XIN YUAN LIAN SHENG

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 a well under pressure and check that the well maintains continuous control and circulation of formation fluids into the well.Hydraulic blowout preventer mainly includes ram type blowout preventer and ring type blowout preventer.Ram BOP is mainly composed of shell,side door,cylinder,cylinder head,piston,piston rod,lock shaft,seal,door 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.

Ram The ram of the blowout preventer is divided into four types:fully sealed,semi-sealed,reduced diameter and cut,which are used for wellhead sealing under different conditions.The semi-sealed ram can seal the corresponding pipe,such as drill pipe,oil pipe,etc.Hang the drill if necessary.When there is no pipeline in the well,the fully sealed ram seals the wellhead.In special cases,the shear ram can cut through the drill.In addition,drilling fluid circulation can be used to throttle and kill the well at the flange outlet on the casing side.According to the shape of the 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,and when there is no drilling tool in the well,it can seal the wellhead for drilling.In coring and logging operations,it can also seal the annular space between kelly pipe,coring tool,cable and wire and the hole.In the case of pressure reducing and regulating valves,drilling tools can be used.The two annular blowout preventers work similarly.When it is found that the kick needs to be blocked,the high-pressure oil delivered by the control system enters the closed chamber at the bottom of the piston from the lower oil port.When the piston pushes upward,the spherical rubber core moves upward along the sphere,while the conical rubber core moves upward on the top cover.The constraint of the piston and the extrusion of the inner cone of the piston move closer to the middle,tightening the drill tool and surrounding,realizing the seal of the drill tool or the complete seal of the wellhead.