Wells – Processes – Dissolving or preventing formation of solid oil deposit
Reexamination Certificate
1999-04-16
2001-06-12
Neuder, William (Department: 3672)
Wells
Processes
Dissolving or preventing formation of solid oil deposit
C166S246000, C166S312000, C166S403000, C210S747300
Reexamination Certificate
active
06244346
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to anti-fouling of injection and recovery wells, and more particularly relates to a method and apparatus for reducing or eliminating fouling of injection and recovery wells with alkane-utilizing bacteria.
BACKGROUND INFORMATION
Many different types of injection wells and recovery wells are widely used. Typical injection wells are used for water supply, groundwater control, solution mining, waste disposal, geothermal energy and to increase oil production. Typical recovery wells are used for groundwater control, capture and treatment, municipal water supplies, domestic water supplies and in the oil and geothermal industries.
Fouling at injection and recovery wells is a major problem worldwide. Chemical and biological incrustation are major causes of decreased well performance and eventual failure. Material comprising bacteria and metal oxides accumulates and clogs the wells. Iron and manganese fouling at well screens is a global problem for water supply and production wells. In addition, metals fouling is a problem at most wastewater treatment plants. For example, iron and manganese bacteria occur widely in wells open to the atmosphere when sufficient iron and/or manganese are present in the groundwater. Such bacteria plug wells by enzymatically catalyzing the oxidation of metals, using the energy to promote the growth of threadlike slimes, and accumulating large amounts of metal hydroxides, such as ferric hydroxide, in the slime. For instance, the bacteria may obtain their energy by oxidizing ferrous ions to ferric ions, which are then precipitated as hydrated ferric hydroxide on or in their mucilaginous sheaths. Iron bacteria produce accumulations of slimy material that have a gelatinous consistency. In addition, they precipitate dissolved iron and manganese. The dual effect of the growing bacteria and precipitating minerals occurs. Precipitation of the iron and rapid growth of the bacteria create a voluminous material that quickly plugs the screen pores of the sediment surrounding the well bore. The explosive growth rates of iron bacteria can render a well useless within a matter of months.
Other forms of iron bacteria induce the precipitation of iron through nonenzymatic means. These bacteria promote precipitation by mechanisms such as: raising pH; changing the redox potential of the water by algal photosynthesis; and liberating chelated iron. Some forms of iron bacteria can reduce iron to a ferrous state under anaerobic conditions.
A conventional method for reducing the amount of iron incrusting materials reaching production well screens, called the Vyredox System, uses a series of injection wells located in a circle around a production well. Oxygenated water is injected into the wells to oxidize iron in solution and promote the growth of iron bacteria so that little iron reaches the production well.
In many wells, incrusting iron cannot be removed before reaching a production well. In these cases, caustic chemicals are added to the well to clear biofouling and free the production well screen. These practices are costly, time consuming and require the production well to be brought off-line, thus disrupting service. Furthermore, the chemicals and their toxic fumes may cause serious injury to the technicians injecting them into the production well.
Other methods conventionally used to control iron bacteria are heat, explosives, ultrasonics, radiation and anoxic blocks.
Despite the above-noted efforts, need exists for the effective reduction or elimination of fouling at various types of injection and recovery wells. The present invention has been developed in view of the foregoing, and to remedy other deficiencies of the prior art.
SUMMARY OF THE INVENTION
In accordance with the present-invention, a method and apparatus are provided for anti-fouling of well inlets and outlets. Alkanes such as a butane substrate are used in combination with oxygen to stimulate the growth of microorganisms near the well inlets and/or outlets. The present alkane/oxygen injection method is a simple and cost effective treatment process to abate and prevent metal fouling at wellheads and other industrial applications by oxidizing dissolved metal concentrations and immobilizing them from the production and supply routes.
An aspect of the present invention is to provide a method of reducing well fouling. The method includes the steps of stimulating growth of alkane-utilizing bacteria adjacent to the well, and reducing the deposition of fouling material on the well with the alkane-utilizing bacteria.
Another aspect of the present invention is to provide a method of reducing well fouling, including the steps of introducing at least one alkane and oxygen to a region of the well susceptible to fouling, and stimulating growth of alkane-utilizing bacteria which reduce the deposition of fouling material on the well.
Another aspect of the present invention is to provide an apparatus for reducing well fouling. The apparatus includes a source of a butane substrate, a source of an oxygen-containing gas, and at least one injector in flow communication with the source of butane substrate and the source of oxygen-containing gas having a distal end located in proximity to at least a portion of the well that is susceptible to fouling.
These and other aspects of the present invention will become more apparent from the following description.
REFERENCES:
patent: 3616216 (1971-10-01), Wegner
patent: 4713343 (1987-12-01), Wilson, Jr. et al.
patent: 5037551 (1991-08-01), Barkley et al.
patent: 5057221 (1991-10-01), Bryant et al.
patent: 5316940 (1994-05-01), Georgiou et al.
patent: 5326703 (1994-07-01), Hazen et al.
patent: 5337820 (1994-08-01), Jenneman et al.
patent: 5342769 (1994-08-01), Hunter et al.
patent: 5384048 (1995-01-01), Hazen et al.
patent: 5441887 (1995-08-01), Hanson et al.
patent: 5678632 (1997-10-01), Moses et al.
patent: 5814514 (1998-09-01), Steffan et al.
Broholm et al., “Toxicity of 1,1,1-Trichloroethane and Trichloroethene on a Mixed Culture of Methane-Oxidizing Bacteria”,Applied and Environmental Microbiology, vol. 56, No. 8, (Aug. 1990), p. 2488-2493.
“Petroleum”,Van Nostrand's Scientific Encyclopedia, Eighth Edition, (1995) pp. 2392-2395, Douglas M. Considine, editor.
Eckert Seamans Cherin & Mellott , LLC
Global BioSciences, Inc.
Neuder William
Towner Alan G.
Walker Zakiya
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