What Is a Blowout Preventer?

The blowout preventer is used to close the wellhead during oil test, workover, completion and other operations to prevent blowout accidents. It integrates the full seal and half seal functions into one. It has the characteristics of simple structure, easy operation and high pressure resistance. , Is a well-sealed wellhead device commonly used in oilfields to prevent blowouts.

blow-out preventer (BOP)

Installed at the wellhead when drilling for oil

Because there are many and complex factors in the formation, each drilling operation has the possibility of blowout, which puts forward higher requirements for well control technology and well control equipment. As the most important well control equipment, once an emergency situation such as overflow, blowout, or blowout occurs during drilling operations, the blowout preventer needs to start the shut-in quickly. At this time, if the blowout preventer fails, it will cause blowout, etc. Vicious accident. Therefore, the rational design of the blowout preventer plays an important role in ensuring the smooth running of drilling operations and personal safety.

Blowout preventer is the most important well control device, which plays an important role in drilling, especially underbalanced drilling. The purpose of designing the blowout preventer is to close the wellbore under pressure, maintain continuous control of the well, and circulate the formation fluids entering the well.

There are two types of hydraulic BOPs: ram BOP and ring BOP. The ram preventer is mainly composed of a housing, a side door, an oil cylinder, a cylinder head, a piston, a piston rod, a lock shaft, a seal, a ram, and the like. The working process is to use hydraulic pressure to push the piston to drive the shutter to close or open, so as to close or open the wellhead, to achieve the purpose of sealing and opening the well.
The ram of the ram preventer can be divided into four types: full-sealed, semi-sealed, reducer and shear. The semi-sealed sluice can be used to close the corresponding pipes such as drill pipes and tubing under different conditions. When necessary, the drilling tool can also be suspended. When there is no pipe in the well, the fully sealed sluice can fully seal the wellhead. In special cases, the cutting sluice can cut the drilling tool. In addition, the flange side outlet of the casing can be used for drilling fluid circulation and throttling well killing operations.

The type of annular blowout preventer can be divided into cone-shaped annular blowout preventer and ball-shaped annular blowout preventer according to the shape of its sealing rubber core, and its structure is mainly composed of a shell, a top cover, a rubber core and a piston. When there is a drilling tool, tubing or casing in the well, the annular BOP can use a rubber core to close the annular space of various sizes. When there is no drilling tool in the well, the wellhead can be completely closed for drilling, coring, and testing. During wells and other operations, the circular space formed by the square drill pipe, coring tools, cables and wires and the wellbore can be closed. With the use of a pressure reducing and regulating valve, the drilling tool can be forcibly raised and lowered by the drill pipe.

The two types of toroidal BOPs have similar working principles. When wells are found to need to be sealed, the high-pressure oil sent from the control system enters the lower part of the piston from the lower oil port to close the cavity to push the piston upward. When it moves upward, the conical rubber core moves closer to the center due to the limitation of the top cover and the squeeze of the inner cone surface of the piston, tightening and embracing the drilling tool to achieve the sealed drilling tool or fully-closed well opening, the piston descends and the rubber core Reset under the action of its own elasticity to open the wellhead. ^[1]

SY / T 5053.1 -2000 BOP and control device BOP SY / T 5053.2-2007 Specification for drilling wellhead control equipment and diverting equipment control system

SY / T 6160-2014 BOP inspection and maintenance