Packer elements are essential for subterranean well completion and hydrocarbon production.  They are used to establish and maintain an annular fluid seal between an inner tubular and a surrounding wall, which may be an outer tubular or an open borehole.  Achieving a reliable annular fluid seal can be challenging, especially in expanded or eroded casing and open boreholes, each of which may have an inconsistent internal diameter due to any number of uncontrollable factors.  Furthermore, although open borehole completions are generally considered to be advantageous from a cost perspective and are known to have hydrocarbon production advantages, cased and cemented wellbore completions have become commonplace because the cemented annulus provides a secure seal between the production casing and the wellbore and stabilizes the casing, making establishing and maintaining an annular seal in the cased and cemented wellbore more reliable and dependable than in an open wellbore. 
Numerous designs and formulations for packer elements are known.  In the past, packer elements were made from chemical-resistant elastomers but those packer elements had limited expansion capacity.  In order to provide a more expansive packer element for use between a production casing and an open wellbore, swellable packer elements were invented and have become widely used for open wellbore completions.  Swellable packer elements contain fluid absorbing compounds that expand as they absorb certain well fluids to provide an annular seal between the production casing and the open wellbore.  However, long term absorption of the well fluids can compromise the strength of the swellable packer element and eventually result in a loss of packer element integrity and a failure of the annular seal. 
There therefore exits a need for a high-expansion packer element that is readily manufactured using known, non-absorptive packer element elastomers.