics
K. Sawayama, T. Ikeda, T. Tsuji, F. Jiang, O. Nishizawa, Y. Fujimitsu
Summary: This study developed a numerical approach to calculate changes in elastic wave velocity with fracture aperture opening and revealed that the velocity can be accounted for by the superposition of a linear function of fracture density and quadratic function of aperture. The relationship between fracture permeability and elastic wave velocity was found to depend on fracture density, but the offset-normalized relationship showed clear linearity with fracture density. The findings suggest that laboratory-scale properties of a single fracture can be applied to multiple fractures on a larger scale.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Engineering, Geological
D. Sassen, B. Abell
Summary: Hydraulic fracture modeling is a crucial tool for decision-making in the unconventional petroleum industry, with rock mechanical inputs and associated uncertainties being the main factors influencing model results. This study presents an integrated method for experimentally measuring elastic mechanical properties using anisotropic ultrasonic measurements at high resolution to represent rock fabric, along with triaxial compressional data.
ROCK MECHANICS AND ROCK ENGINEERING
(2022)
Article
Multidisciplinary Sciences
Yoshio Kono, Koji Ohara, Nozomi M. Kondo, Hiroki Yamada, Satoshi Hiroi, Fumiya Noritake, Kiyofumi Nitta, Oki Sekizawa, Yuji Higo, Yoshinori Tange, Hirokatsu Yumoto, Takahisa Koyama, Hiroshi Yamazaki, Yasunori Senba, Haruhiko Ohashi, Shunji Goto, Ichiro Inoue, Yujiro Hayashi, Kenji Tamasaku, Taito Osaka, Jumpei Yamada, Makina Yabashi
Summary: Understanding the structural origin of SiO2 liquid and glass at high pressures is crucial, and experimental evidence of a bimodal behavior in the translational order of silicon's second shell and breaking of local tetrahedral symmetry has been found.
NATURE COMMUNICATIONS
(2022)
Article
Geochemistry & Geophysics
Chunfang Wu, Jing Ba, Lin Zhang, Jose M. Carcione
Summary: Tight sandstones pose challenges for seismic characterization of fluid detection and identification. In this study, we propose a modified model to describe wave attenuation and velocity dispersion and analyze the impact of crack properties on wave propagation using experimental data.
Article
Energy & Fuels
Muhammad Zahid Afzal Durrani, Syed Atif Rahman, Maryam Talib, Ghulam Subhani, Bakhtawer Sarosh
Summary: This study focuses on the quantitative characterization of deep, tight, and heterogeneous reservoirs using the azimuthal prestack seismic anisotropic inversion approach. The results obtained from this approach help in identifying hydrocarbon pathways and optimizing reservoir field development. The study successfully characterized the orientation and density of fractures in recently discovered oilfield reservoirs and improved fracture prediction accuracy.
SPE RESERVOIR EVALUATION & ENGINEERING
(2023)
Article
Geosciences, Multidisciplinary
Arqam Muqtadir, Saud Al-Dughaimi, Taqi Alzaki, Jack Dvorkin
Summary: This study compares the P-wave and S-wave velocities obtained under different hydrostatic loading conditions using ultrasonic pulse transmission experiments. The results show significant differences in velocities when a smaller hydrostatic stress is added to axial stress, but these differences become smaller as the hydrostatic stress increases. The findings suggest that laboratory hydrostatic experiments can be used for in-situ velocity estimates even under strong in-situ contrasts between the vertical and horizontal stresses.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Geosciences, Multidisciplinary
Rui Li, Yingfang Zhou, Wenbo Zhan, Jianhui Yang
Summary: This study investigates the effect of fluid-solid-hydrate spatial distribution on the elastic properties of hydrate-bearing sediments. The results show that the dominant hydrate morphology changes from pore-filling to load-bearing as hydrate saturation increases. At low saturations, the formation of hydrate around gas bubbles results in a significant enhancement in compressional wave velocity, while shear wave velocity is less affected. An empirical model is developed to calculate compressional and shear wave velocities, which is validated by experimental measurements.
MARINE AND PETROLEUM GEOLOGY
(2022)
Article
Computer Science, Interdisciplinary Applications
Ehsan Pegah, Huabei Liu, Xiaoqiang Gu, Ali Gholami
Summary: In this study, a new method was developed to estimate the drained elastic moduli in saturated granular soils by assuming cross-anisotropic properties. The validity of the proposed method was confirmed through comparison with experimental results. The findings of this study can be used as a reference for characterizing the anisotropic elastic stiffness parameters of saturated granular soil deposits in a reasonable and inexpensive manner.
