Wells – Processes – Placing or shifting well part
Reexamination Certificate
2002-05-15
2004-03-23
Neuder, William (Department: 3672)
Wells
Processes
Placing or shifting well part
C166S118000, C166S134000, C166S217000
Reexamination Certificate
active
06708770
ABSTRACT:
BACKGROUND OF THE INVENTION
2. Field of the Invention
This invention relates generally to methods and apparatus for drilling and completing subterranean wells and, more particularly, to methods and apparatus for a drillable bridge plug, frac plug, cement retainer, and other related downhole apparatus, including apparatus for running these downhole apparatus.
3. Description of Related Art
There are many applications in well drilling, servicing, and completion in which it becomes necessary to isolate particular zones within the well. In some applications, such as cased-hole situations, conventional bridge plugs such as the Baker Hughes model T, N1, NC1, P1, or S wireline-set bridge plugs are inserted into the well to isolate zones. The bridge plugs may be temporary or permanent; the purpose of the plugs is simply to isolate some portion of the well from another portion of the well. In some instances perforations in the well in one portion need to be isolated from perforations in another portion of the well. In other situations there may be a need to use a bridge plug to isolate the bottom of the well from the wellhead. There are also situations where these plugs are not used necessarily for isolation but instead are used to create a cement plug in the wellbore which may be used for permanent abandonment. In other applications a bridge plug with cement on top of it may be used as a kickoff plug for side-tracking the well.
Bridge plugs may be drillable or retrievable. Drillable bridge plugs are typically constructed of a brittle metal such as cast iron that can be drilled out. One typical problem with conventional drillable bridge plugs is that without some sort of locking mechanism, the bridge plug components tend to rotate with the drill bit, which may result in extremely long drill-out times, excessive casing wear, or both. Long drill-out times are highly undesirable as rig time is typically charged for by the hour.
Another typical problem with conventional drillable plugs is that the conventional metallic construction materials, even though brittle, are not easy to drill through. The plugs are generally required to be quite robust to achieve an isolating seal, but the materials of construction may then be difficult to drill out in a reasonable time. These typical metallic plugs thus require that significant weight be applied to the drill-bit in order to drill the plug out. It would be desirable to create a plug that did not require significant forces to be applied to the drill-bit such that the drilling operation could be accomplished with a coiled tubing motor and bit; however, conventional metallic plugs do not enable this.
In addition, when several plugs are used in succession to isolate a plurality of zones within the wellbore, there may be significant pressures on the plug from either side. It would be desirable to design an easily drilled bridge plug that is capable of holding high differential pressures on both sides of the plug. Also, with the potential for use of multiple plugs in the same wellbore, it would be desirable to create a rotational lock between plugs. A rotational lock between plugs would facilitate less time-consuming drill outs.
Additionally, it would be desirable to design an easily drillable frac plug that has a valve to allow fluid communication through the mandrel. It would be desirable for the valve to allow fluid to flow in one direction (e.g. out of the reservoir) while preventing fluid from flowing in the other direction (into the reservoir). It is also desired to design an easily drillable cement retainer that includes a mandrel with vents for circulating cement slurry through the tool.
Finally, it is desired to provide a wire line adapter kit that will facilitate the running of the drillable downhole tool, but still be releasable from the tool. Once released, the wire line adapter kit should be retrievable thus allowing the downhole tool to be drilled. Preferably, the wire line adapter kit should leave little, if any, metal components downhole, thus reducing time milling and/or drilling time to remove plugs.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the issues set forth above.
SUMMARY OF THE INVENTION
In one embodiment a subterranean apparatus is disclosed. The apparatus may include a mandrel having an outer surface and a non-circular cross-section and a packing element arranged about the mandrel, the packing element having a non-circular inner surface such that rotation between the mandrel and the packing element is precluded. The mandrel may include non-metallic materials, for example carbon fiber.
In one embodiment, the apparatus exhibits a non-circular cross-section that is hexagonally shaped. The interference between the non-circular outer surface of the mandrel and the inner surface of the packing element comprise a rotational lock.
In one embodiment the apparatus includes an anchoring assembly arranged about the mandrel, the anchoring assembly having a non-circular inner surface such that rotation between the mandrel and the anchoring assembly is precluded. The anchoring assembly may further include a first plurality of slips arranged about the non-circular mandrel outer surface, the slips being configured in a non-circular loop such that rotation between the mandrel and the slips is precluded by interference between the loop and the mandrel outer surface shape. The first plurality of slips may include non-metallic materials. The first plurality of slips may each include a metallic insert mechanically attached to and/or integrally formed into each of the plurality of slips wherein the metallic insert is engagable with a wellbore wall. The anchoring assembly may also include a first cone arranged about the mandrel, the first cone having a non-circular inner surface such that rotation between the mandrel and the first cone is precluded by interference between the first cone inner surface shape and the mandrel outer surface shape. The first plurality of slips abuts the first cone, facilitating radial outward movement of the slips into engagement with a wellbore wall upon traversal of the plurality of slips along the first cone. In this embodiment, the first cone may include non-metallic materials. At least one shearing device may be disposed between the first cone and the mandrel, the sharing device being adapted to shear upon the application of a predetermined force.
The anchoring assembly of the apparatus may further include a second plurality of slips arranged about the non-circular outer surface of the mandrel, the second plurality of slips, the slips being configured in a non-circular loop such that rotation between the mandrel and the slips is precluded by interference between the loop and the mandrel outer surface shape. The second plurality of slips may include non-metallic materials. The second plurality of slips may each include a metallic insert mechanically attached to and/or integrally formed therein with the metallic inserts being engagable with the wellbore wall. The anchoring assembly may also include a second collapsible cone arranged about the non-circular outer surface of the mandrel, the second collapsible cone having a non-circular inner surface such that rotation between the mandrel and the second cone is precluded by interference between the second cone inner surface shape and the mandrel outer surface shape, wherein the second plurality of slips abuts the second collapsible cone, facilitating radial outward movement of the slips into engagement with the wellbore wall upon traversal of the plurality of slips along the second collapsible cone. The second collapsible cone may include non-metallic materials. The second collapsible cone may be adapted to collapse upon the application of a predetermined force. The second collapsible cone may include at least one metallic insert mechanically attached to and/or integrally formed therein, the at least one metallic insert facilitating a locking engagement between the cone and the mandrel. The anchoring assembly may in
Lehr Douglas J.
Slup Gabriel
BJ Services Company
Neuder William
LandOfFree
Drillable bridge plug does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Drillable bridge plug, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Drillable bridge plug will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3237524