Double-porosity modelling of oscillatory gas motion and contaminant transport in a fractured porous medium

Technical Report · Tue Dec 01 04:00:00 EST 1987

OSTI ID:5494174

Nilson, R H; Lie, K H ^[1]

---

1. S-Cubed, La Jolla, CA (United States)

A double-porosity model is used to describe the oscillatory gas motion and associated contaminant transport induced by cyclical variations in the barometric pressure at the surface of a fractured porous medium. Flow along the fractures and within the permeable matrix blocks is locally one-dimensional. The interaction between fractures and blocks includes the Darcian seepage of fluid as well as the Fickian diffusion of contaminant. To guard against artificial numerical diffusion, the FRAM filtering remedy and methodology of Chapman is used in calculating the advective fluxes along fractures and within blocks. The entire system of equations, including the fracture/matrix interaction terms, is solved by a largely implicit non-computational time step is large compared to the cross-block transit time of Darcian pressure waves. The numerical accuracy is tested by comparison with exact solutions for oscillatory and unidirectional flows, some of which include Darcian seepage or Fickian diffusion interaction between the fracture and the matrix. The method is used to estimate the rate of transport of radioactive gases through the rubblized chimney produced by an underground nuclear explosion.

• Research Organization: Lawrence Livermore National Lab., CA (United States); S-Cubed, La Jolla, CA (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5494174
• Report Number(s): UCRL-CR-109637; SSS-R--87-8621; ON: DE92010442
• Country of Publication: United States
• Language: English

Related Subjects

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE
450201* -- Military Technology
Weaponry
& National Defense-- Nuclear Explosions & Explosives-- Containment
99 GENERAL AND MISCELLANEOUS
990200 -- Mathematics & Computers
ATMOSPHERIC PRESSURE
DIFFUSION
ENVIRONMENTAL TRANSPORT
EXPLOSIONS
FLUID FLOW
FRACTURED RESERVOIRS
GAS FLOW
MASS TRANSFER
MATHEMATICAL MODELS
POROSITY
RADIONUCLIDE MIGRATION
UNDERGROUND EXPLOSIONS
VARIATIONS