Abstract
A short-term, pulse injection tracer experiment conducted in fractured quartzitic sandstone at Kukuan, Taiwan was analyzed. Tracer transport at the test site was dominated by advection but a specific attenuation mechanism leading to breakthrough curve (BTC) tailing also seemed to exist. Matrix diffusion was hypothesized as the transport mechanism that results in the tailing. This hypothesis was proved by comparing the field BTC with numerical simulation results obtained by the general-purpose flow/transport simulator, TOUGH2, based on a single-fracture conceptual model. Due to the lack of accuracy of estimating the interporosity flux by the conventional double porosity model (DPM), TOUGH2 was incorporated with the multiple interacting continua (MINC) scheme to simulate the transient characteristics of the interporosity flux. In MINC, rock matrix is discretized as a series of continua according to the perpendicular distance from the fracture that adjoins the matrix. The closer the rock matrix is to the fracture, the finer the rock matrix is discretized. This concept is fundamentally different from DPM in that rock matrix is no longer treated as a single continuum. Simulation results by TOUGH2-MINC have successfully reproduced the observed BTC tailing even under the dominating advection effect. Sensitivity studies showed that TOUGH2-MINC is sensitive to parameters including fracture aperture (2b), matrix porosity (nm) and effective molecular diffusion coefficient in matrix (Dm). If 2b, nm , Dm , are respectively 200 µm, 2%, 10 -11 m 2 s -1 , and if hydrodynamic dispersion coefficient
Highlights
Fluid flow and solute transport in fractured rock have attracted a lot of attention in recent years
This continuum is further discretized in a direction transverse to the flow direction by multiple interacting continua (MINC) according to specified volume fractions
A short-term tracer experiment conducted in fractured sandstone was analyzed
Summary
Fluid flow and solute transport in fractured rock have attracted a lot of attention in recent years. These subjects are closely related to various fields of application, e.g., energy extraction in geothermal reservoirs, the fate and transport of contaminants in the subsurface, and the final disposal of spent nuclear fuels in fractured media. The last application concerns, among others, how radionuclides migrate through the interconnected fracture network. This problem can be analyzed by numerical modeling of tracer transport through fractured media. A successful modeling of tracer transport in fractured media relies on a realizable description of the inherent heterogeneity and associated uncertainties of the complex, interconnected fracture network
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
