The present invention relates generally to operations performed and equipment utilized in conjunction with subterranean wells and, in an embodiment described herein, more particularly provides equipment and methods for use in underbalanced well completions.
At times it is useful to be able to isolate a portion of a tubular string, such as a production tubing, drill pipe, liner or casing string, from the remainder of the tubular string. For example, while drilling underbalanced, it is useful to be able to periodically trip a drill string in and out of the well without killing the well. In that instance, a valve may be interconnected in a casing string, the valve being opened upon tripping in the drill string, and the valve being closed when the drill string is tripped out of the well. A valve suitable for such an application is described in U.S. Pat. No. 6,152,232, the entire disclosure of which is incorporated herein by this reference.
Other uses include running completion assemblies (including perforated or slotted liners) after drilling underbalanced, drilling overbalanced in areas of lost circulation to prevent kicks and loss of mud while tripping the drill string, and drilling in deep water where pore pressure and fracture gradient provide a narrow window for acceptable mud density and use of lower mud density is desired.
From the foregoing, it can be seen that it would be quite desirable to provide improvements in underbalanced well drilling and completions, in other operations, and in equipment utilized in these operations.
In carrying out the principles of the present invention, in accordance with an embodiment thereof, an apparatus is provided which is an improvement over prior equipment utilized in the operations described above.
In one aspect of the invention, a well system is provided. The well system includes an apparatus positioned in a well and a tool conveyed through the apparatus in a container. The container engages the apparatus, actuating the apparatus and separating from the tool, as the tool is displaced through the apparatus.
In another aspect of the invention, an apparatus for use in a subterranean well in conjunction with a tool conveyed through the apparatus in a container is provided. The apparatus includes an engagement device which engages the container, preventing relative displacement between the container and the apparatus, as the tool is conveyed through the apparatus.
In yet another aspect of the invention, a valve for use in a subterranean well in conjunction with a tool conveyed through the valve in a container is provided. The valve includes a passage formed longitudinally through the valve, a closure assembly which selectively permits and prevents flow through the passage, and an engagement device which engages the container as the tool is conveyed through the passage. The closure assembly permits flow through the passage when the container is conveyed into the passage, and the closure assembly prevents flow through the passage when the container is removed from the passage. Engagement between the container and the engagement device separates the tool from the container.
These and other features, advantages, benefits and objects of the present invention will become apparent to one of ordinary skill in the art upon careful consideration of the detailed description of a representative embodiment of the invention hereinbelow and the accompanying drawings.
Representatively illustrated in
As depicted in
Another tubular string 20 is positioned in the casing string 14. The tubular string 20 is used in the system 10 to convey a tool 22 through the passage 18. Representatively, the string 20 is a drill string. However, the string 20 could be another type of conveyance, such as a production tubing string, a wireline, etc., in keeping with the principles of the invention.
The tool 22 could be a drill bit, a perforated or slotted liner, a mud motor, a production tool, a completion tool, a drilling tool, a packer, a multilateral tool, or any other type of well tool. Representatively, the tool 22 is a drill bit used to drill a wellbore extension 24 below the casing string 14. In this situation, it may be desirable to close the valve 12 while the string 20 is tripped in and out of the wellbore 16, such as when drilling overbalanced or underbalanced, but the valve would be opened when the drill bit 22 is conveyed therethrough into the wellbore extension 24 for further drilling.
In a unique feature of the invention, the drill bit 22 is conveyed in a container 26 attached to the drill string 20. As the container 26 is conveyed into the valve 12, the container engages the valve, operates the valve to open a closure assembly 28 of the valve, and then the container disengages from the tool, allowing the tool 22 to be conveyed into the wellbore extension 24 on the drill string 20, without the container.
One advantage of this system lo is that the container 26 may be configured so that it can accommodate a variety of tools, and so a different container does not have to be constructed for each tool conveyed through the valve 12. For example, the container 26 may be used to convey the drill bit 22 through the valve 12 during drilling operations, and then the same or a similar container may be used to convey an item of completion equipment (such as a packer, etc.) through the valve after drilling operations are completed.
