Waste Isolation Pilot Plant Shaft Seal Salt Consolidation Modelling

摘要

The numerical code TOUGH28W was modified to calculate porosity and permeability changes due to salt consolidation. The porosity change was modeled as a function of pore pressure and depth in the salt. The permeability was coupled to the porosity using log-linear models. The Waste Isolation Pilot Plant (WIPP) lower shaft seals and surrounding formation were modeled. Crushed salt is one of the key components of the sealing system, and to gain understanding of the consolidation of the crushed salt after seal emplacement, TOUGH28W simulations were performed. The results showed the salt consolidation is greatly affected by the pore pressure. After 100 years of simulation, the porosity of the crushed salt for a log-linear model has decreased from 0.1 to a value of 0.035 at the bottom of the crushed salt column and the minimum permeability in the crushed salt column after 100 years of consolidation is 4x(10^-22) m².