Hydrologic Tests at Characterization Well R-14

McLin, S. ; Stone, W.

Los Alamos National Laboratory

关键词: Water Wells;    58 Geosciences;    Water Tables 58 Geosciences;    Aquifers;    Hydraulic Conductivity;   

DOI  :  10.2172/835900
RP-ID  :  LA-14107-MS
RP-ID  :  W-7405-ENG-36
RP-ID  :  835900

美国|英语

来源: UNT Digital Library

【 摘 要 】

Well R-14 is located in Ten Site Canyon and was completed at a depth of 1316 ft below ground surface (bgs) in August 2002 within unassigned pumiceous deposits located below the Puye Formation (fanglomerate). The well was constructed with two screens positioned below the regional water table. Individual static depths measured for each isolated screen after the Westbay{trademark} transducer monitoring system was installed in mid-December 2002 were nearly identical at 1177 ft bgs, suggesting only horizontal subsurface flow at this time, location, and depth. Screen 1 straddles the geologic contact between the Puye fanglomerate and unassigned pumiceous deposits. Screen 2 is located about 50 ft deeper than screen 1 and is only within the unassigned pumiceous deposits. Constant-rate, straddle-packer, injection tests were conducted at screen 2, including two short tests and one long test. The short tests were 1 minute each but at different injection rates. These short tests were used to select an appropriate injection rate for the long test. We analyzed both injection and recovery data from the long test using the Theis, Theis recovery, Theis residual-recovery, and specific capacity techniques. The Theis injection, Theis recovery, and specific capacity methods correct for partial screen penetration; however, the Theis residual-recovery method does not. The long test at screen 2 involved injection at a rate of 10.1 gallons per minute (gpm) for 68 minutes and recovery for the next 85 minutes. The Theis analysis for screen 2 gave the best fit to residual recovery data. These results suggest that the 158-ft thick deposits opposite screen 2 have a transmissivity (T) equal to or greater than 143 ft{sup 2}/day, and correspond to a horizontal hydraulic conductivity (K) of at least 0.9 ft/day. The specific capacity method yielded a T value equal to or greater than 177 ft{sup 2}/day, and a horizontal K of at least 1.1 ft/day. Results from the injection and recovery phases of the test at screen 2 were similar to those from the residual-recovery portion of the test, but were lower by a factor of about two. The response to injection was typical for a partially penetrating well screen in a very thick aquifer.