Annular blowout preventers are usually equipped with large gates with ram-type blowout preventers. During operation, a sealed annular space is formed between the pipe string and the wellbore. When there is no pipe string in the well, the well can be closed alone, but It will not work after a few times of use, and long-term shut-in use is not allowed.
When the conical rubber core annular blowout preventer shuts in, the pressure oil from the hydraulic control system enters the lower oil chamber (closes the oil chamber) and pushes the piston to move up quickly. The rubber core cannot move up due to the restriction of the top cover. Under the action of the surface, it is forced to squeeze and shrink the drilling tool towards the center of the wellbore, encircling the drilling tool, and seal the annular space of the wellhead. When there is no drilling tool in the well, the rubber core is squeezed toward the center and contracted until the hollow part of the rubber core is filled with rubber, thereby completely sealing the wellhead. At the same time, the hydraulic oil in the upper oil chamber flows back to the oil tank through the hydraulic control system pipeline.
When opening the tapered rubber core annular preventer, the pressure oil from the hydraulic control system enters the upper oil chamber (opening the oil chamber) to push the piston down quickly. The squeezing force of the inner cone of the piston against the rubber core quickly disappears, and the rubber core expands outwards by the elasticity of its own rubber to restore its original shape, and the well head is fully opened. At the same time, the hydraulic oil in the lower oil chamber flows back to the oil tank through the hydraulic control system pipeline.
We have different types of annular BOP for your different application.
