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
More filters
Journal ArticleDOI
Variation in pore systems with tectonic stress in the overthrust Wufeng-Longmaxi shale of the southern Sichuan Basin, China
TL;DR: In this paper, a systematic comparative analysis was conducted in the Changning area to detect the tectonic deformation of organic-rich shale, and the results indicated that a larger strain, under higher horizontal compression stress, decreased the bulk porosity in the shale of the forelimb areas, despite the content of the mechanically weak component (e.g., TOC or clay minerals) being similar in both.
Journal ArticleDOI
Characteristics, capability, and origin of shale gas desorption of the Longmaxi Formation in the southeastern Sichuan Basin, China.
Xianglu Tang,Xianglu Tang,Zhenxue Jiang,Shu Jiang,Lijun Cheng,Ningning Zhong,Ling Tang,Jiaqi Chang,Zhou Wen +8 more
TL;DR: The results show that the shale gas desorption process within the Longmaxi Formation varies significantly, and organic matter (OM) is the most important controlling factor, leading to a rapid decrease in shale gas Desorption capability.
Journal ArticleDOI
Organic-induced nanoscale pore structure and adsorption capacity variability during artificial thermal maturation: Pyrolysis study of the Mesoproterozoic Xiamaling marine shale from Zhangjiakou, Hebei, China
Liangwei Xu,Liangwei Xu,Liangwei Xu,Keji Yang,Keji Yang,Lifei Zhang,Luofu Liu,Zhenxue Jiang,Xiao Li +8 more
TL;DR: In this article, the authors analyzed two low-maturity Xiamaling marine shale samples with different TOC contents in Zhangjiakou of Hebei, China and established a general evolution model of nanoscale pore structure and methane adsorption content (MSC).
Journal ArticleDOI
The pores evolution of lacustrine shale induced by smectite-to-illite conversion and hydrocarbon generation: upper Triassic Yanchang Formation, Ordos Basin, China
TL;DR: In this article, the effect of synchronous hydrocarbon generation and smectite-illite conversion on the formation and evolution of pores in lacustrine shales from the Chang #7 (C7) Member of the Upper Triassic Yanchang Formation in Ordos Basin, China.
Journal ArticleDOI
The role of residual bitumen on the pore structure of organic-rich shales from low to over mature: Insight from shale and coal samples after the hydrous pyrolysis
Peng Luo,Ningning Zhong +1 more
TL;DR: The role of residual bitumen on the pore structure of organic-rich shales from low to over mature is investigated in this paper, where the authors investigate the role of the soluble and insoluble residual bituminous on pore structures.
References
More filters
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.
Related Papers (5)
Unconventional shale-gas systems: The Mississippian Barnett Shale of north-central Texas as one model for thermogenic shale-gas assessment
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