Annular blowout preventer use requirements?

BOP product introduction

1. Function

Under the cooperation of the hydraulic control system, when there are drilling tools in the well, annular spaces of different sizes can be closed; when there is no drilling tool in the well, the well head can be completely closed. In the process of coring and logging, if a blowout occurs, the annular space formed by the kelly, coring tools, cables and wire ropes and the wellbore can be closed. Through the cooperation of pressure reducing valve, pressure regulating valve and buffer accumulator, it is possible to learn 18-degree butt-welded drill pipe without fine thread for forced tripping operation.

2. The working principle of the annular blowout preventer

The annular blowout preventer is operated by a hydraulic control system. When closing, the pressure oil enters the closed cavity at the lower part of the piston from the oil port in the middle of the housing, pushes the piston upward, and the cone of the piston squeezes the rubber core. Due to the limitation of the top cover, the rubber core cannot rise and can only be squeezed to the center of the wellhead until the drilling tool is tightly grasped or the wellhead is completely closed, thereby achieving the purpose of sealing the well.

When it is necessary to open a well, operate the reversing valve of the hydraulic control system to make high-pressure oil enter the open cavity of the upper part of the piston from the oil port on the shell, push the piston down, close the cavity to release the pressure, and eliminate the effect on the cone of the rubber core The rubber core gradually resets under the action of its own elastic force and opens the wellhead.

BOP manufacturers

3. Requirements for the use of annular blowout preventers

(1) When a blowout occurs when there is a drilling tool in the well, the well head can be controlled by the annular blowout preventer, but do not close it for a long time. One rubber core is easily damaged, and the other has no locking device. Unless there are special circumstances, it is not used to seal empty wells.

(2) Snubbing operations with annular blowout preventers must use drilling tools with a slope of 18 degrees. When crossing the joints, the speed of tripping and drilling should be slow, and the rubber guards on all drilling tools should be completely removed.

(3) When the annular blowout preventer is closed, when the shut-in pressure is lower than 5Pa, the drilling tool can move up and down. However, rotating drilling tools is prohibited.

(4) It is strictly forbidden to open the annular blowout preventer to release the pressure in the well to avoid puncturing the rubber core.

(5) After each well is opened, check whether it is fully opened to prevent damage to the rubber core.

(6) After cementing, plugging and other operations, the inner cavity should be flushed and the switch should be flexible.

(7) When installing or removing the annular blowout preventer, special attention must be paid to the gasket and steel ring groove, and no damage or scratches are allowed.

(8) After entering and exiting the target layer, try to shut in the well with the drilling tool every trip to check the sealing effect of the rubber core. If it does not meet the requirements, it should be replaced immediately.

(9) According to relevant standards, wellhead annular blowout preventers should be tested regularly.