Article
Multidisciplinary Sciences
K. Larkin Spires, John P. Castagna, Sheyore John Omovie
Summary: The change in the saturated bulk modulus of a saturated rock is calculated by selecting an effective bulk modulus of the solid constituents in advance. The variation in solid properties, especially in organic-rich shales, leads to uncertainties in predicting the change in the saturated bulk modulus. A semi-empirical rock physics model is used in this study to estimate the pore space compressibility and other parameters, and it is found that the effective solid material modulus is best fitted by the Reuss bound when organic content is high. The model also shows the limitations of Gassmann's equation when organic content is high.
SCIENTIFIC REPORTS
(2023)
Article
Geosciences, Multidisciplinary
Tang Pan, Chen Daizhao, Qian Yixiong, Wang Yuanzheng, Yang Bo
Summary: This study investigates the types of microbial carbonates present in the Upper Ediacaran of the Tarim Basin and reconstructs the pore evolution processes of the potential reservoir rocks. The results show that these microbial carbonates have low porosity and permeability and were subjected to long-term diagenetic processes. The most important reservoir spaces are contributed by vugs and dissolution-enlarged pores, while cementation greatly reduces the pre-existing pores.
ACTA GEOLOGICA SINICA-ENGLISH EDITION
(2022)
Article
Geosciences, Multidisciplinary
Parisa Tavoosi Iraj, Mojtaba Rajabi, Rasoul Ranjbar-Karami
Summary: This study investigated the petrophysical properties and heterogeneity rate of the Fahliyan Formation in southwestern Iran. The analysis revealed that low energy lagoonal facies dominated by meteorically dissolved mud are the best reservoir intervals, while intensively cemented and compacted facies formed the tight zones in the reservoir. Heterogeneity assessment showed that Layer-1 is the most heterogeneous unit, while Layer-2 and Layer-3 exhibit similar behavior. Porosity distribution histograms indicated that Layer-3 has more heterogeneous pore types and network. Image log-derived porosity distribution showed homogeneous pores in Layer-1 and heterogeneous pores in Layer-3 due to extensive dissolution and development of fractures.
NATURAL RESOURCES RESEARCH
(2023)
Article
Geosciences, Multidisciplinary
F. C. C. Nogueira, M. A. Nicchio, F. Balsamo, J. A. B. Souza, I. V. L. Silva, F. H. R. Bezerra, D. L. Vasconcelos, B. R. B. M. Carvalho
Summary: This study investigates how the intensity of the cataclasis deformation mechanism influences petrophysical properties in deformation bands of arkosic sandstones and conglomerates affected by normal fault zones. The study found that different cataclastic textures within a normal fault zone have an impact on properties such as porosity. The amount of cataclastic matrix can be used to estimate the relative porosity reduction of deformation bands, which could greatly influence our understanding of reservoir properties in faulted arkosic sandstones.
MARINE AND PETROLEUM GEOLOGY
(2021)
Article
Engineering, Geological
Ting Ai, Shiyong Wu, Ru Zhang, Mingzhong Gao, Jifang Zhou, Jing Xie, Li Ren, Zhaopeng Zhang
Summary: The study showed that as the water soaking time increased, the pore sizes in coal expanded and new pores developed, leading to changes in mineral composition and structural characteristics. The mechanical properties and ultrasonic wave velocity of coal decreased with increasing water-soaking time, and could be expressed by exponential functions.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2021)
Article
Acoustics
Hamed Aghaei, Grigory M. Penkov, Dmitry A. Solomoichenko, Ali Toorajipour, Dmitry G. Petrakov, Hamed Jafarpour, Sayantan Ghosh
Summary: The present study highlights the importance of density as a moderator variable in understanding the relationships between compressional and shear wave velocities, effective stress, and rock's petrophysical and elastic properties. The study analyzed fourteen subsurface sandstone samples and found that higher density samples exhibited greater Delta Vp and Delta Vs compared to lower density samples with similar porosity and permeability. The results also showed that effective stress had a better fit with Delta Vp and Delta Vs for lower density samples. Density was found to be well correlated with Delta Vp in lower density samples and Delta Vs in higher density samples.
Article
Energy & Fuels
Yizhong Zhang, Bin Ju, Maolin Zhang, Chenchen Wang, Fanhua Zeng, Rongrong Hu, Long Yang
Summary: The study on salt precipitation in high-salinity shale reservoirs revealed a substantial reduction in porosity and absolute permeability, with a stronger impact on larger pores and throats, leading to the disruption of fluid flow channels and changes in pore size distribution. Results predict a decrease of about 20.4% in methane adsorption capacity due to salt precipitation, with the potential for even smaller adsorption capacity at higher temperatures.
