In response to the problem that the damage mechanism and influencing factors of the reservoir destabiliza-tion caused by the thermal decomposition of natural gas hydrate are not clear,the coupled heat-fluid-solid model of the hydrate deposition layer and the elastic-plasticity intrinsic model of the solid skeleton of the reservoir under the action of such coupled model have been established in consideration of the formation heat transfer,pore fluid seep-age and deformation damage of solid skeleton due to the thermal decomposition of hydrate.Based on the secondary development of the USDFLD subroutine of ABAQUS software,the orthogonal numerical simulation experiments were carried out to analyze the sensitivity of the thermal injection temperature difference,the absolute permeability of the hydrate deposition layer,and the effective principal stress difference to the influence of the deformation damage of near-well reservoir in the the hydrate deposition layer and the influence mechanism.The results show that the sen-sitivity to the influence of the deformation damage of near-well reservoir is in descending order of the effective prin-cipal stress difference,absolute permeability,and thermal injection temperature difference;the deterioration of the mechanical properties of the near-well reservoir and the decrease of the effective stress caused by the thermal de-composition of hydrate are the main reasons for the deformation damage;the larger the effective principal stress difference is,the larger the maximum value of the equivalent plastic strain is,and the location of the most severe deformation damage in the near-well reservoir is always located in the direction of the minimum horizontal geostress in the borehole under the influence of the the non-uniformity of the horizontal geostress.This study provides a ref-erence for the natural gas hydrate extraction with the thermal stimulation method and drilling operations of hydrate-bearing formations.
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