Research And Design Of Throttle Pressure Control System For Fine Pressure Control Drilling

As the continuous development of the oil exploration and development to the deep complexity areas,the safety drilling problems of the narrow density window are increasingly prominent,and have become technical bottlenecks of affecting and restricting the oil exploration and development process and drilling in many oil fields. In view of the safety drilling problems of the narrow density window,the international community raises a new drilling technology, named MPD (Managed Pressure Drilling).It has developed to precise MPD stage till now. Precise MPD can effectively solve the problem of narrow density window drilling,reduce the down hole complex situation,reduce non-productive time and improve drilling efficiency and safety. Domestic research to precise MPD starts lately, which is still in the stage of technology introduction,apply research and integrated innovation stage.Based on the wide investigation of the present researches of precise MPD technology at home and abroad,combined with pressure control principle of precise MPD,construction technology and the supporting equipment,this paper has made a deep research on the throttle pressure control system and got the following research results.First,through the research to the control principle of bottom hole pressure of the precise MPD,it gets the control parameters which can real-time control the bottom hole pressure most easily. It analyzes the generation methods of back pressure, provides the theory basis for the design of control system solution.Second,according to the control parameters,it researches the drilling equipment composi-tion and working process of bottom hole pressure control system of precise MPD, completes the design of the whole control system solution and the configuration of integrated equipment,and analyzes the key process of realizing methods and equipment control process of normal drilling,tripling and making a connection. Third,it deeply analyses the composition of the well’s mouth throttling back pressure control system of precise MPD,establishes the mathematical model of the control system, analyzes the characteristics of the model and the correction demands. Combined with fuzzy control and conventional PID control,it puts forward the fuzzy adaptive PID throttle pressure control algorithm which can satisfy the precise pressure control requirements and completes the design of the algorithm.Fourth,according to the principle of PID control and fuzzy PID control,it builds a simulation model of back pressure control system based on MATLAB/Simulink module. It makes the simulation research and analysis of control system,determines the related parameters of the control algorithm that meet the requirements of precise MPD control system performance and builds a fuzzy PID control enquiry form.Fifth,based on Siemens S7-300PLC hardware and software platform,it designs a ground throttling pressure automatic controller,completes the design of the hardware structure and the development of the control programs and the human-machine interface,forms a distributed control system of throttling back pressure and completes the test of the controller performance in lab.The precise MPD system overall solution and the independent-designed throttling pressure automatic control system formed by this paper. It can realize the real-time precise control for the well mouth backpressure,and it gets a strong adaptive ability,simple operation and easy to operate and control for field technical personnel. It makes a significant guiding meaning and a practical value for the precision of precise MPD pressure control and the localization of the equipment configuration of our country.