LIQUID CARBON DIOXIDE CLEANING OF WELLBORES AND NEAR-WELLBORE AREAS USING HIGH PRECISION STIMULATION
First Claim
1. A method for cleaning a wellbore and near wellbore areas in a formation comprising the steps of:
- inserting a desired length of tubing into said wellbore;
introducing a treatment medium comprising liquid carbon dioxide through said tubing into one or more locations within said wellbore and into at least a portion of said formation adjacent to said wellbore; and
vaporizing at least a portion of said treatment medium after it is injected into said wellbore.
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Accused Products
Abstract
A method to clean a wellbore and the near wellbore area adjacent to the wellbore of a hydrocarbon bearing and/or coal bed methane formation adjacent to the production zone of the wellbore is provided. Specifically, a method for removing liquids such as water and/or oil from the near wellbore formation is provided. Furthermore, A method to clean a casing inserted into a wellbore is also disclosed. A method for cleaning a wellbore of fracturing fluid, with or without proppant is also disclosed. Each of the methods includes the steps of injecting either liquid carbon dioxide or a treatment medium comprising liquid carbon dioxide into a wellbore through tubing such that the location at which the treatment medium is administered may be controlled. In some embodiments, pressure within the wellbore is regulated in order to either maintain the treatment medium in the liquid state, or allow at least a portion of the treatment medium to vaporize upon introduction into the wellbore. Once the treatment medium has at least partially vaporized it will loosen and/or entrain undesirable materials from within the wellbore or casing, and may also act to mobilize any water and/or oil present by causing the water to effervesce and/or by dissolving any oil. These processes may act to defeat capillary pressure mobilizing the water and/or oil such that it may be blown or pumped to the surface or, if the present invention is practiced in a coal bed methane formation, may be driven into the coal bed methane formation such that it may no longer impose a barrier to methane production. In certain embodiments, the gaseous portion of the treatment medium is allowed to escape through the wellhead, carrying with it the undesirable materials.
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Citations
73 Claims
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1. A method for cleaning a wellbore and near wellbore areas in a formation comprising the steps of:
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inserting a desired length of tubing into said wellbore; introducing a treatment medium comprising liquid carbon dioxide through said tubing into one or more locations within said wellbore and into at least a portion of said formation adjacent to said wellbore; and vaporizing at least a portion of said treatment medium after it is injected into said wellbore. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A method for cleaning deposits from a portion of casing in a wellbore in a formation, comprising the steps of:
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inserting into said casing a known length of tubing such that said tubing terminates at a known location within said casing; introducing, through said tubing, treatment medium comprised of liquid carbon dioxide to said known location; impinging said casing with said treatment fluid; removing at least some deposits from said portion of said casing; regulating the pressure within the wellbore to partially vaporize said treatment medium such that the partially vaporized treatment medium entrains said deposits; and allowing said partially vaporized treatment medium and entrained deposits to exit said casing. - View Dependent Claims (25, 26)
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24. A method for cleaning deposits from the surface of one or more perforations in a casing in a wellbore in a formation, comprising the steps of:
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inserting into said casing a known length of tubing such that said tubing terminates at a location within said casing which is adjacent at least one of said one or more perforations; introducing, through said tubing, treatment medium comprised of liquid carbon dioxide to said known location; impinging said surface of said one or more perforations with said treatment fluid; removing at least some deposits from said surface of said one or more perforations; regulating the pressure within the wellbore to partially vaporize said treatment medium such that the partially vaporized treatment medium entrains said deposits; and opening said wellbore to allow said partially vaporized treatment medium and entrained deposits to exit said casing.
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27. A method for fracturing a fluid bearing formation having a wellbore comprising the steps of:
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introducing a quantity of fracturing fluid into said wellbore sufficient to fracture said formation; introducing a treatment medium comprising liquid carbon dioxide into said wellbore; and vaporizing at least a portion of said treatment medium. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36)
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- 37. A wellbore treatment medium comprising liquid carbon dioxide and alcohol, surfactant, corrosion inhibitor, acid, iron-control chemical abrasive, acid, and/or biocide.
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39. An apparatus for introducing a treatment medium into desired space comprising:
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a storage means for storing a quantity of a treatment medium; a pumping means for delivering said treatment medium to a transport means; said transport means inserted into said space and operable to transport a quantity of said treatment medium to a location within said space; and means for directing said treatment medium onto a location within said space; wherein said treatment medium is comprised of liquid carbon dioxide and said space is defined by at least a portion of a wellbore, a casing within said wellbore, a region of a wellbore located in a hydrocarbon bearing formation adjacent a volume of said hydrocarbon bearing formation to be fractured and/or at least a portion of a hydrocarbon bearing formation near said wellbore. - View Dependent Claims (40, 41, 42, 43, 44)
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45. An apparatus for hydraulically fracturing a fluid bearing formation having a wellbore therein comprising:
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a first pumping means for delivering a treatment medium comprising liquid carbon dioxide to a first transport means; a second pumping means for delivering a fracturing fluid to a second transport means; said second transport means inserted into said wellbore; said first transport means inserted into said second transport means and operable to transport a quantity of said treatment medium to a location within said second transport means; and means for directing said treatment medium such that it mixes with said fracturing fluid producing a second fracturing fluid and said second fracturing fluid impinging a fluid bearing formation. - View Dependent Claims (46, 47, 48, 49)
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50. A method for cleaning a wellbore and near wellbore areas in a coal bed methane formation comprising the steps of:
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inserting a desired length of tubing into said wellbore; introducing a treatment medium comprising liquid carbon dioxide through said tubing into one or more locations within said wellbore and into at least a portion of said formation adjacent to said wellbore; and vaporizing at least a portion of said treatment medium after it is injected into said wellbore. - View Dependent Claims (51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62)
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- 63. A wellbore treatment medium comprising liquid carbon dioxide and alcohol, surfactant, corrosion inhibitor, acid, iron-control chemical abrasive, acid, and/or biocide.
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65. An apparatus for introducing a treatment medium into desired space comprising:
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a storage means for storing a quantity of a treatment medium; a pumping means for delivering said treatment medium to a transport means; said transport means inserted into said space and operable to transport a quantity of said treatment medium to a location within said space; and means for directing said treatment medium onto a location within said space; wherein said treatment medium is comprised of liquid carbon dioxide and said space is defined by at least a portion of a wellbore, a casing within said wellbore, a region of a wellbore located in a coal bed methane formation and/or at least a portion of a coal bed methane formation near said wellbore. - View Dependent Claims (66, 67, 68, 69)
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70. A method for removing liquids from a wellbore and the near wellbore areas of a coal bed methane formation comprising the steps of:
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inserting a desired length of tubing into said wellbore; introducing a treatment medium comprising liquid carbon dioxide through said tubing into one or more locations within said wellbore and into at least a portion of said formation adjacent to said wellbore; and vaporizing at least a portion of said treatment medium after it is injected into said wellbore. - View Dependent Claims (71, 72, 73)
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Specification