The invention relates to oilfield tools, and more specifically to methods and devices for temporary well zone isolation. In particular, the invention relates to temporary well zone isolation devices with frangible barrier elements and methods for the disintegration of frangible barrier elements.
In a production well, a production string composed of the production tubing and other completion components is used to transport production fluid containing hydrocarbons from a downhole formation to the surface of the well. This production tubing is typically pressure tested to insure that no leaks will form under the pressure of actual production. It is desirable to find leaks before production fluid is introduced into the tubing because of the gross inefficiencies of post-production repair. Typically, a temporary well barrier, or temporary plug, is used to seal off a particular segment of the production tubing, or well zone, for pressure testing. Often, the well zone consists of essentially the entire well. Fluid is then introduced above the temporary well barrier and pressurized to detect leaks. After testing, the temporary well barrier must be removed from the production string.
Several types of well isolation devices using temporary well barriers exist in the prior art, including the Model E Hydro Trip pressure sub by Baker Oil Tools, the OCRE Full Bore Isolation Valve and Multi-Cycle Tool by Baker Oil Tools, and the Mirage Disappearing Plug from Halliburton. While some well isolation devices use valves to control well flow, it is often desirable that once the temporary well barrier is removed, substantially the full inner diameter of the production tubing is restored. One type of temporary well barriers typical of the prior art include solid barriers held in place by a support assembly. To remove the barrier, the support assembly is retracted or sheared off to allow the solid barrier to drop through the wellbore. Designs relying on gravity for removal of the plug, however, have limited applications in substantially horizontal wells.
To extend well-isolation to horizontal wells, plugs were developed that provide a large bore in the well isolation device after removal of the temporary well barrier without dropping the temporary barrier into the wellbore. These plugs are broadly referred to as disappearing plugs. One type of disappearing plug operates by recessing the temporary well barrier into the housing of the well isolation device. One disappearing plug from Baker Oil Tools, for example, recesses a flapper into the tool where it is isolated from the production flow path.
Other disappearing plugs operate by disintegrating a frangible well barrier, typically by impacting the barrier or setting off an explosive charge. Total Catcher Offshore AS in Bergen has developed several well isolation devices employing this type of plug, such as the Tubing Disappearing Plug (TDP), the Tubing Disappearing Smart Plug (TDSP), and the Intervention Disappearing Smart Plug (IDSP).
U.S. Pat. No. 6,026,903 by Shy et al. describes a bidirectional disappearing plug which is capable of selectively blocking flow through a flowbore of a tubing string disposed within a subterranean well. The plug may subsequently be disposed of, leaving little or no restriction to flow through the flowbore, and leaving no significant debris in the flowbore by causing a rupture sleeve to penetrate the plug member and destroy the plug's integrity.
The aforementioned disappearing plugs currently in use, while an improvement over previous technology, are less than ideal because they lack reliability, especially in environments where wells deviate from vertical.
Disclosed herein is a temporary well isolation device. The temporary well isolation device has a housing that is sealingly disposable in downhole tubing. The housing has an axial passage through the downhole tubing, where a first end of the passage is in fluid communication with the downhole tubing above the housing and a second end of the passage is in fluid communication with the downhole tubing below the housing.
The temporary well isolation device also has frangible barrier element within the housing, where the frangible barrier element is sealingly engaged in the passage blocking fluid flow through the passage. The frangible barrier element bears a load from fluid pressure. The temporary well isolation device also has a disengageable constraint in contact with the frangible barrier element so as to redirect the load on the frangible barrier element from a first component of the load to a second component of the load, thereby preventing rupture of the frangible barrier element.
Some embodiments of the temporary well isolation device have a pump for increasing the pressure above the frangible barrier element to rupture the frangible barrier element. In some embodiments, the first component of the load is the tensile component and the second component of the load is the compressive component. The shape of the frangible barrier element may be such that the load on the frangible barrier element having the constraint disposed thereabout is substantially compressive and the load on the frangible barrier element upon the constraint upon the constraint being disengaged is substantially tensile.
Also disclosed herein is a method for disintegrating a frangible barrier element disposed in a passage of a temporary well isolation device where the frangible barrier element blocks fluid flow through the passage and thereby supports a load from fluid pressure. The method includes facilitating rupture of the frangible barrier element from a first component of the load by structurally increasing the ratio of the first component of the load to a second component of the load. In some embodiments, the method may also include increasing the fluid pressure above the frangible barrier element. In some embodiments, the first component of the load is the compressive component and the second component of the load is the tensile component. Structurally increasing the ratio of the first component of the load to the second component of the load further may include disengaging a constraint.
