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Modification of Microstructural and Fluid Migration of Bituminous Coal by Microwave–LN2 Freeze–Thaw Cycles: Implication for Efficient Recovery of Coalbed Methane.
- Source :
- Natural Resources Research; Oct2024, Vol. 33 Issue 5, p2173-2191, 19p
- Publication Year :
- 2024
-
Abstract
- To improve the efficiency of coalbed methane and recoverability of reservoirs, enhanced fracturing technology is usually required to improve the low porosity and permeability status of coal reservoirs. As a feasible method for strengthening permeability, microwave–LN<subscript>2</subscript> freeze–thaw (MLFT) cycles modify the microscopic pore structure of coal through the coupled effect of temperature stress changes, phase change expansion, and fatigue damage. <superscript>1</superscript>H nuclear magnetic resonance combined with fractal dimension theory was used to characterize quantitatively the pore system and geometric features of coal. The geometric fractal model constructed using the T<subscript>2</subscript> spectrum indicates that the fractal dimensions D<subscript>p</subscript> and D<subscript>e</subscript> have high fitting accuracy, demonstrating that percolation and effective pores exhibit good fractal characteristics. D<subscript>p</subscript> and D<subscript>e</subscript> are correlated negatively and positively, respectively, with the cyclic parameters. The relevance analysis shows that the NMR fractal method can reflect the pore–fracture heterogeneity of coal, which has a significant effect on the percentage of fluid migration space. This study reveals that MLFT cycles have significant enhancement effects on promoting the extension of multi-type pores structures within the coal matrix, as well as the connectivity and permeability of cracks. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 15207439
- Volume :
- 33
- Issue :
- 5
- Database :
- Complementary Index
- Journal :
- Natural Resources Research
- Publication Type :
- Academic Journal
- Accession number :
- 179357013
- Full Text :
- https://doi.org/10.1007/s11053-024-10348-y