Hydropneumatic packer

The utility model relates to a hydropneumatic packer used for filling steam for a thickened oil well in an oil field. An upper joint of the packer is connected with a heat insulation pipe or an oil pipe through screw threads, and a lower joint is connected with a tail pipe through screw thread. After steam enters a center pipe through the heat insulation pipe, a decompression valve is fixed by pins and closed, and therefore, air pressure pushes a steel ball embedded in the center pipe to move outwards. At that time, liquid is pushed by the steel ball to jack up the center of a rubber cylinder, and the lower end of the rubber cylinder moves upwards simultaneously. A propeller also moves upwards along with the lower end of the rubber cylinder, and a spring in a booster extends along with the movement of the propeller. As the rubber cylinder does not expand any longer after the rubber cylinder contacts a sleeve pipe, the pressure of the center pipe increases. After the pressure achieves definite value, two pin nails which are used for fixing the decompression valve are cut off, the decompression valve is opened, and the steam enters a target layer through the decompression valve. The center pipe has no pressure after the steam is filled, and the rubber cylinder is not be sealed any longer. The decompression valve is closed automatically, and base oil can not enter the heat insulation pipe. When the operation is lifted, the utility model can not clamp the well, and blowout can not occur. Therefore, the utility model can be widely used in the operation of steam filling for the thickened oil well in the oil field.