Experimental investigation of hydrate accumulation distribution in gas seeping system using a large scale three-dimensional simulation device

A novel three-dimensional natural gas hydrate physical simulation device, with a capacity of 0.196 m(3) and maximum operating pressure of 32 MPa, was designed and developed to study the accumulation and exploitation of hydrate-bearing sediment in the natural environment. Acoustic, electrical, and thermal properties at different positions can be collected in real-time to analyze the evolution of hydrate-bearing porous media during the accumulation of hydrate or the production of natural gas. A preliminary experiment was performed to investigate the behaviors of hydrate formation and aggregation in sediment in conditions simulating a gas seeping system. The experimental results showed the methane seeping route has a critical effect on hydrate formation and accumulation within the sediment, and the location of hydrate-rich region. The distribution of hydrate in sediment was controlled by fluid flow field, which was also proven by the simulation of FLUENT (TM) code. A modified form of Archie's law was used to correlate hydrate saturation with the electrical resistivity data. The process of hydrate growth, that hydrate first cement and bridge grains, is also deduced from the acoustic velocity data. (C) 2012 Elsevier Ltd. All rights reserved.