西南石油大学学报(自然科学版)

Previous Articles     Next Articles

Study on Excess Pore Pressure by Natural Gas Hydrate Dissociation

Zhang Wei1,2*, Li Xinzhong1, Li Qingping1, Cao Jing1   

  1. 1. General Research Institute,China National Offshore Oil Corporation,Chaoyang,Beijing 100028,China
    2. Postdoctoral General of Institute of Mechanics,Chinese Academy of Sciences,Haidian,Beijing 100190,China
  • Online:2015-08-01 Published:2015-08-01

Abstract:

For the engineering risk caused by natural gas hydrate dissociation during the offshore hydrocarbon resource exploitation
and ocean engineering construction processes,a theoretical model is proposed for the analysis of excess pore pressure
due to the gas hydrate dissociation. The theoretical-analytical method is adopted in the study. Firstly,based on the phase behavior
models before and after the hydrate dissociation and the general gas law in thermodynamics,the volume expansion model
of sediments caused by the hydrate dissociation is derived,and then,according to the soil compression and swelling behavior
in soil mechanics,the theoretical-analytical model is obtained for the analysis of excess pore pressure by the hydrate dissociation.
The reasonability and validity of the model have been verified by the representative submarine landslide case. Besides,a
parametric analysis has been performed to investigate the complex affecting parameters in the model. This study is of important
theoretical value and practical significance to understand the evolution mechanism of the excess pore pressure resulting from
the hydrate dissociation,ensure the hydrate reservoir stability and avoid the project risk.

Key words: natural gas hydrate, hydrate dissociation, volume expansion model, excess pore pressure model, parametric
analysis