Thermal performance of natural gas hydrate wellbore with different insulation materials

Huge amounts of gas hydrate exist in offshore deepwater reservoirs, whose exploration and productions depend on the development of cost-effective transport solutions. The control of temperature field in the near wellbore region is critical for preventing the regeneration of hydrate during transportation of the produced fluid. To simulate the transient process, this study develops a 2D heat transfer model for the wellbore area based on the finite difference method. The model is validated with the steady-state temperature profile and the results of numerical simulation. Four different insulation materials are employed in the simulation, and their corresponding thermal performances are evaluated and compared. It is shown that the soil on the seabed can give a certain insulation to the produced fluid in the wellbore and enhanced insulation can be obtained by adding an insulation layer. Furthermore, the model clearly illustrates that, using the micro phase change materials (MPCM) as the insulation layer, which has high energy storage potentials, the wellbore can significantly extend the fluid holding time during the shut-in process.

Automated summary

A large amount of gas hydrate exists in offshore deepwater reservoirs, and cost-effective transport solutions are crucial for their exploration and production. This study develops a 2D heat transfer model for the wellbore area to control the temperature field and prevent hydrate regeneration during fluid transportation. Different insulation materials are evaluated, showing that seabed soil and added insulation layers can significantly enhance insulation, especially when using micro phase change materials (MPCM) with high energy storage potentials.