COMPUTERS AND GEOTECHNICS
(2022)
Article
Energy & Fuels
Xiaolong Guo, Bin Yan, Juyi Zeng, Guangzhi Zhang, Lin Li, You Zhou, Rui Yang
Summary: The study developed a novel Bayesian elastic impedance variation with an angle and azimuth inversion approach for directly estimating the fluid indicator in fractured carbonate reservoirs. The method allows for reasonable estimation of reservoir parameters with relatively high accuracy, reliable indicating the presence of fractured gas-bearing reservoirs.
Article
Geochemistry & Geophysics
Shengbiao Liu, Tongcheng Han, Li-Yun Fu
Summary: Fractures are common in hydrate-bearing reservoirs and can cause anisotropic acoustic properties, influencing the velocities during formation and dissociation processes. The study shows that velocities increase and decrease during hydrate formation and dissociation, respectively, with floating hydrate evolving to bridge fractures and gradually transforming during dissociation. This research provides insights into hydrate distribution and its effects on acoustic anisotropy in fractured reservoirs during formation and dissociation, improving the accuracy of hydrate assessment.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geosciences, Multidisciplinary
Hongbing Li, Jiajia Zhang, Haojie Pan, Qiang Gao
Summary: Carbonate reservoirs with complex pore structures significantly impact the elastic properties and seismic responses. Existing inversion methods are designed for clastic rocks, lacking a simultaneous method for carbonate reservoirs. The proposed Bayesian nonlinear inversion method can accurately predict pore structure and physical parameters for complex reservoirs.
SCIENCE CHINA-EARTH SCIENCES
(2021)
Article
Mathematics, Applied
Linlin Sun, Zhikang Chen, Suyu Zhang, Liu Chu
Summary: This paper extends the wave based method to solve two-dimensional anisotropic elastic wave problems by introducing a new approach to address the lack of basis functions. The accuracy and efficiency of the method are validated through two examples.
APPLIED MATHEMATICS LETTERS
(2021)
Article
Geochemistry & Geophysics
Li Chuang, Pan Jian-guo, Wang Hong-bin, Li Hui-zhen, Feng Chao, Zhou Jun-feng
Summary: This study analyzes the physical and seismic properties of deep carbonate reservoir samples in the Tarim Basin, China. The results show that the pore structure of carbonate rocks controls their physical and seismic properties. Additionally, there is a good correlation between P- and S-velocities, and the P- and S-velocity ratio can be used as an index for rock typing. For tight carbonate samples, apparent velocity dispersion at a seismic exploration frequency band can be observed, and this dispersion is controlled by the pore structure.
APPLIED GEOPHYSICS
(2022)
Article
Multidisciplinary Sciences
Takeshi Tsuji, Tatsunori Ikeda, Ryosuke Matsuura, Kota Mukumoto, Fernando Lawrens Hutapea, Tsunehisa Kimura, Koshun Yamaoka, Masanao Shinohara
Summary: The study presents a new continuous monitoring system based on small seismic sources and DAS technology, which enables continuous monitoring of multi-reservoirs in extensive areas at a relatively low cost. Field experiments showed that monitoring signals could be detected at a distance of 80 km, with identification of temporal variations having an error of less than 0.01%.
SCIENTIFIC REPORTS
(2021)
Article
Geography, Physical
Cheng Peng, Changchun Zou, Shuxia Zhang, Huaichun Wu, Qingtian Lu, Hesheng Hou, Chengshan Wang
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2020)
Article
Multidisciplinary Sciences
Kouamelan Serge Kouamelan, Changchun Zou, Chengshan Wang, Konan Roger Assie, Cheng Peng, Ohouo Rebecca Mondah, Koffi Alexis N'dri, Eric Thompson Brantson
SCIENTIFIC REPORTS
(2020)
Article
Geochemistry & Geophysics
Kouamelan Serge Kouamelan, Changchun Zou, Konan Roger Assie, Cheng Peng, Koffi Alexis N'dri, Ohouo Rebecca Mondah
Summary: The Cretaceous interval is characterized by significant geological changes, with the petrophysical properties of the Upper Cretaceous Songliao Basin in NE China and Goban Spur Basin in NW Europe showing sensitivity to past environmental shifts. Gamma-ray and resistivity reactivities are responsive to organic-rich shale deposition and marine-water level shifts, providing insights into paleoenvironmental changes in both terrestrial and marine systems. These changes are associated with geochemical evidence, suggesting that gamma-ray and resistivity can serve as alternative means for marine and continental paleoenvironmental comparison.
JOURNAL OF GEOPHYSICS AND ENGINEERING
(2021)
Article
Geochemistry & Geophysics
Yuan Wu, Xiaolei Li, Qingjie Gong, Xuan Wu, Ning Yao, Cheng Peng, Yuede Chao, Xuyang Wang, Xiulang Pu
Summary: Through analyzing samples from two weathering profiles in Dunhua, Jilin Province, the geochemical lithogene LG01 demonstrates good heredity and inheritance, indicating stability during weathering. Furthermore, the validity of the composition classification method based on LG01's acidic similarity was verified.
