Patent Application
20080245535
In the hydrocarbon recovery arts, actuation tools are a familiar component of most wellbore operations. Many different wellbore tools require setting once they are appropriately positioned in the downhole environment. Some examples include packers and bridge plugs although it will be recognized by those of skill in the art that many other devices also require setting. In many cases, the setting operation of such devices requires an axial motion. While hydraulic pressure derived from hydrostatic well pressure or from a pressure increasing action may be sufficient for some devices, others, because of their particular construction, are not settable based upon direct application of hydraulic pressure and instead require alternate actuation.
Since there are a large number of different types of tools and a large number of types of actuation, the art is always in search of alternative actuation tool configurations.
An actuation tool includes a mandrel; at least one protrusion in the mandrel representing a deformation of the material of the mandrel resulting in the mandrel having a lesser axial dimension than it does with the protrusion removed or diminished; and a fluid inlet positioned to facilitate application of pressure to one of an inside or outside surface of the mandrel.
A method for applying a linear force includes applying pressure to the tool described immediately above, undeforming the at least one protrusion and causing extension of the mandrel due to the undeforming.
Referring now to the drawings wherein like elements are numbered alike in the several Figures:
Referring to
Each deformed portion 14 is formed by a circumferential radially inward collapse of the material of mandrel 12 to form inside dimensions 22 of portions 14 that are smaller than an inside dimension 24 of an undeformed portion 26 of mandrel 12. In some configurations, the difference in inside dimension(s) 22 to inside dimension(s) 24 is substantial while in other configurations, it may be less. Moreover, it should be noted that in different portions 14 in the same mandrel 12, the inside dimensions 22 may be different in order to create a staged actuation. This is possible because depending both upon the axial length of a deformed portion 14 and the amount of deformation of that portion 14, the angle presented by the frustocones 20 is varied. The greater the angle, the higher the hydraulic pressure required to undeform the portion (and the greater the length change). Where different configurations of the portions 14 are included in the same tool, then, the tool will extend more slowly as individual portions undeform in a sequence governed by their individual angular structure.
Alternatively, to the forgoing explanation of sequenced elongation of the mandrel 12, it is also possible to create such sequencing by varying the thickness of the material at individual deformed portions 14. In this alternative, the thinner material sections will undeform first followed sequentially by the next successively thicker section. It will also be appreciated that angularity and material thickness can also be used together in some embodiments.
Facilitating creation of the deformed portions, in one embodiment, is a plurality of lines of weakness in the material of the mandrel. These lines of weakness are substantially circumferential and may represent a complete circumference or a broken circumference as desired. The lines of weakness in one configuration may be grooves in the material of mandrel 12 located at numerals 30, 32 and 34. It is to be noted that the lead lines for numerals 30, 32, and 34 not only point to nodes of deformation of the mandrel 12 but also indicate which surface of mandrel 12 is grooved. The grooves in one embodiment are positioned such that when the deformation of the deformed position 14 is effected, the grooves close.
While preferred embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.
