Abstract: A rubber cylinder includes rigid seal rings on both ends, a packer, and a bridge. The rubber cylinder comprises a wire seal ring, a filament seal ring, and rigid seal rings. The wire seal ring abuts the filament seal ring and is disposed below the filament seal ring. The wire seal ring comprises a plurality of wires intersecting each other and a colloid bonding all the wires together. The filament seal ring comprises a plurality of high-temperature high-pressure resistant filaments intersecting each other and a colloid bonding all the filaments together. When the wire seal ring is disposed below the filament seal ring, friction between the wire seal ring and a central tube and/or a casing reduces an axial pressure transferred to the filament seal ring. Such reduction further reduces the occurrence of an extruded shoulder.

Abstract: A hardness of an upper end portion of a rubber cylinder is greater than a hardness of a middle portion, so that when the upper end portion bears a first axial pressure, the deformation of the middle portion in a radial direction is greater than the deformation of the upper end portion in the radial direction. A packer and a bridge plug include the rubber cylinder. The hardness of the upper end portion is greater than the hardness of the middle portion. When the upper end portion is subject to the first axial pressure, the upper end portion more likely transfers the first axial pressure to the middle portion and a lower end portion instead of deforming radially itself. A relatively small first axial pressure can be used to enable the middle portion and the lower end portion to deform radially, thereby achieving an overall seal of the rubber cylinder.

Abstract: A rubber cylinder with rigid seal rings on both ends, a packer, and a bridge. The rubber cylinder comprises a wire seal ring, a filament seal ring, and rigid seal rings. The wire seal ring abuts the filament seal ring and is disposed below the filament seal ring. The wire seal ring comprises a plurality of wires intersecting each other and a colloid bonding all the wires together. The filament seal ring comprises a plurality of high-temperature high-pressure resistant filaments intersecting each other and a colloid bonding all the filaments together. When the wire seal ring is disposed below the filament seal ring, friction between the wire seal ring and a central tube and/or a casing reduces an axial pressure transferred to the filament seal ring, Such reduction further reduces the occurrence of an extruded shoulder.