Research On Umbrella Tools Suitable For Solid-state Fluidized Extraction Of Natural Gas Hydrates

Natural gas hydrate,which is widely distributed in nature.It is the largest organic carbon storage mode on the earth,accounting for more than 50%of the total.It is also a kind of clean energy source which is highly efficient.A new idea of solid fluidizaion mining technology for deep water shallow gas hydrate is proposed by China.The method avoids the decomposition of the hydrates and directly breaks them into solid particles by mechanical tool,which breaking the traditional thinking of natural gas hydrate mining methods.Then through the system of isolated fluidization,gas-liquid-solid multi-phase lifting pipeline and separation,the natural gas can be collected.Based on this idea and the features of this process,this paper has designed an umbrella-like mining tool which can break and collect natural gas hydrate.A three-dimensional model of the tool was designed and established.The structural mechanics analysis was also carried out,according to the force analysis of the mining tool under working conditions.The structural parameters of the tool are also optimized.It can prove that this mining tool is technically feasible for gas production from hydrate sediment.The main research work is as follows:(1)Based on the investigation of mechanical crushing principle and tool mechanism research at home and abroad,combining with the solid fluidization mining process of natural gas hydrate,an umbrella-liking mechanical mining tool which is suitable for seafloor shallow non-diagenetic gas hydrate was proposed.The working principle of the tool is also designed.(2)According to the mining principle of the tool and the existing drilling process parameters,the detailed design of the umbrella-liking tool structure was carried out,from the prototype of the concept tool to the improvement to the whole.The overall structure of the umbrella-like mining tool was completed using drawing software.(3)Based on the solid fluidization mining working conditions,the multiphysics simulation software was used to simulate the umbrella-liking mining tool model in the seafloor gas hydrates condition.According to the characteristics of the seafloor natural gas hydrate reservoir and the empirical formula,the specific force conditions of the mining tool and the parameters such as the working rotational speed and the traverse speed can be calculated.Strength check also carried on some important parts of the tool.(4)Based on the established simulation model and analysis method,the research on the force of the tool under the conditions of different tool arm materials,different sizes of bolt joint structure and tool arm deployment angle under certain working conditions is carried out.so that the preliminary design of the model would be optimized and revised to verify the technical feasibility of the mining tool.It also analyzes the influence of the main parameters of the tool on the mining process.Finally,the modal analysis of the umbrella mining tool was carried out to further confirm the correctness of the structural design and provide a basis for subsequent dynamic research and analysis.In summary,this paper proposed a new mining tool based on natural gas hydrate green mining technology and created a simulation model of numerical simulation of seafloor non-diagenetic hydrates.It is optimized by simulation software and the research results were followed by the seabed.The mechanical crushing simulation study of non-diagenetic hydrates and the structural design and optimization of mechanical mining tools provide simulation models and methods,which have a supporting role in the study of submarine non-diagenetic hydrate mechanical mining.