Downhole In-situ Measurement Device Dynamics Analysis And System Control Research

The downhole in-situ measurement device integrates two functions of coring and measurement,which are more comprehensive in oil and gas exploration and more accurate and reliable in data measurement than the current coring tools that only have the ability of coring,and have a greater development prospect.In this paper,the motion characteristics of the device are studied by computer software and the simulation results are analyzed and discussed systematically to understand the working condition of the device in the downhole and to improve its structural design shortcomings.First,the composition and working principle of the downhole in-situ measurement device are analyzed in detail.The kinematic analysis of the actuator of the device is carried out by the complex vector method,and the equations of position,velocity and acceleration of each rod of the mechanism are obtained.Based on the kinematic parameters obtained from the kinematic analysis,a dynamic static analysis model of the mechanism was established,the variation law of the force and moment of each rod in the mechanism was analyzed,and the maximum load force of each module hydraulic cylinder was derived.On this basis,the workflow of the device and the implementation plan of the hydraulic system are designed and studied.According to the system technical index,the system pressure and flow rate were determined,and the parameters of core hydraulic components were calculated in detail.Next,the kinematics and dynamics of the downhole in-situ measurement device were simulated in ADAMS software to analyze the motion and force of the device in terms of velocity,displacement and joint moment.The analysis shows that the downhole in-situ measurement device has low-fluctuation of speed in each direction,no inflection point of the displacement curve,no motion interference of each mechanism,and smooth operation;the driving force of each module meets the design requirements,and the structure and transmission system of the device is reasonably designed,which can realize downhole centering and measurement.Finally,based on the simulation analysis results,the problem of structural dead points of the core-taking mechanism is solved and the pushing and leaning mechanism is optimized.The optimized main pushing and leaning arm has 60.1% less maximum equivalent force and41.5% less maximum deformation than before the optimization,and its strength has been greatly improved;while the minimum pushing and leaning force is increased by 15.5%,the required driving force is reduced by about 11.9%,which shows that the optimized pushing and leaning mechanism requires less driving force to meet the requirements of the working pushing and leaning force of the device and achieves the purpose of optimization.The purpose of optimization is achieved.