Journal ArticleDOI
Mechanisms of shale gas storage: Implications for shale gas exploration in China
Fang Hao,Huayao Zou,Yongchao Lu +2 more
TLDR
In this paper, two models were proposed to predict the variation of gas sorption capacity and total gas content over geologic time as a function of burial history, and the results showed that the changes in GSC of organic-rich shales are quite low at an elevated temperature and pressure and with the presence of moisture.Abstract:
This article reviews the mechanisms of shale gas storage and discusses the major risks or uncertainties for shale gas exploration in China. At a given temperature and pressure, the gas sorption capacities of organic-rich shales are primarily controlled by the organic matter richness but may be significantly influenced by the type and maturity of the organic matter, mineral composition (especially clay content), moisture content, pore volume and structure, resulting in different ratios of gas sorption capacity (GSC) to total organic carbon content for different shales. In laboratory experiments, the GSC of organic-rich shales increases with increasing pressure and decreases with increasing temperature. Under geologic conditions (assuming hydrostatic pressure gradient and constant thermal gradient), the GSC increases initially with depth due to the predominating effect of pressure, passes through a maximum, and then decreases because of the influence of increasing temperature at greater depth. This pattern of variation is quite similar to that observed for coals and is of great significance for understanding the changes in GSC of organic-rich shales over geologic time as a function of burial history. At an elevated temperature and pressure and with the presence of moisture, the gas sorption capacities of organic-rich shales are quite low. As a result, adsorption alone cannot protect sufficient gas for high-maturity organic-rich shales to be commercial gas reservoirs. Two models are proposed to predict the variation of GSC and total gas content over geologic time as a function of burial history. High contents of free gas in organic-rich shales can be preserved in relatively closed systems. Loss of free gas during postgeneration uplift and erosion may result in undersaturation (the total gas contents lower than the sorption capacity) and is the major risk for gas exploration in marine organic-rich shales in China.read more
Citations
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Journal ArticleDOI
Relationship between pore characteristics and occurrence state of shale gas: A case study of Lower Silurian Longmaxi shale in the Upper Yangtze Platform, South China
TL;DR: In this paper, focused ion beam-helium ion microscopy and low-pressure N2 adsorption were used to investigate the pore characteristics of Lower Silurian Longmaxi shale.
Journal ArticleDOI
Making sense of micro-fractures to the Longmaxi shale reservoir quality in the Jiaoshiba area, Sichuan Basin, China: Implications for the accumulation of shale gas
TL;DR: In this paper, the effects of micro-fractures on shale reservoir properties and shale gas accumulation were also analyzed, where porosity, permeability test, gas adsorption, scanning electron microscopy (SEM), fluid spontaneous imbibition, nano-CT, micro-CT and core observations were used to determine the types and characteristics of microfracture in the Longmaxi shales, Jiaoshiba area.
Journal ArticleDOI
The dichotomy in noble gas signatures linked to tectonic deformation in Wufeng-Longmaxi Shale, Sichuan Basin
TL;DR: In this paper, the authors present measurements of the bulk gas composition, stable isotopes, and noble gas volume fraction and isotopes for shale gas samples collected from gas wells in the Wufeng-Longmaxi Shale, the southern Sichuan Basin, China.
Journal ArticleDOI
Influence of Pore Structure Particularity and Pore Water on the Occurrence of Deep Shale Gas: Wufeng–Longmaxi Formation, Luzhou Block, Sichuan Basin
Xueyuan Li,Shangbin Chen,Yiwen Wang,Yingkun Zhang,Yang Wang,Jianfa Wu,Junjian Zhang,Jamil Khan +7 more
Journal ArticleDOI
Geological controls and methane sorption capacity of marine shales of the Fuling shale gas field in the eastern Sichuan Basin, China
TL;DR: In this article, a series of high-pressure methane sorption isotherms were performed on the Upper Ordovician Wufeng and Lower Silurian Longmaxi shale samples in the Fuling shale gas field to investigate the effects of organic matter content, thermal maturity, clay minerals, pore structure, temperature, and pressure on methane carbon dioxide sorption capacity.
References
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Journal ArticleDOI
Unconventional shale-gas systems: The Mississippian Barnett Shale of north-central Texas as one model for thermogenic shale-gas assessment
TL;DR: In this article, the authors estimate that the Barnett Shale has a total generation potential of about 609 bbl of oil equivalent/ac-ft or the equivalent of 3657 mcf/acft (84.0 m 3 /m 3 ).
Journal ArticleDOI
Morphology, Genesis, and Distribution of Nanometer-Scale Pores in Siliceous Mudstones of the Mississippian Barnett Shale
TL;DR: In this article, the authors used scanning electron microscopy to characterize the pore system in the Barnett Shale of the Fort Worth Basin, Texas, showing that the pores in these rocks are dominantly nanometer in scale (nanopores).
Journal ArticleDOI
Fractured shale-gas systems
TL;DR: The first commercial United States natural gas production (1821) came from an organic-rich Devonian shale in the Appalachian basin this article, which is a continuous-type biogenic (predominant), thermogenic, or combined biogenic-thermogenic gas accumulations characterized by widespread gas saturation, subtle trapping mechanisms, seals of variable lithology, and relatively short hydrocarbon migration distances.
Journal ArticleDOI
The importance of shale composition and pore structure upon gas storage potential of shale gas reservoirs
Daniel J.K. Ross,R. Marc Bustin +1 more
TL;DR: The effect of shale composition and fabric upon pore structure and CH 4 sorption is investigated for potential shale gas reservoirs in the Western Canadian Sedimentary Basin (WCSB) as mentioned in this paper.
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