SEALING ELEMENT

摘要

The invention comprises a uniquely shaped sealing element or elements for a packer. In an application using a stack of elements, the upper element is configured so that at least a portion of its inside diameter represents an interference fit with the mandrel onto which it is mounted. A built-in moment within the packing element occurs as a result of the partial interference fit. Additionally, a taper is provided which, in effect, shifts the point of contact of the upper element closer to a central element, tending to better give extrusion support to the central element. The taper also facilitates the creation of a resistive moment which fights the tendency of the upper element to extrude in the upper outermost corner of the upper element, for example. The central element can also be installed on a mandrel with interference throughout its length to create a built-in radial force urging the element back into its original shape after it is expanded and allowed to relax. Using such shapes, the need to mechanically stretch the elements longitudinally, after they are relaxed so that the packer can be withdrawn without interference in a close running situation, is eliminated.