XIN YUAN LIAN SHENG

The blowout preventer is used to seal the well head in oil testing, workover and completion operations to prevent blowout accidents. It integrates full sealing and semi-sealing functions in one, and has the characteristics of simple structure, easy operation and high pressure resistance. It is a sealing wellhead device commonly used in oil field to prevent blowout.

The blowout preventer is an important well control device, which plays an important role in drilling, especially in underbalanced drilling. A blowout preventer is designed to close the hole under pressure, maintain continuous control of the well, and circulate formation fluids entering the well.

The blowout preventer mainly includes ram preventer and ring preventer. Ram BOP is mainly composed of shell, side door, cylinder, cylinder head, piston, piston rod, lock shaft, seal, ram and so on. The working process is to use hydraulic piston to drive the ram 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 a blowout preventer can be divided into four types: fully sealed, semi-sealed, reduced diameter and shear ram, which are used for sealing well under different conditions. The semi-sealed ram can seal the corresponding pipe such as drill pipe and oil pipe, and the drill pipe can be suspended if necessary. When there is no pipeline in the well, the fully sealed ram can completely seal the wellhead. In special cases, the shear ram can cut the drill. In addition, drilling fluid circulation and throttling kill operations can be performed at the flange outlet next to the casing.

According to the shape of its sealant core, the annular BOP can be divided into conical annular BOp and spherical annular BOp. Its structure is mainly composed of four parts: shell, top cover, rubber core and piston. When there are drilling tools, tubing or casing in the well, the annular BOP can seal various annular Spaces with a rubber core. When there is no drilling tool in the well, the well head can be completely closed during drilling, coring, logging and other operations, and the annular space formed by the kelly pipe, coring tool, cable, and steel wire can also be closed.

The two types of annular blowout preventers work similarly. When it is found that the kick needs to be sealed, the high-pressure oil delivered by the control system enters the closed chamber under the piston from the lower oil port and pushes the piston upward. The spherical rubber core moves upward along the spherical surface, while the conical rubber core is constrained by the top cover, squeezed under the inner cone of the piston, moves to the center, pulls and holds the drill tool tightly, so that the drill tool is sealed or completely sealed, and the wellhead is opened.