Article
Geochemistry & Geophysics
Andrea Perez-Silva, Yoshihiro Kaneko, Martha Savage, Laura Wallace, Emily Warren-Smith
Summary: Geophysical observations suggest that pore fluid pressure changes correlate with slow slip events (SSEs) at certain subduction zones. By developing numerical models and varying the characteristics of pore pressure perturbations, the researchers were able to reproduce the properties of SSEs observed in different subduction zones. The study suggests that large permeability values in the shear zone where SSEs occur are needed to explain the observed SSE properties.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Multidisciplinary Sciences
Mimonitu Opuwari, Blessing Afolayan, Saeed Mohammed, Paschal Ogechukwu Amaechi, Youmssi Bareja, Tapas Chatterjee
Summary: This study classified and zoned the rock units of the OW oilfield in the Bredasdorp Basin offshore South Africa based on core permeability, porosity, and lithofacies. The results provided insights into the reservoir quality and flow units, and a novel sandstone reservoir zonation classification criteria was developed. This study demonstrated a robust approach to delineate flow units and provided valuable information for the understanding of the petrophysical properties of the OW oilfield.
SCIENTIFIC REPORTS
(2022)
Article
Engineering, Environmental
Mohamed K. K. Salah, H. T. Janjuhah, Josep Sanjuan, Elsa Maalouf
Summary: This study collected a large number of carbonate rock samples from southern Lebanon to investigate their lithofacies, pore types, diagenetic processes, and their impact on petrophysical and elastic properties. Results show that diagenetic processes have different impacts on porosity and permeability, leading to variations in seismic wave velocities. Factors such as composition, rock texture, pore types, and pore aspect ratios also have significant effects on the elastic properties of the rocks. These findings are crucial for a better understanding of both onshore and offshore carbonate rocks, which can host hydrocarbon, groundwater, and geothermal energy resources.
BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
(2023)
Article
Environmental Sciences
Yonggang Zhao, Chunyu Zhang, Tao Lei, Shanghua Si, Shenghua Lai, Lei Li, Liuqi Shi
Summary: In this study, the micro-geological properties of tight sandstone reservoirs in the northwestern Ordos Basin were systematically analyzed, revealing different pore structures and petrophysical properties influenced by the sedimentary microfacies and diagenetic processes.
FRESENIUS ENVIRONMENTAL BULLETIN
(2022)
Article
Energy & Fuels
Hongjian Zhu, Jian Gao, Manping Yang, Erxiu Shi, Yanjun Lu, Yu Qi, Mingbo Wei, Wanxin Wang
Summary: This article compares the microstructure and petrophysical properties of undeformed and naturally deformed shales in the Southeast Sichuan Basin. The results show that undeformed shales have more developed organic pores, while deformed shales are dominated by carbonate solvopores, clay-hosted pores, and microfractures. Deformed shales exhibit larger CO2 and N2 adsorbed contents, pore surface areas, and pore volumes. Additionally, deformed shales have higher porosity and permeability compared to undeformed shales due to the presence of a more open pore-fracture network.
Article
Chemistry, Multidisciplinary
He Li, Jieyan Cao, Jiexin Lu, Yi Lu, Shiliang Shi, Zheng Wang, Xin Guo, Qing Ye
Summary: This study investigates the evolution of pores and cracks in coal during low-temperature oxidation using nitrogen adsorption, scanning electron microscopy (SEM), and ultrasonic testing. The results show that oxidation increases microporous structures and promotes the development of mesopores and macropores in coal. Additionally, as the temperature rises, the oxidation effect becomes more significant, while the pore morphology remains largely unchanged.
Article
Mathematics, Interdisciplinary Applications
Na Zhang, Shuaidong Wang, Zheng Li, Shuhui Guo, Ruochen Wang
Summary: A precise evaluation of the fluid movability of coal sedimentary rock is crucial. NMR technology is used to assess the rock samples and construct a prediction model for the fluid movability. The results indicate the correlation between mineral components, pore structure parameters, and FFI, and provide a guide for fluid type classification and estimation in coal reservoirs.
FRACTAL AND FRACTIONAL
(2023)
Article
Geosciences, Multidisciplinary
Samuel W. Scott, Lea Levy, Cari Covell, Hjalti Franzson, Benoit Gibert, Agust Valfells, Juliet Newson, Julia Frolova, Egill Juliusson, Maria Sigridur Guojonsdottir
Summary: The Valgarour database is a compilation of data describing the physical and geochemical properties of Icelandic rocks. It includes petrophysical properties, mineralogical and geochemical data obtained through various analyses. The database serves the purpose of interpreting geophysical data, parameterizing reservoir models, and improving the understanding of the relationship between rock type, hydrothermal alteration, and petrophysical properties.
EARTH SYSTEM SCIENCE DATA
(2023)