Annular Blowout Preventer: Operational Principles and Safety Guidelines

Annular Blowout Preventer: Operational Principles and Safety Guidelines

The Annular Blowout Preventer (BOP) is an integral part of well control, operating through a hydraulic control system. Understanding its working principle and4 1/16" Annular BOP adhering to Annular Blowout Preventerspecific operational requirements are essential for ensuring the effective sealing of the well and maintaining safety standards.

Annular Blowout Preventer Size:

4 1/16" Annular BOP，7 1/16" Annular BOP, 11" Annular BOP, 9 5/8" Annular BOP, 13 5/8" Annular BOP

Annular Blowout Preventer Pressure:

5000psi, 10000psi, and hight pressure BOP High Pressure BOP15000psi

Working Principle:

The hydraulic control system governs the operation of the annular blowout preventer. When in the closed position, high-pressure oil from the middle oil port of the shell enters the lower closing cavity of the plunger, propelling the plunger upwards. The cone plunger then compresses the rubber core, constrained by the top cover. The rubber core is pushed towards the center of the well, achieving the crucial goal of sealing the well.

To open the well, the directional control valve in the hydraulic control system is manipulated. This action directs high-pressure oil from the upper part of the shell to the upper open cavity of the plunger, causing it to descend. The closed cavity releases pressure, relieving the extrusion pressure on the rubber core. The rubber core gradually resets under its own elastic force, facilitating the opening of the wellhead.

Operational Requirements:

Precautions during Blowouts:

When a blowout occurs with drilling tools present, the annular blowout preventer can be employed to control the wellhead. However, it is advised not to keep it closed for an extended period due to potential damage to the rubber core and the absence of a locking device. It is not suitable for sealing an empty well unless under special circumstances.

In Stripping Operations:

Tools with an 18-degree inclined slope are necessary for stripping operations with the annular blowout preventer. When encountering a joint, slow down the tripping speed, and remove all rubber protectors from the drill.

Closed State Requirements:

When the annular blowout preventer is closed, the shut-in pressure should be below 5 Mpa. Drilling tools can move up and down, but rotation is strictly prohibited.

Draining Borehole Stress:

It is strictly forbidden to drain borehole stress by opening the annular blowout preventer to safeguard the rubber core from potential damage.

Well Opening Checks:

Every time the well is opened, a thorough check must be conducted to ensure it is fully open, preventing any tearing of the rubber core.

Post-Cementing Operations:

After well cementing and leakage operations, the lumen should be rinsed, and the switch mechanism must be kept flexible.

Installation and Removal:

Special attention must be paid to the seal ring and steel ring groove during the installation or removal of the annular blowout preventer. Any damage or scratches are strictly not allowed.

Objective Layer Entry:

Upon entering the objective layer, a drilling tool should be employed to shut-in the well using the rubber core. If this does not meet the requiremAnnular BOPents, immediate replacement is necessary.

Regular Testing:

In accordance with relevant standards, the wellhead annular blowout preventer's pressure should undergo regular testing.

Adhering to these operational requirements ensures the effective and safe utilization of the annular blowout preventer in drilling operations, preventing potential hazards and enhancing overall well control measures.