Design And Simulation Analysis Of Hydraulic Motor Of Shale Gas Coring Robot

Shale gas coring robot(full name shale gas long horizontal section rotary sidewall coring robot)is a new special exploration robot developed and designed for the difficult problem of coring in long horizontal section of shale gas in Sichuan and Chongqing area.As the direct driving device of shale gas coring robot bit,the performance of hydraulic motor determines whether the whole shale gas coring robot can normally complete the downhole coring task.Therefore,based on the selection of the three gear hydraulic motor,this paper innovates and improves its design,so that it can stably and reliably drive the large diameter coring bit in the shale gas well environment of high temperature,high pressure and high corrosion.The acquisition of the large diameter high quality core is conducive to improving the accuracy of the laboratory core sample analysis and testing,and provides the shale gas reservoir evaluation in Sichuan and Chongqing areas for more detailed geological data.Firstly,the research status of hydraulic motor for conventional rotary sidewall coring instrument at home and abroad is analyzed,which provides reference basis and target direction for the design of shale gas coring motor.Then,taking small volume,large torque,long life and high reliability as the design breakthrough point,the coring motor system design and modeling,multi-rigid body system simulation calculation,three-dimensional flow field dynamics analysis,finite element analysis of key parts assembly and other tasks are completed.According to the working principle of coring motor as a whole,the rock breaking mechanism of coring bit and the specific environment of shale gas well,the operating parameters such as drilling pressure,rotation speed,torque,breaking force and the model of high temperature oil are determined.Then,the specific structure of coring motor is introduced,and its working principle and selfcharacteristics are analyzed.On this basis,the relationship between them is analyzed the key components are designed and checked.At last,SolidWorks software is used to model and assemble them.In the simulation calculation of multi-rigid body system,the correctness of the design of the variable gear transmission system of the coring motor is verified by ADAMS simulation calculation.The dynamic simulation of the flow of high temperature oil in the coring motor under the rated working condition is carried out by Fluent,which proves the radial hydraulic pressure balance of the torque output gear of the coring motor.It is beneficial to extend the service life of the coring motor in the well,and it also verifies the correctness of the structural design.ANSYS Workbench software is used to analyze the static and dynamic characteristics of the assembly of the key parts of the coring motor in combination with the specific operating parameters of the shale gas well.The static,modal,harmonic response and transient analysis results of the key parts are studied when the coring motor works in the shale gas well.This verifies the rationality of the design and provides data support for the next step of engineering use,optimization design and fatigue life prediction of each component.According to the above simulation results,the designed coring motor can be used as the power driving device to drive the large diameter coring bit of shale gas coring robot.At the same time,CAD and CAE technology are introduced in the process of design and research,which greatly improves the quality of product design and shortens the production cycle of product manufacturing,and has certain engineering application value and theoretical research significance.