Experimental Study and Numerical Simulation of Overlying Layer Soil Failure Caused by Hydrate Decomposition

Abstract

During the exploration of hydrates or oil and gas exploitation through the hydrate layer, heat transfer causes hydrates to decompose. The gas and water generated by this decomposition increase the pressure of the gas in the decomposition zone, resulting in excessive pore pressure. The seepage of gas and water and the decomposition of hydrates lead to soil deformation, which may be caused by soil softening. This may lead to geological disasters, such as ocean landslides, seabed subsidence, and even gas explosions. The natural phenomena of soil eruption caused by hydrate decomposition currently include Siberian pits and Bermuda craters. From these two natural phenomena, climate change is considered to affect hydrate decomposition, causing ocean acidification and dissolved oxygen consumption, which may have more serious consequences than global warming alone. Therefore, it is extremely important to study how hydrate decomposition causes soil to erupt and release gas into the ocean and the atmosphere. This paper is primarily based on on-site data collected from the Siberian pit in the case of hydrate decomposition resulting in increased pore pressure, resulting in soil eruption. The relationship between the thickness of the upper cladding layer, the pressure causing the destruction of the upper cladding layer, and the destruction length of the upper cladding layer was obtained through numerical simulation.