Oil Mobility Estimation and Recovery Optimization

The overall objective of this thesis was to improve the use of investigation data from contaminated site with light hydrocarbons. In particular, this work focused on: - To confirm the validity of the method to estimate the oil mobility in the formation, for heterogeneous conditions, called bail-down test. And, to define which interpretation method is the most relevant. - To understand the impact of the groundwater table variations on the oil thickness in the monitoring wells, and on its mobility. First, bail-down test simulations were performed at laboratory scale, on a radial pilot, filled with homogeneous sand. Then, a significant number of tests were performed on a studied site and interpreted. This work allowed to confirm the bail-down test validity for estimating the oil mobility in the formation. The key assumption to explain why these tests are valid whereas some of the assumptions and boundary conditions are not met during the tests, is based on the low mobility of the oil due to its viscosity. Secondly, the impact of the groundwater table variations has been manually and automatically measured on the studied site, during months. These measurements allowed to describe in detail the impact, which is different between confined and non-confined oil conditions. In addition, a model has been proposed and tested to simulate oil thickness depending on groundwater table level. This model allowed to estimate the thickness and the position of the oil in the formation, and its hydraulic conductivity. Overall, this study gives key elements to improve the investigation phase of site contaminated with light hydrocarbons, and to optimize the use of the collected data. Last, confirming the significant impact of the groundwater table fluctuation on the oil thickness and the validation of the bail-down test to estimate the oil mobility, this study shows the need to consider the oil mobility rather than the oil thickness for designing an oil recovery project. (author)