Research On Heating Control Of Simulated Wellbore Based On Heat Transfer Model

The high temperature and high pressure simulation wellbore is an important device to test the performance of perforating equipment,which can provide the temperature and pressure close to the downhole environment.The heating control system is an important guarantee to control the perforating equipment to reach the required target temperature for detection.Therefore,the research on the heating control system of the simulation wellbore is of great significance.This article,based on the high temperature and high pressure of daqing perforating equipment testing center simulation wellbore experimental device,establish simulation wellbore heating system of physical model and mathematical model,and to control the heating temperature parameters of the choice of optimized analysis,and then to adjust the parameters of PID controller and the retrograde setting,multiple target simulation wellbore heating control scheme and the optimization of the temperature parameters for the research.Firstly,the research background and significance of this paper are briefly described,the development status of simulated wellbore heating system at home and abroad is summarized,and the research content of this paper is proposed.The demand of heating control system in actual production is analyzed,and the optimization scheme is put forward.This paper briefly describes the significance and relevant background of the research on the simulated wellbore heating control,and introduces the development of the simulated wellbore heating system at home and abroad and the research on the optimization of the heating furnace control by different institutions.Then,the main content of each chapter is briefly introduced.Based on the structure and material data of each part of the simulated wellbore heating system,the physical model of the simulated wellbore heating system with high temperature and high pressure was established,and the physical model of the simulated wellbore containing fluid and perforating equipment was simplified.The common heat transfer methods and numerical solution methods are introduced,the energy conservation equation is established according to the simplified model,and the mathematical model of the simulated wellbore heating system is established.The difference equation is used to discretize the time and space regions,and the energy equation is transformed into a discrete equation.According to the actual situation,the initial conditions and boundary conditions of the heat transfer model were established,and the mathematical software Matlab was used for simulation calculation.Through numerical simulation,the central temperature of perforating equipment,the thermal conductivity of simulated wellbore and the change of heat dissipation with time were analyzed.Staged heating method is used to simulate the temperature rise of wellbore system,and multi-objective programming optimization algorithm is used to select the heating temperature of different stages in staged heating method.The heating temperature in the range of different stages was taken into the optimization process,and the optimal heating scheme under different target temperatures was calculated by computer simulation,and the selection trend of heating temperature under different target temperatures was analyzed.The soaring curve method is used to solve the magnification factor,pure lag time and time constant of the controlled object.Combined with Z-N empirical formula,the control parameters in the PID controller are calculated,the control model of the heating system is obtained,and the comprehensive performance of different regulation modes is analyzed.After the establishment of the experimental system and the planning of the experimental process,the heating experiment of the heating furnace and the staged heating experiment of the simulated wellbore were carried out.The effectiveness of the heat transfer model and the optimization scheme were verified by analyzing the experimental curve.