Abstract: A device and method for sealing a first cylinder in a fixed position inside a second concentric cylinder. The inner cylinder has an annular depression in its wall at the point of sealant placement, which causes the wall of the inner cylinder to intrude inwardly. The depression is filled with a partially compressible fluid and is covered over by a malleable/ductile sleeve. The inner cylinder is placed within the outer cylinder with the covered annular depression positioned at the desired sealing point. A cylindrical displacement device is directed through the inside of the inner cylinder where it encounters the intrusion of the annular depression. The displacement device is forced past the annular intrusion and pushes the wall outward. The partially compressible fluid is forced to expand outward under the malleable/ductile cover in a manner that intrudes into the annular space between the inner cylinder and the outer cylinder and into contact with the outer cylinder.