Research On The Measurement And Control Technology Of Steerable Drilling Tool

Dynamic point-the-bit rotary steerable drilling(DPRSD)technology is the highest level of the current drilling technology.As the core component of the DPRSD tool,the static and dynamic performance of the stabilized platform determines the technical indexes,such as the build rate and the minimum build angle.In this dissertation,the measurement and control system was studied based on a self-developed DPRSD tool system.The main researches and conclusions are listed as follows:1.A review of rotary steerable drilling tools was introduced.The principles of various steerable drilling tools were analyzed,and the similarities and differences between the DPRSD tools and other drilling tools were compared to clarify the research objective.2.The measurement and control system of the steerable drilling systems was optimized to realize the data acquisition of stabilized platform rotation speed and tool face angle.The datas were transmitted between control module and data acquisition module through the CAN bus to control the tool face angle of steerable drilling tool.3.The data fusion method for double triaxial gravity accelerometers was proposed to eliminate the effect of axial acceleration and tangential acceleration of the stabilized platform.The complementary filtering method was adopted to solve the reverse jump of tool face angle at the timepoint of start-up.The tool face angle was measured steadily and accurately through the two processing methods.4.Two control schemes,which called three closed loop and four closed loop,were used to control the tool face angle based on PID control algorithm and Active Disturbance Rejection Control(ADRC)algorithm.The experiment and simulation step performance tests of the two control schemes were compared and analyzed.The conclusion is that compared with the threeloop control scheme,the speed of the four-loop control is slightly lower.The best performance of rapidity and stability is the first-order nonlinear ADRC algorithm.5.Various operating conditions of downhole were simulated in laboratory,the different control schemes and algorithms were used to test the anti-disturbance performance of the prototype.It lays a foundation for the development of practical DPRSD tool.The conclusion is that compared with the three-loop control scheme,the anti-disturbance performance of the fourloop control is improvemed obviously.The tool face angle fluctuation,which is caused by the stick-slip condition,can be better restained by the four-loop control scheme.The best antidisturbance performance is the first-order nonlinear ADRC algorithm.