process known to the industry and does not require specific disclosure with respect to how it is accomplished in a completion operation the temporary plugging of the devices can be useful to allow for the density of the string to be reduced thereby allowing the string to u201c float u201d into a highly deviated or horizontal borehole this is because a lower density fluid gas or liquid than borehole fluid may be used to fill the interior of the string and will not leak out due to the hardenable material in the devices upon conclusion of completion activities the hardenable material may be removed from the devices to facilitate production through the completion string another operational feature of temporarily rendering impermeable the devices 10 is to enable the use of pressure actuated processes or devices within the string clearly this cannot be accomplished in a tubular with holes in it due to the pressure holding capability of the devices 10 with the hardenable material therein pressure actuations are available to the operator one of the features of the devices 10 that assists in pressure containment is the shoulder 20 mentioned above the shoulder 20 provides a physical support for the matrix 14 that reduces the possibility that the matrix itself could be pushed out of the tubular in which the device 10 resides in some embodiments this can eliminate the.