Water tight and gas tight flexible fluid compensation bellow

1. An apparatus for protecting a functional fluid, comprising:

an outer pliant shell;

an inner pliant shell disposed inside the outer pliant shell, wherein a sealed space separates the inner and outer pliant shells, and wherein the inner pliant shell defines a variable volume for receiving the functional fluid; and

a filler filling the sealed space, the filler including a sorbent mixed with a liquid, the sorbent being configured to store a foreign fluid.

2. The apparatus of claim 1 , further comprising at least one spacer disposed in the space and separating the inner and the outer pliant shells, the at least one spacer having at least one passage along which the filler flows.

3. The apparatus of claim 1 , wherein the liquid is one of: (i) a hydrocarbon liquid, (ii) a gel, (iii) a grease.

4. The apparatus of claim 1 , wherein the liquid is pressurized to at least a value greater than atmospheric pressure.

5. The apparatus of claim 1 , further comprising a gas inhibiting lining applied to at least one of the outer pliant shell and the inner pliant shell.

6. The apparatus of claim 1 , further comprising a hydraulic source configured to circulate the functional fluid into and out of the variable volume.

7. An apparatus for protecting a functional fluid used in a wellbore in which an environmental media resides, comprising:

a conveyance device configured to be disposed in the wellbore;

a well tool positioned along the conveyance device and exposed to the environmental media, the well tool including:

an outer pliant shell,

an inner pliant shell disposed inside the outer pliant shell, wherein a sealed space separates the inner and outer pliant shells, and wherein the inner pliant shell defines a variable volume for receiving the functional fluid,

at least one ring-shaped body disposed in the space and separating the inner and the outer pliant shell, and

a filler filling the sealed space, wherein the filler includes at least one of: (i) a fluid pressurized to at least a value of a pressure external to the outer pliant shell, and (ii) a sorbent configured to store the environmental media; and

a hydraulic source positioned along the conveyance device and configured to circulate the functional fluid into and out of the variable volume.

8. The apparatus of claim 7 , wherein the variable volume includes a first volume and a second larger volume.

9. The apparatus of claim 7 , wherein the hydraulic source is a device configured to use the functional fluid in the wellbore.

10. The apparatus of claim 9 , wherein the wellbore device is selected from one of: (i) a drilling motor, (ii) an actuator, (iii) a hydraulic motor, (iii) a motor for operating a hole enlargement device.

11. A method for protecting a functional fluid used in a wellbore in which an environmental media resides, comprising:

forming an enclosure having an outer pliant shell, an inner pliant shell disposed inside the outer pliant shell, wherein a sealed space separates the inner and outer pliant shells, and wherein the inner pliant shell defines a variable volume;

at least partially filling the sealed space with a filler that includes a sorbent mixed with a liquid, the sorbent being configured to store a foreign fluid;

positioning the enclosure along a conveyance device conveyed into the wellbore;

at least partially filling the variable volume with the functional fluid;

circulating the functional fluid into and out of the variable volume using a hydraulic source while the enclosure is in the wellbore.

12. The method of claim 11 , wherein the variable volume includes a first volume and a second larger volume.

13. The method of claim 11 , further comprising pressurizing a fluid in the filler to at least a value of a pressure external to the outer pliant shell.