Research On BOP And Sealing Of The Snubbing Unit In Water Injection Well With High Pressure

To the traits on the snubbing unit of the water injection with high pressure,the new technics is put forward and the new blowout preventer (BOP) equipment is developed after analyzing the study and application status quo on the snubbing units and equippments around the world and disclosing the working principle and sealing mechanism on the different BOPs.The new technics adopts the new type of the BOP and sealing equipment,which is consisted of the core shutter BOP and the assistant coupling detectors and the balance system at the well head.The working principle is that the tubing coupling is taken out of the well between the two shutter BOPs by turns,the on-off operation is controlled by the signals from the detectors and before the operation on the BOPs,the balance system will balance the pressure gap between the two BOPs to decrease the system strike and prolong the life time of the top sealing rubber core.The sealing module is consisted of the polymer materials and the high spring rubber which are sulfurized in one part. The module is cheap and easy to replace. During the working time,the resist-grind ring is beared the touching pressure between the tubing and rubber and also helps the rubber seal the loop space. So,the sealing module can decrease the wear and tear and prolong the life time of the rubber.To the calculation of the sealing pressure,the paper adopts the theory on the infinite long rectangle rubber with big distortion on both sides.Based on the theory,the approximate connection between the distortion and force of the rubber is introduced. The rubber core can seal the pressure at the conditions of the rational structural parameters with the help of the relation.The electric-hydro control system is used to be in control of the BOP. As the key,the paper guide the transmission function of the execution organ,take it in the whole system,found the control model and apply the software of MATLAB for the simulation to meet the design.The coupling detector adopts the design combined the hydraulic pressure bridge circuit and assembled sealing,which can assure the static-act pressure balance on the detector head, accomplish the balance between the spring force in advance and the radial touching force when the coupling pass the detector head and the radial displacement,detect the coupling position in accuracy and transform the control signal which can control the other equipments.The high and low pressure balance valves on the pressure system adopt the new electric-hydro complex control on-off vales. The guide valve control the pressure oil to drive the main vale so as to accomplish the pressure fluid in the sealing space to be on and off,which can assure the shutter BOPs to take action at the condition of pressure balance during the working time.