科研之友
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摘要
A heterogeneous nature of rough-walled rock fractures complicates a recovery of DNAPL trapped in fractured rock aquifers, which forms a persistent plume within the fractured rocks and present a long-term source of contamination. Experimental studies were conducted to suggest a criterion for the physical displacement of DNAPL from rough-walled fractures in the context of capillary number (N(ca)), a dimensionless number representing the ratio of the viscous to capillary forces. A series of experiments using water, surfactant solution and dense fluid were conducted in the range of capillary number from 2.29 x 10(-4) to 3.41 x 10(-2). The experimental results suggested that a higher capillary number than 1 x 10(-2) be required for a near complete DNAPL removal (more than 95% of initial saturation) from rough-walled fractures. For capillary number on the order of 10(-3), DNAPL can be mobilized or recovered to some degree. For the capillary number below 1 x 10(-3), any kind of remedial fluids would have no effect on physical displacement. It is suggested that remedial fluid utilizing physical displacement be formulated to comply with N(ca) > 1 x 10(-2) to maximize a complete physical removal and the fluid utilizing chemical solubilization or reaction do with N(ca) < 1x10(-3) to minimize unwanted migration.
- 出版日期2011-9-11
