Casing annulus leakage repair method and system
a leakage repair and annulus technology, applied in the direction of insulation, borehole/well accessories, construction, etc., can solve the problems of insufficient pressure isolation between the casing strings, more frequent problems, and not solving the problem entirely
Inactive Publication Date: 2022-01-20
SAUDI ARABIAN OIL CO
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Benefits of technology
The patent describes a method of repairing leaks in a cement sheath by using a heat-deforming material that can be applied while the material remains in place within the opening. The material is cooled while it solidifies and plugs the opening, thereby repairing the leak. The method also involves reducing the temperature of the surrounding area to activate the heat-deforming material. The technical effect is the efficient and effective repair of leaks in cement sheaths, which can prolong the life of oil and gas wells.
Problems solved by technology
Sufficient pressure isolation between casing strings has been an oil industry problem since its inception.
Cement is used to seal the annulus between concentric casing strings, but cement fundamentally shrinks as it cures, resulting in micro channels and micro-annuli in the cement.
Such problems occur more frequently in gas wells because of higher pressures and lower media viscosity.
These improvements in cement chemistries have resulted in better performance for sealing between casing strings (CCA sealing), but they have not solved the problem entirely.
In particular, micro channels can still develop in the casing after the curing of the cement, which results in CCA leaks that are not detected until long after the casing is cemented.
Currently, retrofit methods for repair of these CCA leaks in gas wells have been difficult to implement and are largely ineffective.
Method used
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[0024]By way of overview and introduction, the present application discloses methods and systems for repairing a leak in a casing of a well. In one or more embodiments, the system can include an underreamer, a cleaning tool (e.g., hydrojet), a tubular (e.g., scab liner), an annular packer tool, and a heater. In accordance with one or more embodiments of the method, a leak such as a casing-to-casing annular (CCA) leak is located in a casing of the well. The casing can include an inner casing string (“inner casing”) and an outer casing string (“outer casing”) with cement separating the inner and outer casings.
[0025]After the location of the leak is determined, an underreamer is used to remove a portion of the inner casing and sometimes the cement at the location of the leak, thereby creating an annular-shaped opening in the inner casing. This annular-shaped opening is then cleaned to remove any debris. It will be appreciated that the formed opening can be a concentric annular, partial...
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A method for repairing a leak in a cement sheath of a casing of a well. A portion of the inner casing and the cement sheath is removed to create an opening that extends through the inner casing and the cement sheath. A tool is inserted within the inner casing to a location adjacent to the opening and one or more segments of a heat-deforming material that are part of the tool is heated to cause melting of the heat-deforming material. The tool is configured to direct the melted heat-deforming material radially outward into the opening. Once cooled, the heat-deforming material plugs the opening, thereby repairing the leak within the cement sheath.
Description
TECHNICAL FIELD[0001]The present disclosure is generally related to systems and processes for repairing a leak in a well and more particularly related to systems and processes for repairing a leak in a casing of a well.BACKGROUND OF THE DISCLOSURE[0002]Sufficient pressure isolation between casing strings has been an oil industry problem since its inception. Cement is used to seal the annulus between concentric casing strings, but cement fundamentally shrinks as it cures, resulting in micro channels and micro-annuli in the cement. The micro channels and micro-annuli can permit gas to flow between the casing strings. Sometimes the gas can flow for thousands of feet between the tubulars and can be measured at the surface wellhead. Further, downhole media can flow from one zone of the well to another via the micro channels (casing-to-casing leak path). Such problems occur more frequently in gas wells because of higher pressures and lower media viscosity. Moreover, casing-to-casing annul...
Claims
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Patent Timeline
Login to View More IPC IPC(8): E21B29/10E21B29/00E21B33/12E21B36/00E21B36/04E21B47/107E21B37/00
CPCE21B29/10E21B29/002E21B33/12E21B37/00E21B36/04E21B47/107E21B36/008E21B33/138E21B33/134E21B33/14E21B29/005E21B29/02E21B33/13E21B29/06
Inventor BOULDIN, BRETTTURNER, ROBERT JOHN
Owner SAUDI ARABIAN OIL CO