Wells – Processes – Preventing flow into strainer while lowering by blocking...
Reexamination Certificate
2000-11-20
2003-04-08
Bagnell, David (Department: 3672)
Wells
Processes
Preventing flow into strainer while lowering by blocking...
C166S205000, C166S317000, C405S128750, C405S128850
Reexamination Certificate
active
06543539
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to soil treatment by injecting or removing fluid, and certain embodiments relate to perforated casings that may be installed in the ground as a part of a soil remediation system. The perforated casings may be inserted into the soil without plugging openings in the casings. The perforated casings may be inserted into the soil without vapor or dust being transported from the soil to the surface through the casing.
2. Description of Related Art
Contamination of subsurface soils has become a matter of concern in many locations. Subsurface soil may become contaminated with chemical, biological, and/or radioactive contaminants. Contamination of subsurface soil may occur in a variety of ways. Hazardous material spills, leaking storage vessels, and landfill seepage of improperly disposed of materials are just a few examples of the many ways in which soil may become contaminated. Contaminants in subsurface soil can become public health hazards if the contaminants migrate into aquifers, into air, or into the food supply. Contaminants in subsurface soil may migrate into the food supply through bio-accumulation in various species that are part of the food chain.
There are many methods for removal of contaminants from subsurface soil. Some possible methods for treating contaminated subsurface soil include excavation followed by incineration, in situ vitrification, biological treatment, and in situ chemical treatment. Although these methods may be successfully applied in some applications, the methods can be very expensive. The methods may not be practical if many tons of soil must be treated.
Another method that may be used to remove contaminants from subsurface soil is a soil vapor extraction (SVE) process. An SVE process applies a vacuum to a production well to draw air through subsurface soil. The air carries volatile contaminants towards the source of the vacuum. Air, water, contaminants and other material may be removed as off-gas from the soil by the vacuum. The off-gas may be transported to a treatment facility. The off-gas removed from the soil may be processed in the treatment facility to eliminate or reduce contaminants within the off-gas to acceptable levels. An SVE process may allow contaminants to be removed from soil without the need to move or significantly disturb the soil. An SVE process may operate under roads, foundations, and other fixed structures.
In situ thermal desorption (ISTD) may be used to increase the effectiveness of an SVE process. An ISTD soil remediation process involves in situ heating of the contaminated soil to raise the temperature of the soil while simultaneously removing off-gas by vacuum. In situ heating may be preferred over convective heating by the introduction of a hot fluid (such as steam) into the soil because thermal conduction through soil is very uniform as compared to mass transfer through soil. Thermal conductivity of an average soil may vary by a factor of about two throughout the soil. Fluid flow conductivity of an average soil may vary by a factor of 10
8
throughout the soil.
Soil may be heated by a variety of methods. Methods for heating soil include, but are not limited to, heating by thermal conduction, heating by radio frequency heating, or heating by electrical soil resistivity heating. Thermal conduction heating may be advantageous because thermal conductive heating is not limited by the amount of water present in the soil. Also, soil temperatures substantially above the boiling point of water may be obtained using thermal conductive heating. Soil temperatures of about 212° F., 250° F., 300° F., 400° F., 750° F., 1000° F. or greater may be obtained using thermal conductive heating. Heaters may be placed in or on the soil to heat the soil. Thermal conductive heating of soil may include radiatively heating a well casing, which conductively heats the surrounding soil. Coincident or separate source vacuum may be applied to remove vapors from the soil. Vapor may be removed from the soil through production wells. U.S. Pat. No. 5,318,116 issued to Vinegar et al. and U.S. patent application Ser. No. 09/549,902, both of which are incorporated by reference as if fully set forth herein, describe ISTD processes for treating contaminated subsurface soil with thermal conductive heating.
A production well may be inserted into the soil. The production well may be placed, vibrated and/or driven into the soil. The production well may include a perforated casing that allows vapor to pass from the soil into the production well. The perforations in the casing may be, but are not limited to, holes and/or slots. The perforations may be screened. The casing may have several perforated zones at different positions along a length of the casing. When the casing is inserted into the soil, the perforated zones may be located adjacent to contaminated layers of soil. The areas adjacent to perforated sections of a casing may be packed with gravel or sand. The casing may be sealed to the soil adjacent to non-producing layers to inhibit migration of contaminants into uncontaminated soil.
In some soil remediation processes, it may be desirable to insert a fluid into the soil. The fluid may be, but is not limited to, a heat source such as steam, a solvent, a chemical reactant such as an oxidant, or a biological treatment carrier. A fluid, which may be a liquid or gas, may be inserted into the soil through an injection well. The injection well may include a perforated casing. The injection well may be similar to a production well except that fluid is inserted into the soil through perforations in the well casing instead of being removed from the soil through perforations in the well casing.
A well may also be a test well. A test well may be used as a gas sampling well to determine the location and concentration of contaminants within the soil. A different type of test well may be used as a logging observation well.
A production, injection or test well may be placed into an augered hole. Cuttings made during the formation of the augered hole may have to be treated separately from the remaining soil. Some soil may be contaminated with extremely toxic chemicals or radioactive contaminants. Augering a hole for a production or injection well may not be feasible because forming the hole would expose workers and the environment to contaminated dust or vapors. For example, soil may be contaminated with a combination of radioactive contaminants, such as plutonium, and organic contaminants. It may be desirable to remediate the soil to inhibit migration of the organic contaminants into adjacent soil. Exposure of workers to even small amounts of dust from plutonium contaminated soil during installation or operation of a soil remediation system may result in illness or death.
As an alternative to placing a production, injection or test well into an augered hole, a well may be inserted into the ground by vibrating or driving the well into the ground. U.S. Pat. No. 3,684,037 issued to Bodine and U.S. Pat. No. 6,039,508 issued to White describe devices for sonically drilling wells. Both of these patents are incorporated by reference as if fully set forth herein. During placement of a perforated casing into the ground, soil may fill and plug the openings in the casing. Plugged openings may inhibit or significantly reduce removal of off-gas from soil adjacent to the well.
SUMMARY OF THE INVENTION
A production, injection or test well for a soil remediation system may include a perforated casing. The casing may be an elongated conduit for introduction or removal of material into or out of the soil. The casing may have any cross sectional shape, including, but not limited to, circular, oval, polygonal, irregular, or rectangular. Perforations in the casing may be, but are not limited to, circular holes, oval holes, irregular shaped, and slots. The casing may be inserted into soil without the soil plugging openings of the perforated casing. In an embodiment, removable material may cover the openings durin
Stegemeier George L.
Vinegar Harold J.
Bagnell David
Board of Regents , The University of Texas System
Meyertons Eric B.
Meyertons Hood Kivlin Kowert & Goetzel P.C.
Stephenson Daniel P
LandOfFree
Perforated casing method and system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Perforated casing method and system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Perforated casing method and system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3052000