Exemplary devices for temporary well isolation with frangible barrier elements and exemplary methods for the disintegration of frangible barrier elements according to embodiments of the present invention are described with reference to the accompanying drawings, beginning with
The structural differences in
The temporary well isolation device of
The temporary well isolation device also features a frangible barrier element (108) within the housing (102). The frangible barrier element (108) is sealingly engaged in the passage (104) blocking fluid flow through the passage (104), which results in the frangible barrier element (108) bearing a load from fluid pressure. The frangible barrier element (108) of
The temporary well isolation device also includes a disengageable constraint disposed about the frangible barrier element (108) so as to redirect the load on the frangible barrier element (108) by joining with the frangible barrier element (108) to form a compression-loaded structure. The disengageable constraint of
While the movable sleeve (112) remains engaged, the frangible barrier element (108) bears a load that is primarily compressive. Upon the movable sleeve (112) being disengaged, the frangible barrier element (108) bears a load that is primarily tensile. This change in the load facilitates rupture of the frangible barrier element. Although the movable sleeve (112) as disclosed above converts a primarily tensile load on the frangible barrier element to a primarily compressive load, any disengageable constraint could be used which facilitates rupture of the frangible barrier element by redirecting the load on the frangible barrier element from a first component of the load to a different component of the load.
Disengaging the movable sleeve (112) is carried out by moving the movable sleeve (112) axially up the housing. As discussed above, many disengageable constraints may be used in practicing certain teachings of the present disclosure. Disengaging the disengageable constraint, therefore, may be carried out by removing at least a portion of the constraint, which includes separating the frangible barrier element and at least a portion of the constraint. Separating the frangible barrier element and a portion of the constraint may include, for example, moving the constraint axially, moving the frangible barrier element axially, moving the constraint radially, and moving the frangible barrier element radially. Removing at least a portion of the constraint may also include dissolving or shearing the constraint.
Disengaging the movable sleeve (112) may further be carried out by a triggering mechanism and a disengaging mechanism which separates the frangible barrier element and at least a portion of the disengageable constraint. This disengaging mechanism typically is a set of components to physically separate the frangible barrier element and at least a portion of the disengageable constraint inside the housing. Alternatively the triggering mechanism is a set of components which actuates the disengaging mechanism.
The moveable sleeve (112) is moved axially by a disengaging mechanism, such as, for example a hydraulic piston, which has been triggered by a triggering mechanism, such as, for example a wireline, a slickline, or a preset electronic timer. Although a wireline activated lift and latch configuration (not shown) is preferable, readers of skill in the art will recognize that many types of triggering mechanisms and disengaging mechanisms maybe coupled to move the moveable sleeve. Examples of useful configurations include, for example, a mechanical-wireline configuration, a wireline activation-pulling tool configuration, a hydraulic cycling trigger configuration, and an electro-hydraulic wireline tool with anchor/stroke function configuration. In other embodiments, these triggering mechanisms and disengaging mechanisms may be coupled to move other types of disengageable constraints, as discussed above. The listed triggering mechanisms and disengaging mechanisms are well known in the prior art.
As previously discussed, the temporary well isolation device includes a disengageable constraint (206) disposed about the frangible barrier element (108) so as to redirect the load (202) on the frangible barrier element (108) by joining with the frangible barrier element (108) to support (204) the frangible barrier element (108) by forming a compression-loaded structure.
In the temporary well isolation device, the first component of the load is the tensile component and the second component of the load is the compressive component. In
In the embodiment of the present invention as shown in
As shown in
The second disc (302) is vulcanized or molded to the disc holder (301) opposite the first disc (304) with the second disc's concave side (310) facing the first disc's concave side (312), so that the interior of the disc holder (301) is sealed. The seal created from vulcanizing or molding the second disc (302) to the disc holder (301) is preferably capable of withstanding pressures of up to 10,000 PSI. As assembled, the two disks and the disc holder form a larger, hollow disc. Either or both of the discs may be scored or etched on one or more sides, to control fragment size and geometry. Alternatively, the discs may be molded with a geometry conducive to controlling fragment size, such as, for example, the “pineapple” geometry used in military hand grenades. Both scoring the disc surface and changing the molded surface geometry of the disc may also be used to facilitate fragmentation. Although a two-piece frangible barrier element is described above, the frangible barrier element may be more than two pieces, or a single piece.
The frangible barrier element illustrated in
As discussed above, the disengageable constraint may be a moveable sleeve which is disengaged by moving the moveable sleeve axially. In alternate embodiments, however, separation of the housing includes an axially movable tubular sleeve wherein is mounted the frangible barrier element, so that the frangible barrier element may be axially separated from the disengageable constraint. The operation of such a configuration is substantially identical to the disengageable constraint composed of an axially moveable tubular sleeve as discussed above.
For further explanation, therefore,
The temporary well isolation device of
The temporary well isolation device of
Disengaging the disengageable constraint (414) of
In particular embodiments, the temporary well isolation device of the present invention may be an integrated part of a Liner Top Packer/Liner Hanger. Alternatively the temporary well isolation device may be configured to be run in the well independently of any other device.
In a typical embodiment, the temporary well isolation device of
It should be understood that the inventive concepts disclosed herein are capable of many modifications. Such modifications may include modifications in the shape of the housing, the temporary well barrier, and the disengageable constraint; materials used; triggering mechanisms, and disengaging mechanisms. To the extent such modifications fall within the scope of the appended claims and their equivalents, they are intended to be covered by this patent.
This application is a continuation application and claims priority to a utility patent application Ser. No. 11/380,816, Attorney's docket number 205-0016US, filed on Apr. 28, 2006, with the same title, by the same inventor, assigned to the same assignee, which is hereby incorporated by reference in its' entirety.
Number | Date | Country | |
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Parent | 11380816 | Apr 2006 | US |
Child | 12390001 | US |