Data processing: measuring – calibrating – or testing – Measurement system in a specific environment – Earth science
Reexamination Certificate
2000-08-24
2001-11-13
McElheny, Jr., Donald E. (Department: 2862)
Data processing: measuring, calibrating, or testing
Measurement system in a specific environment
Earth science
Reexamination Certificate
active
06317694
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a method and apparatus for fabricating a well used for monitoring and remediation of contaminated soil and ground water. More specifically, the present invention relates to a method and apparatus for selecting a sand pack mesh for a filter pack and a well casing slot size for a well using soil classification data derived from a cone penetrometer test.
2. Description of the Prior Art
In a standard well, a bore hole is first drilled into the ground. Normally, the well water is sampled as part of a water quality monitoring program. A well casing is then inserted into the bore hole. Normally, the well casing houses a pumping mechanism or other mechanical components which comprise the operational features of the particular well.
The well casing will normally include a portion that is permeable to groundwater. The remainder of the well casing is typically impermeable to insure proper hydraulic flow of the liquids through the well casing at a specific depth intervals, as dictated by the design of the casing.
The space in between the exterior surface of the well casing and the interior surface of the bore hole is then filled with an annular fill material. This annular fill material, which operates as a filter or cleaning device, may be a permeable material, such as gravel or sand.
Water, which is pumped through the well is directed through a filter or cleaning device placed in the annular space of the well casing. Ground water so directed will capture impurities or contaminants leached or dissolved from the surrounding soils into the groundwater, thus passing impurities or contaminants from the surrounding soils to the filter or cleaning device along the screened portion of the well casing.
In the past selection of the filter (also known as the gravel pack or primary filter pack) and well casing slot size which is based on the filter pack was an extremely time consuming, expensive and difficult process requiring soil sampling, sieve analysis, and reference to standard recommendations. What is needed is a relatively simple method and apparatus by which a user can select the sand pack mesh and the well casing slot size when the soil type which is contaminated has been identified.
SUMMARY OF THE INVENTION
The present invention overcomes some of the disadvantages of the prior art including those mentioned above in that it comprises a relatively simple yet highly effective method and apparatus for selecting a filter pack and the well casing slot size for a well which uses soil classification data derived from cone penetrometer tests.
The user of the method and apparatus of the present invention uses a piezocone to measure soil properties in an area of contaminated soil or non-contaminated soil and then determine the soil type at specific depths within the soil. The soil doesn't always need to be contaminated. Sometimes wells are installed in clean areas to determine background chemistry and hydrologic properties.
A multisensor probe, such as a probe that generates a laser induced fluorescence intensity plot of the area of soil contamination which is superimposed on a soil boring log identifying the soil type at specific depths within the soil can lead to a detailed subsurface characterization. The soil type for the area of contaminated soil is identified from load cell data and the contamination is identified by the laser induced fluorescence intensity plot. When the user identifies the soil type for the area of soil contamination, the user accesses one of a pair of lookup tables to select the sand pack mesh and the well casing slot size for the specified zone. The lookup tables sets forth the filter pack and well screen slot size for soil descriptors based on the 9-scale and soil descriptors based on the 12-scale of Robertson and Campanella.
REFERENCES:
patent: 5664628 (1997-09-01), Koehler et al.
Farrar Jeffrey A.
Kram Mark L.
Kalmbaugh David
McElheny Jr. Donald E.
The United States of America as represented by the Secretary of
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