Research On Optimization Control Technology Of Throttling Back Pressure In Controlled Pressure Drilling

As oil drilling technology continues to develop towards complex formations,the problem of narrow-density safe drilling has become increasingly prominent,which has become a bottleneck problem that restricts oil exploration and development technology.In order to effectively solve this problem,A managed pressure drilling(MPD)technology has been proposed by the United States in the 20th century,Its main characteristic is precisely controlling the annulus pressure profile of the wellbore,making the the bottom hole pressure in precisly control state,effectively avoiding downholes,well leaks,well collapses,etc.And also increasing the efficiency and safety of drilling.At present,foreign MPD technology can realize the integration of real-time monitoring and control systems based on downhole and ground parameter measurement,and has been applied in many oil fields.Based on this practice,technological innovation is continuously carried out.Compared with foreign MPD technology,domestic MPD technology started late,and most of the drilling technology came from abroad.At the same time,the domestic measurement of wellhead parameters is used to indirectly obtain the change of downhole pressure.There is no integrated monitoring and control system.Domestic research on this aspect is still in an integrated innovation stage.This paper is based on extensive research and the current status of technical MPD at home and abroad.Combined pressure control principle and control strategy of MPD,construction technology and supporting ground equipment.the wellhead back pressure was selected as control parameter.And established a mathematical model for the throttle control system of the back pressure.According to the characteristics of the model,an improved particle swarm optimization algorithm for PID neural network(IPSO-PIDNN)is designed.Based on the algorithm,an optimized control system for the throttle back pressure of the MPD is tested in the field.This paper has achieved the following research results:1?This paper extensively investigates the technical literature on bottom hole pressure control of MPD in home and aboard,and studies the related principles of bottom pressure control,supporting equipment composition and control process,This paper also analyze the factors affecting bottom hole pressure,and the wellhead back pressure is used as the control parameter of the optimized control system for the throttle back pressure of the MPD.2?This paper analyzes the pressure control principle and control strategy of MPD,and combines the characteristics of the throttle valve in the ground throttle manifold to establish a mathematical model of the throttle back pressure control.At the same time,the throttle valve generates pressure waves.According to the characteristics of pressure transmission in the wellbore,a pressure transfer model is established to shorten the control time and guide the setting of the throttle pressure control.Ensuring that the annulus pressure is in a narrow-density safety window.3?According to the characteristics of the mathematical control model of the throttle back pressure,an improved particle swarm optimization algorithm for PID neural network(IPSO-PIDNN)is proposed.Based on the algorithm,an optimized control system for the throttle back pressure of the MPD is established in the MATLAB environment.The simulation results of the model are compared with various control algorithms to prove that the optimization algorithm is more suitable for throttling pressure control.4?Based on an optimized control system for the throttle back pressure of simulation model,combined with the existing instrumentation and control unit of the well site,this paper designs an optimized control system for the throttle back pressure of the MPD.The real-time monitoring and data acquisition module and control module are integrated,and the field application is applied.The system passes the field test and the software system runs well.The control model can meet the requirements of the field application and ensure the safe operation of the drilling.