in the form of a wellbore casing 4 prior to setting of the packer assembly 2 the packer assembly 2 includes a packer device generally designated 6 mounted on a base member in the form of a base pipe 8 the base pipe 8 includes a coupling 9 at either end thereof for coupling the base pipe 8 to a tubular string not shown such as a completion string or a production string not shown the packer assembly 2 may be run into the wellbore casing 4 on the tubular string not shown prior to setting of the packer device 6 as will be described in more detail below the tubular string not shown may also be used for pulling the packer assembly 2 out of the wellbore casing 4 some time after the packer device 6 has been set the packer device 6 includes an upper end ring 10 and a lower end ring 12 the packer device 6 includes a deformable sleeve 14 which extends around the base pipe 8 from the upper end ring 10 to the lower end ring 12 the deformable sleeve 14 is formed from steel and has a wall thickness in the range of 1.