a borehole plug or packer for treating is designed to be flowed back to a surface location after use . when the treatment is concluded pressure from above is relieved or lowered , and well fluid is flowed back , so that the plug or plugs disengages at slips designed to resist differential pressure from above . the application of differential pressure from below causes the lower slips to release one or more of such plugs in the hole into specialized sub surface or surface capture equipment so that well pressure is relieved before removal of the plugs from specialized subsurface or surface capture equipment . sensors to obtain and store data can be incorporated into the plugs or into objects landed on the plugs so that when brought to the surface the data can be processed and used in aid of production .