APPLIED GEOCHEMISTRY
(2021)
Article
Geochemistry & Geophysics
Caowei Wu, Changchun Zou, Tao Wu, Luyi Shen, Jianping Zhou, Chunhui Tao
Summary: The TDIP method plays an important role in seabed mineral exploration, as it can directly quantify the volume content of metallic minerals and approximately determine the size of metallic particles. Surveys in the marine environment are more efficient, and using a short time delay is more suitable for successful TDIP measurements in high-salinity environments.
MARINE GEOPHYSICAL RESEARCH
(2021)
Article
Energy & Fuels
Xixi Lan, Changchun Zou, Zhihong Kang, Xingwei Wu
Summary: This study introduces a multi-class positive and unlabeled machine learning method based on semi-supervised learning for identifying carbonate log facies. By leveraging labeled and unlabeled data simultaneously, the method improves the identification of log facies, especially showing superior performance in handling minority classes.
Article
Geochemistry & Geophysics
Caowei Wu, Changchun Zou, Cheng Peng, Yang Liu, Tao Wu, Jianping Zhou, Chunhui Tao
Summary: The study investigates the effects of mineralized structures on the induced polarization (IP) and electrical conductivity properties of seafloor sulfide-bearing rocks using numerical simulations. The results show that the total chargeability and electrical resistivity are influenced by the type and volume content of sulfides, as well as the aspect ratio and tortuosity of the seafloor sulfides.
Article
Geochemistry & Geophysics
Yang Liu, Changchun Zou, Qiang Chen, Jinhuan Zhao, Yanlong Li, Jianye Sun, Changling Liu, Cheng Peng, Caowei Wu
Summary: This study developed a simulation framework for monitoring gas hydrates using cross-hole electrical resistivity tomography (CHERT) and verified its effectiveness through numerical and physical experiments. The results showed that proper electrode layouts can yield satisfactory monitoring results, which is of great significance for gas hydrate production.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
Shuxia Zhang, Changchun Zou, Cheng Peng, Liwen Yan, Xingwei Wu
Summary: This study investigates the effects of pore structure on physical properties in reef-shoal carbonate samples from the Tarim Basin through experiments and numerical simulations. The results reveal three correlation trends between pore structure parameters and physical properties, depending on the pore structure type. The classification of pore structure and the determination of controlling factors significantly improve the predictions of acoustic velocity and permeability. These findings are essential for the exploration and development of reef-shoal carbonate reservoirs.
JOURNAL OF GEOPHYSICS AND ENGINEERING
(2022)
Article
Geosciences, Multidisciplinary
Guangzheng Jiang, Yuntao Tian, Qingtian Lv, Mike Sandiford, Yizuo Shi, Changchun Zou, Feng Ma, Chenglong Deng, Lijuan He, Shengbiao Hu
Summary: This study investigates the inversion of past ground surface temperature changes using borehole temperature measurements. The results show that there has been a rise of approximately 2K since 0.1-0.6 thousand years before present (BP) and a rise of approximately 10K since 20 thousand years BP. The findings emphasize the importance of borehole heat-flow profiles as a record of climate changes and the need for climate correction in heat-flow determinations.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Engineering, Marine
Xixi Lan, Changchun Zou, Cheng Peng, Caowei Wu, Yuanyuan Zhang, Shengyi Wang
Summary: Characterizing the electrical properties of hydrate-bearing sediments, especially resistivity, is crucial for reservoir identification and saturation evaluation. This study simulated different micromorphologies of hydrates at the pore scale and analyzed the relationship between hydrate morphology and resistivity quantitatively. The size of the throat was found to be the most critical factor affecting resistivity.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2023)
Article
Geochemistry & Geophysics
Xixi Lan, Changchun Zou, Cheng Peng, Caowei Wu
Summary: The electrical resistivity tomography (ERT) method is crucial for studying electrical properties at the core scale, and the resistivity image inversion reconstruction technique is essential for ensuring measurement accuracy. However, traditional machine learning (ML) methods are not capable of evaluating the uncertainty in reconstruction results, which have high nonlinearity. In this article, a novel Monte Carlo (MC)-Net ML scheme is proposed to quantitatively estimate the uncertainty of ERT image reconstruction. The proposed scheme utilizes the MC dropout strategy and multiple stochastic methods to approximate Bayesian inference, providing a reliable quantification of uncertainty for intelligent inversion tasks.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2023)
Article
Computer Science, Information Systems
Shuxia Zhang, Cheng Peng, Changchun Zou
Summary: This paper proposes an automatic core orientation method by comparing planar geologic features in drill-core scans and microresistivity images. The method can eliminate human errors and has higher accuracy, especially for core scan images with non-distinct features. It has wide application potential in the fields of hydrocarbon exploration and development, scientific drilling research, and basic geological surveys.
