An evaluation of gas migration phenomenon in shallow ground using two phase flow analysis

Abstract

A conceptual diagram of upward gas migration in a shallow ground, hydrogeological structure model and two phase flow model of groundwater and methane were constructed in this study using results of the survey and the test which were performed for the shows of the natural gas in the surface adjacent to the fault and its fractured zone. Numerical simulation of the methane upward movement in the ground was conducted by using these models. The results showed that capillary pressure, methane saturation of around 0.02-0.03 at 100m deep, fault fracture zone, and trap structure caused by fault displacement could reproduce the behavior of the methane movement in the shallow ground.