A numerical simulation prediction method for seabed landslide induced by sea area natural gas hydrate decomposition

Abstract

The invention belongs to the technical field of evaluation of influence of natural gas hydrate on environment. The invention discloses a numerical simulation prediction method and system for submarinelandslide induced by sea area natural gas hydrate decomposition, and the method comprises the steps: building a real natural gas hydrate system distribution model of a research area, predicting the upward movement depth of BSR when hydrate stabilization conditions are changed through the numerical simulation method, and determining the hydrate decomposition area and volume; based on a pore pressure calculation model, considering the volume change of the BSR underlying free gas along with the pressure before and after the hydrate is decomposed, and calculating the change of pore overpressure and effective stress in sediments caused by natural gas hydrate decomposition after the BSR is moved upwards; and mole-Coulomb strength criterion is used as a guide, and a finite element strength reduction method is adopted to calculate the stability safety coefficient of the slope, so that whether the submarine landslide can be induced by hydrate decomposition occurring when stable conditions arechanged is quantitatively predicted. The method has universality in other natural gas hydrate development areas.

Description

technical field [0001] The invention belongs to the technical field of evaluating the impact of natural gas hydrate on the environment, and in particular relates to a numerical simulation prediction method for submarine landslides induced by decomposition of natural gas hydrate in sea areas. It specifically relates to a numerical simulation prediction method for calculating whether the free gas released by hydrate decomposition can induce submarine landslides when the stability conditions of natural gas hydrates change and the bottom boundary of hydrates moves upward. Background technique [0002] Currently, the closest prior art: [0003] Natural gas hydrate mainly exists in shallow marine sediments and plateau tundra. Due to its huge amount of resources stored and its cleanliness, it will become an important alternative energy source in the future. Its estimated geological reserves exceed the known geological reserves of natural gas on land in the world. sum. In addition...

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Problems solved by technology

Whether the dissociation of natural gas hydrate in the sea area is controversial in the current research will induce submarine landslides, and a numerical simulation method for quantitative prediction is provided to calculate when the hydrate stability conditions change in specific gas hydrate development areas (such as deposition effect, sea level drop or increase in geothermal gradient caused by abnormal heat flow, etc.), whether the resulting hydrate decomposition can induce submarine landslides

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