Tracer Tests in a Fractured Dolomite: 4. Double Porosity, Multiple-Rate Mass Transfer Processes in Two-Well Convergent Flow Tests;Water Resources Research

摘要

Two-well convergent-flow tracer tests conducted in the Culebra dolomite (Rustler Formation, New Mexico, USA) are analyzed with both single-and multiple- rate, double-porosity models. Parameter estimation is used to determine the mean and standard deviation of a Iog- normal distribution of diffision rate coefficients as well as the advective porosity and longitudinal dispersivity. At two different test sites, both mukirate and single-rate models are capable of accurately modeling the observed data. Estimated model parameters are tested against breakthrough curves obtained along the same transport pathway at a different pumping rate. Implications of the rnultirate mass-transfer model at time and length scales greater than those of the tracer tests include the instantaneous saturation of a fraction of the matrix and the possibility of a fraction of the matrix remaining unsaturated at long times.