MEASUREMENT OF NONEXCHANGING PORES DURING MISCIBLE DISPLACEMENT IN SOILS

Abstract

A simple tritium tracer-vacuum distillation technique was used to determine the percent nonexchanging pores in soils during miscible displacement. Data for soil columns packed with three different soil types are presented and compared with the results of previously reported values. After two pore volumes of displacement only 1 to 2 percent of the pore water had not exchanged with the displacing fluid. Previous published work, based upon either mathematical models or experimental data, show considerably greater values for nonconducting pores in soils. The time required for two pore volumes of displacement in the packed soil columns was sufficient for diffusion of tracer into essentially all of the slowly conducting and nonconducting pores. A simple tritium tracer-vacuum distillation technique was used to determine the percent nonexchanging pores in soils during miscible displacement. Data for soil columns packed with three different soil types are presented and compared with the results of previously reported values. After two pore volumes of displacement only 1 to 2 percent of the pore water had not exchanged with the displacing fluid. Previous published work, based upon either mathematical models or experimental data, show considerably greater values for nonconducting pores in soils. The time required for two pore volumes of displacement in the packed soil columns was sufficient for diffusion of tracer into essentially all of the slowly conducting and nonconducting pores. © Williams & Wilkins 1976. All Rights Reserved.