configuration includes a way to apply annular pressure to the reservoir 34 and compensate for dissipation of the fluid 36 into the material 24 a passage 40 is formed through the material 24 and an end ring 42 the passage 40 provides for fluid communication between the annulus 26 and another chamber 44 formed in the material 24 a pressure equalizing device 46 such as a floating piston a membrane etc separates the annulus fluid 38 from the fluid 36 in the reservoir 34 while transmitting pressure from the annulus 26 to the reservoir in this manner pressure in the annulus 26 is available to pressurize the fluid 36 and u201c drive u201d the fluid into the material 24 if needed and the fluid 38 can enter the chamber 44 as the fluid 36 dissipates into the material 24 referring additionally now to fig4 a portion of the swellable material 24 is representatively illustrated in further enlarged scale from another alternate configuration of the well tool 20 the portion of the swellable material 24 illustrated in fig4 includes the reservoir 34 which in this embodiment does not include the pressure transmitting and equalizing features described above for the configuration of fig3 instead the configuration of fig4 includes features.