In-situ permeability measurements with direct push techniques: Phase II topical211 report

摘要

This effort designed, fabricated, and field tested the engineering prototype of211u001ethe Cone Permeameter(trademark) system. The integrated system includes the 211u001einstrumented penetrometer probe, air and water pumps, flowrate controls, flow 211u001esensors, and a laptop-controlled data system. All of the equipment is portable 211u001eand can be transported as luggage on airlines. The data system acquired and 211u001edisplays the process measurements (pressures, flows, and downhole temperature) in 211u001ereal time and calculates the resulting permeability. The measurement probe is a 2 211u001einch diameter CPT rod section, incorporating a screened injection zone near the 211u001elower end of the rod and multiple sensitive absolute pressure sensors embedded in 211u001ethe probe at varying distances from the injection zone. Laboratory tests in a 211u001elarge test cell demonstrated the system's ability to measure nominally 1 Darcy 211u001epermeability soil (30 to 40 Darcy material had been successfully measured in the 211u001ePhase 1 effort). These tests also provided a shakedown of the system and 211u001eidentified minor instrument problems, which were resolved. Supplemental numerical 211u001emodeling was conducted to evaluate the effects of layered permeability 211u001e(heterogeneity) and anisotropy on the measurement system's performance. The 211u001egeneral results of the analysis were that the Cone Permeameter could measure 211u001eaccurately, in heterogeneous media, the volume represented by the sample port 211u001eradii if the outer pressure ports were used. Anisotropic permeability, while 211u001ereadily analyzed numerically, is more complicated to resolve with the simple 211u001eanalytical approach of the 1-D model, and will need further work to quantify. 211u001eThis phase culminated in field demonstrations at the DOE Savannah River Site. 211u001eSaturated hydraulic conductivity measurements were completed at the D-Area Coal 211u001ePile Runoff Basin, and air permeability measurements were conducted at the M Area 211u001eIntegrated Demonstration Site and the 321 M area. The saturated hydraulic 211u001econductivity measurements were the most successful and compared well to relevant 211u001eexisting data. Air permeability measurements were more problematic, primarily due 211u001eto clay covering pressure measuring ports and preventing pressure communication 211u001ewith the sensors. Very little discreet air permeability data existed for the 211u001esites.