The Design Of Control System And Subsea Distribution Unit In Deepwater Oil And Gas Field

Subsea production control system is to achieve the bridge surface water base stations and subsea production systems,is the core of the exploration and development of subsea oil and gas fields.A handful of large multinational corporations have mastered the design,manufacture and installation of subsea production control systems,and there is still a long way to go in this area in our country.With the rapid growth of China’s consumption of oil and gas resources,domestic oil companies urgently need to develop all-electric subsea production control system to support China’s development of deep-water and ultradeepwater oil and gas resources and shorten the gap with developed countries in the field of full electrical control.The all-electric subsea distribution unit undertakes the task of connecting shore base station facilities and subsea control facilities and is a key component of the all-electric subsea production control system.Based on the research of the function and structure of all-electric subsea distribution unit,the related design of subsea distribution unit is completed.Firstly,the development of subsea production control system is introduced.The structure of common subsea distribution unit is analyzed and studied.The function and structure of all-electric subsea distribution unit are defined according to the working conditions and design requirements.Secondly,the overall mechanical and electrical integrated package structure of all-electric subsea distribution unit is designed by Solid Works software.An all-electric subsea distribution unit system structure designed by modular method is proposed.The main circuit voltage shell,low voltage conversion pressure shell and high voltage conversion shell to complete the completion of the subassembly of the integrated packaging.Based on the first strength theory,the strength calculation and stability checking of the under-pressure distribution shell are completed.The ANSYS Workbench software is used to carry out the finite element analysis of the pressure shell to ensure that the subsea distribution unit can be adapted to the deep water surroundings.Subsea distribution unit high-pressure conversion shell using the combination of internal heat sinking oil and high compression ratio gas cooling,and finally using COMSAL and MATLAB software,respectively,on the energy converter 2D model and gas-liquid combination of the slowpressure mechanism Simulation analysis;Subsea distribution unit main control circuit shell is used to heat the end cover heat conduction cooling.Analysis and comparison of high voltage AC transmission,DC transmission mode,determine the use of metal wire loop transmission mode for the subsea distribution system to provide the required power.This paper analyzes the equalization and current sharing techniques of two-transistor forward converter,PWM control and ISOP combined system,and proposes to adopt the method of dual-tube forward topology based on PMW to combine MOSFET components through the input series / output parallel connection Achieve subsea distribution system of 1.2KV DC high voltage power to 400 V DC medium voltage power and 400 V DC medium voltage power to 48 V,24V DC and other low voltage DC conversion.A structure of subsea signal distribution system consisting of surface monitoring layer,backbone layer and subnet layer is proposed.According to the OSI / RM model,a hierarchical model of backbone network protocol based on TCP / IP protocol is designed.The RS485 protocol,Mod Bus / RTU protocol,intelligent Ethernet technology based on TCP / IP protocol and application layer custom protocol are combined to realize the communication control of subsea control facilities and the signal acquisition of subsea production facilities.Finally,OPTISYSTEM software was used to establish the optical fiber communication model of point-to-multipoint downlink control signals,which verified the feasibility of the downlink control signal communication system and analyzed the factors affecting the optical fiber communication quality.The optical fiber wavelength division multiplexing Communication system to achieve the subsea production information upload,simulation and verification of the WDM system feasibility and correctness.