In order to avoid the problems such as submarine landslide and wellbore integrity failure caused by the excess pore pressure induced by the decomposition of natural gas hydrate during the production process of deep-water wells,the change of sediment compressibility and fluid density during the hydrate decomposition process in the production stage was comprehen-sively considered,and a model for the total volume expansion of sediment caused by hydrate decomposition was established combining with the principle of mass conservation.A calculation method of the excess pore pressure induced by the decompo-sition of natural gas hydrate was obtained,and the influence of different factors on the excess pore pressure induced by hydrate decomposition was discussed by taking a deep-water well in a gas hydrate bearing formation in the South China Sea as an ex-ample.The result show that the excess pore pressure increases with the increase of initial hydrate saturation and sediment po-rosity,and the increase of excess pore pressure will inhibit the further decomposition of hydrate,so its increase amplitude de-creases and has a maximum value.In addition,the excess pore pressure will increase with the increase of the buried depth of natural gas hydrate,but is less affected by the water depth.The research results can provide a theoretical basis for the safe production of deep-water wells.
natural gas hydrateexcess pore pressurehydrate developmentfactor analysis
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