Temporal Ground Penetrating Radar (GPR) Imaging of an Oil Release Within a Porous Medium: A Description of Anomalous GPR Characteristics During the Degradation Process and a Contaminated Area Determination Method

Abstract

We present a feasible method to evaluate the ability of ground penetrating radar (GPR) to detect underground oil contaminated areas. An in-situ simulation of the process of underground oil pollution was conducted and GPR was used for 180 consecutive days. Based on detection results, deductions were made regarding the abnormal GPR characteristics collected during the degradation process and the factors influencing these anomalous GPR results. A contaminated area determination method and an oil content analysis method were also developed using GPR results. Results indicated that the oil contaminated area was abnormally characterized by a high-amplitude wave during the initial stage of degradation. In the first 20 days, the ratio of the maximum amplitude and the initial amplitude remained between 0.7 and 0.8. After the 20th day, the ratio reduced, and it reduced to 0.1 after 120 days, which was below a detection level. In addition, the water content in the soil had a large effect on the anomaly; the higher the soil water content, the clear the abnormal characteristics of oil pollution. The area of the abnormal zone was well described using the time-slice method, which is indicated by the amplitude ratio and GPR energy at different positions at the same time. Finally, there was a positive correlation between soil oil content and GPR amplitude, but no quantitative relation was constructed between the two.