In the drilling and completions industry it is common to run a whipstock and a mill in the same run by hanging the whipstock from the end of the mill string. Once the whipstock has landed at a selected position and orientation within the borehole, the whipstock is anchored in place and will bear weight. Because the whipstock is necessarily thinner at the uphole end thereof, it has commonly been a practice in the industry to use a relatively large lug at the uphole end of the whipstock to support a set down weight from the mill string that is used to separate the mill from the whipstock, such as by shearing a screw. This arrangement presents a heavy piece of material that must be removed from the path of the mill. Milling the lug often damages the mill due to interrupted cuts, but is nevertheless often performed because of a lack of alternatives. Accordingly, improvements in affixation and release arrangements, particularly for mills, are well received by the industry.
A downhole affixation and release assembly includes a first component; a second component, and an interconnection device for at least temporarily securing the first component to the second component, the interconnection device operatively arranged to at least partially degrade upon exposure to a fluid.
A cutting assembly includes a mill operatively arranged to cut through a wall; a whipstock for directing the mill into the wall, the whipstock including an interconnection device for securing the mill to the whipstock during run-in, the interconnection device operatively arranged to at least partially degrade upon exposure to a downhole fluid.
A method of affixing and releasing two components includes, affixing a first component to a second component with an interconnection device; running the first and second components downhole; and degrading the interconnection device by exposing the interconnection device to a fluid.
The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike:
A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures.
Referring now to
After the whipstock 14 and the mill 12 are in place, e.g., by use of an anchor assembly for the whipstock 14, an event is triggered to release the release member 18. For example, if the release member 18 takes the form of a shear screw, applying a set down weight to the mill 12 will shear the release member 18, thereby freeing the mill 12 from the whipstock 14, as shown in
Alternatively, as shown in
The interconnection device 15 can be formed from materials that are degradable by exposure to a variety of fluids capable of being pumped, present, or delivered downhole such as water, acid, oil, etc. The degradable material could be a metal, a composite, a polymer, etc., or any other material that is suitably degradable and that can withstand the loads necessary to initially hang the whipstock 14 from the mill 12 during run-in, prevent distortion of the whipstock 14 during loading, etc. However, as described above, it may be possible to avoid very high set down loading by simply degrading the release member 18 after the whipstock is locked by the downhole anchor assembly, and thus, the interconnection device 15 may comprise just a release member in some embodiments. In one embodiment, the interconnection device 15, (i.e., the lug 16 and/or the release member 18) is manufactured from a high strength controlled electrolytic metallic material and is degradable by brine, acid, or aqueous fluid.
That is, materials appropriate for the purpose of degradable interconnection devices as described herein are lightweight, high-strength metallic materials. Examples of suitable materials, e.g., high strength controlled electrolytic metallic materials, and their methods of manufacture are given in United States Patent Publication No. 2011/0135953 (Xu, et al.), which Patent Publication is hereby incorporated by reference in its entirety. These lightweight, high-strength and selectably and controllably degradable materials include fully-dense, sintered powder compacts formed from coated powder materials that include various lightweight particle cores and core materials having various single layer and multilayer nanoscale coatings. These powder compacts are made from coated metallic powders that include various electrochemically-active (e.g., having relatively higher standard oxidation potentials) lightweight, high-strength particle cores and core materials, such as electrochemically active metals, that are dispersed within a cellular nanomatrix formed from the various nanoscale metallic coating layers of metallic coating materials, and are particularly useful in borehole applications. Suitable core materials include electrochemically active metals having a standard oxidation potential greater than or equal to that of Zn, including as Mg, Al, Mn or Zn or alloys or combinations thereof For example, tertiary Mg—Al—X alloys may include, by weight, up to about 85% Mg, up to about 15% Al and up to about 5% X, where X is another material. The core material may also include a rare earth element such as Sc, Y, La, Ce, Pr, Nd or Er, or a combination of rare earth elements. In other embodiments, the materials could include other metals having a standard oxidation potential less than that of Zn. Also, suitable non-metallic materials include ceramics, glasses (e.g., hollow glass microspheres), carbon, or a combination thereof In one embodiment, the material has a substantially uniform average thickness between dispersed particles of about 50 nm to about 5000 nm. In one embodiment, the coating layers are formed from Al, Ni, W or Al2O3, or combinations thereof In one embodiment, the coating is a multi-layer coating, for example, comprising a first Al layer, a Al2O3 layer, and a second Al layer. In some embodiments, the coating may have a thickness of about 25 nm to about 2500 nm.
These powder compacts provide a unique and advantageous combination of mechanical strength properties, such as compression and shear strength, low density and selectable and controllable corrosion properties, particularly rapid and controlled dissolution in various borehole fluids. The fluids may include any number of ionic fluids or highly polar fluids, such as those that contain various chlorides. Examples include fluids comprising potassium chloride (KCl), hydrochloric acid (HCl), calcium chloride (CaCl2), calcium bromide (CaBr2) or zinc bromide (ZnBr2). For example, the particle core and coating layers of these powders may be selected to provide sintered powder compacts suitable for use as high strength engineered materials having a compressive strength and shear strength comparable to various other engineered materials, including carbon, stainless and alloy steels, but which also have a low density comparable to various polymers, elastomers, low-density porous ceramics and composite materials.
While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.