Assessing the conveyance of fluidized natural gas hydrate in a horizontal tubing

This study evaluates the transportability of clayey-silt natural gas hydrate (NGH) solid particles during solid fluidization in horizontal tubing, a crucial step in recovering marine NGH. Non-uniform solid particle distribution in horizontal flows can cause unstable operations and financial losses. Thus, assessing transportability is necessary to avoid these issues and harness the potential of NGH as an alternative energy source. This study introduces a model based on each phase's two-layer approach and momentum balance equation, considers potential hydrates (re)formation, and overcomes previous models' limitations. Moreover, it assumes that the critical settling velocity marks the moment when the lower bed of solid particles stagnates, thereby leading to the disappearance of frictional pressure in the lower bed. The proposed model is evaluated and compared with existing models using a laboratory dataset and the South China Sea offshore field dataset and found to provide the highest prediction accuracy and precision. Moreover, it reveals that the tubing diameter, solid particle diameter, and solid particle concentration are the major influential parameters affecting the solid particle conveyance. Consequently, the proposed model is suitable for evaluating the transportability of those solid particles in horizontal tubing, making it ideal for assessing their transportability in pipelines.

Automated summary

This study introduces a model based on each phase's two-layer approach and momentum balance equation to evaluate the transportability of solid particles (such as NGH) in horizontal tubing. Through evaluation and comparison with experimental and offshore field datasets, the proposed model is found to have the highest prediction accuracy and precision.