Dynamic Analysis And Experimental Study On Automatic Steering Drilling Tool

Automatic steering drilling tool is a kind of function of realizing automatic steering with drill synchronously in the process of drilling string carrying out rotary drilling. In the drilling process, the friction resistance and torsional resistance are not big, drilling speed is very fast, footage of drill is not small, well drilling is with high drilling speed, construction period for well is short and the track of wellbore is smooth and easy to be adjusted, which is regarded as the main development trend for steering drilling and China is still not fully mastering this key technology. Based on former research on "theories and experimental analysis of automatic vertical drilling system", this paper makes deep and detailed analysis of dynamic behavior and working status under automatic steering drilling and situations causing real-time dynamic deformation and stress under conditions of different drilling pressures, drilling speeds and bias forces through large amount of simulation analysis and with combination of experimental simulations, in which vibration problem is the core problem. The research of this topic has great significance in developing suitable automatic steering drilling system for our country and speeding up exploration and exploitation of our deep resources. Specific research contents are as following:Briefly introduce source, background and research significance of automatic steering drilling tool as well as latest progress of research on automatic steering drilling tool both at home and abroad and summarize following development trend of automatic steering drilling tool. Through comparisons of theoretical analysis methods of drill string dynamics, it is found out that it is workable to adopt energy method to analyze drill string dynamics system with automatic steering function and propose main technical channels for analysis of automatic steering drilling tool dynamics.Automatic vertical drilling system is a special structural form of automatic steering drilling tools and the working principle of this system is the same as that of static pushing type automatic steering drilling tool and research on existing vertical drilling system can fully meet the requirements of this research. It elaborates the working principle and working requirements of offset mechanism and analyzes the design requirements for core components of offset mechanism. It finds out that there is "control dead zone" with adoption of bias vector control scheme through comparisons of two control schemes; generally following minimum energy principle and recent principle, the control scheme adopted offset displacement is the best and provides block diagram of control algorithm for steering tool. Make assisted analysis of offset mechanism design by making use of Solid Words 3D analysis software, clarify the geometric relations and topological relations among different components through analyzing overall assembly of offset mechanism and provide a reasonable and effective design method for study of automatic steering drilling tool.Construct mechanical analysis model of automatic steering drilling tool BHA steering force with adoption of vertical and horizontal bending continuous beam method. Analyze mechanical theory of automatic steering drilling tool BHA, which includes 3D analyzing problem diving into two 2D problems, mechanics on inclination plane P as well as mechanical analysis on azimuth plane Q, which find out that the steering force of drilling bit of automatic steering drilling tool has relationship with angle of deviation and drilling pressure around drilling bit, hole curvature, location of stabilizer, quantity and specifications and other factors. Study the state of motion under offset force with adoption of ADAMS software intuitively. Through continuous explorations and improvements, this method will provide related theoretical basis for automatic steering drilling tool in selecting suitable parameters, improving reliability of drill pipe operation as well as designing anti-abrasion device for drill pipe.In the process of analyzing dynamics laws of automatic steering drilling tool BHA, it describes the axial, lateral, torsional of automatic steering drilling tool BHA as well as the coupled vibration rule among them. Because in the drilling process, automatic steering drilling tool couples axial, lateral and torsional three vibration states, meanwhile, the drilling tool is also affected by central guiding force of offset mechanisms and applying Hamilton principle to make dynamics analysis of it can reflect practical dynamics relations in a accurate and real way. This model proves that when rotating mechanism works underground under the function of offset mechanisms, its produced vibration is with full coupling, that is influence and interaction exist among all vibration forms.Simulate vibration characteristics of automatic steering drilling tool BHA under conditions of different drilling forces, drilling speeds and offset forces with adoption of ANSYS software, in which include establishment of ANSYS related model, primary hypothesis, related parameter, defining material property and establishing drillstring model etc. Analyze axial vibration, transverse vibration, torsional vibration as well as coupling vibration finite elements and other theoretical content under the function of offset force. Meanwhile, analyze dynamic stress of offset mechanism and strain distribution under different drilling speeds and different drilling pressures and find out positions with 2.55m,1.8m,1.5m and 0.15m away from drilling bit and these four places are weak vibration of offset mechanism in motion process.Finally, demonstrate the proposed experimental methods and thoughts in this paper through experimental research on automatic steering drilling tool BHA and analyze the principles and simulation analysis results of drill string vibration test. Demonstrate the feasibility of experiment and expand argument for experimental cases, including construction and principle of drilling system, design of experimental system, result data of experiment as well as other contents of its analysis. The attained results can provide reliable basis for optimized structure design of automatic steering driHing tool BHA.