Research On Intelligent Layered Injection And Production Control Technology Of Electronically Controlled Hydraulic Downhole

Most of Chinese oilfield exploitation is in the late stage of development with high water cut,and the contradictions between layers are intensified,and the difficulty of exploitation increases rapidly.Intelligent layered injection and production technology is one of the effective means to improve oil recovery,but there are problems such as poor flexibility and low efficiency in the actual application process.The layered injection and production technology combined with electro-hydraulic is the main direction of intelligent completion development of oilfields at home and abroad,and the advantage of this technology is that it can flexibly and effectively control the downhole layered injection flow,reduce the mutual interference between layers and improve the recovery rate of the oilfield.In this thesis,aiming at the problems of low communication efficiency and poor control accuracy in the traditional layered water injection control system of pure electric and pure liquid,an electronically controlled hydraulic layered injection and production system is proposed.Firstly,the communication system based on DC power carrier is introduced,and the well-toground communication circuit based on single-core steel pipe cable is designed.On this basis,the electro-hydraulic composite layered injection and production method is proposed,and the electronically controlled hydraulic layered injection and production system based on motor control method and solenoid valve control method is designed and realized,and the experimental research of the two control methods is carried out,the advantages and disadvantages of each are analyzed,and finally the in-depth study of the solenoid valve control method is determined.In addition,the relationship between injection pressure,hydraulic slip sleeve nozzle opening and injection and production flow was studied,and the downhole control circuit of the solenoid valve control method was studied,and the control software of the downhole and upper computer was designed.The influence of different communication distances and different loads on the control system was analyzed,and the DC-DC filter circuit was designed to solve the electromagnetic interference problem caused by the underground solenoid valve during operation,and the downhole control circuit was optimized.Finally,on the basis of the optimization of the circuit of the electronically controlled hydraulic downhole control system,the indoor high temperature and high pressure experiments of the electronically controlled and hydraulic control systems,as well as the on-site drilling test,were carried out.The experimental results show that the system can accurately switch the underground water injection layer,and at the same time can effectively transmit the hydraulic signal to the piston of the well slide jacket,so as to realize the indirect control of the opening of the hydraulic slide jacket nozzle of each layer of the downhole,which is of great significance for the fine water injection and efficient exploitation of the water injection well.