Referring additionally now to
When closed as shown in
Referring additionally now to
The drill bit 22 is contained in the sleeve 36 between a shoulder 42 formed internally on the sleeve and a plug or abutment 44 closing off a lower end of the sleeve. If desired, the drill bit 22 may additionally be secured relative to the sleeve 36, for example, using shear screws 46 or another type of securing device. However, preferably the drill bit 22 is permitted to rotate and/or reciprocate within the container 26.
The abutment 44 may be secured relative to the sleeve 36 using shear screws 48, or another type of securing device. Preferably, the abutment 44 is made of a tough but relatively easily drillable material, such as a composite material, relatively soft metal, etc. The abutment 44 may be bonded to the sleeve 36, for example, using adhesives or other bonding agents.
The sleeve 36 could also be made of a composite material (or another relatively easily drillable material), in which case the sleeve and abutment 44 could be molded together, or otherwise integrally formed. If the sleeve 36 is made of a composite material, then the seal surfaces 50 may also be made of a composite material, or another relatively easily drillable material.
As the container 26 is conveyed into the valve 12, the abutment 44 contacts the closure assembly 28 and pivots the flapper 30 downward, thereby opening the passage 18. Damage to the flapper 30 and seat 32 is prevented in part by the abutment 44 being made of the relatively easily drillable material.
The sleeve 36 then enters and maintains the flapper 30 in its opened position. Again, damage to the flapper 30 and seat 32 may be prevented by the sleeve 36 being made of the relatively easily drillable material. Sealing engagement between the seals 38 and seal surfaces 50 formed externally on the sleeve 36 isolates the closure assembly 28 from debris, etc. in the passage 18.
For example, during drilling operations this sealing engagement may prevent cuttings from becoming lodged in the closure assembly 28. The sleeve 36, or a similar sleeve, may be positioned in the valve 12 while the casing 14 is cemented in the wellbore 16, in which case the sleeve would prevent cement from contacting the closure assembly 28.
As described above, a lower end of the sleeve 36 contacts the shoulder 40, preventing further downward displacement of the sleeve relative to the valve 12. If the shear screws 46 or other securing devices are used, then at this point a downwardly directed force may be applied to the drill bit 22 (such as by slacking off on the drill string 20 to apply the drill string weight to the bit) in order to shear the screws 46. However, if the drill bit 22 is not secured to the sleeve 36 (other than being contained between the shoulder 42 and abutment 44), then this step is not needed.
Referring additionally now to
As illustrated in
However, if the abutment 44 is releasably attached to the sleeve 36, such as by using the shear screws 48 as depicted in
After the drill bit 22 has cut through or otherwise released the abutment 44 from the sleeve 36, the drill bit and drill string 20 are used to drill the wellbore extension 24. When the time comes to trip the drill string 20 out of the wellbore, or otherwise raise the drill bit 22 back up through the valve 12, the drill bit will eventually contact the internal shoulder 42 in the sleeve 36. As the drill bit 22 is raised further, the sleeve 36 will also be raised therewith, and with the sleeve no longer maintaining the flapper 30 in its open position, the closure assembly 28 will close off the passage 18.
Of course, a person skilled in the art would, upon a careful consideration of the above description of representative embodiments of the invention, readily appreciate that many modifications, additions, substitutions, deletions, and other changes may be made to these specific embodiments, and such changes are contemplated by the principles of the present invention. Accordingly, the foregoing detailed description is to be clearly understood as being given by way of illustration and example only, the spirit and scope of the present invention being limited solely by the appended claims and their equivalents.
Number | Name | Date | Kind |
---|---|---|---|
4606416 | Knighton et al. | Aug 1986 | A |
6142226 | Vick | Nov 2000 | A |
6152232 | Webb et al. | Nov 2000 | A |
6167974 | Webb | Jan 2001 | B1 |
6343658 | Webb | Feb 2002 | B2 |
6557637 | Dore et al. | May 2003 | B1 |
Number | Date | Country | |
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20050034854 A1 | Feb 2005 | US |