Nanopores in the shale play a vital role in methane adsorption, and their structural characteristics and origins are of great significance for revealing the mechanism of methane adsorption, desorption, and diffusion. In this paper, through low-temperature ashing and low-pressure gas adsorption experiments, the nanopore structure of original shales and ashed shales was quantitatively characterized, and the nanopore origins in the transitional shale of lower Permian in eastern Ordos Basin were analyzed. The results show that the pore volume (PV) and specific surface area (SSA) of nanopores in transitional shale reservoirs are 0.0217-0.0449 cm/g and 13.91-51.20 m/g, respectively. The average contribution rates of micropores (<2 nm), mesopores (2-50 nm), and macropores (50-100 nm) to PV are 18.78, 72.26, and 8.96%, respectively, and the average contribution rates to SSA are 66.19, 33.10, and 0.71%, respectively. In addition, it is found that the average contribution rates of inorganic minerals and organic matter to the SSA of micropores are 55.9 and 44.1%, respectively, and the average contribution rates to the SSA of mesopores are 92.3 and 7.7%, respectively. Combining the adsorption properties of the main clay minerals and kerogen in shale, it is concluded that organic pores control the adsorption of methane with an absolute advantage in transitional shales. It is of great significance to understand the mechanism of methane occurrence, desorption, and diffusion in shales by clarifying the origins of multiscale pores.
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http://dx.doi.org/10.1021/acsomega.1c06568 | DOI Listing |
Sci Rep
November 2024
State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi'an, 710069, Shaanxi, China.
The tectonic of the Middle and Late Ordovician in the western margin of the north China Platform is complex, and the accumulation models of organic matter of the Wulalike Formation formed during this period are still unclear. Total organic carbon (TOC) content, mineral composition, organic carbon isotope composition, as well as the major and trace elements in the shale samples were all measured in this study. The Wulalike Formation was formed during a tectonic transition from a passive continental margin to an active continental margin.
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October 2024
Petroleum Engineering College, China University of Petroleum (Beijing), 102249, Beijing, China.
As oil production increasingly transitions from shallow to deep formation, the need for efficient PDC cutters to drill through deep hard rock becomes paramount. Currently, there is a lack of effective methods for optimizing cutter shapes and their cutting parameters. This study addresses this gap by developing a rock-breaking mechanism model for PDC cutters and proposing a Stability Index (SI) based on cutting force variations during the cutting process.
View Article and Find Full Text PDFHeliyon
September 2024
Department of Geosciences, Universiti Teknologi PETRONAS, 31750, Tronoh, Perak, Malaysia.
ACS Omega
September 2024
Exploration and Development Research Institute, PetroChina Daqing Oilfield Co., Daqing City, Heilongjiang Province 163318, China.
Accompanying the commercial exploitation of shale oil and gas in North America, shale oil has gradually become an important resource, sparking great interest among countries around the world in recent years. In this study, focusing on the Paleogene Shahejie Formation in Bohai Bay (Eastern China), techniques such as CT, nitrogen adsorption, mercury injection capillary pressure (MICP), and nuclear magnetic resonance (NMR) were used to characterize the pore structure and mobility of the shale reservoir. Based on the X-ray CT data, the pore radius of the shale reservoir is in the range 0.
View Article and Find Full Text PDFNatl Sci Rev
August 2024
State Key Laboratory of Lithospheric and Environmental Coevolution, School of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China.
An increase in atmospheric O has been proposed as a trigger for the Cambrian Explosion at ∼539-514 Ma but the mechanistic linkage remains unclear. To gain insights into marine habitability for the Cambrian Explosion, we analysed excess Ba contents (Ba) and isotope compositions (δBa) of ∼521-Myr-old metalliferous black shales in South China. The δBa values vary within a large range and show a negative logarithmic correlation with Ba, suggesting a major (>99%) drawdown of oceanic Ba inventory via barite precipitation.
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