Temporal Dynamics of Fluid Stabilization: Investigating its Influence on Lnapl Migration and Saturation in Porous Media

Abstract

The subterranean migration of light non aqueous phase liquids (LNAPL) continues until it achieves a state of equilibrium. This specific state is defined by the stabilization period, which represents the length of time required for the external fluid to reach a point of equilibrium where it is unable to advance any further. The physical and chemical features of the soil, including wetting and non-wetting fluids, determine stabilization time. Laboratory experiments examined how different timeframes affected LNAPL movements. A 70 cm x 70 cm x 3.5 cm tank was employed, with a specified area of interest (AOI) defined. Non-destructive simplified image analysis was used to determine saturation levels at certain horizontal and vertical regions. The study tested a specified amount of LNAPL during a drainage-imbibition cycle at different times. Images collected from AOI were evaluated in MATLAB and Excel. To determine how these changes affect LNAPL migration. Experiments were conducted at intervals of 2, 4, 6, 8, 10, and 12 hours to investigate the temporal occurrence of LNAPL for a sandy soil in six different stages: Stabilize, Drainage-I, LNAPL injection, Drainage-II, Imbibition-I and Imbibition-II. A fluctuating water table created a dynamic system. The system reached dynamic equilibrium, and buoyant force lifted the entrapped LNAPL after a 12-hour interval for each stage. 2 hours of investigation showed the maximum longitudinal and lateral saturation at one point. This study found that the stability period for a system is closely related to the rate of LNAPL removal, whether entrapped or entering via preferential flow.

Keywords: SIAM, LNAPL, AOI, Equilibrium