Mechanical Analysis And Optimization Of Key Parts Of Natural Gas Hydrate Undisturbed Uniform Speed Rope Drilling And Coring Tool

The undisturbed uniform speed rope drilling and coring tool is a coring tool for extracting seabed leaking natural gas hydrate samples.The application of rope fishing technology makes the whole process have the advantages of high working efficiency and short time consumption.Due to the complexity of the seabed,in the process of coring,the tool is the first to contact the key parts of the seabed gas hydrate rock layer.The process of penetrating the hydrate may disturb it or cause a phase change.This will affect the composition and content of the extracted leaky hydrate rock samples.In addition,after the coring of the thin-walled impact tube that contains the extracted sample is completed,the liner with a full core is not easy to be extracted from the thin-walled impact tube,and it will cause the thin-walled impact tube to work when the load is large during the working process.Problems such as insufficient stability.In order to solve the above problems,this article is based on the idea of reducing the resistance of the tube shoe penetration into the hydrate process and preventing the buckling of the thin-walled impact tube.An example of an interference-free uniform-speed rope drilling and coring tool that does not exceed 90mm,using ANSYS Workbench finite element analysis software and LS-DYNA nonlinear display dynamics analysis software to optimize the structure and size of the key parts of the coring tool,respectively,and Reinforcement analysis of thin-walled impact tube.The optimization results of the structure size of the tube shoes show that when the size parameters of the tube shoes are:l=25mm,?=22°,?=10.35°,l1=11mm,l2=14mm,?=1.0mm,the strength requirements are met,And the penetration resistance of tube shoes is reduced by 3.6kN.For the reinforcement of the thin-walled impact tube,the angle ?=10° on both sides of the reinforcing rib is adopted,and the number is ni=20,that is,the reinforcement angle is 200°.The critical pressure of the thin-walled impact tube is 164.2 before reinforcement The kN increases to 182.3kN,and as the reinforcement angle increases,the critical pressure increases approximately linearly.The research results have a certain reference value to reduce the resistance of the tube shoe to penetrate the rock layer,increase the rigidity of the thin-walled impact tube,and thus improve the fidelity of the rock sample.It also avoids the decrease of the strength of the bottom sediment layer to a certain extent.Submarine landslides and many other drilling safety issues.