Design And Research On The Mechanism Of Long Horizontal Shale Gas Coring Crawling Robot

As equipment for the oil and gas industry,horizontal well crawlers can be equipped with different logging instruments to enter long horizontal well sections for completing downhole environmental sampling and testing.Their excellent performances have been widely recognized by the society.Relying on the Sichuan International Cooperation Project of "Research on the Rotary Sidewall Coring Robot for Long Horizontal Section of Shale Gas”,and aiming at the difficulty of downhole entry of shale gas in the long water section of Sichuan-Chongqing area,a kind of underground crawling core-removing robot with horizontal well crawling function was designed to solve the problem of core-instrument feeding in the long horizontal well section in Sichuan-Chongqing area.Focusing on the key mechanical of the crawler of horizontal wells,a method of the combination of design,optimization and computer simulation is used to study it.The working condition of the crawler was studied,and the resistance of the crawler in the horizontal well was determined.According to the overall requirements,the transmission design and mechanical analysis of the crawling mechanism were carried out,and the overall design of the crawling mechanism was completed based on this.After that,the program selection was carried out for the centralization mechanism,and the power input design was determined.According to the working requirements of the crawler,a new type of push against locking mechanism is proposed,and the mechanical analysis and dynamic scheme selection of it are completed.A knuckle mechanism is proposed as a crawler serial joint,and then the crawler module connection function is completed.Based on the size design of the crawler's key mechanism,the design of the crawler was optimized.The functional relationship between the positive pressure of the crawling wheel and the length of the crawling arm,and the relationship between the extension speed of the crawling arm and its length both are established.Orthogonal test analysis method and multi-objective optimization theory are used to complete the optimization design and 3D modeling of each structure of the crawling mechanism.The function relationship between displacement and size of the push against locking mechanism is established,and the structure size of the support arm is optimized.Aiming at the circular arc problem of horizontal well tubes,an arc-shaped locking block is designed,and the 3D modeling of the supporting locking mechanism is completed.The interference analysis of the knuckle was conducted to determine the effect of the knuckle's workspace on the crawler's cornering ability,and the 3D modeling of the knuckle was completed.The assembly of the steering knuckle is analyzed by ANSYS Workbench to obtain its weak point of stress and optimize the design.After re-analysis of the optimized model,the results show that the stress concentration is reduced.After optimization,the overall stress reduction rate is about 22.32%,and the overall deformation reduction rate is about 23.39%.Aiming at the problem of high temperature and high pressure underground,a combination of slip ring combination seal and O-ring seal was proposed.Finite element analysis of the slip ring combination seal is performed.The results show that the external pressure increases and the seal stress also increases,but the overall stress is less than the allowable stress of the slip ring material.At this time,the slip ring seal is in a safe state,and the sealing effect is better.Solidworks was used to simulate the actual working conditions and a 3D model of horizontal well pipe was established.Using the virtual prototype simulation technology of ADAMS,the movement simulation of the crawler in the horizontal well was carried out.When the crawler encountered problems such as bosses,grooves,obstacles and curved well tubes,the corresponding motion simulation test was completed.The test results show that the crawler can effectively pass various obstacles.The fluctuation range of supporting force and righting force is small.The crawler can run stably under the influence of various obstacles and has good motion performance.